Jolida 202a Tube Rolling Question 12ax7 12at7

Hi guys, a while back I purchased a jolida 202A to power my desktop speakers. I like the combination very much for accoustic/percussion music as nothing can quite beat it. However my $200 14 watt hong-kong amp is better for rock.
Before testing the other amp I thought it was simply a property of the speakers. But after putting the Jolida in my main setup I'm experiencing the same downfalls.

I don't really know how to pick tubes in order to get the qualities I'm looking for, so I was hoping that you guys could help out.

What I like about the sound now:
-Crisp details throughout the frequency spectrum
-Very speedy attack and decay on accoustic instruments

What I don't like:
-Very dry quality in the upper mids / lower HF
-Not enough tube bloom and warmth, too sterile
-The distortion at high power isn't like my little class A, (which just tends to get more blended and bloomy) but instead sounds rather grating in the high end and loses the bass.

Tubes I'm using right now:
4x JJ E34L's - Power
2x Electro-Harmonix 12ax7's in the preamp circuit
2x PhillipsECG 12AT7's as power drivers

I believe that the amp originally came with 4x 12AT7's though.
Forgot one detail

What I want:
A warmer fuller sound (less dry and sterile)
More in the upper bass (for rock)

Thanks for any suggestions
You must extirpate the EH 12AX7s. They are the culprit. The tube with the most midrange warmth and bloom is likely to be a long plate Blackburn Mullard ECC83. Any British tube would be better, The Brimar CV4004 is still widely available. The Russian tubes are not known for a pronounced midrange. The Germans make the best of 12AX7 type according to many, however more for clean transparent but strong signals but they have become outrageously expensive the 12AX7 smooth plates and ECC803s by Telefunken are legendary. Also try JJ new production KT77s outputs for headbanging. Do the same with the 12AT7s use Mullard 50s or 60s Blackburn ECC81s

You really should try this tube. Its a winner. Drive, bass,excellent imaging and stage, with the smoothness of NOS Mullard or Brimar. Many NOS types are nice sounding, but just dont have the drive that make music sound real with the exception of the Tele ECC803s in the 12AX7 family IMHO.

I agree that the EH 12AX7 are not helping you. Your JJ's and Philips are good tubes.
I agree with the comment to get rid if the EH tubes. I have two Jolida amps and have done a lot of rolling. My favorite combination is the new Tung-Sol reissue ECC803S to replace the 12AX7, the GE 12AT7 where applicable (yes, the lowly GE) and Ei 6CA7 fat bottles for the power tubes.

The Tung-Sols are the only current 12AX7 I like and the only one that doesn't lose out to the 5751. I like it a lot. The GE 12AT7 is very inexpensive and is a little on the warm side, which balances the Tung-Sol nicely. The Ei fat bottles can be had from Kevin Deal at Upscale and are far less strident than many of the current production types.

In order of priority, in my opinion, would be to replace the pre tubes, then the power tubes, and the 12AT7s last.

Having said all that, I do not find Jolida amps to be particularly problematic when it comes to stridency. The Mullards in the pre section would certainly warm things up...maybe too much. I find them to be a bit too much toward the Yin, but they do offer a very nice and warm dimensionality to the mix. I certainly see why some like them.
I strongly agree with the above posts recommending new 12AX7s. The EH12AX7s were the stock preamp tubes in my amp and replacing them definitely yielded the the most noticeable and profound changes in sound. I found the the Groove Tubes GT12AX7M to be a huge improvement in warmth, dimensionality, and overall listenability (really helped eliminate much of the hardness I previously heard in the upper frequencies). I think both the Groove Tubes and Tung-Sol reissues would provide you with a much nicer sound than your EH12AX7s provide, and would be a cost effective upgrade if NOS tubes are out of your budget.
Good luck.
Thank you very much for the prompt, informative responses.

I ordered a pair of Tung Sol 12ax7's and a pair of the GE 12at7s.

I'm trying to figure out what specific mullard is being refered to. Will any of the blackburn series 12ax7's do, or is there a specific model I should look into?
Nah, if it's a Blackburn production, it will have the Mullard characteristics. There are many Mullards with different labels. The main thing is to look for the characteristic code of B in the date codes.
How do you guys feel about the Ei 12AX7's? It's supposedly based on the tele long plate design.
Montytx, i have a questions from you.
What is the characteristic code of B in the data codes?
Btw,i have a pair of Mullard 12ax7 and Telefunken 12ax7 both branded Fisher.Which one should i used for my Jolida JD100 cd player ?, machine on it's way this week with a regular 12ax7 stock.
I like the Ei 12AX7, but its not quite as good as either the Tele 803S or even the new Tung Sol ECC803S. Much smoother and better dynamics than the EH tube though.
Mullard used the Philips code system on their tubes. The first 3 digits of the code, usually found on the lower part of the glass and very hard to see, are of little consequence. The 4th digit, often beginning right under the first 3, will designate the Philips factory that produced the tube. The "B" indicates the tube was made in the Blackburn factory and is a genuine Mullard, regardless of what the label says. The last 2 digits will indicate the year and month...sometimes another digit indicating the week that the tube was made.

