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Vintage threads from the first ten years
1967 Marshall 100w Lead Need Help
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 8/7/1998 7:25 AM |
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MSD |
1967 Marshall 100w Lead Need Help Does anyone know if there is two drop resisters(8.2k and 10k)on the B+ line(H.T line)or, is there three drop resisters (8.2k,10k,10k)on the B+ line on a late 1967 Marshall Super Lead Plexi head? In addition, Does that same head use the six diodes for the rectification circuit or does it use four diodes for the circuit? Any info would be greatly appreciated. Mark |
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| 8/12/1998 6:52 AM |
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| David |
Hi I have 4 schematics for a Marshall 100w head (model 1959).Two are dated 1970 so probably don't apply.The other two are a type#z which shows 3 drop resistors- 10k,10k and 8.2k and a 4 diode bridge circuit and a type 1959T (tremelo)which shows the 3 drop resistors and a six diode centre tapped power supply.The schematics are all in Michael Doyle's "The History of Marshall".The number of diodes in the power supply circuit will depend on the power transformer.-4 diode bridge or six diodes in the centre tapped circuit. hope this helps David |
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| 8/12/1998 8:06 AM |
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| John C. Evosevic |
Read the other reply. If you're gonna go by schematics that's fine, but either one might be OK. I've noticed that the older the Marshall is, the more deviation from the schematics there is. I've seen all sorts of combinations of 8.2k and 10k resistors, bias feed resistors in values from 82k to the "official" 220k, etc. Me, I'd use all four-8.2k,10k,10k,10k. |
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| 8/14/1998 10:12 AM |
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| Derrick | I too have a 100w 1967 Marshall plexi, and I recall it having eight diodes for rectification, and one for the bias supply (origional)! The schematic is on page 204 ofthe book The History of Marshall. I'm sure on of the two diagrams on that page are yours. Good luck, -Derrick |
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