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to mod or not to mod my new tube amp?????

I asked this question before -- but want to take one more crack since I've had a hard time getting figuring this one out.....

I own a Jolida 302BRC bought last year. So far, all I have done is replace the power cord.

I would like a bigger sound, somewhat better soundstage, and a little more punch in the bass. Otherwise I love it.

For my budget. I have two options:
A.
(1) replace stock tube. I am thinking of (2) 12AX7 Mullard reissue
(2) 12AT7 RFT(1 quad) 6CA7 EH. This will cost around $150.

B.
I e-mailed Mike Allen at Jolida. He wrote back:

We can modify the amp for $200. Involves Hexfred diodes, fast recovery soft power up, ceramic resistors for the grid, highly stable and low noise probably the best you can get, and custom made coupling caps. You will still keep that great decay of the amp but you will see a jump up in the attack of the amp.

So, what do I do?!?!?!?!?! This is all very new to me and I could really use some advice.

Thanks -- Marty

We can modify the amp for $200. Involves Hexfred diodes, fast recovery soft power up, ceramic resistors for the grid, highly stable and low noise probably the best you can get, and custom made coupling caps. You will still keep that great decay of the amp but you will see a jump up in the attack of the amp.
martyw
rleff
1,065 posts
 
what speakers is this amp driving?
leatherneck1812
116 posts
 
Underwood HIFI has an ad for a Jolida 502b right now. It reads in part:

"We can also order the amp(502b)set up for EL-34 tubes.
In this configuration it does 50 watts per channel and has the warmer more liquid sonics of the EL-34 while sacrificing some of the tighter more controlled bass and better detail of the 6550/KT-88 tube."

Mods IMHO won't give your EL34 tubes more punch.

I would look for a different amp with kt-88 tubes.

jax2
3,031 posts
 
I'd agree with Tvad - you won't get the improvements you are after for a $200 mod as described. I also don't think they'll come swapping tubes to any great degree, and great NOS tubes are pretty expensive and somewhat risky. What you describe as your goals, a fuller sound with better staging and bass, may indeed be realized going the route of a KT88 based tube amp. I've owned the 302B and have listened extensively to two friend's 502B's and I could tell you the fuller sound and better bass would be realized there. I don't know that the soundstaging ever occurred to me as any better via the KT88 Jolida. You might try listening to other options in the same ballpark (Cayin, Prima Luna, etc.). Don't rule out SS completely either...though they may not have the soundstage depth they can certainly achieve width and definition and will likely give you improved extension as well. There are tradeoffs either way. You just have to listen for yourself and see what works best for you.
elevick
2,637 posts
 
For some reason, Jolida always puts crap tubes in their units. I've never seen a Jolida yet that didn't benefit from replacing the stock tubes...
However, I can't stand the Mullard reissues. They are nothing like the real thing. Start with replacing the driver and gain tubes. Leave the 6CA7/EL34's for later.
Check out www.upscaleaudio.com www.echohifi.com www.tubesandmore.com or get unrealistic and check out www.tubeworld.com or www.tubeman.com for expensive choices.
martyw OP
68 posts
 
Thanks all. I am running them with a pair of quad 21l2s. What other amps would you recommend I listen to?

Thanks
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