So i got this Ampeg SVT-100 as a trade. The last owner took out the 6550's and replaced with kt88's but did nothing else to the amp.
Actually I haven't even opened up the amp as I literally just got it. Don't even know if there is a bias pot somewhere in there. I guess I can find out if I can locate the schematic...
In the meantime...Am I ok running it like that before I have a chance to open it up?
Cheers.
Last edited by tribi9 on Fri Aug 27, 2010 8:15 pm, edited 1 time in total.
This sounds like a more recent version of the V4. If it was designed for 6550s you might need to do a minor rebias for the KT88s, but that really depends on how hard/soft the KT88s are compared to what the original bias setting is. Could be fixed, ie no bias pot.
The odds are it's OK to run it without rebiasing, (assuming it was properly biased in the first place) but be safe and don't dime it until you do check out the bias. If the KT88s redplate when you take it off standby, shut it down immediately and check out the bias.
Last edited by David Root on Fri Aug 27, 2010 3:30 am, edited 1 time in total.
it looks like 80's the black face plate and thicker logo.
by looking at the inside i'm not sure how much it borrows from the V4 or the SVT. it looks to be it's own circuit I'm guessing they where profiting off of the SVT model name.
As most ampegs it's still probably a very cool amp!
no bias pot. it's a fixed resistor.
At this time Ampeg does not display schematics online. However, if you wish to obtain a physical copy of product schematics, please contact the LOUD Technologies Inc. Service Center at 1-800-898-3211.
The SVT-100 was produced in 89-90 and endorsed by Van Halen's Mike Anthony. It was not a high number production run. They also made the SVT-100T which was the combo version of the head.
Actually it does have a bias pot. You might be able to see it on this pic. I actually haven't taken any measurements yet but Im going to bias it for the kt88's.
is it a bias or a hum pot? I'll admit the information I was able to find was very little. Ampeg in the 80's was a disaster. The history of ampeg sort of skips over the 80's... 1978... 1990. I'm really glad they turned it around in the 90's but they are starting to have issues again.
SVT-100
Preamp: 3 x 12AX7
Power: 4 x 6550
Single channel, two inputs
6 knobs (V,MV,B,M,T,P) bs, gain switch
mfg. 1986-1992
This amp was a modified V5 amp from the MTI days and made into a bass amp. When SLM bought Ampeg they recieved a supply of V5 heads. They made a few small component changes in the preamp and had the SVT-100. none of the SVT-100's were built from scratch.
The SVT-100t is a solid state amp, nothing in common with the SVT-100 except name.
MTI took Ampeg production to japan in the 80's. SLM took over Ampeg in 1986 and brought the SVT production back to the USA but only made 500 SVT's under the "Skunkwords" department over the next 5 years.
