Hiya, hope all's well. I have the op amps (AD843KN) and capacitors (AMPOHM: FP-CA-1-AU) lined up for replacement in my Jolida JD9 phono stage. I've already rolled the tubes to good effect and the op amps are a doddle to change. It's the caps I'm worried about.
I've been losely following this thread:
Jolida JD-9A phono amp hybrid Magic...
Where is the left hand solder of the left hand cap connected, is it not connected above as it appears different to the pic below?
Trouble is, I can see from the pics where to solder (more or less) and I admit I'm a total newbie but with pictures like these I can get through it no problem. However, the article suggests removal of the "old capacitors", and I could do with someone double confirming which ones these are please.
There's a pic of the layout here and you can see the six op amps in the top right too.
Thanks in advance good people. Ultimately I'll then populate this page with many photo's along the way, hopefully bringing together the info from other sites (which isn't complete in any one instance, there's always the need to trawl around).
I've been losely following this thread:
Jolida JD-9A phono amp hybrid Magic...
An externally hosted image should be here but it was not working when we last tested it.
Where is the left hand solder of the left hand cap connected, is it not connected above as it appears different to the pic below?
An externally hosted image should be here but it was not working when we last tested it.
Trouble is, I can see from the pics where to solder (more or less) and I admit I'm a total newbie but with pictures like these I can get through it no problem. However, the article suggests removal of the "old capacitors", and I could do with someone double confirming which ones these are please.
There's a pic of the layout here and you can see the six op amps in the top right too.
An externally hosted image should be here but it was not working when we last tested it.
Thanks in advance good people. Ultimately I'll then populate this page with many photo's along the way, hopefully bringing together the info from other sites (which isn't complete in any one instance, there's always the need to trawl around).
Last edited:
There's a small green capacitor next to each valve (they'd be on the right of the valves as viewed in the photo above), these are doubtless the ones to remove but I thought I'd better confirm.
Incidentally, the op amp change alone has made the overall sound much cleaner and more detailed, perhaps as you'd expect with slew rates like that. It's quite a difference. However, it's brought with it a change in timbre at least in the lower frequencies as the bass seems a half step lighter in tone.
I'm hoping the caps will correct/change things further but as the op amps are part of the signal path etc I figure it's better to be as clean as possible as soon as possible then tailor the rest of the system around it (different tubes/speakers etc).
Incidentally, the op amp change alone has made the overall sound much cleaner and more detailed, perhaps as you'd expect with slew rates like that. It's quite a difference. However, it's brought with it a change in timbre at least in the lower frequencies as the bass seems a half step lighter in tone.
I'm hoping the caps will correct/change things further but as the op amps are part of the signal path etc I figure it's better to be as clean as possible as soon as possible then tailor the rest of the system around it (different tubes/speakers etc).
The caps your looking for are the output coupling caps. if you follow the wire from the output rca jacks you will find the proper caps to pull.
Very timely thread as I myself have just purchased and modded a JD9. I went with mundorf supreme 1.0uf for the output caps. I had 2 linear technologies LT1028acn which i put in the input position (the 2 right most in your pic). I added some jantzen crosscap 1.0uf bypass the electrolytics in the power supply.
I plan on adding two 1000uf 25v to the power supply, 2-4 more LT1028 to play with, and upgrading the resistors on the gain/loading board. I'll post some pics next time I open it up.
Very timely thread as I myself have just purchased and modded a JD9. I went with mundorf supreme 1.0uf for the output caps. I had 2 linear technologies LT1028acn which i put in the input position (the 2 right most in your pic). I added some jantzen crosscap 1.0uf bypass the electrolytics in the power supply.
I plan on adding two 1000uf 25v to the power supply, 2-4 more LT1028 to play with, and upgrading the resistors on the gain/loading board. I'll post some pics next time I open it up.
The cap change has made a significant improvement to the positives of enjoying the music, but it's also made a slight contribution to the negative. There's now a background "hiss".
It's not too bad but that's as technical as I can get, it's definitely a hiss and not a hum. Is it my lousy soldering or something else?
Thanks.
It's not too bad but that's as technical as I can get, it's definitely a hiss and not a hum. Is it my lousy soldering or something else?
Thanks.
in the thread over at audiocircle there is talk of not replacing all 6 opamps with AD843KN. could this be your problem? try replacing the original opamps into the output position. ( the ones on the left in your pic above.)
If your going to open it up reflow your solder joints, and make sure the opamps are seated into the sockets securely.
good luck.
True enough. I replaced the old op amps back in the outputs and the hiss reduced a lot, they're right when they say it's not ideal using the AD843KN in all six slots.
The sound was very sharp with them all in but a little thin, I did a bit more listening with the old ones back in and there's a nicer vbalance overall, noteably more bass 'authority' I guess is the word that seems to fit.
I'll have a look at other op amps now and maybe try the LT or BB's as an experiment.
I'm trawling around at the moment and looking at different datasheets but someone will have knocked up a quick comparison table somewhere I'm sure. The LT1028's you mentioned look pretty damn quiet though.
