So I swapped the tube in my Valvetronix out...

[JeffB]

And in some ways its HUGE improvement...

and others....blech...

I swapped out the original ElectroHarmonix for a Groove Tube 12ax7C(hinese)

The good points from the tube swap

1) MUCH more articulate and responsive to the touch..it tightened up the low end on the JB remarkably well. Everything is just tighter, and it makes the chugga chugga very easy :bigthumb:

2) HUGE increase in gain...prolly half again as much gain available on tap...and it's much more useable

3) MUCH less noisy..overall...not nearly as much hiss/white noise..night and day here :bigthumb:

4) sounds warmer....

Now for the bad

1) The amp lost about 1/3 to 1/2 its bass/low end...... it lost some thump/punch that can't be gained back when turning up the bass :blackeye:

this is the big one...

2) COMPRESSION OVERLOAD....OMG....:earl: its like having a compressor on all the time...all the models got compressed, dark, "round".and "small" sounding...just like my stupid Tonelab sounded. This obviously helps with the tightness...but the amp lost it's crunch factor, sparkle, and high end....the playing response is better, but the tone is just..compressed all to hell....."narrow"......what it gained in articulation it lost in "organics".

Any suggestions from the gurus on what tube to try next?....I want to keep the articulation...while "opening" the amp back up.....I really don't want to put the EH back in it..the sag/lack of response is just too annoying on the higher gain models.

 

[STRATDELUXER97]

Re: So I swapped the tube in my Valvetronix out...

And in some ways its HUGE improvement...

and others....blech...

I swapped out the original ElectroHarmonix for a Groove Tube 12ax7C(hinese)

The good points from the tube swap

1) MUCH more articulate and responsive to the touch..it tightened up the low end on the JB remarkably well. Everything is just tighter, and it makes the chugga chugga very easy :bigthumb:

2) HUGE increase in gain...prolly half again as much gain available on tap...and it's much more useable

3) MUCH less noisy..overall...not nearly as much hiss/white noise..night and day here :bigthumb:

4) sounds warmer....

Now for the bad

1) The amp lost about 1/3 to 1/2 its bass/low end...... it lost some thump/punch that can't be gained back when turning up the bass :blackeye:

this is the big one...

2) COMPRESSION OVERLOAD....OMG....:earl: its like having a compressor on all the time...all the models got compressed, dark, "round".and "small" sounding...just like my stupid Tonelab sounded. This obviously helps with the tightness...but the amp lost it's crunch factor, sparkle, and high end....the playing response is better, but the tone is just..compressed all to hell....."narrow"......what it gained in articulation it lost in "organics".

Any suggestions from the gurus on what tube to try next?....I want to keep the articulation...while "opening" the amp back up.....I really don't want to put the EH back in it..the sag/lack of response is just too annoying on the higher gain models.

Hello Jeff....You know I have the 120 VTH Head and how much I Love it...I have a set of RCA Black Plate(Long Plate)12AX7s in mine since about day 1....Maybe you can happen upon 1 on e bay? It made my amp stronger,bassier,and gave the amp more headroom,plus "rounder"is another good thing I Noticed.Mostly the amp just sounded overall better...Don't rule out the new Tung Sol 12AX7 tubes also.Nice sounding tube in my BF Fender combo stuff! Hope all is well? Haven't been on much,but I'm still around.

Here's the 7025 versions of the same tubes I have in my own Valvetronix head...Not cheap,but they'll last awhile and are great tubes!

http://cgi.ebay.com/50s-Pair-RCA-Bl...1QQihZ005QQcategoryZ67816QQrdZ1QQcmdZViewItem

 

[ratherdashing]

Re: So I swapped the tube in my Valvetronix out...

Honestly, I don't think it's smart to change the tube in a tube-driven modeller, unless it dies. The thing is programmed to expect a specific response from the tube, and when you change the tube it has no way of compensating for it. To the software, the tube is simply an input-output device: it sends an input signal to it to get a desired output signal. It is not the same as changing tubes in a tube amp.

 

[STRATDELUXER97]

Re: So I swapped the tube in my Valvetronix out...

Honestly, I don't think it's smart to change the tube in a tube-driven modeller, unless it dies. The thing is programmed to expect a specific response from the tube, and when you change the tube it has no way of compensating for it. To the software, the tube is simply an input-output device: it sends an input signal to it to get a desired output signal. It is not the same as changing tubes in a tube amp.

Can't say I agree with you on your post on this to Jeff....I have great ears and I replaced the tubes in my own amp about 2 years ago...0 problems and still have great tone! The tone is better than the stock tubes..

I had the exact same scenario in my Fender Cyber Twin amp using the same tubes...My ears do hear a difference.

 

[beggar_guitar]

Re: So I swapped the tube in my Valvetronix out...

Interesting...

If this won't in fact damage the amp my friend would probably try this in his Vox.

I'll wait and see whether or not it does any damage before giving him any ideas.

 

[ratherdashing]

Re: So I swapped the tube in my Valvetronix out...

