[2004-09-01]

I lucked across this Dynaco FM-3 at my local surplus shop. They rarely have any actual audio equipment, so it was quite a find. It sounded pretty good as-is, but I couldn;t help doing some upgrades anyway.

The first step was to clean it up and replace the coupling caps with new Orange Drops. You can't tell from the photo, but I replaced the rectifier with a cool Amperex and the audio output tubes with Telefunken 12ax7s.

I replaced the strange little PEC boards with discreet components on circuit boards from SDS Labs. He also makes a board to replace the can capacitor with discreet caps, but my FM-3 had very little hum, so I left the can intact.

Some nice insulated RCA jacks fit in the existing holes pretty nicely. That's it. Simple but quite effective. The sound went from vintage muddy with a notable lack of high frequencies to a modern balanced frequency response. I wonder if the sound before modifications is due to old drifti component vaues, or if it was designed to sound this way. I also aligned it according to a copy of the original manual I found online, but it didn't help much. I guess it was aligned fairly well when I got it.