Ampeg SVT II (non pro) Power Tubes

[die monster die]

Hey,
I haven't been around for a while. I think this might be the best forum to ask my question.
I have an SVT II bass head for years. I was playing in noise bands, and was use to set the gain knob on 2,5 (there is no master volume knob). It was sounding good, but too loud to some live sound technician.
Gain on 1, sound's not that good, so i took two power tubes off the amp, in order to use the same gain input, having sorta the same sound, but quiter.

It worked with 4 power tubes instead of 6, for a year or two, before it became unstable. It's been for repair since.

I wonder if what i did is related to it unstability...
I'm about to get it back, and don't play loud bands anymore.
I want to keep it, but will probably need to keep it quiet. How could i make it even quiter and keep sounding good?
Would taking two more tubes out a good idea?

Thanks.

 

[Psychobassguy]

Gain on 1, sound's not that good, so i took two power tubes off the amp, in order to use the same gain input, having sorta the same sound, but quiter.

It worked with 4 power tubes instead of 6, for a year or two, before it became unstable. It's been for repair since.

I wonder if what i did is related to it unstability...

Yes. Search for the term reflected impedance for an explanation.

I'm about to get it back, and don't play loud bands anymore.I want to keep it, but will probably need to keep it quiet. How could i make it even quiter and keep sounding good?

Use an inefficient power hungry cabinet. An Acme Low B 2x10 in 4 ohms should do nicely.

Would taking two more tubes out a good idea?

No.

 

[chaosMK]

Maybe run something to cut your volume in the FX Loop. Get that thing fixed

 

[anderbass]

How could i make it even quiter and keep sounding good?
Would taking two more tubes out a good idea?

Thanks.

Leave all 6 powertubes in and get yourself a sansamp VT-pedal

 

[JimmyM]

If you must have power tubes for distortion, you should get a V4B. 100w tube, sounds just as good as an SVT.

 

[blastjv]

Try engaging the graphic EQ and bringing the level on that down? Might serve as a poor man's master volume (or vice versa with the graphic level up and the gain down which is how I use it?)

-JV

 

[Alex1984]

Does the old volume pedal thing that they had for the V4's work on an SVT?

 

[nashvillebill]

Does the old volume pedal thing that they had for the V4's work on an SVT?

Looks like it should. Basically it plugs into the External Amp jack and grounds the signal through a pot.

 

[die monster die]

Thanks!

Maybe run something to cut your volume in the FX Loop. Get that thing fixed

Hey, i actually thought about it a while ago! I wonder how how it would affect the sound, thought. I'll give it a try.

...
Yes. Search for the term reflected impedance for an explanation.

I've been teached transistors, not tubes. I'm too young for this. Didn't think it would change the output impedance though... + a "pro" made it for me. They didn't mind. Well...

...
Try engaging the graphic EQ and bringing the level on that down?

Oh yeah, i haven't seen the head for two years, i wasn't sure there was a eq level... I'll try that too!

Use an inefficient power hungry cabinet. An Acme Low B 2x10 in 4 ohms should do nicely.

What about a 8ohm speaker on a 4ohm output? Would it do the trick? I sold my 210HE but still have my 410HE.

 

[HagenToke]

Thanks!

Hey, i actually thought about it a while ago! I wonder how how it would affect the sound, thought. I'll give it a try.


I've been teached transistors, not tubes. I'm too young for this. Didn't think it would change the output impedance though... + a "pro" made it for me. They didn't mind. Well...


Oh yeah, i haven't seen the head for two years, i wasn't sure there was a eq level... I'll try that too!


What about a 8ohm speaker on a 4ohm output? Would it do the trick? I sold my 210HE but still have my 410HE.

I see I'm a little late but anything SVT non pro I have to get in on.
Personally what I'm about to try is making a volume box an sticking it in the "FX Loop"
Tomorrow lol.

 

[BassmanPaul]

I see I'm a little late but anything SVT non pro I have to get in on.
Personally what I'm about to try is making a volume box an sticking it in the "FX Loop"
Tomorrow lol.

Yes you are a little late! The OP was last on line here on December 08 2013.

 

[mattwear]

I tried adding a volume pot into the effects loop of my SVT II in order to crank the preamp gain, but found I couldn’t get the kind of overdrive desired. My SVT II preamp is so punchy and dynamic and sweet that it stays cleanish until very loud, to a point then kinda starts sounding a bit flabby. Could be that it needed different tubes perhaps to allow for more OD, but I didn’t experiment any further.
I’ve had better success just hitting the front end with a dirt pedal.

 

[Wasnex]

I tried adding a volume pot into the effects loop of my SVT II in order to crank the preamp gain, but found I couldn’t get the kind of overdrive desired. My SVT II preamp is so punchy and dynamic and sweet that it stays cleanish until very loud, to a point then kinda starts sounding a bit flabby. Could be that it needed different tubes perhaps to allow for more OD, but I didn’t experiment any further.
I’ve had better success just hitting the front end with a dirt pedal.

I did a similar experiment on my 87 Skunk. Instead of a volume pot I ran an MXR KFK graphic EQ from the Pre Out to the Power Amp In. I didn't get any distortion until the Volume control on the amp was almost maxed, and I wasn't completely confident I wasn't overdriving the KFK.

I believe Ampeg used to offer sort of a Master volume pedal.
Relevant posts:
Who here gigs with a Blue Line (vintage) SVT?
Who here gigs with a Blue Line (vintage) SVT?
This is the original location of the quote from the previous link:
Current Production Ampeg Heads - Heritage vs VR
Who here gigs with a Blue Line (vintage) SVT?

Of course you can read the entire threads as well.