AudioCircle
Audio/Video Gear and Systems => The Vinyl Circle => Topic started by: undertow on 16 Dec 2008, 04:35 pm
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Go to Page 10 for all new info on this upgrade and simplified part explanation. Thanks
(http://www.audiocircle.com/image.php?id=17403)
(http://www.audiocircle.com/image.php?id=17402)
(http://www.audiocircle.com/image.php?id=17401)
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Where were you three weeks ago when I ordered my modded Joli from Underwood HiFi / Parts ConneXion? I haven't gotten it yet but I sure look forward to it. It will have the Burr-Brown 627's in all six slots - well you can see what they say on their web-site for a level 3 mod. After the warranty period I can see myself putting in those big caps and hopefully hearing a big improvement.
What cartridges have you tried this with to good effect?
Gary
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Hello undertow,
First I do agree that the coupling caps are a huge improvement in the JD9 and which cap to choose is a matter of personal preference. I have tried many different capacitors in this piece but never the ClarityCap.
I did however find that upgrades to the power supply also made a significant improvement. Better filter capacitors and yes, better diodes improved the frequency extremes.
The JD9 is a giant "Little Killer" and right out of the box, it is well worth it's small price of admission. A few teaks here and there and you have a phono stage you could live with for a long time.
Thanks for sharing!
Have a wonderful Holiday Season
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Hey Lifer...
Yeah the 627s will work.. The 637's are the same but do not use the coupling cap I guess internally and alows for higher gain circuits to be a little quieter and smoother, with better top and bottom extension from what the word on the street is.. So bottom line is I guess if you can use the 637's that is the way to go if it is possible. .But the 627 will work just fine...
As for the rest of it I do after more testing this weekend agree the Burr Brown chip is in fact very silky, and the best overall in the voice/midrange for a tad more depth and warmth(maybe)... But they are a bit Soft as a warning, this thing has a ton of gain so depending on the rest of your system it may or may not matter much, you can crank it up to get some full blown dynamics and some more authority in the bottom end..
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Hi Response audio,
Yes caps are cost and preference associated :-)
Thanks
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I'm curious how many hours it took these Claritycap MR caps to fully break in to your pre outputs.
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I can't talk to the break-in period for those big caps, but I would like to note that this is a really fine phono pre in its current state of customization. Without going into a long review - enough of those out there already, I would just say that the only problem I have with it is the fact that it only can handle one tonearm at a time. One day I will have to get one with more inputs, or a second phono pre. Perhaps a mono one.
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I'm curious how many hours it took these Claritycap MR caps to fully break in to your pre outputs.
Most of the break in occurs before 100 hours.
Out of the box they actually sound pretty good, but it takes a little while for the soundstage to open up.
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Hi Undertow, I would like to preform this mod (good work!) but from your pictures I can't tell which pins I need to solder the new caps to, can you take another close-up pic??
Thanks!
BP
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Ditto for me (not entirely sure of which pins to solder)---I just ordered a Jolida JD-9A based on what your fine modifications will offer. Thanks for being so explicit with your directions and pictures--just a bit nervous about hitting the wrong pins.
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I bought the AD843KN opamps (x6) new and when I installed them (all 6) all I got was alot more noise and very little gain. I double check the installation and it was good. I went back to the original opamps and everything is back to normal. Anyone know why this happened and could you share some insights as to why?
Regards
Alx
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The AD843KN are not at all usable as a replacement for all 6 OPA's in the Jolida. You'll get a lot of nasty noise instead of "nasty subsonic level bass". I have tried them, too. You may use two of them for the output stage only, where they work quite well. They sound a bit less harsh than the original OP37. I also doubt that replacing the output coupling caps will make such a big difference, I have tried several caps and the result was not so overwhelming. The Jolida is sounding far too bright and I would be grateful if somebody had an idea who to reduce the treble a bit.
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Dr. Ear,
Thanks. I have completed many changes that where not adressed in this post. Most are for noise reduction and in turn have made marked improvements.
As far as the AD843, I think the +/- 5 volt rail voltages are what is causing the noise. And this kind of alligns up with your comment of using it on the out put stage, which has +/- 15 v rails.
Regards
Alx
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The AD843KN are not at all usable as a replacement for all 6 OPA's in the Jolida. You'll get a lot of nasty noise instead of "nasty subsonic level bass". I have tried them, too. You may use two of them for the output stage only, where they work quite well. They sound a bit less harsh than the original OP37. I also doubt that replacing the output coupling caps will make such a big difference, I have tried several caps and the result was not so overwhelming. The Jolida is sounding far too bright and I would be grateful if somebody had an idea who to reduce the treble a bit.
Which caps have you tried? Have you rolled any tubes?
I used Claritycap ESA's in mine and it warmed it up a bit.
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The AD843KN are not at all usable as a replacement for all 6 OPA's in the Jolida. You'll get a lot of nasty noise instead of "nasty subsonic level bass". I have tried them, too. You may use two of them for the output stage only, where they work quite well. They sound a bit less harsh than the original OP37. I also doubt that replacing the output coupling caps will make such a big difference, I have tried several caps and the result was not so overwhelming. The Jolida is sounding far too bright and I would be grateful if somebody had an idea who to reduce the treble a bit.
I found my JD-9A to be a little bright for years until I found the solution that worked for me. Sovtek LPS tubes and remove the spring-loaded tube covers. The LPS tubes seem to be on the lower gain side which seems right for the Jolida. I have 2 sets of the LPS tubes and they both sound great in the JD-9A. Any NOS or "premium" tubes I tried seemed to have a little too much gain and the mids seemed to get a little thin due to that. The LPS tubes make the Jolida sound pretty flat in frequency response to my ear. They have better smoothness and extension than the stock Chinese tubes in both the bass and the treble. They have better definition than the Groove Tubes "Mullards" I tried which were close, but no cigar. They left imaging pretty hazy and didn't seem to have the same extension in the bass and treble... a slightly brighter sound overall due to lack of deep bass and "air". Soundstage didn't stay in focus as well. Removing those tube covers added a little more energy in the low frequencies for me, made the mids sound a little less "forward" or "congested" and I didn't notice any increase in hum or noise as I feared I might. Definitely use the low-level outputs for a standard active receiver or preamp if you're not doing that... I find myself using the 150pf capacitance setting for most modern carts or the 220pf setting for some vintage or vintage design carts.
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Today I tried LT1115 OPA's and built in the stock output coupling caps. Next I swapped to JJ (former Tesla) ECC83 tubes (with gold pins). The sound is still a bit on the bright side but acceptable.
The worst combination I have tried until now was the superb Electro Harmonix gold pin tubes together with Mundorf M-cap Silver-Gold caps. This set sounded extremely detailed with incredible micro dynamics but unfortunately way too bright. The Mullard tubes were not bad, too, but not a Revealing. Maybe I will try the OPA627 in the output stage and leave the pretty silent 1115 where they are now. Has anybody compared the OPA627 to the AD843K?
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.... oh yes, the tube covers may indeed change the sound a bit, maybe by increasing the temperature of the tubes. I don't have any other explanation why a cylinder made of thin Aluminium should have an influence on sound quality.
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I tried the Electro Harmonix gold pins too and agree they sounded very bright and had no deep bass output in the JD-9A. Try the Sovtek LPS. They're not expensive. I swear they sound very close to flat in the Jolida. Just slightly warm, with nice "air", definition and frequency extension. A little more dynamic than "entry-level" too. I'm pretty picky and was about to give up on the Jolida until I tried the Sovteks without the tube covers.
Actually... I have a sample using a Technics 1200, Audio Technica PRO13E cart and the Jolida handy. Not the best cart and I think the tonearm was set a hair too low on this try, but I think the Jolida is sounding pretty balanced now.
http://www.4shared.com/audio/JAtZrDGq/Josie_ATPRO13E.html
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I just ordered a JD-9A. Could someone let me know what value the stock output coupling capacitors are? Reason i'm asking is I would like to increase the capacitance and I think i'm going to try some Jupiter HT 2.2uf at 1.5" diameter.
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It was also 1uf in my unit.
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Hi,
I had all the bright problems and no tube rolling or IC swapping would fix it.
I made numerous changes to the grounding, transformer position and shielding as well as removing the PCB for the resistor/cap loading and output HI/LO option PCB.
Regards
Alx
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The AD843KN are not at all usable as a replacement for all 6 OPA's in the Jolida. You'll get a lot of nasty noise instead of "nasty subsonic level bass". I have tried them, too. You may use two of them for the output stage only, where they work quite well. They sound a bit less harsh than the original OP37. I also doubt that replacing the output coupling caps will make such a big difference, I have tried several caps and the result was not so overwhelming. The Jolida is sounding far too bright and I would be grateful if somebody had an idea who to reduce the treble a bit.
Dr. Ear,
What are you using for a front end and for amplification? I can definatly hear a difference in my system when changing caps. I use a 1.5uf instead of the 1uf and the bass is as tight as I have gotten with my system.
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What could one expect from higher values, like 2,2 or 3,3 µF?
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I use a Technics SL-1210Mk5G with either AT150ML, AT20SLa or AT33PTG cartridges. Amplifier is a Yamaha A-S2000. I have some good quality Panasonic 3,3 µF film caps in my box, which I will try today. It is not so much work changing these caps. I will post the result.
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I use a Technics SL-1210Mk5G with either AT150ML, AT20SLa or AT33PTG cartridges. Amplifier is a Yamaha A-S2000. I have some good quality Panasonic 3,3 µF film caps in my box, which I will try today. It is not so much work changing these caps. I will post the result.
If you don't like bright, maybe try a different cart. Those all lean towards bright. In exchange, you get some crazy detail a lower-priced tubed phono stage maybe isn't the best thing to compliment.
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Yes, I know that AT's have a tendency to sound bright, but I like the sound of the 20Sla, there is something special with it. For me it is the best cart I´ve ever owned. BTW, the AT MM's son't sound so bright when connected with 100-200 pF.
I forgot to mention my Denon DL103R, which is not bright at all, but with the Jolida it is.
I have just replaced the 1µF output coupling caps with 3,3 µF Panasonic metallized polyester caps which I had in my spare parts box. After listening to several records I have the strong impression that the sound of the JD9 is more balanced now. Highs are the same but there is more weight and body in the lower register. I like what I hear and I will leave them in there except somebody has a good argument against it. I am asking myself why Jolida built in such a small value cap, should it act as a subsonic filter?
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Yes, I know that AT's have a tendency to sound bright, but I like the sound of the 20Sla, there is something special with it. For me it is the best cart I´ve ever owned. BTW, the AT MM's son't sound so bright when connected with 100-200 pF.
I forgot to mention my Denon DL103R, which is not bright at all, but with the Jolida it is.
I have just replaced the 1µF output coupling caps with 3,3 µF Panasonic metallized polyester caps which I had in my spare parts box. After listening to several records I have the strong impression that the sound of the JD9 is more balanced now. Highs are the same but there is more weight and body in the lower register. I like what I hear and I will leave them in there except somebody has a good argument against it. I am asking myself why Jolida built in such a small value cap, should it act as a subsonic filter?
Man,, you don't mess around eh? Good on you,, I'm really thinking hard about picking one of these up and comparing it to my Super it.
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Dr. Ear,
What are you using for a front end and for amplification? I can definatly hear a difference in my system when changing caps. I use a 1.5uf instead of the 1uf and the bass is as tight as I have gotten with my system.
alx, this seems to be the definitive solution. The Jolida sounds much more balanced now with 3,3 µF than with the stock 1µF caps. Lower Mid and Bass levels are now comparable to a Pro-Ject Tube Box II SE.
Maybe Mundorf Supreme, Claricaps and Auricaps aren't the right approach because they were designed for tweeter crossovers with emphasis on perfect treble reproduction. The Panasonic film capacitor sounds very good to me.
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alx, this seems to be the definitive solution. The Jolida sounds much more balanced now with 3,3 µF than with the stock 1µF caps. Lower Mid and Bass levels are now comparable to a Pro-Ject Tube Box II SE.
Maybe Mundorf Supreme, Claricaps and Auricaps aren't the right approach because they were designed for tweeter crossovers with emphasis on perfect treble reproduction. The Panasonic film capacitor sounds very good to me.
Hmmm interesting!... and not even expensive if larger film caps are all that's necessary. May I ask what tubes are you guys running that sound good with the larger capacitors? Sounds like something I should definitely try. Any chance of a sound sample?
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Tubes did not make such a huge difference, I have tried TAD, Mullard, JJ and Electro Harmonix. Latter were the most bright sounding tubes. High end caps? Just think of Nelson Pass amps, there are no special parts in there, but they sound great.
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How many of Nelson's amps have caps in the signal path? ;)
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Still no complaints about the 3,3µF output coupling capacitor? (Until now I could not hear any unwanted effects, just better bass).
