Guys,
I just completed a couple more mods to my Jolida. I put .22 Sprague caps on the power caps as a bypass & I put in a pair of Caddock resistors. WOW! A big increase in clarity from the resistors and an increase in bass from the caps.
Then I remembered that someone on another forum said that the 12au7's had less output, so I put in a NOS set of Seimen's - the gain went down to closer to what the other components are.
The resistors are a PIA to install so I only put in one set. Maybe I will feel up to putting in the other set next week... but so far - so good! I will post again when I do the other set.
I just completed a couple more mods to my Jolida. I put .22 Sprague caps on the power caps as a bypass & I put in a pair of Caddock resistors. WOW! A big increase in clarity from the resistors and an increase in bass from the caps.
Then I remembered that someone on another forum said that the 12au7's had less output, so I put in a NOS set of Seimen's - the gain went down to closer to what the other components are.
The resistors are a PIA to install so I only put in one set. Maybe I will feel up to putting in the other set next week... but so far - so good! I will post again when I do the other set.
Wire Nut,
Any reason you used .22uf caps for bypassing the power supply caps? Did you just put two of them in? Also what voltage are those? I'm looking to mod my PSU section next and I've notice others have used 1uf caps.
I'm also looking for what type of diodes to buy to replace the ones onboard as well as that seems to be a pretty common modification. Also which resistors did you replace? Thanks for the help!
Any reason you used .22uf caps for bypassing the power supply caps? Did you just put two of them in? Also what voltage are those? I'm looking to mod my PSU section next and I've notice others have used 1uf caps.
I'm also looking for what type of diodes to buy to replace the ones onboard as well as that seems to be a pretty common modification. Also which resistors did you replace? Thanks for the help!
For anybody that is looking to upgrade their JD9, I made a step by step guide to upgrading the caps, opamps, tubes, and installing dampening material. I hope this guide helps those that are looking to upgrade.
Comments and suggestions welcome!
Step by Step guide
Comments and suggestions welcome!
Step by Step guide
I have mine modded with CC MR coupling caps, Amtrans AMCH loading caps(not for a novice), and gold lion tubes. Bypassed, or upgraded PS caps and Vampire copper RCA jacks are up next.
IMO, it's a fantastic phono pre. Very versatile due to the adjustable loading switches and high available gain. It also sounds very good, clean and very dynamic. My only complaints are the blinding LED(which will be fixed soon, too) and lack of rumble filter.
IMO, it's a fantastic phono pre. Very versatile due to the adjustable loading switches and high available gain. It also sounds very good, clean and very dynamic. My only complaints are the blinding LED(which will be fixed soon, too) and lack of rumble filter.
The mods really do take the JD9 to the next level. I was hoping to get "moderate" improvement from the unit but was pleasantly surprised by how dramatic it truly became after I did those 4 upgrades.
The biggest difference was a HUGE increase in clarity. Luckily, it did not make the sound "too bright" but rather maintained the musicality while clearing up the soundstage. The original sound compared to the upgrade can be described as "muddy."
The JD9 really does benefit tremendously by the upgrades and I think it take it into the range of phono preamps that cost $1,000's of dollars.
I did quite a few mods to mine, ditto to above, the clarity is really top notch, it is actually "warmer" meaning more tube sound, the imaging and soundstage are better as well. Here is what it looks like now.
Turntable Forum • View image - V-Caps
Turntable Forum • View image - V-Caps
From what I can see(need new glasses), it appears there's already a 12K resistor in series with the LED.
I intend to mod my JD9 which I bought from a seller at Audiogon. Before I carryout this mod, I need to change the operating voltage from 120V 60 HZ to 220V 50HZ. Can anyone advise me how I should get about on doing the power conversion. I have tried to get the information Jolida USA, unfortunately they have not responded to my request.
I think all you have to do is switch the voltage switch inside the unit. You can see it on the picture here at this link (and in the mod download instruction guide which is also available there):
Jolida JD9 phono preamp Upgrade Guide
In the interests of full disclosure, and hindsight is a wonderful thing, but I think the cap mod was worthwhile but I'm not convinced about switching the op amps or any other mods really.
I'm not 100% I'd put money on a preference in a blind test with op amps anyway and as noted above, half of the changes I made were as a result of someone getting excited on another thread and I the benefits had their pitfalls.
This is an interesting op amp video, make of it what you will.
http://www.youtube.com/watch?v=bpTv2jAree8
The dampening is your call of course but a step too far for me although I hope it pays off (and that someone actually answers your question).
I recently put this against an all tube EAR and it held it's own. I'm a sucker for tubes though (but the prices aren't realistic for me).
Best
I'm not 100% I'd put money on a preference in a blind test with op amps anyway and as noted above, half of the changes I made were as a result of someone getting excited on another thread and I the benefits had their pitfalls.
