I came into ownership of a 1973 Univox Stage 720 2 x 12″ combo amplifier. This thing had its speakers stomped in, the particle board cabinet was rotting to shreds, and it needed a few minor electronic repairs. I took this as an opportunity to custom build a head cabinet of my own design. I… Continue reading Univox Stage 720 Rehousing
I picked up this vintage Heathkit Phono amplifier in a trade with the intention of converting it into a guitar amplifier. It had a Phono/Line switch on the front which is a perfect location for a 1/4″ input jack. The components in this unit have never been replaced, so I had low hopes of… Continue reading Heathkit EA-1 Guitar Amplifier Conversion
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
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
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
I originally picked up some broken pedals so I could use the cases for my own prototype designs. However, this Tokai Analog Delay would be really cool if I could get it working again. It’s an ’80s (I’m guessing) knock-off of a Boss DM-3. It uses an MN3205 BBD chip and an NE571 compander. … Continue reading Tokai TDL-1 Repair
