Preamp Tubes for Ampeg SVT?

Tubes and transistors and transformers oh my!

Moderator: gravesbass

Post Reply
User avatar
NoXX
Posts: 1078
Joined: April 6th, 2010, 12:24 pm
Location: Portland, Oregon

Preamp Tubes for Ampeg SVT?

Post by NoXX »

Hi Folks,

Time for a quick question on tubes.... having spent far too much time reading the Talkbass version of the world, I thought I'd ask the fine folks here who have tube amps what they prefer in the way of preamp tubes. I currently have 3x JJ 12AX7's (ECC83 S) in my SVT-IIP preamp. They sound way better than the knackered tubes it came with (and it seems that Ampeg are now shipping units with JJ's in as stock), but I'm interested in your practical experience with preamp tube rolling. There does seem to be many distinct camps - some say that as long as they are "decent", it doesn't matter, while others point to the first tube being the most critical, and the one to experiment with the most. I see lots of folks with full-blown SVT's on this site, so I'd love to hear what you folks are rocking inside :D

Cheers!
In the topsy-turvy world of heavy rock, having a good solid piece of wood in your hand is often useful...
User avatar
AzWhoFan
Posts: 2866
Joined: March 14th, 2008, 10:57 am

Re: Preamp Tubes for Ampeg SVT?

Post by AzWhoFan »

i cannot speak to that particular amp, but I will say this:
tube preamp design has come along way in the last 4 or 5 years, to the point where using NOS tubes doesn't always yield huge changes. Now, there's a big caveat there IMHO.
I still think it's worth investing in NOS tubes, but I also think it's worth doing as much research as you can before you drop 50 to 150 smackers hoping to find "the one".
I'll also say that NOS tubes have produced huge improvents in tone in my guitar amps. In my lone (SB300) tube bass amp? Not so much at all.
I'll agree with what you mention below, in that changing V1 ususally will yield the biggest change, assuming V1 is what's driving the tone stack.

Tube power sections are another story altogether. IMO, really good iron (transformers) and power tubes make a HUGE difference in the tone of the amp (assuming your preamp tubes are in good shape).
User avatar
Frenchy-Lefty
Posts: 1329
Joined: August 1st, 2009, 6:19 pm
Location: Sint Maarten, N.A

Re: Preamp Tubes for Ampeg SVT?

Post by Frenchy-Lefty »

AzWhoFan wrote:i cannot speak to that particular amp, but I will say this:
tube preamp design has come along way in the last 4 or 5 years, to the point where using NOS tubes doesn't always yield huge changes. Now, there's a big caveat there IMHO.
I still think it's worth investing in NOS tubes, but I also think it's worth doing as much research as you can before you drop 50 to 150 smackers hoping to find "the one".
I'll also say that NOS tubes have produced huge improvents in tone in my guitar amps. In my lone (SB300) tube bass amp? Not so much at all.
I'll agree with what you mention below, in that changing V1 ususally will yield the biggest change, assuming V1 is what's driving the tone stack.

Tube power sections are another story altogether. IMO, really good iron (transformers) and power tubes make a HUGE difference in the tone of the amp (assuming your preamp tubes are in good shape).


+1
I used Groove Tubes Gold in my SVP II - It worked but I don't think you'd hear much difference over the JJ's.
KingOfAmps
His Majesty
His Majesty
Posts: 185
Joined: March 11th, 2008, 7:25 pm
Location: nashville tennessee

Re: Preamp Tubes for Ampeg SVT?

Post by KingOfAmps »

I don't have any specific answers to offer up but would simply say you should survey the current landscape of tube offerings, consult with 2 or 3 informed tube users (players & tech types), look at your budget (everyone has a max $ they're comfy stayin' under whether it's $20 or $200/per tube), then just buy.

My experience has been pretty good following this course and I think it's about as good as can be taken considering the moving target that tubes seem to be. Fortunately I haven't needed tubes in a while but my experience has been that quality can "float" around among and between mfgs. like smoke at a campground.
As not seen on TalkBass!
User avatar
NoXX
Posts: 1078
Joined: April 6th, 2010, 12:24 pm
Location: Portland, Oregon

Re: Preamp Tubes for Ampeg SVT?

Post by NoXX »

Thanks everyone ! Much obliged
In the topsy-turvy world of heavy rock, having a good solid piece of wood in your hand is often useful...
User avatar
gravesbass
Posts: 1694
Joined: May 27th, 2008, 6:15 pm
Location: S.F. Bay Area, CA
Contact:

Re: Preamp Tubes for Ampeg SVT?

Post by gravesbass »

I used Sovtek 12AX7 tubes (Russian Made) in my Ampeg SVT-4's. They get dirty if needed if you crank up the gain. Sovtek is a good cheaper dirty tube. If you want clean, go with JJ's or GT's
User avatar
NoXX
Posts: 1078
Joined: April 6th, 2010, 12:24 pm
Location: Portland, Oregon

Re: Preamp Tubes for Ampeg SVT?

Post by NoXX »

gravesbass wrote:I used Sovtek 12AX7 tubes (Russian Made) in my Ampeg SVT-4's. They get dirty if needed if you crank up the gain. Sovtek is a good cheaper dirty tube. If you want clean, go with JJ's or GT's


Awesome! thanks a lot. I will dabble sometime :).
In the topsy-turvy world of heavy rock, having a good solid piece of wood in your hand is often useful...
kosmicwizard
Posts: 50
Joined: January 25th, 2011, 4:40 pm

Re: Preamp Tubes for Ampeg SVT?

Post by kosmicwizard »

I also have J/Js in my svt-ll (non-pro) seems there are a few of us with this amp on leftybassist. I think Ampeg puts them in their Heritage line as they are the best current production tube today, i won't buy NOS tubes to try them out, but if you do i suggest a telefunken tube or a ruby high gain. Without a master and a gain on our amp trying different tube types (i.e. 12ax7, 12at7) will result in dirtier or cleaner tone than different brands will. Cheers.
User avatar
bigevilrobot
Posts: 452
Joined: March 29th, 2011, 11:00 am

Re: Preamp Tubes for Ampeg SVT?

Post by bigevilrobot »

JJ (Tesla previously) is the stock tube for most tube amp builders these days, save for Mesa.

In my experience, the pre-amp section isn't going to benefit a whole bunch from switching tube brands around.
However putting different tube types of the same socket will yield some minor changes to tone.
So replacing a 12AX7 with anything from a 5281 (or ECC84), 12AU7, 12AY7, or 12AT7 will provide a different rate of gain in the preamp based on where you place them in the chain.
Post Reply