[4Play]

I have a Jolida JD-202BRC and I am currently running stock tubes. This will be my first tube roll, and I am clueless as to what brands would give a significant difference.

This is a list of what comes with the amp from Jolida.

2 matched pairs (4) of  6CA7/EL34 power output
2 pcs. 12AX7A pre-amplifier,
2 pcs. 12AT7 power drivers

What brand of tubes would you recommend that would be the best upgrade. If there are more than one, please list them as well.

Any help you can provide will be greatly appreciated.

[KR500]

Hi ;
I own the same Jolida model amp and purchased it from the US dealer back around 2005 or so .
It had the stock  brown tubes which are either Chinese or Russian and they sound okay.
I have had good luck the last 15 years or so with the JJ preamp tubes I purchased from their Eurotubes US importer . I have read a number of comments online the last several years  that mention their vintage  tooling equipment in Czechoslovia has become worn out and the power tubes are just no longer any good . Is that true ? I have no idea .
I purchased a matched quartet of well recommended Svetlana Winged C EL34 power tubes from a reputable US dealer for maybe around $100 or $150 for the Jolida , can't remember . Anyway, one 34 flamed out about a minute after the dealer warranty ended with another tube  following right behind . I put the brown OEM Jolida power tubes back in . The JJ preamp tubes have worked fine and seem a very good balance of value/sound . It's a dormer amp and I haven't used it a great deal since picking up a closeout special on a Class A SET amp around 2008.
Good luck with your upgrade project .Maybe someone can give better tips on what to get these days for your amp

[4Play]

KR500... Thank you for your input. I'm curious why you no longer use the Jolida. Like you, I am running stock tubes and the sound is fantastic. I have read that tube rolling will produce different sound quality, and I am curious to how better it will be.

Not sure if you are familiar, but The Tubestore carries a good selection of tubes. They also offer two sets of upgrades for the JD-202 but they are way over my budget. If no one else replies, I think I will order tubes from them and see for myself if they are as good or better than the stock tubes.

Do you plan on ever using the Jolida again?

[KR500]

Hi , I still listen to the Jolida , it's a decent Class A/B  amp .
It's just a spare though so don't use it much as I picked up a better tube amp on closeout that is Class A
I think it was Tube Depot where I got the 34's from

[Captainhemo]

Hi
I've had  the Jolida JD302CRC for a couple years now and have tried quite a few  tubes.
My favourite combointation  is the Canada Fuller EL3Gs from Parts Connexion w1/yr waranty,  early 60's Amperex ECC83's(12AX7) from TC Tubes ,  and Mullard CV4024 (12AT7) from Jim McShane. . I ended up picking up  extra of the preamp and driver tubes liked them so much
A really decent  low cost alternative for the  power tubes are the Shuguang EL34B's, I have a quad from the  tubestore and they  are an exellent bang for the buck. There are a few  variaties of the Shuguang EL34-B now, some "specail tube orders" that are supposed to be good.  I believe Doug's Tubes had a few  different flavours a while back and one in particular was  quite popular, you d hae to shoot him an email  for mor einfo.  I've also have a quad of JJ KT77's that  work well but  there is always  reliablity  reports with the JJ's, I've had no issues with mine.

I've also tried  12ax7/ECC83:
Raytheon, New Pro. Mullard <- didn't like at all, EH 5751 GP's,  a pair of late 50's LP Mullard ECC83, 6n23P rockets
ECC81/12AT7:
Sylvania, GE, EH,  stock Chinese...

The only ones i really didn't like were teh  New production Mullard 12AX7's, found them grainy and not overly musical.


-jay

[4Play]

Jay... Thank you for your advice and input. This will give me something to think about when I place my order.

Are there other Jolida owners who can recommend brands of tubes that were above and beyond your expectations?

