This is one of the rare JTM50 Watt Black Flag (reverse logo) plexi panel Marshalls. Many of these were tube rectified, this example is diode rectified. |
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Cabinet rear. |
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Transformers are original and are Drake. OT is the later 784-139 (earlier JTM-50s typically had the 128 OT) and PT is a 1202-133. The 133 puts more than 500V to the power tube plates with modern line voltage as opposed to the 118 transformer's 430-450V. One cap can has been replaced. |
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Closer look. Bulgin mains interface. |
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Closer look at preamp side. |
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Some electrolytics have been replaced. Circuit is a shared cathode on V1. 100 pf bright cap on volume pot. |
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Bias capacitors have been replaced. Output capacitors are 0.1 uF (JTM45 style) which really gives this beast a lot of thump. No grid resistors are present. I did add a pair. |
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Picture of entire board. The amp is very quiet until you put a signal into it. |
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