• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

VTL Stereo 50


2007-10-31 11:32 pm
Any owners out there?
I picked one up one a few weeks back and I'm trying to restore it .
Someone replaced the blown bridge rectifier for the DC heaters off the circuit board and installed a larger rectifier on the back chassis.
All the heaters including the power tubes are now DC.
The only schematic from SDS labs indicates AC heaters for the power tubes.
It makes no sense as the traces are in tact in this amp and it has to be all DC or all AC, as the pin 2 of the 5881 tubes connects to the other pin 2 of the 5881 in that channel then the trace continues to pin 4/5 of the 12at7.
If the pin 2 of the power tubes was to be AC, then the trace would have to be cut and a DC line to the 4/5 of the 12at7.
Anyone have one of these that can open it up and have look? I have one other pix from another fellow and there are white jumpers installed, it's hard to trace from a pix.