Vintage VT40 amplifier in new Fliptops head box.
Working but needs TLc to get it to 100% so it is being sold as
a project amp, no warranty.
Circa 1976. This is the master volume model.
It came to us as part of an amp lot many years ago and we found it had been modified at some point to run 6550 power tubes.
This was an option on these amps offered by Ampeg back in the day.
It came with a nice pair of JJ KT88 (a 6550 sub) installed.
Amp has new Filter cps, some bypass caps and resistors (see pics)
Comes with a good used set of preamp tubes.
NOTE on the KT88, we discovered the keyways had been broken off on these but new keyways adapters were installed and they work fine.
We believe this had happened because the had just stuck these tubes in on top of the old tube clamps so they were just floating a bit.
We have removed the old clamps and installed a pair of NOS 6550 clamps which hold them in there nice and tight.
Amp operation and issue description:
Amp was tested an hour on each channel and seems to be stable, good tone.
Slight background hum but pretty normal we find for these amps.
When amp is first taken out of standby it takes a few seconds to warm up.
Not sure why this is but suspect it just takes those KT88 a bit longer to get going.
The standby switch can have that "pop" when engaged, pretty typical of these amps.
Don't like it but your are applying 500v + to the circuit after all. May benefit from a new switch.
Reverb works but noise floor is higher than we'd like.
Channel two is noisier than channel one.
The sensitivity switches don't seem to show any difference
between setting one and two on both channels.
Master volume pot is scratchy. The knob on this pot does not line up with the others and
we suspect the pot was changed at some point.
You sill see a black blob on the Reverb board. This is just some semi permanent glue to hold down a trace that was coming up.
It will need a more permanent solution for a repair. You will see this same glue on some of the hold down nuts for added insurance against them lossening due to
Besides the circuit mod to use the 6550/KT88 power tubes, he amp has a had an IEC 3 pin plug in connector added for the power cord as
well as an internal fuse holder for the 6A fuse that protects the AC outlet.
We cut out a few other small mods and restored the amp to original specs in a couple of places.
If you have good tech skills, patience and time this will make a nice working amp.
While there is no warranty on this amp, we do supply a 10% one time discount code to help with the cost of any parts you may need for the repair/restoration.
Once again we just don't have any more time to spend on this one so hopefully we can move it on to someone who can put it back on the road.
Feel free to contact us with any questions.