Can't say I agree with you on your post on this to Jeff....I have great ears and I replaced the tubes in my own amp about 2 years ago...0 problems and still have great tone! The tone is better than the stock tubes..

I had the exact same scenario in my Fender Cyber Twin amp using the same tubes...My ears do hear a difference.

You misunderstood. I'm not saying there won't be a difference ... in fact there WILL be differences and that's the problem. It's a crap shoot. Some models may sound great with a different tube, and others may sound a lot worse. Like I said, the computer expects a SPECIFIC response from the tube, and when you change that response, then everything the modeller was designed to do goes out the window.

If you put higher gain preamp tubes in your JCM 800, you get a JCM 800 with higher gain. If you put a higher gain tube in a modeller, there is no telling what you'll get. It's not a simple equation at all.

 

[STRATDELUXER97]

Re: So I swapped the tube in my Valvetronix out...

Interesting...

If this won't in fact damage the amp my friend would probably try this in his Vox.

I'll wait and see whether or not it does any damage before giving him any ideas.

Because the 12AX7s in the Valvetronix act as power amp tubes,I can see the reasoning behind the post....I'm saying it hasn't changed anything and the amp sounds great with these tubes...Another person's mileage may vary?:laugh2:

12AX7 tubes are designed to work around their certain parameters...Quite possibly the Valvetronix amp actually cathode(self biases)in their given positions within the circuit anyway.If this is true,then it wouldn't matter anyway what 12AX7/7025 tube got placed in the amp...Again 0 problems and great tone in my own amp though.

 

[STRATDELUXER97]

Re: So I swapped the tube in my Valvetronix out...

You misunderstood. I'm not saying there won't be a difference ... in fact there WILL be differences and that's the problem. It's a crap shoot. Some models may sound great with a different tube, and others may sound a lot worse. Like I said, the computer expects a SPECIFIC response from the tube, and when you change that response, then everything the modeller was designed to do goes out the window.

If you put higher gain preamp tubes in your JCM 800, you get a JCM 800 with higher gain. If you put a higher gain tube in a modeller, there is no telling what you'll get. It's not a simple equation at all.

Good post.....Read my other post also...I'm just saying back,that I've changed my tubes when I got my new Valvetronix 120 VTH head...Great tone and no problems....Call me crazy,call me lucky? :laugh2: :fingersx:

If those tubes that come in our Valvetronix amps are no longer available to us in say 3 years,do we sell these amps,or do you feel we'd have to have the Vox factory re-bias our new 12AX7s to work right in the amp? Hope Vox planned ahead? LOL

If you put higher gain preamp tubes in your JCM 800, you get a JCM 800 with higher gain. If you put a higher gain tube in a modeller, there is no telling what you'll get. It's not a simple equation at all.

The tube itself works though and won't harm the circuit,it's just that the given tube has more or less gain and self biases in the Marshall...I agree and it's probably the reason in my case(That the RCA tubes kick a$$ in my amp!).....I'm just letting Jeff know this really and it was the point of chiming in...

 

[JeffB]

Re: So I swapped the tube in my Valvetronix out...

hanks everyone for the comments...

John..thanks for pooping in..hope you are well...and thanks for the tips on tubes..but yeesh...that one set you linked to costs almost as much as the amp is worth used :laugh2: (and I only need one)

I guess I was looking for more of a reccomendation from commonly available 12ax7s from GT, EH, Sovtek, Svetlana,JJ, etc...

On some models the compression/roundness helps...but on some its just horrid..the new tube did add some complexity to the mids...thats for sure...

I hear what you are saying RD, ...but a ton people swap out the tubes in these things? IDK...

anyone else have any reccos?

 

[STRATDELUXER97]

Re: So I swapped the tube in my Valvetronix out...

hanks everyone for the comments...

John..thanks for pooping in..hope you are well...and thanks for the tips on tubes..but yeesh...that one set you linked to costs almost as much as the amp is worth used :laugh2: (and I only need one)

I guess I was looking for more of a reccomendation from commonly available 12ax7s from GT, EH, Sovtek, Svetlana,JJ, etc...

On some models the compression/roundness helps...but on some its just horrid..the new tube did add some complexity to the mids...thats for sure...

I hear what you are saying RD, ...but a ton people swap out the tubes in these things? IDK...

anyone else have any reccos?

I Know Jeff.....The tubes aren't cheap buddy! In my case they wer worth it,though I had the RCAs and still have quite a few from several years ago...

 

[ParameterMan]

Re: So I swapped the tube in my Valvetronix out...

You misunderstood. I'm not saying there won't be a difference ... in fact there WILL be differences and that's the problem. It's a crap shoot. Some models may sound great with a different tube, and others may sound a lot worse. Like I said, the computer expects a SPECIFIC response from the tube, and when you change that response, then everything the modeller was designed to do goes out the window.

If you put higher gain preamp tubes in your JCM 800, you get a JCM 800 with higher gain. If you put a higher gain tube in a modeller, there is no telling what you'll get. It's not a simple equation at all.

