Jvm tube advice

[gadgetfreak]

I know people are tired of these posts but I can't find a current one on my amp. I scored an amazing rail of nos amperex and rca 12ax7s and want to know if I'm not really playing loud is it even worth it to go nos in power section.

If I don't do old glass I have no clue about cp el34s. I'm new to marshall and these tubes. My Jvm205 H came with kt77s used from a guy so I need some good advice on what kind to look at. I know all the manufactures,,,which ones are known to be good for 34s etc.

If nos will make a difference even at lower moderate volume I'm game for that. I've been looking at RFT'S and some old mullards but I like the price better on RFT'S. Not sure if I'll even hear a difference in tone. Now the preamp tubes I use there cleary is a difference from the cp tubes I had in there. Thanks

 

[chee16]

My personal advice, I wouldn't go NOS for the power tubes, you have some nice preamps there, use those and get some current production power tubes that fit your needs. The reason I wouldn't go with NOS is because the price for a matched pair is gonna be high, and it's hard to say if you will hear the difference. maybe once you have had the amp for a while and know which PT's you prefer (KT77 vs EL34 vs 6ca7). Plus, preamp will last a long time, whereas powertubes wear out, even the old glass (though they apparenly last a lot longer).

I am loving the EH6ca7 tubes in my TSL602. I recently swapped them out with the Winged C EL34's I have and I much prefer the 6ca7. It is described as inbetween the EL34 and 6L6. Tigheter bottom, less mid grit, crisp highs. I have had them in for a while now and they are holding up well. I run a Mullard I63 in v1, sylvania long black plate in v2, GE grey plate in v3 and a GE grey plate in the PI. You should be good with those amperex and RCA's.

 

[gadgetfreak]

I've been reading good things about the EH power tubes on here lately. I have been using the search feature trying to find what people like..

I think I will try some EH's and I'm going to buy some RFT's because I found a guy selling a stellar pair for just dollars more than new production. I've heard great things about them as well. How are the WInged C's for El34's? I think folks are totally getting hooked up on the price selling them, I remember buying them for an old Bogner that used 6l6's and they were cheap now people are getting crazy money for them and most don't even come with original boxes so I stay clear.

 

[chiliphil1]

I like the EH in the power section. It worked very well for me. I found and you may have seen that the JVM hates Russian pre amp tubes. The PI and valve either 2 or 3 (can't remember) will pop Russian tubes quick. The power section is fine with whatever you want to run, lots of guys liked the kt77's, I never tried them because the EH 34's were fine for me. Bias a little warm and it's a beast. As far as pre amp, mine may have had an issue but the only tubes it liked were the stocks. I tried the EH and it kept blowing them, I got some Shuguang and it blew one of those too. The stock Sino tubes seemed to work best in the pre amp on mine.

Never tried any NOS or anything like that so I'm not much help there but stay away from the Russian 12ax7's and the EH are great in the power section.

 

[Trophlin]

I like the EH in the power section. It worked very well for me. I found and you may have seen that the JVM hates Russian pre amp tubes. The PI and valve either 2 or 3 (can't remember) will pop Russian tubes quick. The power section is fine with whatever you want to run, lots of guys liked the kt77's, I never tried them because the EH 34's were fine for me. Bias a little warm and it's a beast. As far as pre amp, mine may have had an issue but the only tubes it liked were the stocks. I tried the EH and it kept blowing them, I got some Shuguang and it blew one of those too. The stock Sino tubes seemed to work best in the pre amp on mine.

Never tried any NOS or anything like that so I'm not much help there but stay away from the Russian 12ax7's and the EH are great in the power section.

Yes, it is V3.

 

[Dmann]

I tried a few combinations when I had a JVM210H.
For Power Tubes, the worst were a set of JJ 6CA7's... just sounded sterile and almost plasticy. Really dark.