The Telefunken tubes are more linear, pure and focused. The Mullards more warm, thick and texturally harmonic. If I were after all my gear could take, I would go with Telefunken. If I wanted to add a liitle more syrup and give up a little extension, I would go with Mullard.

I hope that helps a little. Personally, I like the reissue Tung-Sol so much I would never spend the extra money on a NOS Tele as they command silly money. Valvos, if the price is reasonable will get you most of the Telefunken sonics for a fraction of the cost.
Kehut, do you know if there is any difference in sound between the standard reissue Tung Sol 12AX7 and the gold plated "ECC803S" version you linked to? I understand some gold pinned tubes are pre-screened at the factory for lower noise but was curious if there is any noticeable difference in the tube's sonic "fingerprint," if you will. I'm interested to see how they might compare to the Groove Tubes in my system.
Hmm the Tung-Sol that I ordered was a standard new 12ax7. Is there really a big difference between that and the gold pin version? I just sort of assumed it would have better contacts. Hope I won't be disappointed.
Sonically, I have not compared them. an ECC803S..(S)or (Special) tube usually is a longer life, lower noise Euro variant type by design than the standard 12AX7. I can say that I really prefer the new TS ECC803S over my 50's vintage TS long black plate 12AX7 and the RCA equivilent. Although the vintage tubes do sound okay, you will hear more focus and tonal richness with better dynamics(drive) in the re-issue. Its a linear sounding tube that has nice detail without any etch or brightness. Im almost willing to bet the new TS re-issue 12AX7 (non gold pin) is identical sounding... the Ecc803s are 2x the price of the std. 12ax7, likely for screening of noise and microphonics and gold pins.
Thanks, Kehut. Looks like I'll be giving these a try.
I would bet the main difference is as mentioned...screening. However, there is an advantage to screening tubes for low noise and matching sections and the gold pins would likely be along the lines of having gold plated inputs on a preamp.

The key element on these tubes is the spiral filament and heavy envelope that keeps noise to a minimum. I'm just hazarding a guess, but I bet the regular tube would sound as good most of the time with a slight variance depending on how well the sections match up.
After letting the tung-sol 12ax7's burn in for a bit I'm willing to make some observations in the difference between these tubes and the EH's.

Unlike the E-H tubes the Tung-Sol's aren't dry sounding. There isn't that 600+ hz air, and low volume level playback benefits immensely.

However, there's still some problems. The TS tubes seem to play a bit hotter in the upper end. There's some added sibilance and at higher volume levels rock playback can become a bit grating. I'm not saying that this is a problem for all speakers; mine happen to be rather bright to begin with. Equalization fixes the problem to some degree, and it's definitely easier to fix some frequency ineqaulities than the overall sonic character.

I'm probably going to try out some mullards.

I recieved my TS 12AX7's today for my 302BRC and although
they improved the bass & center image, they are a bit
hard, and I lost the air that my Dali's have a ton of
that I love. I was blaming burn in, but since you have
burnt yours in, and have basically the same effect, I will
look for other tubes as well. I am trying to improve
on the stock 12AX7's (Which I assume are Sovteks??) but
I put them back in, and the magic came back to the Dali's.
Let me know what you find that you think is better
than the stockers. Maybe some Telefunkins or Mullards??

I'm sorry to hear the Tung-Sol tubes didn't work out for you. The Mullards will likely be juuuuuust right. They certainly have a very lush and harmonic tone to them and are far from the last word in top end extension.

If you start rolling some of your other tubes, the TS might come in handy. If you find that you enjoy tube rolling, don't pass up the chance to try the 5751 (lower gain) tube in place of the 12AX7. Conrad Johnson used to use them in a lot of their gear and they almost always have balanced least the early milspec tubes tend to.

Let us know how you like the Mullards.
I'll try out some mullards and see what the result is.

The Teles are very intriguing, but the price range is far from attractive.
Robx - don't know if you saw my post relative to Jolida 502B tube upgrade. It's at the link below...might be of some interest.
Tubes I'm using right now (replacing the stock JJ's):
4x Electro-Harmonix
2x telefunkien 12ax7's
2x GE 12AT7's
power cable - Zu BOK

The sound was all warm until I installed the GE tubes, then everything went a bit brighter on me. The sound surprised me so much that I bought a couple more for back up. I think I'll try some Ei 6CA7 fat bottles next. Thanks for the suggestion Montytx