[KR500]

Well it's been several years, now so I sent Smithers up to the tube vault to check. The 34 power tubes that died prematurely on my Jolida were Russian Tung-Sol's, not Winged C as I mentioned earlier . I kept the pair that didn't sizzle out.... but haven't used them since their brothers passed away.
I had a pair of the Tung-Sol Russian 12AX7 tubes and they were detailed and on the bright side a bit too much. Took them out and put Phillips JAN NOS ones in . Pretty good tubes for the $

[KR500]

4Play, thank you so much for posting this topic , it made me get my Jolida back in to the main rack and I noticed right away it's a better match with my high efficiency Seas full Rangers than the Class A SET amp I had been using for the last 5 years or so.
I have been listening and enjoying . Vinyl esp. sounds better
The SET amp sounded better than the Jolida on my Audio Nirvana 12 inch FR drivers, but 2 years ago I switched to the Seas 8 inches and the Jolida definitely likes them more than the AN's

[mjosef]

Here are my fav. tube array...
GL KT77
RFT 12AT7
GL ECC83/12AX7
Got them from Jim McShane, tested and guaranteed.

[raindance]

I'm a huge fan of Shuguang or Valve Art EL34B power tubes. I'm not sure what is in your amp - some of them shipped with Shuguang tubes and some had the EH EL34's. If you have the Chinese fat bottle brown base tubes and want a change,  try the EH 6CA7. I've tried JJ KT77 tubes in my Jolida and they sounded great,  but were temperamental.

For the small tubes, I LIKE the new Soviet Mullard 12AX7. In this particular circuit it sounds rich and warm. I also find the JJECC83 to be just fine,  a bit leaner. Avoid the JJ ECC803S; very microphonic.

The 12AT7 phase splitter: I have some great NOS tubes you could try.  pm me. Otherwise,  I just use JJ ECC81.

How do you bias the amp?  You can change the sound a bit by varying bias current. Jolida usually asks for 40mA. If you back it off to 35mA or even the low 30's, you'll get a bit more richness,  if that's what you want. At the higher bias point the amp is more linear and approaches "solid state" character.

Do you have the sub out option? If you do,  stop using it. The amp will have more dynamics, better imaging and better bass extension.

[Octadyn]

4play - It's hard to recommend a tube without knowing your entire system and what you want to improve (it's all personal). So that said I had and Octave V70se and later a V110. All tubes will sound different from each other meaning no 2 12ax7's/12at7's will sound the same when from different manufacturers. Although some may sound similar there are differences in sound stage imaging and depth. You really need to try them for yourself. When I had Dyn C1's I liked a warmer sounding tubes. Mullards for the little guys and something like the original Tung sol 6550 solid black plates followed by the grey plates. Telefunken is a nice neutral but detailed sound. Original Gec CV6091 was punchy and had very sparkly highs. The latter tubes IMO didn't mix real well with the Dyn's. But when I got Raidho D1's and later D2's those tubes sounded killer.  The original Tung Sol sounded horrible with the Raidho's.  So that's why I say you have to try them yourself.

[KR500]

I have a Phillips 12AT7 JAN NOS tube w/ 8726 AHB marked and a Phillips 12AT7  one with 8826 AJZ marked for my Jolida amp's 12AT7 tubes
Anyone know what the different 8000 numbers and 3 alpha character codes stand for ?
Maybe the 8726 stands for 26th week of 1987?

thanks

[rotarius]

The Shuguang EL34 are pretty decent but with loose bass.  EH 6CA7 are much better in this regard and worth a try.  Try the Sovtek 12ax7LPS if you don't want to pay for NOS ones.  You cannot go wrong with any type of RCA 12ax7 though.  Swapping the 12AT7 will affect the sound the least.

[KR500]

Thanks for the info rotarius , I agree the Sovtek 12lps is an excellent tube . It sounded the best in my phono preamp compared to various new and NOS tubes in a comparison .
I did try the EH 6CA7's in my amp but they were noisy and had a buzz so returned them to the depot . I just haven't had much positive experience withy EH branded tubes , the AX and AT 7's I had were also either noisy or underwhelming.

[rotarius]

Odd, they seem more robust others I have used but you can get noisy tubes from any manufacturer.  Just depends on how much your dealer paid for them and how much screening they did. 

[KR500]

Rotarius , I got the tubes from Tube Depot and they promptly took them as a return
It might be the amp although the Chinese , Raytheon and Ruby 34's worked fine