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SVT3 PRO incoming. Tube and cab suggestions?

S

Skullsuicide99

May 25, 2020
134
82
#1
I just snagged an Ampeg SVT-3 Pro for $399 shipped off reverb! It's in excellent condition and the gut shots are there to match!

I am primarily a guitarist and this is my dream bass rig in construction. Never owned a nice bass amp.

Saying that, I am a electrical engineer and I build and modify vintage tube amps regularly, and I have a massive stock of tubes. Everything that comes in my shop studio that I keep (obviously the SVT3 is a keeper) I fully retube. I have well over 100 new tubes, probably another 100 that have some degree of use on them, and a decent selection of NOS/VOS that won't liklely be going in the Ampeg. However I do have a solid stock of GE 12AU7's that I use rarely and would have no problem tossing one of those in there, as I never use them in guitar amps. And have a ton that I snagged for $4 a pop a while back.

What would you all recommend? I am fine with a bit of experimentation as well.

I don't have a cab for it at the moment, and have to save some cash. I am sold on Ampeg for the cab. Most likely a 4x10, but open to a 6x10 at the right price and time. I want to keep it under $400-500 and local (is that realistic?) but I am not going to sacrifice my 'dream tone' for a little bit of cash, if you catch my drift. I have heard of suggestioms for the "E" cab. Does anyone have any other options or thoughts?

Is there anything to check specifically on a used bass cab that would be any different than a used guitar cab?

This will be in my shop/studio and will not be physically going anywhere. The shop/studio is reasonably sound proofed (not acoustically treated) but volume is not a problem.

I may be getting rid of the genz-benz combo to fund the cab, but I am not sure as it's not bad to have a little combo to toss around.

What are your thoughts on keeping the genz benz? I feel that it sounds good overall and very easy to move. Financially I am fine to hold onto it and get the Ampeg cab, but I honestly am kind of torn.

Sorry for the wall.


TL;DR
Preamp tube suggestions for SVT3 PRO.
Cab Suggestions (ampeg only) for the SVT
Should I keep a 210 combo to have it around?
 
#3
agedhorse said:
Why do you want to change the tubes?

As an EE, wouldn't you want to identify that there is an issue, an actual problem before fixing a problem?
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Personally everything that comes in starts Out fresh.

Maybe I should have implied brand and more for tone.

I am familiar with guitar tone and how different tubes impact the tone on a guitar amp. Not a bass amp.

I don't know where this amp would be more or less ideal with a brighter tube say on V1 here, or a darker tube in V3.

You can hand me a guitar amp and I know how from experience what sounds better where. I can't do that with a bass amp because I don't really know what I am looking for as my ear is not trained onto bass tone like it is to guitar tone.

That's all.
 
#4
Also there is no problem with the amp. I will make sure everything functions as it comes.

I just want a good baseline of the tone when it comes in knowing what it sounds like with what you guys recommend.

I have no problem rolling tubes through and seeing what I like better once my ear is trained on the SVT. I just want a starting point that is a good place to start if you know what I mean.

The good thing is that I probably won't have to order any, as I have pretty wide variety of preamp tubes that are new.
 
#7
Tube rolling in an SVT-3Pro is more a matter of subjective evaluation of tone than electrical engineering and problem solving. De gustibus non disputandum est.

I've found that cranking up the gain on mine brings out the qualities I like. The preamp tubes are driven into nonlinearity, and every tube is going to respond a little differently operated that way.

@Skullsuicide99, your best approach is to take the lid off and start trying different tubes, there's no telling what brand will please your ears. I'm not sure how much difference the 12AU7 is going to make, it's used as a White cathode follower to drive the MOSFETs. Unless the one that's in there is actually bad, I doubt there will be much difference. As for the others - experiment. Get the manual and schematics from the Ampeg web site, different tubes are involved in different EQ controls and the "Tube Gain" control. (Note that "Tube Gain" doesn't have much effect until you get pretty loud.)

You may also want to read through SVT3Pro Bias Setting. Read the whole thread, and take the warnings about the sensitivity of the bias control very seriously.
 
#8
rickdog said:
Tube rolling in an SVT-3Pro is more a matter of subjective evaluation of tone than electrical engineering and problem solving. De gustibus non disputandum est.

I've found that cranking up the gain on mine brings out the qualities I like. The preamp tubes are driven into nonlinearity, and every tube is going to respond a little differently operated that way.

