repair

1969 Elk Pro-Sonic Restoration Part 2 – Success

The Hum was caused (of course) by faulty capacitors. In this case it was the filter capacitor on the negative bias voltage was a complete open circuit, causing my bias voltage to be around 40V AC RMS. This was causing the hum. In the end I did a complete recap of this amplifier, installed two… Continue reading 1969 Elk Pro-Sonic Restoration Part 2 – Success

repair

1969 Elk Pro-Sonic Restoration Part 1 – Hum

I came across a vintage tube amplifier on a local Facebook trading group, that piqued my interest. An ELK (Echo) Pro-Sonic EB-103 from 1969. The trader had been holding on to it, despite it missing both speakers (it’s a 2 x 10), all of its tubes, and someone even took the potentiometer knobs. I gave… Continue reading 1969 Elk Pro-Sonic Restoration Part 1 – Hum

repair

Grant Avanti Amp Restoration

A friend of mine brought me this fairly rare Vancouver-made amplifier to fix up. It had some scratchy pots, but more importantly it was made in the “Widow Maker” style, lacking a power transformer. This can be quite dangerous. Depending on how the AC plug is inserted, and the wiring in your house/studio, it’s possible that the… Continue reading Grant Avanti Amp Restoration