Unique Tube Amps for Guitar

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The Repairs

Valco Tremo-Tone

Royal Freshman

Kay 703

JMP Super Lead

Acoustic 370

JMP Super Lead Repair

Here's some chassis photos of a 1972 Marshall JMP Super Lead 100 watt amp.

The owner had two. One needed some new power supply electrolytics, and the other needed a new standby switch. If you look closely, the switches had plastic handles (bats), which are now extremely rare.

The owner also wanted the impedance selector changed to a modern one. These old JMPs had an impedance selector that was a jumper wire on a plastic handle. The problem was it kept falling out, usually at inappropriate times, like in the middle of a show! The back side of the amp (not shown) had glue from duct tape he used to tape the handle in place.

Unfortunately, replacing the impedance selector lowers the amp's value as a vintage collector item. The owner, however, used these amps on a daily basis and wanted them to work well.

We're talking huge vintage tone -- rock and roll heaven, even at low volumes, but even better when turned up


Check out my tube guitar amp repair blog (on MySpace)

Natural health research and writing is my main career. I'm a licensed naturopathic physician. www.naturdoctor.com and LinkedIn

Building and selling tube amps for guitar and HiFi is a hobby based on my previous career as an Electrical Engineer. Ampersand Amps