Just made a comparison between the Jolida and the phono stage of my refurb'd Yamaha A-1 integrated. My wife, uncorrupted like always, said that the difference is very small (with a small advantage for the A-1, which sounds a tiny bit warmer and music is a little more fluent).
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Still no complaints about the 3,3µF output coupling capacitor? (Until now I could not hear any unwanted effects, just better bass).
Just made a comparison between the Jolida and the phono stage of my refurb'd Yamaha A-1 integrated. My wife, uncorrupted like always, said that the difference is very small (with a small advantage for the A-1, which sounds a tiny bit warmer and music is a little more fluent).
I will have to give that a try eventually then. I just compared the Jolida to an inexpensive solid-state amp (Vincent PHO-111) and the Jolida sounded more accurate to me in every department, except for that it really does seem to lack just the tiniest bit of bass weight. If this mod cures that, I'll be in heaven! I wish I understood more about what changing the value of those caps does. My understanding of electronics just doesn't go that far. I've been soldering and fixing things a long time though, so there shouldn't be much risk. If I don't like it, I can go back to the original value, maybe use a more premium cap.
You guys should try the Sovtek LPS in there though. They have a better balance than anything else I've tried in the Jolida. The gain of these tubes seems to be just about right and the sense of correct timing I got with the original tubes remains. These are a little less "hard" sounding in the mids though and have better frequency extention and "air" at both ends.
Here's another rip using the Sovteks and an AT440MLa. That last rip I put up really sucked. Turntable setup was a bit off and I've since started using even more capacitance with the old Audio Technica PRO13E to give it a little more "zing". I don't think this rip sounds any brighter than a 440MLa would sound with any phono stage and it should do a better job of showing the nice tonal balance I'm getting with the Sovteks. Just a smidge of added bass weight and I would be SO happy with this phono stage. So, thanks for the tip on the caps! Hope it works for me too. I will report back with the results eventually, maybe even with some "before" and "after" rips. I still haven't ordered any caps yet...
http://www.4shared.com/file/IO6NwgGH/AT440MLa_and_Jolida.html
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Just putting in the Sovteks, making a better power cord and using the recommended switch settings worked fine on my system.
After watching the mylar on the Maggies move around on a very bass heavy PJ Harvey album, I really don't think any additional bass would be a good idea.
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The 1µF Capacitor in the signal path is for DC blocking only. If the value is a little low it will also impair bass response. It is no big thing to solder in two 2,2 µF film capacitors, they are not expensive at all. If there is a better bass response after this modification, like it was in my case, one can later on invest a little bit more in a so called "audio grade" auri-, gold- or mystery cap. If the preamplifier where the Jolida is hooked on has already a DC blocking input cap one could remove the cap in the Jolida at all.
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I guess I'm gonna' have to give it a go and order some caps today. I would certainly always wonder now if I don't try it... lol. Do you happen to know the voltage rating on those caps, so I don't have to remove my Jolida from the rack, open it up and look right now? I guess it's not supposed to matter if you use a higher voltage rating with film caps? Any advantage to using a cap with a higher voltage rating than required?
SteveFord... I agree the Jolida doesn't really seem to need "more" bass. The balance seems pretty nice to me and the upper bass seemed to have a little more "kick" than with the solid-state phono stage I compared it to. I guess what I would hope for is just a touch more extension or definition in the lowest frequncies. The solid-state did seem to beat the Jolida in that department. Seemed to help keep the soundstage a bit more defined and stabile.
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i used Panasonic ECQ Series Metal Poly Fim caps because I already had them. 3,3µF/100V, they have the same size as the stock caps. There is no advantage using higher voltage caps, they are just getting bigger. I don't know how much the use of better quality caps would improve the sound. My experience with the expensive Mundorf (1µF) was a mixed bag, superb micro dynamics and resolution but lack of bass and too much treble. If there is no significant DC offset in the output, or if the amplifier is equipped with input coupling caps one could replace them with a wire bridge. I would have done so but my preamplifier is DC coupled.
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i used Panasonic ECQ Series Metal Poly Fim caps because I already had them. 3,3µF/100V, they have the same size as the stock caps. There is no advantage using higher voltage caps, they are just getting bigger. I don't know how much the use of better quality caps would improve the sound. My experience with the expensive Mundorf (1µF) was a mixed bag, superb micro dynamics and resolution but lack of bass and too much treble. If there is no significant DC offset in the output, or if the amplifier is equipped with input coupling caps one could replace them with a wire bridge. I would have done so but my preamplifier is DC coupled.
I got antsy and looked while I was waiting for your reply. The stock caps are 250 volts, so I guess I'll stick with that. I'll order some 2 or 3uf... or possibly a few values... maybe some extra 1uf in case I don't like the change but a slightly better quality 1uf makes a difference. I'll try to post some results and rips next week.
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The change in bass is just the property of the Mundorf cap compared to the cap you're using now.
Replacing the 1uf cap with a 3.3uf cap shouldn't make any difference above 20hz. If you were to use a smaller cap, then it could affect something in our audible hearing range.
FYI, Mundorf and Claritycap are designed for electronics, as well as speaker, hence the 630v rating. If you're looking for something smooth on a budget, check out Auricaps or Obbligato. Or check out V-cap Cu or Duelund Cu.
As for me, I'm happy with my Claritycap ESA. I may swap it out for a extra pair of Claritycap MR's though.
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The change in bass is just the property of the Mundorf cap compared to the cap you're using now. Replacing the 1uf cap with a 3.3uf cap shouldn't make any difference above 20hz. If you were to use a smaller cap, then it could affect something in our audible hearing range.
Technically you're right. Maybe my preamp has an unusual input impedance. If you follow the thread there is another one who believed to hear some better bass with an higher value.
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Technically you're right. Maybe my preamp has an unusual input impedance. If you follow the thread there is another one who believed to hear some better bass with an higher value.
I still haven't ordered anything. The only thing I could find from my usual parts sources were 600 volt polyester film "orange dips" which probably wouldn't fit in the same space due to the higher voltage rating or polypropylene tube capacitors like the "audiophile" ones you guys say may sound even brighter. I was tempted to try a budget version of those... I got frustrated, confused and gave up looking. I'll have to check out some different electronic parts sites...
Have you guys seen this?
http://www.audiogon.com/cgi-bin/cls.pl?ddpreaphon&1268332056&demo&3&4&
It doesn't look like a clone. It looks like the Jolida down to every part and every wire. I wonder if the Chinese factory that manufactures for Jolida decided to go into business for themselves? I bet there's trouble over this...
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This is absolutely identical. The same happened some years ago to Mr. Levinson with his "Red Rose" line of amps when the Chinese factory decided to sell them under the label of "Korsun" and later "Dussun".
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This is absolutely identical. The same happened some years ago to Mr. Levinson with his "Red Rose" line of amps when the Chinese factory decided to sell them under the label of "Korsun" and later "Dussun".
i dunno about the jolida situation, but you got it exactly backwards w/red rose. what happened is that mark levinson decided the korsun (now known as dusson) gear was good, and he re-labeled it and marked up the prices 5-8 times... :o he did the same thing w/his re-labeled aurum cantus speakers.
i have a nice korsun 50wpc integrated amp that i bought used for $150 shipped, direct from hong kong - original price was ~$250. red rose was selling them for $2k.
doug s.
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From the marketing point of view Red Rose was first and then came Korsun (or Dussun). I owned a V8i for a few months. It was not so bad for the price. It is ridiculous how much Red Rose wanted for their "clone".
BTW, I have never seen any specifications of the Jolida's RIAA curve .
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From the marketing point of view Red Rose was first and then came Korsun (or Dussun). I owned a V8i for a few months. It was not so bad for the price. It is ridiculous how much Red Rose wanted for their "clone".
BTW, I have never seen any specifications of the Jolida's RIAA curve .
uh, no, actually, korsun was out before red rose - how do you think mark levinson discovered it? :scratch: yust cuz you may have heard of red rose first doesn't mean it was first.
doug s.
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i emailed pacific walve the following question:
"hi,
does shenda make this for jolida, or the other way around?
thanks.."
answer (which took all of two minutes):
"Shenda makes Jolida"
doug s.
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i emailed pacific walve the following question:
"hi,
does shenda make this for jolida, or the other way around?
thanks.."
answer (which took all of two minutes):
"Shenda makes Jolida"
doug s.
I guessed they were the manufacturer for Jolida. The real question is if Shenda has the rights to the design or if it's Jolida's patented design used without permission. That question was not answered at all. It looks like Jolida may be rebadging stuff designed and built by Shenda because there is other Jolida-looking Shenda gear I wasn't aware of and I haven't heard about any trouble yet. I'd be curious to see what Jolida has to say on the subject. They lead you to believe you're getting an exclusive product designed in the USA by Jolida and built overseas. I wonder if Jolida is really owned by the Chinese company or was just a USA distributor for them without even having exclusive rights to sell their products?
EDIT: Or on the other hand, Shenda just might be in the wrong here since the Audiogon ad I linked to was just removed and the Pacific Valve site says... "This product has been temporarily removed from our catalog."
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I've had the Jolida JD-9 in the past and while it sounds OK in stock form I wouldn't call it a giant killer, it's seems at the retail price to be priced about right for what you get. What I haven't read in this thread is any comparison of the modded JD-9 to other phono stages that sell for more $.
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I've had the Jolida JD-9 in the past and while it sounds OK in stock form I wouldn't call it a giant killer, it's seems at the retail price to be priced about right for what you get. What I haven't read in this thread is any comparison of the modded JD-9 to other phono stages that sell for more $.
I'm going to be comparing a stock one (other than the Sovteks) to a solid-state Pro-Ject Phono Box SE II tomorrow. I've decided if the Jolida wins, I'll quit picking at it's slight imperfections and just enjoy it, maybe try higher value and / or higher quality output caps eventually. If it loses, I'll keep the Pro-Ject. My guess is it's very "round" sound has something to do with how high the gain is and how you have to use the outputs with resistors on them for a standard preamp or receiver. I think it might sound better using the full output and a passive preamp. I know when you reduce the level of a source by adding resistance, funny things tend to happen with tone... like if you have a CD player with an output control and turn it down, it'll sound a little different.
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I thought the Pro-Ject Phono Box SE II sounded promising at first. But, I don't think it's going to work out. It has better frequency extension and detail than the Jolida, but it just sounds harsh and not quite right to me in some way I can't quite explain. I just don't like it. I took a peek inside and there's nothing in there but ICs and those tiny micro parts they use in PC cards. I'm sure this and the tiny PC board traces are what's "choking" the sound and making it harsh. The unit could never be modded or even repaired outside of replacing the whole PC board. I think they have a lot of nerve selling this as the "new version" of a phono stage that was well-reviewed, built 1000 times better and has absolutely nothing in common with this one.
So, I guess I have renewed respect for my Jolida. It may not be perfect, but, it always sounds powerful, reasonably refined and reasonably involving once I listen a few minutes and my ears adjust to the "round" sound. Definitely seems like it was worth the price and I'm not likely to find anything better without spending more.
Hope the place I bought the Pro-Ject from has a good return policy for non-defective items... didn't even check. I really thought I was going to like this, based mostly on what I've read about the completely different older version. I didn't think I'd want to return it.
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An interesting oberservation. I am testing a Pro-Ject Tube Box II SE at the moment and find the sound much more pleasing. It is warmer sounding than the Jolida thus more involving and has better channel separation, too. Belive me, the Tube Box II SE does not sound harsh at all.
There are high quality Burr Brown OPA's inside, fine tubes with substantial dampers and not such flimsy aluminium caps. The housing is solid like a brick and does not need extra damping. And it is very quiet. I have listened to MM's only by now, AT20Sla, AT150MLX and AT25, and have not tried my AT33PTG or the DL103.
Depending on the environment the Jolida may be a better choice for some, esp. with not so treble friendly speakers or when the listening room is heavily damped. With my very revealing NS-2000 speakers the Tube Box sounds better.
Both pre's share the same much-too-bright blue LED which I will rip out soon.
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Glad to hear your search is going better than mine. I've heard great things about The Tube Box SE. The case for the solid-state was about brick-sized and brick heavy too. I was shocked to find absolutely nothing I would consider "audiophile quality" inside! Really, not that shocked after listening to it a couple days.
Does the second phono stage look like a new, improved version of the first one that should be sharing the same name and reputation? Notice how the case is twice as big as it needs to be just to deceive...
(http://www.audiocircle.com/image.php?id=30019)
(http://www.audiocircle.com/image.php?id=30020)
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A friend has both the Phono Box II SE and the Tube Box II SE. We made a short comparison a few weeks ago. As far as I can remember was the difference not so huge, but the Tube Box was preferred for its warmer sound. Maybe you should also try the Tube Box II SE? If you still like the Jolida more after this you can keep it and don't need to worry about it any more.