@Skullsuicide99, your best approach is to take the lid off and start trying different tubes, there's no telling what brand will please your ears. I'm not sure how much difference the 12AU7 is going to make, it's used as a White cathode follower to drive the MOSFETs. Unless the one that's in there is actually bad, I doubt there will be much difference. As for the others - experiment. Get the manual and schematics from the Ampeg web site, different tubes are involved in different EQ controls and the "Tube Gain" control. (Note that "Tube Gain" doesn't have much effect until you get pretty loud.)

You may also want to read through SVT3Pro Bias Setting. Read the whole thread, and take the warnings about the sensitivity of the bias control very seriously.
Click to expand...

Thanks for an answer. I will Google the manual and print it out. I know it's subjective, I have gone through tons of amps and even tube to tube I understand that things vary.

I will definitely read about the bias setting.

Would you recommend starting dark (JJ) or starting more bright (Tung-Sol) for example? Experimentation is not a problem at all for me. I just am totally unfamiliar with the amp. And TBH other than technical specs (more EE) I don't actually know a ton about tube bass amps or bass amps in general. I know the iconic ampeg rumble that I like, and that's about it. It's the tone I have craved for a long time. I just happened to have the cash at the right moment and found an awesome deal.
 
#9
Skullsuicide99 said:
Why the (assumed) bitterness? Have I done anything offensive that I am unaware of?
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Probably because you assumed wrong?

All I suggested (and posted quite simply) was to have fun with your project.
 
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#10
agedhorse said:
Probably because you assumed wrong?

All I suggested (and posted quite simply) was to have fun with your project.
Click to expand...

I apologize, I should not have assumed but it just seemed that way. If you have any ideas I am totally open to them.

Edit: @agedhorse I do apologize, wanna start fresh a la tabula Rosa? I have done some research on you and it seems like you have a massive knowledge base. Sometimes I come off rude too on things that I know well.
 
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#11
agedhorse said:
Probably because you assumed wrong?

All I suggested (and posted quite simply) was to have fun with your project.
Click to expand...
Yeah, just toss a smiley emoji on the end to diminish textual ambiguity. :)

I'm curious what the tube rolling reveals, although I have no intention of ever going down that path myself. @rickdog seems to have tossed you a few good bones to gnaw on.

I'd say if you aren't hard pressed for cash, keep the combo for gigs, jams, etc. as it's perfect for "pick up and go". You aren't planning to do that with your Ampeg rig.
 
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#13
abarson said:
Yeah, just toss a smiley emoji on the end to diminish textual ambiguity. :)

I'm curious what the tube rolling reveals, although I have no intention of ever going down that path myself. @rickdog seems to have tossed you a few good bones to gnaw on.

I'd say if you aren't hard pressed for cash, keep the combo for gigs, jams, etc. as it's perfect for "pick up and go". You aren't planning to do that with your Ampeg rig.
Click to expand...

Keeping it around does make sense. I figure that I may as well. Especially because I bought it really cheap (I think it was under $200 for sure) a long time ago and it's always been good to me (even though it hasn't always had much use) but I can attest to it being reliable for me. Would be handy to grab and go.

Also I think it sounds decent enough and probably better than what I would end up with down the line if I were to sell it and want a new combo down the line, and I already know what I have and it's totally reliable.
 
#17
I think I figured out my approach. Load it up with JJ's (dark) then load it up with Tung-Sol (bright) then play around with intwrmixing them as the extremes and fill roll some more 'in the middle' tubes throughout, as the days go. I am very meticulous and will see what I like. I have a feeling that I am going to prefer darker based on some things I have looked at.

I just checked my stock, and have a ton of the GE 12AU7's and they are rarely used in guitar amps. May as well put them in something. And again I paid $4 a pop.
 
#18
A few people like brighter tubes for Ampeg (Electro Harmonix, although I find that they are a hair noisier than others). In almost any amp I like Tung Sol RI in V1. JJ 12AX7 are popular too.

I particularly enjoy Ampeg heads through Mesa cabs. Feel like it takes off the blanket a little.
 
#20
I switched from tung-sol to JJ (groove tubes ecc83s) in my Trace Elliot Hexa Valve in order to have less harsh upper mids and treble. The JJ also have a nice tight bottom end and are more quiet then those tung-sols in between playing. I am very happy with these JJ tubes.
 

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