This is an interesting op amp video, make of it what you will.
http://www.youtube.com/watch?v=bpTv2jAree8
The dampening is your call of course but a step too far for me although I hope it pays off (and that someone actually answers your question).
I recently put this against an all tube EAR and it held it's own. I'm a sucker for tubes though (but the prices aren't realistic for me).
Best
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Hi Invention/Nathanjh13,
Thanks for your advise, as you have suggested, I can do the voltage conversion easily. However, as the instruction manual indicated, I need to change the fuse to 3.5 A, VAC fast blow fuse.
Regarding the upgrade, my seller has sent me the following components:
The details of the parts are as follows:
1. OPA 627 AU- 5no
2. Resistor- 12R- 1No
3. Resistors Riken- 10R gold plated- 8No
4. Resistor Riken- 12 gold plated - 1No
5. Auricap 1.0+/-10%400V- EGA7956-37- 2No
6. Mudorf M E-cap- 220uf 63 VDc- 10No
7. Blackgate Rubycon- 10uF 250V- 5No
8. Tung-Sol- 12Ax7- Made in Russia- 2 Nos.
Kindly advise me the above parts are for which area of the circuit upgrade. It is obvious that tube rolling and capacitor bypass have been anticipated, but the Munforf caps, I believe should be for the power supply upgrades? If you can enlighten me which area I should upgrade first. In other words, what will really enhance the performance of JD9A, is it really worthwhile to full upgrade or should I stick to tube rolling and auri-cap by pass?
Another forum I noted that some have used Bybee Music trail upgrade to the DC power supply. What is your opinion on this direction?
Have a nice day and complements of the festive season.
Cheers
Thanks for your advise, as you have suggested, I can do the voltage conversion easily. However, as the instruction manual indicated, I need to change the fuse to 3.5 A, VAC fast blow fuse.
Regarding the upgrade, my seller has sent me the following components:
The details of the parts are as follows:
1. OPA 627 AU- 5no
2. Resistor- 12R- 1No
3. Resistors Riken- 10R gold plated- 8No
4. Resistor Riken- 12 gold plated - 1No
5. Auricap 1.0+/-10%400V- EGA7956-37- 2No
6. Mudorf M E-cap- 220uf 63 VDc- 10No
7. Blackgate Rubycon- 10uF 250V- 5No
8. Tung-Sol- 12Ax7- Made in Russia- 2 Nos.
Kindly advise me the above parts are for which area of the circuit upgrade. It is obvious that tube rolling and capacitor bypass have been anticipated, but the Munforf caps, I believe should be for the power supply upgrades? If you can enlighten me which area I should upgrade first. In other words, what will really enhance the performance of JD9A, is it really worthwhile to full upgrade or should I stick to tube rolling and auri-cap by pass?
Another forum I noted that some have used Bybee Music trail upgrade to the DC power supply. What is your opinion on this direction?
Have a nice day and complements of the festive season.
Cheers
Ah right sorry, the only modifications that I have made are in the first few posts of this thread.
I find tube rolling something of a can of worms and not always the case that more expensive tubes sound better. It's been said before but tubes are a moving target and comparison in real world terms is an itch that is, in many peoples eyes, too time-wasting to scratch.
You are geared up to modify many more items than I did so I cannot offer any sensible advice. As mentioned earlier I found the cap changes worthwhile but I'm not sure about the op amp ones.
Listen very carefully I would say.
All the best with it, take good care.
I find tube rolling something of a can of worms and not always the case that more expensive tubes sound better. It's been said before but tubes are a moving target and comparison in real world terms is an itch that is, in many peoples eyes, too time-wasting to scratch.
You are geared up to modify many more items than I did so I cannot offer any sensible advice. As mentioned earlier I found the cap changes worthwhile but I'm not sure about the op amp ones.
Listen very carefully I would say.
All the best with it, take good care.
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Thanks for your suggestion, I totally agree that sound depends on personal preferences. When you go through the part list which I have indicated, can you advise me where the "Riken resistors" and Mudorf Caps" should be replaced. Please do not get me wrong, these parts were sent as a bonus as the previous owner has included these with JD9A. However, the previous owner did not send me any information on the upgrade. When I Googled, I think Level 3 MOD according to:
Underwood HiFi: JD-9
If you can advise me where the parts should go, I shall appreciate you a lot. I wanted to make use of these expensive components on the JD9A, but all depends on how far I should go on the upgrade.
From the discussion I had so far, the capacitor upgrade, tube rolling and OPA substitution are the best options available to take the JD9A to a higher level.
Look for your specific advice on this.
Cheers
Underwood HiFi: JD-9
If you can advise me where the parts should go, I shall appreciate you a lot. I wanted to make use of these expensive components on the JD9A, but all depends on how far I should go on the upgrade.
From the discussion I had so far, the capacitor upgrade, tube rolling and OPA substitution are the best options available to take the JD9A to a higher level.
Look for your specific advice on this.
Cheers
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