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Your pictures came with a little delay, it did not see them before. The II SE is entirely SMD'd which needs less space. The sockets are soldered directly to the pcb. There are 5 OPA's per channel whereas the old model has only 3. Electronics are getting smaller. IMHO this is indeed an improved version. Of course, you are right regarding your comments about the size of the housing.
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Your pictures came with a little delay, it did not see them before. The II SE is entirely SMD'd which needs less space. The sockets are soldered directly to the pcb. There are 5 OPA's per channel whereas the old model has only 3. Electronics are getting smaller. IMHO this is indeed an improved version. Of course, you are right regarding your comments about the size of the housing.
I don't think 5 op amps is an improvement when 3 quality ones will do. Both models have all the parts soldered directly to the PC board. The difference is the new model uses cheesier op amps and those micro resistors and caps which I do not consider audiophile quality at all. Also, they cannot be upgraded or even replaced. The "improved model" is absolute rubbish compared to the old one. My ears told me that before I opened it up to see if there was any hope of getting good sound out of it. They ought to be ashamed of themselves selling that as "audiophile" gear for over $300.00. It's worth about $50.00 tops and there are more musical sounding $50.00 phono stages using full-sized parts. All electronics are not getting smaller, certainly not "audiophile" electronics. It's just that a couple companies went cheap. The only other phono stage I'm aware of that uses these micro parts is the NAD PP-2, another phono stage that doesn't sound all that great. Coincidence? At least the NAD sells for a much more realistic $100.00.
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I just discovered something that made my Jolida sound twice as smooth. The overly "forward" sound is gone and both frequency extremes are smoother and more extended. I'm hearing deep bass I haven't heard from my vinyl rig in a long time.
The fix?... I found the capacitors for capacitance loading in the Jolida are tiny, cheap ceramic discs. Definitely not the first thing you want in your signal path. I turned off all the capacitance switches and used Y-adapters and loading plugs with silver mica caps in them instead. 91pF seemed about right for most modern moving magnets that liked the 100pF setting. The Y-adapters add a little capacitance. HUGE difference. Smoooooth and more extended. Definitely try this if you have a Jolida you're not 100% satisfied with yet. It's no small difference and it's all for the better. I thought about replacing the stock caps with silver micas, but the stock ones are tiny and I'd be worried about ruining the PC board traces trying to install the larger silver micas with larger leads. The plugs and Y-adapters work fine though.
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You didn't happen to take any pics? 8)
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You didn't happen to take any pics? 8)
You want pics of the stock caps?... or how to do the capacitance plugs? I can take some...
The first pic shows how to use them. Just plug the plug into the Jolida, your turntable into one of the jacks and the loading plug into the other. The second pic shows the silver mica soldered into an RCA plug. They're non-polar, so just one lead to the plug tip and the other to the ground. I did use a cheapo heat sink clip with a 90 degree bent tip on the lead between the cap and where I was soldering. The plug tip particularly seems to hold a lot of heat for awhile. Not sure how necessary that was or how easily silver micas are damged by heat. There are a couple dealers on eBay who will sell you a few silver micas without ridiculous shipping charges or a minimum order. You have to watch the size if you want to be able to put the covers on your plugs. I've bought some silver micas that are much bigger, even though the values and voltage ratings were lower (I believe these are 300 volt). Maybe older ones?... I also found the plugs on eBay from a Chinese dealer for less than $1.00 each shipped. Pretty snazzy plugs... These really come in handy if you have a phono stage with fixed capacitance and a vintage cartridge that likes higher capacitance. Just have to find the right value.
Here's a rip I did using the new loading plugs and an Ortofon Blue. I think it sounds less "round" and harsh in the upper-mids and closer to "reference" than any rip I've made with the Jolida yet. That song doesn't have a ton of bass, but I can definitely hear it's going deeper now. The sound is just less "congested" overall. I should have made another rip using the switch on the Jolida for comparison, but I didn't think of it. The main reason I made that rip was to compare different values of capacitors and find the best one, not to compare the silver micas vs. the ceramics in the Jolida. I'm working with an older AT cartridge now to try and find the perfect capacitance and make plugs that work for that.
http://www.4shared.com/file/0eJpNWzf/new_caps_91pF.html
EDIT: My friend says he likes this one I did with 86pF capacitors better (2 43pF in parallel). I think it's just a little too thick in the mids. I may end up with a value between 86 and 91. I'll have to try some different music and keep comparing...
http://www.4shared.com/file/niz3h2tD/new_caps.html
ANOTHER EDIT: I just got a pair of Python Y-adapters from eBay and they sound better than the ones shown in the photo and used in the rips. They sound a touch more "open" and detailed for some reason, still very smooth. Maybe the conductors in the other ones were very thin? Anyhow... Pythons recommended if you want to try this and need decent, reasonably-priced Y-adapters.
(http://www.audiocircle.com/image.php?id=31455)
(http://www.audiocircle.com/image.php?id=31456)
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FWIW, I just purchased a pair of new prod Gold Lions, tantalum resistors for the loading switches and in series with the tube, and also Amtrans AMCH film caps for the loading switches. Unfortunately, that rig is down for the moment as my speakers are being finished.
I'm curious to hear your impression of MR vs. VSF in this circuit.
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face,
Honestly I have not heard Gold Lions, I found the new production Tung-Sol 12AX7's excellent in this unit, but for High power MC or MM it is much better with 12AU7's as they are 30% of the gain a 12AX7 provides.
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The resistors are AN Tantalum from Parts Connextion. I've used them in other applications and have been pleased. I'm also only changing out only the resistors I use for loading, not all of them. Sorry, no extra 100R's at the moment.
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I just ordered a pair of the Vishay Var-Series "Naked" 100R. Chris at parts connexion says these are now the best resistors in the world which he carries for any phono loading. They are just to the market I guess and they just started taking orders like 2 months ago on them.
They are crazy looking suckers and very pricey at 3 times the cost of the other premium types, but I figured if I need to pay 20 bucks to fed ex from canada why not? Also I spoke with him about the space in the JD9a for the input board on these, I doubt they would fit easily at all, so Instead I will simply just turn off the Load dip's all together, accept for the Gain switches of course, and just solder these right onto the WBT's jacks giving plenty of space and a direct connect to the load just simply putting one of these on each jack from center pin to ground pin on each channel... Should be exciting! Check out the link to these resistors.
http://www.partsconnexion.com/resistors_vishay_var.html
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You needed to use the macro feature of your camera for last 2 pics.
Interesting post/changes nonetheless.
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That's for the info and images Undertow.
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That's starting to be a SERIOUSLY tweaked out Jolida! Wish I could hear it!
For the less inspired, my experiment using silver mica capacitance loading plugs instead of the cheap internal ceramic caps has worked out very, very well. The cloudy, harsh in the upper midrange and light on the bass "Jolida sound" has almost completely cleared up. I think it sounds way more open, extended and detailed now and this is a very cheap and easy tweak. I have no idea why they put ceramic disc caps as the first thing in the signal path. All the other parts seem much better suited to where they are in the circuit.
Here's a rip done with an AT440MLa. This cart was always extremely lean sounding and pretty much unlistenable with the Jolida. There's actual bass now!... and it sounds detailed... not just bright in the upper mids. Still not the richest sounding cartridge with the Jolida, but a huge improvement I think. Just smoother, more balanced and more "open" sounding. This is with the Python Y-adapters from eBay and 89pF capacitance plugs (a 50pF and a 39pF in parallel). This value seems to sound best with my Ortofon 2M Blue as well.
http://www.4shared.com/file/tiUfwuHa/jolida_89pf.html
EDIT: It would probably help to post the same rip using the Jolida's 100pf setting instead of my capacitance plugs. Less bass weight, detail, frequency extension... Not as smooth... The whole tonal balance does seem to get a little top-heavy which is probably the reason for the "brightness" people talk about, along with the lack of deep bass and smoothness in the highs. This little mod really makes QUITE a difference... and you don't even have to take the cover off. Here's the rip using the Jolida's cheapo internal ceramic discs for capacitance loading... I think it would be tempting to set the tonearm settings a little differently to try and get rid of the "congested" sound from the cheapo ceramic caps. Probably another cause for the "bright" sound people complain about.
http://www.4shared.com/file/85CDYmNh/jolida_using_internal_100pf_ca.html
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royphil345,
For sure the loading devices do make a difference, they choke off some of the transparency of this unit. The loading resistors and caps are easily done by just connecting right to the back of the RCA inputs.
However, if you modify that micro board it is a serious task! But I did, only for the future if I need to test a different loading, but I only replaced the single resistor I needed, which in this case was suggested by Partsconnexion as the best of the best, the Vishay naked "Z"… Pricey at 15 bucks a pop, however, they are SMALL enough unlike the barrel type resistors from Audio Note etc…. to fit anywhere you want, its no bigger than the 3 cent Radio shack style resistors on it now due to this resistor is flat and tall, opposed to large and round like other replacements. Luckily it’s the best you can get as well.
Anyway I replaced this first… It did have a significant change in tone and I would say added a slight transparency the old resistor did not being a little hazy… Now the Bass maybe became more defined with this for sure.
HOWEVER, because I have been crazy enough to use a pair of Duelunds in this unit just for experimental purposes and ended up with great results, I decided to also order on top of the "Loading" resistor a pair to replace the "GAIN" resistor's as well.
In the Jolida of course you have 3 choices:
70-db gain = resistor value of 1k or 1000 ohms
85-db gain = resistor value of 100 ohms
95-db gain = resistor value of 33 ohms
Well I needed a little more bite than the 70 db provided for my MC cart. with .4 mV output, and less than the 85 db as it got really strong. So I went with a 470 ohm Naked "Z" to replace right in the middle getting me somewhere between 75 and 78 db… This worked excellent, but the unexpected side effect, this was the most significant sound upgrade to this unit yet!
First the Gain not just the loading resistors in the unit REALLY were choking off the dynamics of the cartridge for sure, because holy cow the background is so silent now, and the bass is so incredible with much smoother top end, and this of course even after the Duelunds and better op amps went in.
This makes sense because this is really the first gain component your Cart. sees coming into the jolida, and it really makes a HUGE difference having a quality resistor right there in line opening up this signal to the gain board and opamps. These resistors are not on the Gain board itself, but on the "Loading" board with the loading caps and resistors that have the dip switches on the back of the unit.
The gain resistor is the one you want to change for sure maybe even over the loading. Also this is a good opportunity to fix the big complaint on this unit putting in your own custom gain setting like I did so its not too high or too low of power. This is funny because Jolida tried addressing this with that other Goofy potentiometer board of course on the outputs so you could use the lower or higher outputs. But one single resistor of high quality right at the input to do it right blows the doors off this unit, I am not kidding.
However, if you wish to do this mod it’s the most difficult because you can melt the dip switch as the connections are so close your iron can physically touch the plastic trying to remove and replace, you would not damage the board or traces too easily overheating it, but just the position of the plastic on the switches makes it a pretty tough one, plus you do have to unscrew the board, both boards the gain stage and the loading board and possibly remove all the wires to make it easier on top of that. Otherwise you could remove the loadingboard from the circuit all together and point to point hardwire, of course this is easy for the loading resistors or caps right at the RCA, but the gain resistor is in series going in and back out of the switches you would be eliminating taking out the loading board, but you would get plenty of space and fairly easy mod if you can trace it and wire it up right. I decided the extra 2 hours doing it right was worth keeping the integrity and original operation of the unit for other cartridge choices in the future.
This might be the single most effective mod to see where your sound stands on this unit, truth is everybody always goes backwards starting with the ouput caps and tubes!
I guess they are the easiest as most of those parts and values are easily seen, and of course in the audio world they are in the top tier of critical components.
But if the signal is generic from the cart. because of this cheesy load and gain resistor combo your already severely limiting your signal integrity, I can hear this clearly after the mod. Remember this is not a powerful electric signal coming off that Cart. its virtually at the mercy of very small signal change, not like an amplifier, preamp, or digital device, it’s a phono amp, and a cartridge is hyper sensitive to its resistance and output levels, so if anything makes sense than the resistors directly loading, and setting the gain or caps connected directly to the dead signal off a passive cartridge are probably the most critical to get right off the bat.
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Yes, I haven't done near as much experimenting as you have... But, I have been coming to the same conclusion that the beginning of the signal chain is extremely important in getting the best sound out of vinyl. It seems accuracy is very important nearest to the source. I've also noticed that different phono stages definitely seem to sound more dramatically different from each other than preamps, amps or other components.
I'm definitely not messing with that little loading board. I thought about putting my silver mica caps in it, but I saw traces and holes for the leads like right on the edge of the board. Looked like a bigger risk than I was willing to take. I'm happy with my capacitance loading plugs. I didn't think there was that much difference among different resistors besides tolerance accuracy, but I guess I'll have look into that now too. Always learning... Thank you very much for all your input. You inspired me to at least try something and my Jolida is sounding a heck of a lot better already. I may go a little further with improving more parts over time. I'm pretty satisfied with it now though. That little tweak really exceeded my expectations and fixed what was bugging me about the Jolida. I imagine sooner or later something else will start bugging me and I'll want to try further improvements... lol. Seems to be the pattern in this hobby...
