Jolida JD9 phono amp hybrid Magic...

undertow · « **on:** 16 Dec 2008, 04:35 pm »

Go to Page 10 for all new info on this upgrade and simplified part explanation. Thanks

Lifer · « **Reply #1 on:** 22 Dec 2008, 02:55 am »

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

Bill Baker · « **Reply #2 on:** 22 Dec 2008, 01:29 pm »

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

undertow · « **Reply #3 on:** 22 Dec 2008, 09:10 pm »

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..

undertow · « **Reply #4 on:** 22 Dec 2008, 09:18 pm »

Hi Response audio,
Yes caps are cost and preference associated

Thanks

sherod · « **Reply #5 on:** 13 Apr 2009, 04:54 am »

I'm curious how many hours it took these Claritycap MR caps to fully break in to your pre outputs.

Lifer · « **Reply #6 on:** 15 Apr 2009, 07:55 pm »

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.

face · « **Reply #7 on:** 16 Apr 2009, 07:36 am »

Quote from: sherod on 13 Apr 2009, 04:54 am

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.

bluepearl · « **Reply #8 on:** 15 Jul 2009, 01:45 am »

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

DoubleHelix · « **Reply #9 on:** 15 Jul 2009, 06:52 pm »

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.

alx_d · « **Reply #10 on:** 16 Apr 2010, 12:51 am »

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

Dr. Ear · « **Reply #11 on:** 23 Apr 2010, 09:57 am »

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.

alx_d · « **Reply #12 on:** 23 Apr 2010, 02:34 pm »

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

face · « **Reply #13 on:** 23 Apr 2010, 02:53 pm »

Quote from: Dr. Ear on 23 Apr 2010, 09:57 am

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.

royphil345 · « **Reply #14 on:** 23 Apr 2010, 06:52 pm »

Quote from: Dr. Ear on 23 Apr 2010, 09:57 am

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.

Dr. Ear · « **Reply #15 on:** 23 Apr 2010, 10:40 pm »

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?

Dr. Ear · « **Reply #16 on:** 23 Apr 2010, 10:43 pm »

.... 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.

royphil345 · « **Reply #17 on:** 24 Apr 2010, 01:07 am »

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

nandi · « **Reply #18 on:** 24 Apr 2010, 02:18 am »

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.

face · « **Reply #19 on:** 24 Apr 2010, 03:12 am »

It was also 1uf in my unit.