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SVP-PRO broken EQ?

Metal Mitch

Metal Mitch

Jul 14, 2003
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#1
Just found a good deal on a used SVP-PRO, and I'm diggin' the tube sound. But it seems like there's a problem with the EQ.

When I bring up the gain til the red peak light comes on, the EQ starts clipping. The yellow EQ clip light goes out to indicate clipping, and you can even hear the nasty solid-state distortion when it happens... like the tube section is overdriving the EQ section. And forget about my high input gain off the pedalboard, I can make it do this with a passive Fender bass and the -15 pad on!

SVP-PRO users, can you tell me if this is normal? I can't imagine Ampeg would design it so the EQ couldn't be used with a little tube overdrive, but it sure seems that way. If it's broken I can still take it back...

TIA
 
#3
Well, the EQ seems to work fine if I back off the gain or the bass knob... and the manual says the yellow light is supposed to turn off momentarily if the signal approaches clipping... but I could make it turn off and STAY off pretty easily :mad:

Ampeg tech support told me there was something wrong too. I took it back to GC and the guitar mgr said "oh that's normal, you're not supposed to run it clipping". Hmmm, every "Ampeg guy" I've ever seen runs his rig in the red... but he agreed to send it out for repair. FWIW Dennis Krager works at the local service center they use, so hopefully they'll catch the problem over there.
 
#4
Actually, I've also found that the graphic EQ section lacks headroom. I guess I'm not the only one!

To avoid clipping the EQ, I will bypass it, or drop the EQ sliders down until the EQ is no longer clipping. Bringing the Level slider down can help as well. Having the EQ set mostly BELOW 0dB definitely helps. Cut more than you boost.

Odd that Ampeg designed the SVP-Pro with a Drive contol, yet didn't provide enough headroom in the following stages of the preamp....
 
#5
Oh well, that's what I was really worried about, that there might be nothing wrong with it! hehe:confused:

I thought it sounded much better with the EQ off anyway, you can really hear the difference when you turn it on - still sounds like Ampeg (solid-state), but not like the raw tube sound... why couldn't they just put an input gain slider on the EQ, they have one for output.
 
#6
Mitch,

I found what you are talking about on mine. I turned the master down and the gain way up and the eq on. The yellow light did go off. I was doing this just to get distortion. The way I usually use it is I turn the the master to about 2:00 or 3:00 and gain about 12:00, then the eq doesn't clip. How high to you have the master knob? Anyway, like you figured out, it does sounds good with the graphic eq off! :bassist:
 
#7
I just never use the graphic EQ. I may if I'm fiddling around, but never during a show.

I just set the bass to max, mid style 4 and mid at 2o'clock, treble at 3oclock to max. Drive between 1-2oclock. Adjust gain until the light barely flickers during normal playing. I just use my fingers to get the grit out of the ampeg, not my feet (pedal switch). I'd rather dig in some to get a little OD, use some dynamics. This pre works great for that.
 
#9
I've noticed the same thing with my SVP-Pro. At first I thought the GEQ distortion was a blown speaker :eek:, then I thought it was dead batteries in my Modulus.

I can avoid the issue by keeping my signal very clean: clip light never comes on (doesn't even flicker); make sure the GEQ doesn't boost the overall signal level. But lately I haven't used the GEQ at all; the vari-mid is enough.
 
#10
Well it finally came back from the shop... they charged GC a bench fee and returned it no trouble found.

So I bought it again, tested it for about an hour and I'm already thinking of returning it again :(

I love the 12AU7 drive, I run a M-80 distortion into the preamp and the drive adds that tube warmth and upper mid roar that you just can't get with a solid state distortion. Schwinn, I set the drive control in the sweet spot about 2:00, -15db pad on, gain until the the red light just starts flashing - about 9:00 if I plug my Ibanez straight in, if I back off the M-80 channel volumes I can go up to about 12:00 or 2:00 on the SVP gain.

But the problem I'm noticing now is, it sucks all the punch and depth out of my tone! I plugged back into my 12 yr old solid state Carvin head and it blows the SVP away for deep tone and punch.

Edit for update: Got it together now. I think they actually repaired the EQ and just didn't tell GC, because I can run into the red without clipping it now. Also dusted off my old BBE 462 I stopped using awhile back, put it in the effects loop of the SVP and I'm back in business. Clear punchy lows along with that Ampeg midrange grind, and no more 12AX7 mush! Plus, the EQ stage sounds really good with the BBE in the circuit. I'm totally high on "tone endorphins" right now. :D Thanks for all the replies, and if you get a chance try the BBE with your SVP. It kills! :bassist:
 

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