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Interesting observations, Undertow:
My friends and I would like to thank you for all this info. You inspired us to upgrade this unit's caps and with great results. After the changes, compared with the stock, this unit is unrecognizable...
Note 1:
The Op-amps recommendations did not work for us - for what ever reason the top of the line AD843KN increased the noise floor in our units (it started hissing on stand-by) without really improving the dynamics. The Burr Brown OPA637BP did not work for me at all - it produced a very high pitched squeel (like a TV would do sometimes) and I yanked it out before there will be damage. Could be a faulty batch of OPA637BP.
Note 2:
Among many others, including ClarityCap MR, AmpOhm, Mundorf Silver in Oil, we tried V-Caps TFTF caps but did not like them at all, in 4 different high resolution systems (two based on ESL panel speakers driven by powerful tube amps, two box speakers' based, driven by SET and OTL): The V-Caps, to our ears, were extremely dynamic (probably the best we heard in that regard) but sounded sterile (chopped off decay, lack of mid range texture, sort of glossed over, overly smooth/slippery and synthetic sounding to our ears). Your mileage may vary and different people have different tastes.
I would like to say that the ClarityCap MR is pretty dynamic too and more than anything it has excellent PRAT but compared to some paper in oil and Mylar in oil caps, it sounded a bit mechanical and solid state like to our ears. It also starts to congest and pinch the sound a bit, when faced with loud and complex audio passages. On the up side it has an excellent mid bass punch.
I believe that to an extent, this is inline with your observation of the ClarityCap MR Vs Duelund cap.
There is more refinement, effortlessness and relaxed sound presentation with the PIO and with some Polyester in oil caps in our mind.
If I had to compare them to amplifier topologies I would say the ClarityCap MR sounds more like push-pull while some paper in oil caps sound more like a SET or an OTL.
Note 3:
As opposed to some views out there, re potential degradation of the sound by by-passing (potential timing/phase distortion), from our experience, most caps benefitted from by-passing with 0.01 uF Vishay MKP1837 and/or 0.01 uF Polystyrene cap - they gave more top end extension and smoothness which translated to more air around the instruments and better ambiance retrieval.
At the end of the day, whatever cap you like, this Jolida JD-9 can be vastly altered for the better by replacing its caps which makes it a great playing ground for audiophiles...
Thanks again, Undertow for your invaluable info!
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The AD843KN are not at all usable as a replacement for all 6 OPA's in the Jolida. You'll get a lot of nasty noise instead of "nasty subsonic level bass". I have tried them, too. You may use two of them for the output stage only, where they work quite well. They sound a bit less harsh than the original OP37. ...
Which are the output opamps? Say, looking from the back of the chassis down at the board? I was thinking they are the set on the right - the ones close to the center of the board. - is that them?
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[snip]
..., go in the unit and change just the first input pair of opamps which in my unit are when you have the unit open and your looking at it from the front the 2 chips all the way to the right inside the unit, [snip]
So from the front the input opamps are to the right and the output opamps are to the left.
mine has the opa37. so the soft burr Brown will stay in in the first two set of slots with the AD834 at output .. and maybe I can have the best of both.
I already change output caps to 1uF Obbligatos by passed with the Vishays. nice smooth with a nice top end that is not overly tinkly.
Also using RCA blackplate 5751s.
Funny thing about the thing is that it does not like my cinrmags /w DL103. A little muddy. So i switched to 100ohm active loading and I like it just fine. A bit more lively but the 103 is pure narcotic. And the DL102 is very nice thru the preamp as well. More detail than you would at first think. And a lot less noise.
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I might be just talking to myself here but here it goes anyway:
So far I have Obbligato's bypassed with .01uF Vishays.
I removed the tube shields and had RCA 5751 black plates.
all nice but it did not rival my Hagerman Cornet2 in imperial breadth and extension. But I don't think that is what this pre is all about anyway because ...
I have been thinking about replacing the wideband RCA 5751 blackplates with current production Tung Sol 12AX7 just to get a AX7 back in play because maybe that is really what the pre wants. Things were just a bit grey as is.
Then my AD843KN opamps showed up in the mail today so I replaced the output set of OPA37 and put in the Tuing Sols.
BIG improvement. Level of presence is whaay Up. I get the feeling "i am done with mods on this baby." detail improved, presence, dynamics, and a bit more openness. Still not as extended as the hagerman but that may it's signature. In any even I now love this Jolida.
thanks you, boys. You been a big help.
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I found the Jolida to be very responsive to tube rolling and I liked the Tung Sols very much in there too. They were my second choice to the Sovtek LPS out of many tubes I tried. Although, that may have changed with the fine-tuning I've done since. I'll never know, because I thought I was decided and gave the Tung Sols away awhile back. Now, I do sort of wished I saved them to try again after a period of tweaking things and finding the perfect settings on the Jolida over time.
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Doroner,
I'm curious what output caps you and your listening panel ended up preferring? Also, Undertow, do you still have the Duelunds in your outputs? I'm wondering if after getting used to them, you might put the Claritycap MR back in for a final evaluation with your favorite music. maybe try a larger value pair equal to the Duelunds. :D
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Hi Sherod,
Sorry for the delay. My notification did not work somehow.
The best overall cap in our mind is the AMP OHM Polyester in Oil Aluminum Foil.
It is the least damaging to the sound, it is the most neutral sounding, the airiest, most detailed (great ambiance retrieval) without being etched or bright and by far the most extended top to bottom cap we tried.
On the negative side if your speakers are on the lean side it will not add beef to the sound like some PIO do. So "the best" not only depends on personal taste (and everybody listens differently and has different preferences) but also what basic system are you starting with and what improvements are you looking for.
Close seconds in our tests are the AMP OHM PIO Copper foil - very rich, seductive mid range, very good presence and tonality to die for, especially with horns and percussion - to my subjective ears it gets the most realistic sounding percussion I have ever heard.
On the negative side - it is not as airy nor as extended as the Polyester in Oil. So life is a compromise - pick your poison.
I would say Diana Krall will sound better with the PIO (more lush, sweeter, less raspy as if she had a cold or something :-)). Big Orchestral Piece will most likely benefit from the Polyester (especially tympani's or any large drum) due to its ambiance retrieval and good extension.
Ironically, the company went bankrupt and hence these caps are no longer in production. There are some talks about getting back to production (Audio Cap in the UK) but nothing came to fruition.
My friends recently tried Obbligato Gold Premium Caps and really loved them. They claim they are pretty close to the AMP OHM Polyester In Oil Aluminum Foil. I never tried so cannot voice an opinion.
For their low price they are surely a low risk buy.
Some other caps we tried and were not impressed with:
V-Caps - over hyped and very pricy. On the positive: it is definitely the most dynamic cap I have heard (feels like your speaker drivers got a turbo motor). Very detailed too. On the negative: it has this annoying gloss-over quality, lack of textures (too slippery smooth) a bit of a chopped off decay. It has no soul in my mind (here is a link for someone who thought along the same lines:http://www.6moons.com/audioreviews/caprolling/caps.html (http://www.6moons.com/audioreviews/caprolling/caps.html)).
I find the Clarity Cap MR to be congested and mechanical sounding compared to the above mentioned AMP OHM Caps. On the positive: it has very good PRAT and mid bass punch (a rocker).
I find the Mundorf Silver In Oil to have smooth airy highs (great for a tweeter cap in a speaker) but sloppy and slow bass (as if reproduced by an under-powereed-for-the-application-SET amp).
The Audio Note Polyester in oil Copper foil, while not a bad cap, does not match these above mentioned to our taste.
It has some nice mid range warmth and is full bodied but is congested (lumps instruments together rather than separates them, when the recordings allows for it).
ModWright caps did not do it for me either - clean sounding but slightly dry and flat sounding (solid state like) - nothing to write home about to my taste, in my system.
I never tried the Duelund nor the silver Audio Note as they are price prohibitive in my mind and after getting "bitten" by the V-Caps I am scared to spend hundreds of dollars just to realize I may not like them.
Bear in mind that this is purely subjective - it may be unavoidable to try different caps for your self to find your soul mate and another advise is to take any cap review (tons of them lately) with a big grain of salt, mine included of course.
Tube wise - after getting so much junk on e-bay (half dead tubes from people claiming NOS) I would say one of the best bets are the Shuguang Psvane 12AX7 from Grant Fidelity: although not as neutral and clean, they are not far behind the Telefunken Smooth Plate clarity wise, very lush, seductive mid range without being syrupy, good bottom end and very sweet: http://grantfidelity.com/site/Pavane_Psvane_Reference_12ax7T_Shuguang_tube (http://grantfidelity.com/site/Pavane_Psvane_Reference_12ax7T_Shuguang_tube)
Enjoy the music!
(http://www.audiocircle.com/image.php?id=39378)
(http://www.audiocircle.com/image.php?id=39379)
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Doronor, do you have anymore feedback or info on the Obbligato gold premium caps. I have a JD-9 unit that I am just going to start making some of these mods on and was wondering. I ordered a pair, figuring for the price its really a no brainer to try them. I am having trouble finding a pair of the ampohm polyester in oil caps since the company is out of business, would the paper in oil aluminum foil caps be a decent alternative?
Dan
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Hi DWR,
From my friend's impression the Obbligato Gold comes damn close to the AMP OHM Polyester In Oil and in fact they think it betters the PIO Copper Foil, in this application.
I have compared the Copper Foil in this application and downstream in my JAS Array 300B/805 SET amp, where it did a better job than in the phono stage (could be that some caps work better in a specific range of voltages than others).
The PIO aluminum foil might be the next closest thing although paper always sounds a bit duller/softer to my ears.
Perhaps try both and post your impression.
I think I am going to try the gain resistor upgrade next to see if it brings some more magic.
I am very thankful for this thread information exchange - I think after music loving this is what this hobby is all about.
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Doronor, I completely agree with your last sentence in that post, I will start with the caps as far as upgrading this unit, and I am sure I will do further upgrades following the info from the postings and info here. Thanks for the info on the caps, and as you said in an earlier post I am just going to have to find out what sounds best to me in my rig.
Dan
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Hai all,
I am going to NZ latest mid of next year. Will station there for years to come. May i know where to buy this phono in NZ?
Best regards,
Wan
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OK fellas, I started the mods today on my JD-9. I started with the caps, and used Obbligato gold premium 1uF 630v caps for my replacements. Wow, there is just no way only changing caps should have that much improvement in the overall sound of the unit. I am pleased way beyond my expectations, I am using Siemens ECC 83 tubes which I like in phono stages and the sound is fantastic. I have a MFSL copy of Supertramp Crime of the Century on right now. So what would any or all of you suggest for the next step (op amps??), maybe someone can put the mods in some kind of order most improvement to least? Thanks guys.
Dan
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Hi Dan,
Glad you found out how good the Obbligato caps are.
These are the proof that one need not spend huge amount of money to get good sound.
I tried them in the input section as well (there are a bunch of 4.7 mfd caps near the op-amps) and they smoothed out the sound.
Also, just recently tried the Vishay Z-foil resistors to replace the 33 ohm ones (my Dynavector 17D3 has 0.3 mV output).
I used 47ohm but given the low cartridge output, I may try to bypass the
resistors altogether just to try (best resistors are no resistors).
The Z-foil is special: more information coming through without thinning of the sound. These are ultra detailed resistors.
More extension top to bottom as well.
All I can suggest is do one upgrade at a time to be able to track what each does.
this unit now is an Audia Flight killer
Happy tweaking!
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I tried them in the input section as well (there are a bunch of 4.7 mfd caps near the op-amps)
Hey Doronor,
could you elaborate a little on which caps your talking about. thanks for your time.
big
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Thanks Doronor, I have looked at those caps that you are talking about, maybe I'll change those out next, also thats good to know about the resistors, I should get very similar results as you since I am using the 17D2 cartridge, sounds you like your Dynavector as much as I do mine. Thanks again man. One more thing do you have a schematic of this unit or no and if so where can I get one?
Dan
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Hello Again,
It is my pleasure to share my experience.
Like I have said apart from enjoying music, this is what this hobby is all about.
After getting inspired to modify my JD-9 by this thread I moved on to my Sonus Faber Grand Piano Home crossover capacitors (6.8 mfd and 10.0 mfd) - first I did one speaker and listen to each one to compare.
One speaker sounded like it had a blanket on it and one did not...:-)
Took two second to realize that the original caps, which seem to be Mundorf Supreme MKP, relabelled as "Sonus Faber" are muffled in the mid range, sloppy in the bass and grainy in the highs, when compared to the Obbligatos.
It is like wearing dirty sunglasses for the longest time and getting used to it, until someone cleans your sunglasses and the clarity is astonishing.
