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Does anyone know what this modification to a Crate GT50 might be? The amp works fine. I opened it to resolder the input jack to the circuit board because it had a short when I plugged into it with a guitar. At first I thought the resistors R104 and R105 had burned up but the amp works fine. The attachments are of the schematic of the amp and a picture of the questionable modification.
GT-50H,_50_Schematics.pdf
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Last edited by weeksville; 12-04-2010, 12:37 AM. -
Crate G50 heater circuit
The resistors are (were) part of the vacuum tube heater circuit.
R104 is 1K ohms
R105 is 470 ohms.
Looks like a virtual center tap, dehumming thing.
Along with C60 & C61.Last edited by Jazz P Bass; 12-04-2010, 02:40 PM. -
I don't see any mod. I see a burnt up resistor and a missing resistor. As JPB said, that is the hum balance resistor circuit. Those burnt up almost certainly when a power tube failed, or a power tube was inserted into a socket facing the wrong way.Education is what you're left with after you have forgotten what you have learned.Comment
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Should I replace the resistors? If so what wattage rated resistors should I use?Comment
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Written right on the schematic.
Note #2
1/4 w 5 %Comment
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Thanks!Comment
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crate stealth gt50
need pic of wiring ,pic you posted only showed 1/2 of board . my name is gordon,, my e-mail is aivlys00@aol.com.. son took amp apart and forgot how wires plugged in ,,need to see other 1/2 of board or the whole thing .. thank you very muchComment
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Is there any part of the board you would like a closeup of? What plug are you looking for?Comment
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