Thanks
The sound was very sharp with them all in but a little thin, I did a bit more listening with the old ones back in and there's a nicer vbalance overall, noteably more bass 'authority' I guess is the word that seems to fit.
I'll have a look at other op amps now and maybe try the LT or BB's as an experiment.
I'm trawling around at the moment and looking at different datasheets but someone will have knocked up a quick comparison table somewhere I'm sure. The LT1028's you mentioned look pretty damn quiet though.
Thanks
Jolida JD9 mods
I am searching for information about modding my JD9 phono preamp and find the this thread has a world of info, almost too much for a beginner like myself.
I was wondering if anyone out there has created a step by step and parts list for some basic mods and would be willing to post it as a starting point for me.
Regards,
I am searching for information about modding my JD9 phono preamp and find the this thread has a world of info, almost too much for a beginner like myself.
I was wondering if anyone out there has created a step by step and parts list for some basic mods and would be willing to post it as a starting point for me.
Regards,
I am just in the process of modding my JD9 and was wondering if you could add a list of all the mods you have done, a component list and detail the results you have had?
Regards,
Regards,
Is there a reason why you do not just solder the new capacitors to the same points as the original ones were removed from, albeit on the back of the PCB?
Regards,
Regards,
you sure can, if they fit. the idea with soldering to the tube output and the output wire is to remove some of the pcb in the path.
Thanks for the information.
I have now replaced all six op amps as suggested, with noticeable improvement.
I now have capacitors to change but I am more used to electrolytic capacitors which are polarity conscious, are these capacitors not?
I just wanted to confirm before doing something catastrophic.
Regards,
I have now replaced all six op amps as suggested, with noticeable improvement.
I now have capacitors to change but I am more used to electrolytic capacitors which are polarity conscious, are these capacitors not?
I just wanted to confirm before doing something catastrophic.
Regards,
Hi guys,
Based on the Audio Circle post I am about to attemp these mods, I shold be picking up my brand new black JD9 from the local Needle Dr tomorrow!!!
Jolida JD9 Upgrades
Obbligato 1.5 caps
Vishay bypass caps on above
Tubes (Ei vintage, Tele smooth plate, or Mullard long plate- one of these should be the cat's meow with the new cart)
B-Quiet with carbon/copper strands glued on top (damping)
Quiet Kote on top (damping)
Parts Express on bottom (damping)
Gold Alloy wire to replace key wires
Neotech wire to replace long run to circut board
Op-Amps
Power cable (very tasty Western Electric that is burning in at this moment)
Why all this hassle? My PS Audio does not have enough gain for the Denon 103r that I just put in a rosewood body!
Based on the Audio Circle post I am about to attemp these mods, I shold be picking up my brand new black JD9 from the local Needle Dr tomorrow!!!
Jolida JD9 Upgrades
Obbligato 1.5 caps
Vishay bypass caps on above
Tubes (Ei vintage, Tele smooth plate, or Mullard long plate- one of these should be the cat's meow with the new cart)
B-Quiet with carbon/copper strands glued on top (damping)
Quiet Kote on top (damping)
Parts Express on bottom (damping)
Gold Alloy wire to replace key wires
Neotech wire to replace long run to circut board
Op-Amps
Power cable (very tasty Western Electric that is burning in at this moment)
Why all this hassle? My PS Audio does not have enough gain for the Denon 103r that I just put in a rosewood body!
Thanks for the pictures earlier in the thread showing where to solder the caps on the bottom of the board. I joined this board because I would like to mod my Jolida as well.
Question for you guys running the ClarityCap MR's, do you need to attach them in the fashion that the guy did from the other thread? I'm not really sure what the "sticky plate" things are, and there appears to be a zip tie connecting the two. Mine are on there way, I've had a stock unit that I've just rolled some tubes in for the last few months. Looking forward to getting some upgrade, my modded 302b is pretty special!
Thanks.
Question for you guys running the ClarityCap MR's, do you need to attach them in the fashion that the guy did from the other thread? I'm not really sure what the "sticky plate" things are, and there appears to be a zip tie connecting the two. Mine are on there way, I've had a stock unit that I've just rolled some tubes in for the last few months. Looking forward to getting some upgrade, my modded 302b is pretty special!
Thanks.
my question is what can be done to dim down this 20 gigawatt LED on the front of it!?!?!? 
it lights up the room when the lights are out!
it lights up the room when the lights are out!
tried a felt tip marker but the ink wont stick. Maybe it's glass and not plastic. Didn't wanna look "ghetto" with a piece o' tape on da front! 😛
LoL - now that is one bright LED. :-0
Can you show a picture of the LED on the inside and the wires to it? Its quite easy to insert a series resistor to dim is down.
For starters try a 2.2k, if thats still too bright, go to a 10k.
Can you show a picture of the LED on the inside and the wires to it? Its quite easy to insert a series resistor to dim is down.
For starters try a 2.2k, if thats still too bright, go to a 10k.
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