I always thought the Sonus Faber Grand Piano Home's tweeter was splashy. Guess what? It was the capacitors fault all along and not the tweeter...
Here are the Jolida mods in photos:
1. Overview:
(http://www.audiocircle.com/image.php?id=40702)
2. 4.7 mfd caps on op-amps board:
(http://www.audiocircle.com/image.php?id=40703)
3. 47R Vishay Z-Film resistors instead of the el-cheapo stock ones (the shiny golden coloured plate)
(http://www.audiocircle.com/image.php?id=40704)
4. Another angle of the Vishay Z-Film Resistors:
(http://www.audiocircle.com/image.php?id=40705)
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Doronor, can you possibly explain or get a pic of exactly where those 4.7 caps get soldered into the op amp board, now I haven't had a chance to open up my unit and look at that board so maybe it is quite obvious, but if not let me know exactly where you soldered those caps in. I also just ordered 4 Telefunken ultra fast soft recovery diodes to replace the stock ones with. Thanks in advance.
Dan
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Hi Dan,
If you open the box on the far right hand side, you will discover the input section of this phono stage.
On top of the PCB board where all the OP-Amps are located there are 8 X 4.7 mfd orange capacitors.
I just changed the far left two with the obbligatos. The issue with swapping caps gets to be lack of space (as you can tell from the hardly ideal positioning of the obbligatos). I cannot help but think this phono-stage could have benefitted from being built from scratch in a larger box, point to point with better wiring, better isolation, better overall components - something like a Joule-Electra build quality.
I do not have schematics of the unit. I wish I had. I would gladly share them. If anyone in this forum has access to the schematics it would be great if they can share, even through a PM.
Can you elaborate on the diodes? (their location, how did the new ones influenced the sound and what made you choose these specific ones?).
Also, I am a bit wary touching the power supply capacitors. Not long ago I replaced the filament heater power supply capacitors (10,000 mfd/25V electrolytic caps) on my JAS Array 2.1 (300B/805 SET Amplifier) from "lowly" Rubycon to Mundorf M-Lytic with poor results - the sound thinned, dynamics got reduced, bass was sloppy. Go figure. Needless to say I put the Rubycon back.
Got better results in the tubes' power supply with Jensen electrolytic caps.
Sometimes this hobby is like cooking. You have to apply trial and error to discover a good recipe.
Happy New Year!
Doron
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OK excellent thanks for that info, I wondered about which caps the obbligatos were replacing, I've looked at that section of the unit and you sure are correct about there being very limited space there. I chose the Telefunken diodes after researching some of the mods that are performed by some of the companies out there. One of them has 3 levels of mods that replace the stock diodes with ultra fast soft recovery diodes. The second level mod uses National Rectifier diodes and the level 3 uses the Telefunkens. When I found the price on them it became a no brainer they are $.51 each, let me know if you want me to try and add 4 to my order for you. I haven't put them in yet as I just ordered them 12-31-10 so if you want 4 let me know and I'll call them Monday and try and add that to my order, the place I ordered from has a $35 minimum order so let me know.
And happy New Year to you too!!!
Dan
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Doron,
Of the eight 4.7 mfd caps I'm curious to know why you chose to replace the two on the far left?
Also, in your pictures it appears as though the Obbligatos occupy the space where two sets of factory 4.7 mfd caps should be, is this just an optical illusion or did you remove / replace those two as well?
Thanks.
BP
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Hi,
The choice of the last output stage was more of an experiment, given that there is no space to change all pairs of caps.
It probably doesn't matter which ones you replace. In any way the results smoother, more relaxed and more detailed sound.
I am into changing my crossover resistors to Duelund Graphite ones.
See what that brings to the table...
Cheers,
Doron
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A bit of an off-topic, although somewhat related:
The Graphite Duelund cross over resistors are an interesting matter.
Apparently they can be be made DIY:
See: http://www.troelsgravesen.dk/graphite.htm (http://www.troelsgravesen.dk/graphite.htm)
and starting at the bottom of the page: http://www.lencoheaven.net/forum/index.php?topic=2887.0 (http://www.lencoheaven.net/forum/index.php?topic=2887.0)
Re the Obbligato Premium Gold in the Grand Piano Home crossover application:
Here is the stock Sonus Faber crossover photo:
(http://www.audiocircle.com/image.php?id=41088)
All run-of-the-mill components, MKP caps (maybe Mundorf MKP if at all), MOX and Cement resistors.
Non of this does justice to the speakers. Many, including me, a loving owner, blamed their tweeter for some splashiness (see following review: http://www.enjoythemusic.com/magazine/equipment/1001/sonusfaber.htm (http://www.enjoythemusic.com/magazine/equipment/1001/sonusfaber.htm)).
The Obbligato Premium Gold are amazing in this crossover application!
They smoothed the top end like nobody's business. 7 years with my Grand Piano Home and Never have I heard them so smooth on top (upper mid range and highs). It is the most un-fatuguing thing. So many recordings which could sound harsh at times are now listenable and enjoyable. Bellisimo!
Bass is also more extended and cleaner than before. Sound floor is low (speakers sound very good even at a low volume levels and details are coming through).
My friend did the same Obbligato Premium Gold upgrade to the crossover of his Tannoy Red 12" speakers and it tamed the compression horn driver quite a bit (it is less shouty) + added clarity/details - so these results are consistent.
Happy tweaking,
Doron
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tantalum resistors for the loading switches and in series with the tube
Can someone identify which resistor is in series with the tube?
Would this be the "grid stopper"?
after some google research it looks like R01 is the grid stopper and is 10k ohms value.
please correct me if wrong.
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Doronor, thank you very much for your post regarding the Obligatto upgrade to the Sonus Faber Grand Piano Home speakers. I have owned mine for 9-10 years as well. I have worked with a lot of component and cable changes to mitigate that slight veil and the grain/brightness in the top end. I am going to make the cap change asap! Do you have any other advice regarding this modification? It appears the crossover is behind the top woofer. Is that correct?
Thanks again!
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Dear Flathead,
The cross over is a PCB which is attached to the inside portion of the binding posts. It is located below the bottom woofer.
Best access can be gained by removing the bottom woofer and removing the foam that covers it.
It has two 8mm nuts to secure it to the back of the binding post short studs.
Given the very limited access, best to use a small and short ratchet (can be obtained at Home Depot) with 8mm cap.
Two upgrades that transform the speakers for me are the Obbligato caps and Duelund Graphite Resistors.
The cross over has the following resistors:
1. 2 X R47, 5W resistors.
2. 1 X 4R7, 10W Resistor.
3. 1 x R15, 10W Resistor.
At first I tried to replace all of them. Not an easy task given the cross over board is small and the Duelund resistors are like pencils (long and narrow). The results was that the tweeter did not play anything as if it is burnt or something. I tried the tweeter on the un-modified speaker to find out it is OK (what a relief!). Than started replacing the resistors back to find out the issue is the two 47R ones.
These are not in the signal path but just parallel and serve as some form of a correction network.
I must have misplaced the values of the 47R or ended up with dead resistors (not sure yet) so I left only the two signal path ones (the 4R7 and R15) and everything worked perfectly. Few days of break-in and these speakers were not recognizable.
Best compliment I ever got about them is from blind veteran drummer who heard them before he touched them to sense their size. He loved them and said it was the best mid-range he ever heard in his life (he uses old Von Schweikert VR-4 if I recall) - the mid range was full, lush, smooth, clean and detailed all at the same time.
He liked the smooth top end too (who would have believed that these can get you a smooth top end!) and the mid bass and said that the only shortcoming of these speakers is lack of the lowest bottom end (Below 35Hz that is) which will be fixable with well integrated subs, if I insist.
But here is the real kicker: he touched the speakers to get a sense of their size and he said: Wow, such a slim and sexy speaker. They sound so big! so much bigger than their size!
So I rest my case here...
These resistors avoid "resistoritis" - a "thinning-of-the-sound" related "resistor-disease".
So they sort of have similar effect to the Vishay naked Z-Foil which were discussed in the following:
http://www.ariaaudio.com/WVVishay.html (http://www.ariaaudio.com/WVVishay.html)
Along with the obbligato, what you get is a fuller midrange, a serious and tuneful bass response (painting behind my head started to rattle) and smooth top end. Everything I dreamt my Sonus Faber could be.
Enjoy the tweak!
Doron
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Doron, thank you again and for the note regarding the Duelund Graphite Resistors. I will try these as well. I will let you know how it goes in a couple of weeks.
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This is great!
I will be thrilled to hear about your results.
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Hello,
After discovering this great thread, I've followed suit in modifying my Jolida as well. I did the Clarity Caps, swapped the op amps, and did some tube rolling and have been very pleased with the results. It seems I'm getting my best sound out of a pair of TJ Full Music 12ax7's. At least out of the few pair I've tried.
After reading some of your comments about swapping the diodes, I'm itching to try that out too. Did you use the same values?
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I will be brief as I recognize this is the vinyl circle. I made the crossover changes last Sunday for the Sonus Faber Grand Piano Home speakers with the Obbligato caps and Dueland 4r7 and 15r resistors. I let the r47 stay as is. Right off the bat this was everything Doronor notes above. Just bit "bloomy" at first and at about 20hrs the sound went shallow with a bit of treble emphasis. Then at about 30hrs the full body and timbre of everything came back. Unbelievable. More detail with no hint of grain. Lower, richer bass and midrange. Spatial cueing in the soundstage also improved significanly. I am grinning from ear-to-ear. Listening to Patricia Barber as I type. Thanks again Doronor and everyone.
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I am so happy for you, Flathead! :thumb:
To me, this is what this hobby is all about:
Sharing information and getting better sound at a reasonable cost.
Keep up the good mod spirit!
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just to get this thread back on track. some pics of my modified JD9. This thread was the inspiration.
(http://www.audiocircle.com/image.php?id=42810)
(http://www.audiocircle.com/image.php?id=42812)
(http://www.audiocircle.com/image.php?id=42813)
(http://www.audiocircle.com/image.php?id=42814)
Thanks to everyone who contributed to this thread. Sounds great too.
big
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Hi Big,
I notice in your pictures that you modified the power supply caps too.
What size caps did you use, what brand and, assuming you did one change at the time, what was audible improvement with these power supply mods?
Also, anyone here tried swapping the RCA connection with better ones (say Vampire)?
Thanks,
Doron
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Hi Big,
I notice in your pictures that you modified the power supply caps too.
What size caps did you use, what brand and, assuming you did one change at the time, what was audible improvement with these power supply mods?
Also, anyone here tried swapping the RCA connection with better ones (say Vampire)?
Thanks,
Doron
Hey Doron,
those are the stock power supply caps. I only bypassed them with 1.0uf film caps.
the Silicon Carbide Schottky Diodes are a bit overkill, I would only recommend them for an all out mod. In terms of sound, the only place I really heard any improvement was in the bass. Tighter, while not having lost any authority. I have also tried SF4007 telefunken diodes. Did not notice a difference, but at the time had not settled on the opamp combo that Im running now.
For opamps Im using AD843KN in the output, op627 in the middle and LT1028 in the right op sockets. Magic :thumb: Previous to that I had op627 at the output and LT1028 at both the input and middle socket.
upcoming mods include Panasonic FC for the powersupply and filtering electrolytic caps, and silver micas for the small ceramics near the opamps.
lots of fun left to be had :D
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Hello all,
So this thread really helped me, it's amazing the difference in sound, I love it and wanted to tell all of you thank you!
Based on this thread, I made a few of the changes and wanted to report out just in case it helps anyone else. I don't know what change made the most difference and don't care because the unit is now substantially better sounding to me in every way.
I have not touched the op-amps but I really want to. I just have a money restriction.
The things I decided to change:
1. Replaced the 100 UF cap's
* These are for the output from the tubes
* used the Obligatos
2. Replaced the 97 pf cap's
* These are for the 100 ohm setting of the input board
* SILVER MICA was used
* No issues soldering to the board, seemed easy enough to me
3. Replaced the resistors for my appropriate for my cartridge:
* replace with Visay naked Z
* I got the 470R and my output is a bit low but I was able to increase the output on my preamp so it worked out fine.
* again, no issues soldering to the board, seemed easy enough to me
4. rewired most of the internal signal cables
* direct soldered to the boards, replacing mechanical connections.
* Used kimber cable that I had hanging around from a pair of old audio interconnects.
* from the output to the RCA jacks I used blue jeans cable (I really like this stuff)
Here is exacatly what I bought from parts connexion: (not endorsing them but they met my needs)
* 2 Vishay Resistor_ 470R Vishay VAR-Series "naked" Z201 Z-FOIL RESISTOR 1%
* 2 Obligatto Film Cap 1.0uF / 630V, Premium Gold Film Cap
* 2 SILVER MICA 91pf 500V CAPACITOR
* WBT solder (just buy it or any high quality silver bearing solder) It's worth 5 times what it costs, take my word for it please, do you self a favor...
