Opening up a Johnson Blueline 50R

This arrived to me with a broken volume potentiometer (the board itself cracked which is a common problem for amplifiers with potentiometers that are PCB mounted directly and then suffer an impacted on the shaft), as well as an intermittent fault with the overdrive channel. After replacing the potentiometer with a modern Alpha one with a dust seal, and by securing some of the 5W “flameproof” power resistors, the amp sounded superb. A very nice, low(er) gain overdrive sound and a very usable EQ – coupled with the stock 12″ Alphatone speaker, I’d rate this at least as highly as the reissued Award-Session Sessionette (which had a Celestion 12″ driver as standard).

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