I'm gonna be cynical here. The thing is a budget modeler. You're saying they took the time to select a specific tube, then shape every model around it's response? Heck, even Johnson/Harman didn't do that with my JM150.($2000+ new) I'm guessing it's whatever is cheapest by bulk order, and that if we did a survey, we'd find multiple tubes have been used.

 

[ErikH]

Re: So I swapped the tube in my Valvetronix out...

Interesting observations. I haven't done any tube swapping in mine yet. I like how the EH sounds.

Saying that modeller was built around the biasing of that specific tube is pretty...umm...silly. No disrepect Matt, but that's just not right. The first run of these amps came with a chinese 12AX7 in them. Only within the last few years have they put the Electro Harmonix tube in.

All the tonal shaping and whatnot is already done in the computer (modeller). The tube is there as part of the valve reactor technology power amp. The tubes are just showing their characteristics in this amp the same as they would any other.

Now, as for other recommendations.......sorry, bro, I just don't have any other than buying a few more 12AX7's and swapping between them.

 

[ParameterMan]

Re: So I swapped the tube in my Valvetronix out...

I like the 50's Sylvania black plate. Near-Mullard warmth and crunch, but almost scooped in comparison. Nice bass.

Tesla E83CC's are also really nice. Telefunken-like balance and clarity. The distortion is a little less hazy than the Sylvania.

You could also try JJ ECC83's. They're supposed to be nice, with good bass.

 

[STRATDELUXER97]

Re: So I swapped the tube in my Valvetronix out...

I'm gonna be cynical here. The thing is a budget modeler. You're saying they took the time to select a specific tube, then shape every model around it's response? Heck, even Johnson/Harman didn't do that with my JM150.($2000+ new) I'm guessing it's whatever is cheapest by bulk order, and that if we did a survey, we'd find multiple tubes have been used.

I was just basically saying that I use the RCA tubes in my own Valvetronix head and that in my case,the tube swap made a positive difference.The inner workings of the amp vs what tubes we use,I thought was a moot point.

 

[Mr. B]

Re: So I swapped the tube in my Valvetronix out...

I tried about half a dozen different tube brands in my AD60vtx and AD30vt when the tone seemed to be getting a little dull. I never found one that worked as well as the original Electro-harmonix 12ax7's. Every other tube "lost" something on the clean or distortion channels, one or the other. I think these amps are really "voiced" for that specific tube. Replacing the older tube really brings them back to life. I replace mine about once a year.

 

[Gearjoneser]

Re: So I swapped the tube in my Valvetronix out...

Mine came with a Sovtek 12AX7A, and I put Sovtek's best tube in it instead, a 12AX7LPS. I'm not sure tubes make a night and day difference in these Vox amps, but they do give a slight improvement in overall fidelity. Worth it for me, I guess.

 

[JeffB]

Re: So I swapped the tube in my Valvetronix out...

Made a huge diff in this AD15VT..I was just emailing Erik about it...

now it sounds (through the speaker) like the VTs sound when using the headphone/line out (i.e. minus the tube)....more gain...more middy/darker, and much more compressed.

Thanks for the suggestions folks. I may just pick up a new EH, or maybe try a couple other tubes first....

I can see why people would like this 12AX7C though..in a regular tube amp...this should be a great tube in something like a Boogie...where you want that liquid compressed tone..or to smooth out/gain up a fizzy marshall or similar.

 

[ErikH]

Re: So I swapped the tube in my Valvetronix out...

I saw your reply here before seeing the email. :laugh2:

Ahh, yeah, I know what that sounds like. I can tell right now I won't like that tube then, not even in my Marshall. That sucker has enough natural compression. It doesn't need any more.

 

[STRATDELUXER97]

Re: So I swapped the tube in my Valvetronix out...

Made a huge diff in this AD15VT..I was just emailing Erik about it...

now it sounds (through the speaker) like the VTs sound when using the headphone/line out (i.e. minus the tube)....more gain...more middy/darker, and much more compressed.

Thanks for the suggestions folks. I may just pick up a new EH, or maybe try a couple other tubes first....

I can see why people would like this 12AX7C though..in a regular tube amp...this should be a great tube in something like a Boogie...where you want that liquid compressed tone..or to smooth out/gain up a fizzy marshall or similar.

Not sure if things have changed much with the Chinese 12AX7 tube over the years,but generally they are a higher gain tube.The LPS Sovtek is another all around great AX7 good in the phase inverter and in preamp positions..Good choice Jeff and try the Tung Sol also...

 

[JeffB]

Re: So I swapped the tube in my Valvetronix out...

I put the EH back in this morning... gained back the organic nature of the amp, and lost that nasty compression..but I also lost the wonderful clarity and articulation It's muddier...but at least it sounds More..err..."real"

I'd say Joe's description of "higher fidelity" is an apt one when I put the Gt12ax7C in

John..yup the C is DEF a high gainer.:laugh2: ...I'm gonna go see what the local shop has this weekend...When I bought this tube (when I got the amp), they had some NOS tubes, Mesa branded, A GT 12ax7R(ussian) and this GT Chinese one I ended up getting....