The best IMHO were Ruby EL34BSTR. Nice and full. fat. warm.
http://www.dougstubes.com/ruby-el34-bstr.html

I tried all kinds of Preamp tubes, and to be honest, when using a parametric EQ in the loop to actually sculpt your tone, the preamp didn't seem to matter that much as they were all high gain. It was more about the "grain" of the gain for me. I also found that having a really good tube for the PI is essential, and I actually started using "Mesa" branded 12AX7's for whatever reason they just seemed to give me a smoother "feel" and response from the amp.

The biggest thing I found with JVM's is getting the Bias right, and this is just my opinion, but you can't go by the numbers. It's the best starting point, but I found I got better results by using my ears... The 210H I owned was a miserable biatch and really sensitive to humidity, air pressure and heat. But I found that it sounded best when Bias'd slightly hot at around 38.5 per tube.

Also, my experience was using a fullstack of 1960AV + 1960BV cabs. tuning for gig volume at a level that competes with acoustic drums, not bedroom / by yourself volumes.

 

[Dmann]

Yes, it is V3.

not sure which you are referring here, but the PI is V5.

http://jvmforum.com/phpBB3/viewtopic.php?t=7255#p75761

 

[SlyStrat]

I'm not a fan of JJ's.
There sound like a blanket is thrown over your amp compared to others.
Winged C's or Shuguangs.
Any NOS in V1.
A JJ will kill the tone.

 

[Matt_Krush]

The cathode follower is the spot that eats Russian tubes.

My B52at100 will destroy one in a year with moderately low usage.

 

[Iwanarock]

Yep it's V3 that doesn't like the Russian tubes. I have EH EL34's in my JVM 410H and love them, but i will say I also liked the original stock Marshall branded tubes. In fact I still have two stock power tubes that one of these days i want to put back in and pull two tubes and run it at 50W to compare.

My JVM has not eaten tubes preamp tubes and I have a mix of EH, JJ and stock Marshall branded pre amp tubes in my 410H. EH in V1 & V2, JJ in V3 and stock in v4 and V5. A lot of JVM users use EH preamp and power tubes.

 

[chiliphil1]

not sure which you are referring here, but the PI is V5.

http://jvmforum.com/phpBB3/viewtopic.php?t=7255#p75761

It's 3 and 5. The PI and then v3 also goes.

 

[Trophlin]

not sure which you are referring here, but the PI is V5.

http://jvmforum.com/phpBB3/viewtopic.php?t=7255#p75761

Sorry, I should have elaborated. I've read that V3 is what fails and is particular with the type of tube. It is the cathode follower. All of the research I have done says that V3 is the only position that matters on tube type.

 

[gadgetfreak]

I have a huge assortment of Russian 12ax7s and chinese. I have never had an issue with V3 blowing Russian tubes. I think a lot of that is internet chatter and then again there tubes they blow... I did find the amp sounded better with Penta Labs in V3,4,5.


It's amazing to hear how the tone with the new old stock tubes is smooth and well rounded no fizzyness going on at all. I put in Tungsol's,Eh's,Ruby HG wouldn't matter and it would be so gainy, I almost feel that at least a good nos in V1/2 to tame some of the gain is necessity after hearing the difference.

I like the tone of the Kt-77's but the amp has had them according to original owner since 2013 and they are sounding weaker lately, just not as much oomph and the amp seem's thinner in a I am familiar with that thin sound power tube going sound. Funny I had some crackling for a couple seconds other day and thought one of my other nos tube was on the fritz but now I believe one of the kt77's is on it's way.

I got some great feedback on Eh's and I bought some RFT's just to try out so I can't wait till next week. Still looking for a 2x12 but I'm being patient waiting for the right one, not in any rush. THe amp sound's amazing cranked, i got to open her up tonight and even with powertube on fritz she sounded great.

 

[chiliphil1]

I have a huge assortment of Russian 12ax7s and chinese. I have never had an issue with V3 blowing Russian tubes. I think a lot of that is internet chatter and then again there tubes they blow...

