Enlighten me on tubes...

ZanaZulu807 · #1 09-21-2011, 06:51 PM

I'm looking to upgrade my tubes to something with a bit more "crunch" in my gain as opposed to subtle break up in sound. I'm using EL34's and I hear that E34L's (particularly JJ's) are a pretty good upgrade as they are a bit more aggressive sounding. Give me some recommendations on different tube types and some reasons why you like them.

rodl2005 · #2 09-21-2011, 07:52 PM

What amp are you talking about?

ZanaZulu807 · #3 09-21-2011, 08:17 PM

My bad, Peavey VB-2...

mustbampeg · #4 09-21-2011, 08:45 PM

I'm interested in this as well. Has anybody done any tube swaps in a VB2? I've heard 6l6s are interchangeable but I'm not sure.

Randy

grendle · #5 09-21-2011, 09:22 PM

"Crunch " generally speaking ( overdrive or distortion) usually comes from the preamp section. These are usually 12ax7 tubes. Most don't sound too different from one another as far as 12ax7 brands go imo. There are differences though in the "crunch" tones, and when the tubes start to break up, as well as overall tonal character. The 5751 preamp tube has less gain and a more "hi fi" sound. Probably not what you want for "crunch" but can add nice character in different positions.

As far as power tubes go, they have their own character as well and different series tubes are usually not interchangeable. Other than that , its all in your ear and your wallet as to what you decide to go with.

T-Bird · #6 09-21-2011, 10:15 PM

Hi.

For me "crunch" comes from the output tubes/OT interaction (and it's inadequacies), not so much from the pre.

My EL34 amps haven't seen much duty lately, but JJ's are as good a place to start as any. To start, because unless copying a certain tone with the same exact rig, it's really impossible to tell what You're after with just a written description.

Unfortunately power tube rolling is more expensive than pre-tube rolling, but there tend to be a dark edge in any silvery cloud I guess.

Regards
Sam

Mr. Foxen · #7 09-22-2011, 02:21 AM

I generally consider crunch to be pre, and growl to be power valve breakup. I reckon with the fair bit of headroom the Peavey has, messing with the pre is probably going to do more for you and cheaper. Do you know how the bias is set in the amp? Maybe if you are thinking of changing the power valves anyway, get your tech to run it a little hotter and see if you like the change, this will wear the valves faster.

ZanaZulu807 · #8 09-22-2011, 07:06 PM

Bringing this up... I'm not too sure about running the tubes hotter, especially after reading about the number of issues some folks have had with this amp involving fuses blowing due to bad or shorted out tubes. I might consider doing some changes to the preamp 12AX7 and see how that does before trying the EL34's...

turunturun · #9 09-23-2011, 04:54 PM

I have swapped the JJ E34Ls with EH EL34s and JJ KT77s and found the E34Ls to be noticeably murkier. that was in a guitar amp though, and you may not notice it with bass depending on style and tone preference.
Also, for a sextet of EL34s you could probably buy yourself a nice sansamp VT Bass pedal, maybe a used VTPro and see how far that gets you. sometimes you can get grit from a pedal that won't come from preamp tube distortion.