Jolida JD9 phono amp hybrid Magic...

bigdirty · « **Reply #80 on:** 30 Dec 2010, 06:29 am »

Quote from: Doronor on 30 Dec 2010, 06:05 am

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

dwr · « **Reply #81 on:** 30 Dec 2010, 03:51 pm »

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

Doronor · « **Reply #82 on:** 31 Dec 2010, 06:15 am »

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:

2. 4.7 mfd caps on op-amps board:

3. 47R Vishay Z-Film resistors instead of the el-cheapo stock ones (the shiny golden coloured plate)

4. Another angle of the Vishay Z-Film Resistors:

dwr · « **Reply #83 on:** 31 Dec 2010, 07:40 pm »

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

Doronor · « **Reply #84 on:** 1 Jan 2011, 09:35 am »

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

dwr · « **Reply #85 on:** 1 Jan 2011, 06:23 pm »

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

bluepearl · « **Reply #86 on:** 3 Jan 2011, 07:23 pm »

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

Doronor · « **Reply #87 on:** 7 Jan 2011, 12:22 am »

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

Doronor · « **Reply #88 on:** 8 Jan 2011, 06:39 am »

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
and starting at the bottom of the page: 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:

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).

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

bigdirty · « **Reply #89 on:** 20 Jan 2011, 02:05 pm »

Quote from: face on 25 Jun 2010, 07:11 pm

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.

flathead · « **Reply #90 on:** 31 Jan 2011, 08:50 pm »

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!

Doronor · « **Reply #91 on:** 1 Feb 2011, 03:25 am »

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

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

flathead · « **Reply #92 on:** 1 Feb 2011, 07:05 am »

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.

Doronor · « **Reply #93 on:** 2 Feb 2011, 07:06 am »

This is great!
I will be thrilled to hear about your results.

Hocdm · « **Reply #94 on:** 7 Feb 2011, 02:58 am »

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?

flathead · « **Reply #95 on:** 12 Feb 2011, 11:11 pm »

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.

Doronor · « **Reply #96 on:** 13 Feb 2011, 05:53 am »

I am so happy for you, Flathead!

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!

bigdirty · « **Reply #97 on:** 13 Feb 2011, 11:23 pm »

just to get this thread back on track. some pics of my modified JD9. This thread was the inspiration.

Thanks to everyone who contributed to this thread. Sounds great too.

big

Doronor · « **Reply #98 on:** 14 Feb 2011, 01:08 am »

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

bigdirty · « **Reply #99 on:** 14 Feb 2011, 01:37 am »

Quote from: Doronor on 14 Feb 2011, 01:08 am

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

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