Happened to me personally. I bought a set of EH gold pins, the amp popped v3 almost immediately. I swapped in one of the others and it popped it. I got those 2 tubes warrantied and it popped those too. The only thing that worked was the stock tube.

 

[big dooley]

even new sensor admitted that most of their tubes are not suited for the cathode follower position or the PI,

 

[MonstersOfTheMidway]

I have a huge assortment of Russian 12ax7s and chinese. I have never had an issue with V3 blowing Russian tubes. I think a lot of that is internet chatter and then again there tubes they blow... I did find the amp sounded better with Penta Labs in V3,4,5.


It's amazing to hear how the tone with the new old stock tubes is smooth and well rounded no fizzyness going on at all. I put in Tungsol's,Eh's,Ruby HG wouldn't matter and it would be so gainy, I almost feel that at least a good nos in V1/2 to tame some of the gain is necessity after hearing the difference.

I like the tone of the Kt-77's but the amp has had them according to original owner since 2013 and they are sounding weaker lately, just not as much oomph and the amp seem's thinner in a I am familiar with that thin sound power tube going sound. Funny I had some crackling for a couple seconds other day and thought one of my other nos tube was on the fritz but now I believe one of the kt77's is on it's way.

I got some great feedback on Eh's and I bought some RFT's just to try out so I can't wait till next week. Still looking for a 2x12 but I'm being patient waiting for the right one, not in any rush. THe amp sound's amazing cranked, i got to open her up tonight and even with powertube on fritz she sounded great.

I, too, have used Russian tubes with spiral filaments in every position in my stock 2007 JVM410H without ever loosing a tube or damage to the circuit. No doubt, a tube can die on you at any time (even one fresh out of the box, so it pays to ask about a dealer's return/exchange policy. Additionally, some modifications are known to blast away at a preamp tube in the cathode position (I know of one particular JVM modification that is likely to increase the voltage to the tube in the cathode follower position and likely to cause malfunction of some tubes in this position. The details of the modification are on the JVM Forum, but unless you are a registered member of the JVM Forum, you cannot have access to the modification section that contains the details of this particular mod-sorry, but I have nothing to do with who does and does not have access to the modification section of the JVM Forum.

About NOS: everyone hears different things so if NOS is your thing, then go for it. I've heard many amps in person where the owners throw in NOS tubes: none ever sounded terrible yet none ever sounded spectacular either-very good but I never was "floored" by NOS.

I've used Electro-Harmonix preamp tubes in various combination: I've used all EH as well as mixed brands. I like the sound of EH in the first two gain stages, but that's not something by which I live and die. I also like EH EL34 in the power amp section-very consistent, very quiet, and very good on low microphonics. So if you are planning on some EH EL34, give a spin.

The KT77 is a tube that I've only used a few times, and that was current production. The Genalex KT77 and the JJ KT77 are the only two I've used in the passed. Both were good overall, but the JJ sounded a little "darker" as if the higher frequencies were somehow cut out or lowered with more low and mids.

I currently run SED Winged =C= EL34 power tubes. They're very quiet and very consistent. These are the original power tubes that came with the amp, and no issues whatsoever. I'm planning one taking these out sometime this year and saving them. I'll probably go with the Tung-Sol EL34, the Electro-Harmonix EL34, or the JJ E34L (aka EL34) but I'm also curious about the JJ EL34-II. Interestingly, all stock preamp tubes (Shuguang 12AX7) went microphonic about 1.5-2 years after I bought the amp, yet the stock power tubes are still going strong.

The preamp tubes are a mix. I run a Tun-Sol 12AX7 in first position/gain stage, JJ ecc83-s in second position/gain stage, JJ ECC83-s or TAD 7025-S in third position/cathode follower (gotta visually check), EH 12AX7 in fourth position/reverb+effects loop mix, and TAD 7025-S in fifth position/phase inverter. This mix works very well, so I'm probably gonna keep it like that for awhile.