Hey everyone,
I have been GASing over this Ampeg SVT-CL and was wondering if anyone could answer a few questions before I pull the trigger.
I plan to try the bass through a 1x16 cab and was wondering what sort of things I should look out for when testing the amp. Are there any "warning signs" that I am buying a busted amp? Any tonal idiosyncrasies that would raise a red flag for people?
Thanks,
DB
I assume that's a 1x15 (not 1x16) cab? Is it 4 ohms? SVTs are designed to drive a 4 or 2 ohm load. 8 is "okay" (according to the designer) if you're not pushing it to high volume. They will put 300W into that load played clean and up to 500-600W cranked into heavy distortion, can the cab take it? Is this the cab you intend to use with it?
For warning signs: get the owner's manual (available from the Ampeg web site) and familiarize yourself with the procedure for checking the bias. If the bias isn't isn't correct according to the lights on the back (after the prescribed warmup) you need to ask the seller some pointed questions. It could need tubes - or it could need more costly repairs.
Start with the gain knob all the way down, the tone controls all flat, and the master up full. Bring the gain knob up gradually as you play. With a reasonably efficient cab it should get "stupid loud" before it starts to distort significantly (this may be limited by your cab, though).
Try adjusting the tone controls, do they work as expected?
Look in the back of the amp while you're trying it out. An orange glow deep inside the output tubes is normal; if the large black structure of the tubes (the plate) starts to glow red, there's something wrong. Note that
while you're playing the bias lights will flicker, but when you stop they should indicate correct bias.
Unplug your bass from the amp (nothing plugged into the amp at all). With the master still up all the way, there should be very little hum or other noise from the speaker. There may be
slight hum or hiss if the gain knob is turned up. While everything is turned up, rap your knuckles sharply on the case, you may hear this a bit through the speaker, but if you hear it a lot there's probably a preamp tube or two that should be replaced. If a tube is extremely sensitive to vibration (microphonic), it may actually feed back, very unpleasant!
A well-running SVT is a thing of joy for a bass player. I love my SVT-CL, but generally don't get to use it (think wine bars and small brew pubs). I have a 4x10 4 ohm cab for it, it's definitely an outdoor toy.