Don't know if I did it all "right" but it sure sounds massively better.
Two pictures:
First shows the overview of the cap replacement and the hard wire of the channels
(important note, these replaced the original caps that I took out from the other side of the board)
(http://www.audiocircle.com/image.php?id=43566)
Second shows the resistors, creepy looking Naked Z, and the silver mica caps...
(http://www.audiocircle.com/image.php?id=43565)
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Thank you Undertow for beginning this thread, because of it and all the nice contributions :thumb: I bought a new JD9 ( JD-9A does not really exist, they are all JD9 factory wise)
After reading all 6 pages and http://www.diyaudio.com/forums/analog-line-level/177243-jolida-jd9-upgrade-mods-clarification.html, I am planning to do what brianhiatt did and others and also will replace the 6 OP37G
BUT, what struck me already from your posts and others when replacing the opamps, as well in in the DIY forums, you replace one opamp for another better opamp.
I have replaced the 6 opamps ( ah well Doug of Asi-Tek.com did it) in the I/V stage and and analogue output stage of my beloved DEQX pre-amp with discrete opamp drop in replacement of Burson Audio. The same ones or similar to what Burson Audio uses in their highly praised HA160D DAC ( http://6moons.com/audioreviews/burson5/4.html)
So I will order 6 OP37G replacements from Burson Audio as they really showed with their DAC and head amp they make wonderful HD opamps discrete replacements
(http://www.bursonaudio.com/_wp_generated/wp46f5899b.gif)
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Thanks everyone so far. This is all getting me excited to do some of these mods.
(...)
The best overall cap in our mind is the AMP OHM Polyester in Oil Aluminum Foil.
(...)
I wonder if someone could clarify what would be the best AMP OHM cap to use since the poly seems to be no longer available. Would it be best to get Paper in Oil/Aluminium Foil or Paper in Oil/Tin Foil?
Looking forward. Thanks again to all so far.
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another option to the burson discrete opamps is this:
http://www.audio-gd.com/Pro/diy/OPA/OPAEN.htm
(http://www.audio-gd.com/Pro/diy/OPA/OPA-SUN1.jpg)
these folks actually made the original burson opamps; these are about 30-40% the price of those offered by burson...
doug s.
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thx Doug
I hope Burson have refined and or further developed them, if your source brought the truth
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thx Doug
I hope Burson have refined and or further developed them, if your source brought the truth
yes, they have, but so has audio-gd - the earth is basically the original burson; their sun & moon are further developed...
doug s.
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I have ordered my Jolida direct in China
except from my Paypal paid confirmation 3 days ago, i have not heard from them (yet)
I am convinced the JD-9 can be made in a world class pre-pre amp
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So I will order 6 OP37G replacements from Burson Audio as they really showed with their DAC and head amp they make wonderful HD opamps discrete replacements
you should only need 2, for the output. The others are only 5v and not enough power for the bursons or audioGD. The audioGD looking for 9 - 25v
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So here is a challenge boys and girls:
Did any of you brave Jolida JD-9 owners try to bypass the high gain resistor altogether (bridge it with a wire instead of a resistor that is)?
I am referring to those with ultra low gain cartridges (Dynavector MC Rubby for instance) who needed step-up transformer to get the proper gain, even with the highest gain settings in the Jolida.
I just thought that less is more and the best resistor is no resistor, which can potentially allow to get rid of the step-up transformer as well (two birds with one rock).
Any thoughts?
Thanks for your input.
Happy listening.
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OH BIGDIRTY
that is not good news. So I have to make a seprate pws for all of them ( I have already ordered 6 and received them.)
Are you sure? Why would "Jolida" power 6 same opamps with different voltages?
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Kyrill,
I can buy a pair or two from you, if you do not need them all but need to understand how it worked out for you as my attempt to change any of these op- amps to even AD843KN or the Burr Brown ended up with utter failure (the AD added noise without benefit and the Burr Brown made a high pitch "TV like" noise and nothing else). Trying to put only two did not really bring anything to table for me and my friends (we all use Dynavector low output Karat 17D3 and Rubby = highest gain settings and NO capacitance loading).
What load settings are you using?
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OH BIGDIRTY
that is not good news. So I have to make a seprate pws for all of them ( I have already ordered 6 and received them.)
Are you sure? Why would "Jolida" power 6 same opamps with different voltages?
next time your inside your JD9 have a look. The transformer is outputting 16-0-16v. regulated to 15v for the output buffer/amp. Its then regulated again, twice, to 5v for the RIAA filter.
So here is a challenge boys and girls:
Did any of you brave Jolida JD-9 owners try to bypass the high gain resistor altogether (bridge it with a wire instead of a resistor that is)?
I am referring to those with ultra low gain cartridges (Dynavector MC Rubby for instance) who needed step-up transformer to get the proper gain, even with the highest gain settings in the Jolida.
I just thought that less is more and the best resistor is no resistor, which can potentially allow to get rid of the step-up transformer as well (two birds with one rock).
Any thoughts?
Thanks for your input.
Happy listening.
Doron, have you tried just flipping all three switches to the off position?
edit: reread your post. flipping all three gain switches off leads to lower gain.
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I even have not my Jolida yet
For some unknown reason they could ship a 5 weeks after ( so next week!) I paid and ordered, so the factory does not have them at stock?
Hi Doronor
That willl take some time. I am a purist, so i will try to find out first how to use all the Burson opamps. If necessary i will build a A123 26650 Lifepo4 battery rig to power all those opamps the better the power for a pre-preamp the more effective for the whole chain afterwards
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Bigdirty,
If you look at the back view, the right hand side switch controls the high output so it is in the "on" position (up position). It still goes through low resistance resistor, hence high gain.
Are you claiming that switching all of them to "off" (down position) and using the high output rca's will yield by-passing the resistor altogether?
Thanks,
Doron
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Bigdirty,
If you look at the back view, the right hand side switch controls the high output so it is in the "on" position (up position). It still goes through low resistance resistor, hence high gain.
Are you claiming that switching all of them to "off" (down position) and using the high output rca's will yield by-passing the resistor altogether?
Thanks,
Doron
Doron,
Im a bit confused by your comments. The Switches have nothing to do with the output rca's. When I switch from using the MM gain setting (1k resistor) to all switches off I get lower volume.
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Bigdirty,
My loading setting (capacitance and impedance are all OFF as I find this works best for my Dynavector 17D3).
When I use the right hand side dip-switch from the three dip-switches:
(http://www.audiocircle.com/image.php?id=45257)
and use the right hand side output RCA's (the high gain ones), I believe this is the highest gain settings.
Are you claiming that putting all three dip-switches on "off" will increase the gain (bypass the resistor)?
I though putting them all in "off" will not output any signal.
Now assuming we are on the same page, my question is if anyone tried to by-pass the resistor behind the right hand side dip-switch (which dictates the gain - the lower it is, the higher the gain)?
By by-passing the high gain resistor I mean - use a bear wire instead of a resistor so the connection is there but without the resistance (or with negligibile resistance that is).
Like in the following photo:
(http://www.audiocircle.com/image.php?id=45258)
Thanks,
Doron
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Hey Folks,
Been on others, new to this one. Happy to be here.
I have a JD9 that is close to a month old. Put in Sylvania NOS 80's 5751's that are better than the original Tung Sol 12ax7's in terms of detail and refinement. I am still getting a pronounced midrange peak that I would say is in the 1k-2.5k range. Very noticeable on some of my jazz lp's. Otherwise I really like the JD9. My other main phone pre is a GCPH which has more upper highs and is more detailed but I does not have the warmth of the JD9. The JD9 is not flabby but does have a nice warmth to it and maybe more slam than the GCPH.
So, my dealer is willing to help mod it and we want to know what mod(s) would we do to specifically get rid of the midrange peak?
Thanks,
Robert A. Oberj
PS: Cart is a Lyra Kleos on an SME 309 with the stock VDH cable. The 309 is mounted on a newly refurb Sota Star with some upgrades.
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So nobody has either experienced the midrange peak or otherwise has an idea to get rid of it?
Thanks,
Robert
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So nobody has either experienced the midrange peak or otherwise has an idea to get rid of it?
Thanks,
Robert
have you tried playing with the loading caps and resistors?
(http://www.audiokarma.org/forums/attachment.php?attachmentid=249933&d=1294948156)
linked from another forum and not verified.
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have you tried playing with the loading caps and resistors?
If you mean replacing them, I have not. I do have the Dip Switch chart and currently am at 230 for my Kleos. I have even tried a few different capacitance setings.
On further listening, it sounds more like an elevated shelf from about 1k to maybe 5k or so. Even with the 5751's it does not have the output on the very top of my GCPH but I can live with that for now. As my room and ears are sensitive to peaky mids and lower treble, this is annoying.
Thanks for your reply,
Robert
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have you tried playing with the loading caps and resistors?
If you mean replacing them, I have not. I do have the Dip Switch chart and currently am at 230 for my Kleos. I have even tried a few different capacitance setings.
On further listening, it sounds more like an elevated shelf from about 1k to maybe 5k or so. Even with the 5751's it does not have the output on the very top of my GCPH but I can live with that for now. As my room and ears are sensitive to peaky mids and lower treble, this is annoying.
Thanks for your reply,
Robert
I would try the LT1028acn opamp in the 5,6 positions with reference to the pic below. In my system, I have found these to possess the most clarity.
(http://www.audiokarma.org/forums/attachment.php?attachmentid=263844&d=1300724755)
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I would try the LT1028acn opamp in the 5,6 positions with reference to the pic below. In my system, I have found these to possess the most clarity.
Thanks for that. I will try them. Any US suppliers that will sell only 2? What I am finding is the LT1028ACN8 .
BTW, clarity is not my issue and all the specs talk about low noise which is also not my issue. Peakiness is the issue.
That board is under one of the metal covers? Where?
Thanks Again,
Robert
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I would try the LT1028acn opamp in the 5,6 positions with reference to the pic below. In my system, I have found these to possess the most clarity.
Thanks for that. I will try them. Any US suppliers that will sell only 2? What I am finding is the LT1028ACN8 .
BTW, clarity is not my issue and all the specs talk about low noise which is also not my issue. Peakiness is the issue.
That board is under one of the metal covers? Where?
Thanks Again,
Robert
The board is under the large rectangular cover near the input rca jacks. 4 screws. the op amps are in sockets so replacing them is a breeze. Digikey is a good source. Sorry I cant address your peakiness issue directly, not hearing what your hearing.
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The board is under the large rectangular cover near the input rca jacks. 4 screws. the op amps are in sockets so replacing them is a breeze. Digikey is a good source. Sorry I cant address your peakiness issue directly, not hearing what your hearing.
Sounds good. I am old enough to have put RAM chips in computers.
Digikey is impressive. Even used the chat and someone got to me in probably less than a minute. Ordered the 2 1028's.
Thanks for all the help, I really appreciate it.
Robert
PS: Is bigdirty related to John Bigboote? Pronounced big boo tae, despite Lazardo calling him bigbooty.
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PS: Is bigdirty related to John Bigboote? Pronounced big boo tae, despite Lazardo calling him bigbooty.
I googled this... thank you. :thumb: To the video store!
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I googled this... thank you. :thumb: To the video store!
don't forget: wherever you go, there you are! 8)
doug s.
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I googled this... thank you. :thumb: To the video store!
You are most welcome.
don't forget: wherever you go, there you are! 8)
doug s.
Indeed! Goldbloom in chaps! LOL
On to the Topic. My 1028's have left St Paul, MN. Maybe I will have them Thurs. or Friday. If needed, should I do other op amps or caps next?
Thanks,
Robert
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Hello Folks,
I put the 1028's in the 5 & 6 positions and much to my surprise it has not caught fire. Took out what appears to be OP376's. Hard to read but I believe that is what they say.
Gonna let it run for a while before I pass judgement, but it may be high end transistor gear clean with warmth. Like what the 5751's do for it only more so. Need more hours and listening though.
Thanks Again,
Robert
PS: Since nobody else seems to be complaining about a midrange peak, could mine be defective? I have not called Jolida yet.
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Mine has a bit of "Bloom" that on some records is awesome and a bit much if they were a bit forward to start with. Mine is in the upper midrange/lower treble area. Tubes helped and I'm going to change caps.
Hibuck....
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Mine has a bit of "Bloom" that on some records is awesome and a bit much if they were a bit forward to start with. Mine is in the upper midrange/lower treble area. Tubes helped and I'm going to change caps.
Hibuck....
Thanks for that, thought maybe I was the only one hearing it.
Letting the new IC's burn in some more but the peak appears to be still with me. Please let us know if the caps help.
Y'all be cool,
Robert
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So the op amps made it better but the upper mids are still peaked. Lower treble seems to be better. Went back to the GCPH which is more detailed with more upper highs and balanced response.
Anybody got a good idea for the next thing to try on the JD9?
