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Jolida sj502a tube advice

Hello
I just bought a Jolida sj502a tube amp and was wondering what tubes would you recommend and what will they do to the sound of the amp.

Currently has Sovtek 6550we x 4, Jolida 12ax7a x 2 and some 12at7 tube with no writing except the model numbe on the side of the tube.

I like a liquid, warmer laid back sound with really good detail and a solid bottom end. I find some of the tubes are to "detailed" and the mids/upper end is right in my face and that doesn't work for me.

Any suggestions would be helpful. This is my 2nd all tube amp but I am still a newb at the tubes. I will tube roll at some point to try it and see the difference. The one thing I love about this amp is it is very quite and really does sound awsome. I'm just looking to warm her up a bit more.
This is how I'm running it
Jolida JD50a control center into the 502 into Energy Veritas 2.3's through Harmonic Tech Pro-9 speaker cables.
I have an Oppo BD-83SE with the upgraded analog section and Sabre DAC's. I am currently trying different IC's as I have a few different ones and I build custom IC's so I am trying those as well. You definateley get instant feedback when I cahenge my IC's which is what I want anyways.

Thanks again but no $400 tubes except maybe to replace the 4 6550s.

Mark
128x128eagleputt

Showing 2 responses by johnsonwu

johnsonwu
467 posts
 
The layout of the Jolida 502 is, unlike Audio Research amps,
so simple that an old-school TV repairman can easily mod with one sheet of instructions.
No need for mega expensive mod shops, just a shopping list of components from ebay and mouser.com and 2-3 hours of the solder tech's time.
I have tried tube rolling an SJ302 without mods,
the results were minimal.
Email me if you have a 302 or 502 and want the list of mods and where to place them.
johnsonwu
467 posts
 
Tube rolling on this unit is a waste of money until you have addressed the obvious flaws:

1. Ultralinear (unless you really need the power run it in triode mode)
2. Coupling caps (get PIOs or Teflons for the 4 coupling caps)
3. high voltage bypass @ the input and driver stage
(use film caps instead of the stock eletrolytics)
4. main filter caps (change to 560uF 400V)

This will be a much better $400 spent than on any NOS or reissue tubes.
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