That's normal, too. The preamp of the SVT is very high gain. Most of what people attribute to power tube compression in its tone is actually the preamp.
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SVT-VR: The Definitive Thread
- Thread starter KingOfAmps
- Start date
That's normal, too. The preamp of the SVT is very high gain. Most of what people attribute to power tube compression in its tone is actually the preamp.
Sounds like you are describing an SVT when the amp's tubes are not biased correctly (to the cold side). Turn it up but it gets nastier, more compressed and not any louder?
I'd suggest having the power tubes checked out. Maybe there is one or more going south that's caused the bias to drift. Maybe the components that maintain the bias need replacement or maybe it just needs to be have the bias set. In any case, probably an easy fix.
Not quite the same tonally to my ears. I know the SVP-CL is designed to replicate the tone of a 70's SVT pre. It sounds different then the pre in the VR when run into the power section of an SVT. I've tried the SVPCL into the power section of both my VR and SVTII in comparison to the VR pre. Ultimately, I prefer the tone of the VR pre over the SVP-CL into either power section.
The stated EQ points are different between the two:
VR treble 4Khz SVP-CL treble 7Khz
Bass 40hz bass 20hz
Not sure if that's why but the 2 pres do sound different.
Is there a way to attenuate it a bit?
Maybe using a 12AT7 or some low output preamp tube?
Do you recommend doing this?
I don't feel to happy with this, it's breaking up too early for me.
Do you think it could be an output tube as well?
let me know
thanks,
Charles
Other than turning down your bass's output, no. With an active bass, there is no need to run the output at high levels.
Nope. It'll screw up the tone controls and the amp will hum like crazy.
I doubt it, but it is possible that the amp is biased too cold. The onboard bias lights are just useless decoration for the most part. One other thing to try is to swap the 12AU7 driver tubes for 12BH7's. Jerrold disagrees with me about this, but I think it gives the amp more clean punch.
The SVT preamp isn't really high gain for most settings.........
The SVT POWER AMP has a really low input needed, which is why the same pre that drives the SVT fine, is NOT good for a power amp like a higher power QSC etc.....
That was the issue with the first SVP-CL, it was too much like the old SVT, and didn't have the output..... later the gain was raised 6 dB which helped a lot.
The 12BH7 has more current capability than the 12AU7. But the SVT has 47K in series with each of the output grids, which means that the high current capability can't really be used.
HOWEVER......... they ARE different tubes, and current ain't everything. The 12BH7 might give a slightly different character to the sound...... Won't probably be a huge difference.
But...... I've known people who could play an electric guitar blindfold, and tell you what wood the neck was, and how the body was attached, just by playing it... so some folks might well be able to pick out the 'BH over the 'AX.......
The SVT POWER AMP has a really low input needed, which is why the same pre that drives the SVT fine, is NOT good for a power amp like a higher power QSC etc.....
That was the issue with the first SVP-CL, it was too much like the old SVT, and didn't have the output..... later the gain was raised 6 dB which helped a lot.
The 12BH7 has more current capability than the 12AU7. But the SVT has 47K in series with each of the output grids, which means that the high current capability can't really be used.
HOWEVER......... they ARE different tubes, and current ain't everything. The 12BH7 might give a slightly different character to the sound...... Won't probably be a huge difference.
But...... I've known people who could play an electric guitar blindfold, and tell you what wood the neck was, and how the body was attached, just by playing it... so some folks might well be able to pick out the 'BH over the 'AX.......
So pretty much I'm out of luck?, 
I wasn't expecting this amp to be so restrictive.
Bummer!,
Guess I'll have to take it back and buy another amp.
thanks,
Charles
I wasn't expecting this amp to be so restrictive.
Bummer!,
Guess I'll have to take it back and buy another amp.
thanks,
Charles
There are 2 different poster's with similar sounding early-breakup problems. The VR has the bias lights while I believe the 87 will not.
I have a VR and after about 2 years on the tubes, it distorted early and would not stay biased. A set of power tubes and a bias returned the expected performance.
In both cases I highly recommend at least testing the tubes and getting the bias set to spec before changing driver tube types. Oh yeah, you should really have the bias set anyway if you do the driver tube swap.
I really believe your missing the obvious place to start as from my experience, you're describing what a cold biased SVT sounds and acts like.
I have a VR and after about 2 years on the tubes, it distorted early and would not stay biased. A set of power tubes and a bias returned the expected performance.
In both cases I highly recommend at least testing the tubes and getting the bias set to spec before changing driver tube types. Oh yeah, you should really have the bias set anyway if you do the driver tube swap.
I really believe your missing the obvious place to start as from my experience, you're describing what a cold biased SVT sounds and acts like.
HI, Jerrold
I have a SVP-Pro on my bench that is giving me headaches. Nothing seems to be faulty, but it doesn't give enough juice to QSC pwramp.
I gives about 10 V (hi-Z scope) out when feeding 100 mV (sine wave, 1 kHz) in. But when feeding QSC power amp (Z ~10 k) it doesn't give enough juice. Does SVP-Pro has that SVP-CL symptom (low output) too ?