Thanks,
Robert
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Omg, I have been following this tread since years. Great development. So the Jolidah is using single or dual OPa?? I saw 4 of them. wath that means?
thanks
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Even though the 1028 has been around for awhile, its quality is unmatched, except by the military version. I don't have a JD-9A, but perhaps one IC in each channel is for regulation?
I suspect the upper mid forwardness is from improper tube bias or lack of tube regulation. This seems to be a common design mistake. I don't know any of this as a fact. Perhaps it's an area that might yield some improvement if you pursue it further. If those are 12A_ series tubes, perhaps they're set for too much gain.
neo
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I've been thinking about this preamp. Maybe finding the right tube will solve that forwardness. I notice dramatic differences. You guys must have discussed this before. Is anyone using Genelex Gold Lion? They are said to be great in preamps, specifically Superphon. They cost about $45 each. But I would seriously consider RAM tubes, maybe some Telefunken. I think your best bet is to contact them and get a recommendation.
http://www.tubeaudiostore.com/tubes.html
neo
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Guys, is there any consensus on which op amps to use in which place for the best results?
I ordered the JD9 from my friends at the Needle Dr and it will arrive at the store this week (I work just a couple of miles from there)
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I put in 6 burr brown OP638BP in mine and the difference was very noticeable.
Steve
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Steve,
Are you sure that is the correct model number as Google turned up no English results?
Thanks, Nut
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hehehehe. Thats what I get when responding to a post before my morning coffee. OPA638BP. Sorry about that, I forgot the 'A'.
Steve (now awake)
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Bummer, it appears to be discontinued as there were no english results for that one either.
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Crap, my bad again, try this Burr Brown OPA 637BP. Sorry, I have been running my ass off on half a dozen projects and I feel that my brain is running on just a few cylinders. You will find references to this chip on the first page of this thread. It is a well known op amp in the audio world. Although it is a little expensive, if you look around, you can find the for less money.
Once again, my bad.
Steve
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Now this one returned lots of hits! Thanks.
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If you do decide to swap out the Opamps, do your self a favor and spend a few bucks and buy an IC puller. It is basically a little set of tweezers with a small horizontal tongue. The IC section in the Jolida is a little tight as there are disc caps (if I remember correctly) on either side of the IC's so it is a little tight. The IC puller would cost less than $10 but makes the job easier. Also, pay attention to the orientation of the chips. These chips have either a white dot or a detent molded into the plastic that will indicate which end pin 1 is. Also, if you are feeling a little nervous regarding the job, drop into Radio shack and buy the cheapest 8 pin chip and practice putting it in the socket to get the feel. It is a very easy job. Unplug the preamp from the mains and let it sit for an hour or two to allow any caps to discharge just to be safe.
The big difference that I heard with the 637BP was the leading edge or transients were more defined. Bells, cymbals, percussion etc all sound more defines. Overall, better tonality and more precise high frequencies. Bass improved also but overall, everything was not precise. Once you are finished with this, changing the output caps would be the next mod. It has been noted throughout this thread and they play a huge part of the sound.
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Steve,
What is the output of the cart you are using? Doroner said he got noise with the high output Op Amps with a low output cart (.3) The Denon I am going to use is even less at .25
Thanks, Nut
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I am using a Blue Point Special EVO III which is a very high output (Output Voltage/Channel 2.5mV).I tried out the Van Den Hul MC10 Special from the other table as it is sitting beside it to see if I hear and noise. The MC10 Special is Output Voltage at 1 kHz at 5.7 cm/s eff.:0.65 mV RMS so that is quite a difference between the two. The VDH is a little higher then yours.I had no noise coming out with the VDH cart. Beyond that, I have no suggestions for you. At 0.65mV, all sounded great
Steve
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I went back through the thread and found the post that Doroner made
"The Op-amps recommendations did not work for us - for what ever reason the top of the line AD843KN increased the noise floor in our units (it started hissing on stand-by) without really improving the dynamics. The Burr Brown OPA637BP did not work for me at all - it produced a very high pitched squeel (like a TV would do sometimes) and I yanked it out before there will be damage. Could be a faulty batch of OPA637BP. "
Something sounds a little miss there. AD843KN made a hiss on standby and the OPA637BP squeeled. I would consider asking Doroner if he made other mods before trying to chips. Something just does not sound right.
Steve
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Regarding the OPA637BP squeal, ask him if he felt as if it was 'self-oscillating". I am just curious at this time.
Damn I love this thread
Steve
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I think it did oscillate and that caused the squealing.
Between you and me Discrete components sound much better (more relaxed and less pinched) so those who went there must be noticing bigger improvement than replacing one op-amp with another. I am using the stock op-amps for now.
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Guys, I have started a thread on the Vinyl Engine about the JD-9 mods: please feel free to take a look:
http://www.vinylengine.com/phpBB2/viewtopic.php?t=39598
I am using the OPA627 in the middle and am having good luck. I will post pix and details this weekend.
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I can't read resistor values, can anyone tell me what these two resistors are? They are both in the third position in thier respective groups:
http://www.audiocircle.com/index.php?action=gallery;area=browse;album=5862
I couldn't get these photos to load to the post so I just included the URL
Thirdeye- I will let everyone on the Engine know about your excellent updates
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By the way I will answer a few issues above as well for posters... And see below for 2011 upgrade updates to this unit.
-One is about the Op amp 843kn, DON'T use it...
The burr brown op637 works fine, not sure why somebody would have a problem with the op637bp version, I think they said they put Op 638bp or something stated in a response above, which I don't know if it even exists? If it does and it squeals its obvious its not an opamp to work in this unit.
_______________________________________ _______________________________________ _____
- FORWARD Midrange....
I believe of course the main output caps can help this, I am using Duelund, Clarity MR's are great too which I originally used.
However, Tubes can somewhat as well change the mid's but not to an extent that might correct it.
Maybe the most effective is getting those SUPER generic Power supply caps out of the unit all together!
The main ones on the board by the transformer for sure, this should help tame the mid glare, as these caps are so generic I don't think they cost 15 cents and they are sizable values.
Go Nichicon at least, and make sure you buy the correct "Metric" sizes and leg spacing to fit them properly.
Also all Nichicon replacements on the input board will help, which there are like 26 caps on it as seen in photos, for sure will make the sound "Richer" and right in the mid's.
If you need better HI's and extension then the AD797 opamp will help over the Burr browns and sound is similar to the AD843kn which is the wrongtype, but the 797 are DEAD silent, and excellent balanced sound. And luckily they are cheaper, but still an expensive op amp if you can even find them, they run about 8 or 9 bucks each.
ZERO OSCILLATION from the AD797 and Burr Brown 637's in my experience.
Good Luck
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PAGE 10
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Wire Nut,
The resistors your looking at are for the Gain in the circuit and in your Jolida book layout those are the gain dip switches for MC-LOW, MC-High, MM. In the photo I think your pointing at MC low. Which means its the smallest value resistor in the bunch. I am not sure look and see which switch its hooked to from the other side.
Anyway MC-Low - switch #3 = 33 ohm
MC-High - switch # 2 = 100 ohm
MM - Switch #1 = 1k ohm(1000 ohm)
Again I think your pointing at switch #3 so just check,
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I am using the lowest output cart I know of - the Denon 103r. So I am using the low output in the three DIP series and 100 ohms in the first set of DIPS
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Actually I am getting too much gain so if I know the value I can go to the next highest one to get it normalized with the rest of the gear- the Jolida has lots to give!!!
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YOU HAVE too much gain?
When it says LOW MC that means its going to give MORE power to make up for the Low output cart you have which somebody at Jolida was Deaf when they designed this unit! Which is why everybody thinks this thing has too much gain, and why your tricked into thinking LOW MC on this unit is useable even with such a tiny signal it has too much power.
If you put it on HIGH MC that means you will get less power.
So you need to turn off switch #3 or Low MC because it is a 33 ohm which is too much power due to too low resistance, and turn on Switch #2 which is 100 ohm and try it, this will cut a substantial amount of gain.
They are all the same by design, MM, MC high or low means nothing, that's just generic Consumer talk, they all use the same circuit and resistors, it just depends how much resistance is needed to cut the gain correctly, every switch and design is identical just with different value resistor attached, all cartridges need the same exact phono amp, just different load and gain resistors ultimately.
12ax7 tubes= 100 % gain in this unit, a 12au7 is ONLY 30% the gain of a 12ax7, so it works with very powerful cartridges perfectly like the MM's and some MC's.
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Hay Buddy; the middle output level is the cat's meow for my stereo!
Great advise!!!!!!!!!!!!
Can you tell me what that value is? I would like to replace with Caddok MK's.
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Dude, I am fearless... look at my TT project. An AR upgrade expert thinks I have one of the best XA upgrades around-bring it on!
http://www.vinylengine.com/phpBB2/viewtopic.php?t=34945&postdays=0&postorder=asc&start=0
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Absolutely right on the skill issue. Can you draw me a picture (art major) so I can get it?
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Okay I will try to clearly explain, no photo needed 8)
So first thing is first, turn off and LEAVE off ALL DIP SWITCHES, they will no longer be of USE.
Now when you open the input stage you see the 2 RCA Jacks on the input correct? Right, so you see the ground wire, and the center pin of the RCA, all you do is put your new 100 ohm resistor one leg on the ground and one on the center pin for each channel. Simple, now your loaded direct! And all your switches stay off, because you are in direct contact, if you turned on a switch for example your 100 ohm on the board again, it simply would be 2 parallel resistors, making it 50 ohms. Obviously you do not need this... NO danger in accidentally putting the switches on, it just would not be right.
Okay for the GAIN resistors, the new found miracle you have experienced when turning on the 100 ohm resistor VS. the 33 ohm you were using.
This is just as simple, but harder to do. Look at the board where the 33 ohm resistor is and right next to it all the way on the right of the board if standing behind the unit you see the wires connecting that little board down to the main input board correct?
There are 4 wires, 1 pair is for the right channel, and 1 pair is for the left channel. They look like a ground and hot wire, just like everywhere else right? Well they are not, they are the same HOT pin no ground its simply a loop going IN and OUT on the main input board, this is just simply inserting your resistor in series for the gain circuit to reduce power, if you put no resistor which is when the DIP switches are off, the unit does not operate as there is no connection.
But now if you just BRidge that hot pin to hot pin for each channel the unit will be constantly connected and no need to turn on dip switches because your already in the circuit.
Also, NO danger in accidentally turning a DIP ON, because it will simply just parallel in another resistor on top of your permanent 100 ohm across those terminals DROPPING resistance which would make it much louder again as if you were in the 33 ohm setting. So this is why now if you do these direct solder connections the entire unit will operate with none of the switches on or in the signal path or the load.
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I have sent an email to Chris at Parts Connexion about the resistors and will pony up to get them. I am getting a little harshness now that I switched to the middle output & suspect it is from the cr@p resistors that came with the JD9.
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I forgot to mention that I have a Rogue Cronus Magnum that uses 12au7's and I have a bunch of tasty NOS tubes to roll in to try - including Brimar 4003's & many others- this will be fun!
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Tube rolling 12AU7's that might be to low of gain with the MC no matter what you do not sure. Maybe putting it back to the 33 ohm resistor with a pair of AU7's is possible, you would want to try that before doing anything else at this point or ordering parts if you plan to roll some 12AU7's you have on hand.
As a SIDE note, I highly suggest you might want to run to a radio shack and buy a bunch of the cheap resistors first of various sizes if you feel the 100 ohm is still too much gain or cuts too much gain. You need to be honest with yourself if you are right where you want to be with the volume control on your preamp and its in the sweet spot.
You can buy 120 ohm, 150 ohm, even 200 ohm or something if you think there is still a little more room to clean up volume and still want to have even better control of the gain. That's up to you, so if the 100 is perfect go for it, but the cost of Caddoks at 5 bucks a pop, or Vishays at 15 will burn you if you decide it was not the perfect size!
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Undertow,
Would you be willing to share a little more information about modifying the power supply area? Do I just read the values of the stock caps on the power supply board and buy higher grade versions of the same? Bypass caps I can understand easily enough.. The other thing I'm not sure exactly which version to get is the diodes? I notice several different ones on parts connexion, I want to make sure I order the correct ones.
Also for the output cable, am I looking at using interconnect cable specifically? Thanks a lot for your help.
Following recommendations on this thread an several other related ones I've modded my JD-9 with all new opamps (627/637BP, LT1028 input), ClarityCap MRs 1.0 uF, RCA Command blackplates 5751. Going to do some input board work once I get my Ortofon Jubilee back form re-tipping. This phono amp does wonders with both LP-12s my roommate and I have, I'm running it into a very modded Jolida 302b and I'm loving the combo.
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HI,
I just reading about modification of the JD9 here for the first time.I have one also and BB op-amp chips should be 637AP not the BP that way it doesn't sound right.
