What tubes to replace Ampeg SVT-3 Pro

MeestorEno · #1 02-09-2011, 03:03 PM

I recently bought a SVT-3 Pro that is probably about 20 years old (I am not sure on how to determine the exact year). What tubes would work well to replace them. I haven't opened it up to see what tubes are in there now, but I would not be surprised if they are stock. I am getting almost no "tube" sound from the amp even when maxing out and playing with the gain and tube gain.

From what I heard the JJ ECC803S (3x12ax7) for the preamp and the JJ ECC83-S or the ECC803S for the amp for the poweramp 12au7 a JJ ECC802-S.

But I am a little confused why they are broken into preamp/amp/poweramp if the tubes are only used for the preamp (ie: they are not power tubes).

JimmyM · #2 02-09-2011, 03:11 PM

some of the tubes are used by the driver section of the power amp. jj's are decent but i prefer nos tubes. not much more than jj's and built a lot better.

RickenBoogie · #3 02-09-2011, 05:26 PM

The tubes may be fine. To get the 3Pro to growl, set the "tube gain" or whatever they call that knob fully CCW, as in off- then crank the gain up a good bit, then crank the volume. Like a real tube amp, to get that snarl, you need to play LOUD.

Verminaard · #4 02-09-2011, 05:36 PM

A full JJ set is about $50.00, just tell them you need a kit for ampeg svt 3 pro. I would put the tube gain to about 9 o'clock and turn the input gain up until the light goes on about 75% of the time. The main volume seems reactive with the input gain, so you have to play with it a bit.The original tubes are pretty crappy in this amp and a new set will make a huge difference. I'm pretty sure we had an identical thread this morning and I believe I posted nearly the exact same thing.

Edit: aah yes here it is Ampeg SVT-3 Pro Tube Gain Issue

And if Jimmy says NOS tubes work better than I would assume that it could very well be the case, but I've yet to try them.

Calaverasgrande · #5 02-09-2011, 06:07 PM

I like JJ preamp tubes a lot. Some folks find them kind of "un-smooth" sounding. I like the ballsy low mid character they have.

Phillips and Sylvania NOS tubes are really great bargains as well.

kosmicwizard · #6 02-09-2011, 06:10 PM

Quote:

Originally Posted by Verminaard

A full JJ set is about $50.00, just tell them you need a kit for ampeg svt 3 pro. I would put the tube gain to about 9 o'clock and turn the input gain up until the light goes on about 75% of the time. The main volume seems reactive with the input gain, so you have to play with it a bit.The original tubes are pretty crappy in this amp and a new set will make a huge difference. I'm pretty sure we had an identical thread this morning and I believe I posted nearly the exact same thing.

Edit: aah yes here it is Ampeg SVT-3 Pro Tube Gain Issue

And if Jimmy says NOS tubes work better than I would assume that it could very well be the case, but I've yet to try them.

It is the same OP. Cheers.

Jim C · #7 02-09-2011, 06:34 PM

I tried tube rolling in my old 3-Pro.
The V1 slot made a minor difference but I didn't think there was THAT much difference in tone between a Chineese cheapie and a Mullard,
I'm assuming you tested the tubes and they are known to be bad?
They might be better than what you will replace them with.

stiles72 · #8 02-09-2011, 07:19 PM

The 3-Pros were introduced in 1993. If you have a serial number you can date the amp:
http://www.ampegv4.com/dating.php
I've tried different brands of tubes in mine, but honestly can't really tell any major difference. When I ever need to re-tube again, I'll probably just go back to stock Sovteks for the cost.

Verminaard · #9 02-09-2011, 08:03 PM

I quoteth from kosmicwizard: "It is the same OP. Cheers."

Too funny!!

Edit: Welcome to the Talkbass forums!!