I'm using the 637AP for output and 627AP Input and Riaa.Tube are Tung-Sol and I used jantzen audio Superior Z-cap 800VDC 1.0uf +/-2% for output cap,The cartridge I'm using is Denon DL304 LOMC and sounds great!
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I'm really starting to like this little gem. This morning I swapped in these http://thetubestore.com/sba-jolida-jd-9.html from some Tung Sols (which ain't bad at all, just rolling....) and moved the 627's over to the from the input to the center and put some 637AP's in the input and left the 1128's in the output spot. I've think I've found the combo for my setup :dance:
(http://www.audiocircle.com/image.php?id=53213)
I put the Obligatto caps in a few days ago as well as some sound deadening material.
(http://www.audiocircle.com/image.php?id=53215)
I removed the blue caps with my solder suck thingie...
I think I'm gonna leave it be for a while and work out some other areas in my system that needs addressing (my Adcom GFA-750 is humming like a bird!!! :|).
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Danska,
As for the power supply, yes just pull the electrolytic caps and replace with equal voltage or higher and values that are in the unit. However, as a warning this could get tricky as many of the caps are lets say 16 mm diameter, or 20 mm diameter etc… depending on the size and value. Some of the higher end Nichicon caps, Elna caps, BLACK gate especially are much larger diameter sizes over the generic capacitors in the unit, so matching exact size might prove difficult especially if you go to the higher cost audio grade types from Parts connexion.
I would say this, anything brand name is better than the 13 cent generic caps that are in the unit stock. Easiest to find that should fit most positions are probably the lower grade I think (VX)? series Nichicon electrolytic caps. I did use a couple Black gates as well, but these don't fit anywhere near the board, they are far to large, and would hit the top if you close it as well, also these have a much larger PIN separation and they had to be modified to fit this unit, I don't necessarily suggest going this route.
The DIODES in the unit are basic ZEENER diodes, I believe they are all 1 amp versions, these can be tricky to fit as well and you need to mind the installation of these and put them in correctly if you flip polartity of the cathode on these they will burn. Basically you can use Cree/Schotkey or whatever fast recovery soft diodes in a 1 amp version.
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What is the difference between OPA637AP and OPA637BP ??
Undertow. You recommended the AD797 op amp, there appear to be numerous variations, can you clarify what the suffix is? (EG: AR, AN, AU, ANZ, BR...)
Thanks.
BP
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can't remember where I read it but the author said that AP's should be used instead of BP in audio operations. I'll try to find it...
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newsflash, for some odd reason the Tung Sol tubes do not like my AT15Sa at all! Sounds like a $10 fisher price toy. The JAN/Philips mix well with it though. The Tung Sol sounds sweet with my Shure M91ed and the V-15iii though.
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newsflash, for some odd reason the Tung Sol tubes do not like my AT15Sa at all! Sounds like a $10 fisher price toy. The JAN/Philips mix well with it though. The Tung Sol sounds sweet with my Shure M91ed and the V-15iii though.
newsflash, for some odd reason the Tung Sol tubes do not like my AT15Sa at all! Sounds like a $10 fisher price toy. The JAN/Philips mix well with it though. The Tung Sol sounds sweet with my Shure M91ed and the V-15iii though.
How are these guys sounding ?
http://thetubestore.com/sba-jolida-jd-9.html
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How are these guys sounding ?
http://thetubestore.com/sba-jolida-jd-9.html
good, don't seem to take or add anything, they're just there. Not sharp or bright and a little less bass than the Tung Sol's but good overall. Much better than the ones that came with it from Da House...
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video of the Jolida Shenda factory...
http://www.youtube.com/watch?v=GiLKzUURIgU
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Been running my JD9 for about 3 years now (see my entry in this thread on page 1). I've been using an Analysis Plus Oval 14 pc for that entire time I guess. I floated the ground on the pc right away but I did it on the wall side (wrongjavascript:void(0);) and didn't change to floating the amp side until a few months ago - nice change.
Last week I got some Pangea signature 14's and wanted to try one on the JD9, but the connectors on these cords are molded on so floating the ground isn't possible. I tried it anyway and it sounded good but not as good as the floated pc. So I looked inside the box for a solution. The grounding on the JD9 is a single point (a star ground I think) - a screw in the bottom of the chassis that many wires hook to. I disconnected the power ground from that screw and wrapped a bit of electrical tape around the connector at the end of the wire so that it wouldn't reform the ground by shifting position. Including taking the cover off and putting it back on this took all of 10 minutes. I hope this is clear.
Now I put the Pangea cord in place and warmed up the JD9. Excellent, a nice match of power cord to amplifier. These cords are inexpensive and very well made. I recommend trying one, especially after floating the ground inside the amp. I figure a lot of people who read this are skeptical that a pc can make a difference - here is a good opportunity to find out for yourself.
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You do realize that's a safety ground right?
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That is SHOCKING!! Well yes, I do. But this is a high risk hobby, right? Seriously, the phono-amp is grounded through the ic's to the pre-amp (which is grounded to the wall outlet) it is also fused.
I run everything (cd, turntable, tuner, phono-amp, and power amps) except the pre-amp with the grounds floated and have done so for decades. It has never been a problem and the sound is far more dynamic and involving this way. Who wants to live forever with dull music. What do you have to lose?
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That is SHOCKING!! Well yes, I do. But this is a high risk hobby, right? Seriously, the phono-amp is grounded through the ic's to the pre-amp (which is grounded to the wall outlet) it is also fused.
I run everything (cd, turntable, tuner, phono-amp, and power amps) except the pre-amp with the grounds floated and have done so for decades. It has never been a problem and the sound is far more dynamic and involving this way. Who wants to live forever with dull music. What do you have to lose?
And it's fine to disagree. With +230vdc B+ in there along with line voltage there is a lot to lose. I buy and sell a lot of gear so if I "forgot" to reconnect it and someone gets hurt then it's on me. In my case I just can't live with that.
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I understand your concern, and agree that it is fine to disagree. But, I would suggest that you can easily float the ground on a spare pc and try it on your JD9. I think that you would be surprised (if not shocked). Good listening to you.
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Hi Undertow....thanks for the new update.....I would suggest that one do one more mod (at least) and that is what I did.....I removed the transformer form the case and put it in a plastic hobby box I got from Frys. This made the biggest change to the sound ( I have done all the mods you suggested and more a few years ago). This is due mostly to the magnetic field that the tranformer produces as well as the mechanical vibration. I used a Oscope probe with the x1 probe and no ground. You can move the probe.around the transformer and wires and see the massive amount of stray AC interference that it produces. Once removed and put in the case I made a umbilical cable that connects the two together (6 feet long). The on/off switch and IEC connector are in the remote box as well. I also removed the LED and wires. The cable that goes.into the phono is shielded and where the wires are outside the shielding I use copper foil tape wrap and made sure to ground the foil to the shield.
If you dont have an Oscope to to try it yourself try getting a stethoscope and place it on the chassis. You will hear the vibration everywhere on the chassis.
Regards
Alx_d
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Undertow...by the way I see the schematic in your post. Any chance of getting a copy? I am sure it would help us all out.
Alx_d
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Undertow. I got your PM for the schematic and sent you a response but never got an answer. Maybe I got sent to your spam folder. Any cahnce you can send it?
Regards
Alx_d
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I have found what I believe the superior output capacitor combo for the money in this unit.
- Output Capacitors better than paying for the DUELUNDS I had in here, and smaller combo than the Clarity MR's which worked are a combination of 1.8 uF Clarity ESA, bypassed by a Mundorf Silver/oil .22 uF. I can suggest these values as you will get a bigger soundstage and deeper bass it seems using this 2.0 uF plus total value over the original 1.0 uF used by Jolida. The nice thing about the cap combo here is its under 100 bucks.
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2012 update.
_______________________________________ _______________________________________ ___
Input Stage-
All capacitors replaced, using Nichicon Audio grade electrolytics, Wima film, and Evox Film caps, as well as taking out the generic ceramic caps replacing with Silver mica's.
-Caddok resistors for Cartridge load resistors, and for Gain resistors replacing the generic input dip switch selection board. For MM carts. of 4.0 mV and above HIGHLY suggest bringing down the input resistor which is a 1000 ohm to maybe a 2000 or even 4000 ohm resistor. Its fine for some MC- carts even to use the 1000 ohm in there, but some of these higher ortofon carts. put out and seem to maybe even overload the input stage on some high output recorded albums.
-Op Amps
As for oscillation issues there are none with AD797 from analog devices which are used in the top grade MBL equipment. Or from Burr Brown op637 even the op627 types seem fine. The 847KN DO NOT WORK.
_______________________________________ _______________________________________ ___
-Output Stage
After re-testing Duelund caps, and Clarity MR... The Clarity MR for the price in the 1 uF size is unbeatable. Now I like the ESA claritys bypassed by Mundorf Silver Oil as well saving space about the same price as the Clarity MR's.
I Removed the output board connected to the RCA's with the little generic Potentiometers on it and run straight cables to the outputs due to using the 12AU7's they are only 30% of the gain and I don't need the LOW output RCA's.
_______________________________________ _____________
- Power Supply
All caps replaced - Nichicon, and Black gates, all bypassed by Solen 1 uF film caps.
Schotky hi speed rectifiers replaced all Diodes 1 amp versions.
Ceramic main fuse at the IEC vs. Glass.
_______________________________________ _____________
- MM carts
I found for really High output MM that I needed 12AU7 tubes to drop the gain, 12AX7's were pretty inflexible for volume control.
-MC Carts.
You can use 12AX7's for MC carts. maybe some will be fine with 12AU7's if its enough gain.
_______________________________________ _______________
I used the 33 gauge Cardas Tonearm wire for inputs, and outputs on the INPUT board to the tube stage.
_______________________________________ _______________________________________ ____
(http://www.audiocircle.com/image.php?id=50780)
(http://www.audiocircle.com/image.php?id=50781)
(http://www.audiocircle.com/image.php?id=50782)
(http://www.audiocircle.com/image.php?id=50783)
(http://www.audiocircle.com/image.php?id=50784)
(http://www.audiocircle.com/image.php?id=50785)
(http://www.audiocircle.com/image.php?id=50786)
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Undertow,
Thanks for the update. This thread has been a great help and inspiration.
Looking at the partial schematic, R6 looks like a good spot for a higher quality resistor. your thoughts on this?
Underwood hifi, on their level 3 mod, upgrade the Single-Phase Bridge Rectifier (vishay DF04) on the phono board. I think this is where they use Telefunken SF4007 ultra-fast soft-recovery diodes. any plans on doing the same for your unit?
thanks again, your JD9 is always fun to see.
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For the LT1028 I see CN8, CS8 and ACN. Which is the proper op amp?
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For the LT1028 I see CN8, CS8 and ACN. Which is the proper op amp?
I used "LT1028ACN8" in the sockets closest to the input in my unit.
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Hi Undertow and others. I'm loving my modded JD9! I'm using it with a Shelter 501. At first I was not a fan. Then I bought a Bob's Devices step up. That changed everything. Plugged into the JD9, it is great.
Now I'm thinking of trying out some 12au7s since the step up adds so much gain. I have Brimar CV4004s in it now, which sounded the best of the odds and ends of 12ax7s I had lying around.
Any tips on best 12au7s to try? My preference would be to roll a few new production tubes before venturing into NOS, unless there are some NOS out there that must be tried.
Also, if I drop the gain with 12au7, am I then better off using the High Output? Which gain settings have the best technical performance?
Thanks!
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Undertow:
Which of the AD797 should be purchased?
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Undertow:
Which of the AD797 should be purchased?
Never mind. The AD797 is too noisy in the input slots. The sound seems rather thin when 4 are used with 2 OPA637. The best sound to me at least is using 6 OPA637, with mundorf 1.5 silver oil. The sound is more fluid and the bass is much more pronounce.
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Back to an old topic. I'm now thinking of trying out these new Burson modules to replace the op amps.
http://www.partsconnexion.com/opamp_burson.html
Chris is also selling extension cords, so they should fit - may on their sides.
Any thoughts as to whether this would be a good or bad idea?
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Old thread, but by way of update I now have the Linear Technologies LT1028 in the right input slots, Burson V5i in the middle slots, and Burson V5 in the output.
Wow!
The real kicker was the V5 in the outputs. I needed the extensions, and some patience to get them to fit (on their sides). But wow did that pay off.
Highly recommended set up.
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Sorry to bring back such an old thread. It has been the inspiration to modify my JD9 II.
In the Underwood modifications they are listing Riken Ohm resistors in the signal path, are these just the loading and gain resistors on the switch board? I noticed also a cheesy resitor and ceramic caps on the MC Low out put RCA's thinking this could also be a spot.
Any help would be wondrous.
-James
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Yes, I know. This a an old, but mighty thread. My question would be about RFI as in radio station interference. Has anyone dealt what that as an issue? Would like to get it taken care of. Also, there seems to be no tube schematic for this JD9. Go figure.
FWIW, this has been a great topic and a lot of good ideas.