It would be interesting to see the schematic of the new bandmaster and see the changes. Otherwise exactly the same.Īs I said before, there are so many people building clones of these amps and they all go by the schematics, and the schematics are not accurate. ![]() The Pro 5E5A and Super 5F4 are the exact same amps except they have a 4 ohm OT for the Super and the 8 ohm OT for the Pro. So the only difference between the 3 amps is the Bandmaster 5E7 has the 10 Meg Feedback Resistor and a OT designed for the 3 speakers. Many of these guys making the re-issue amps would go by the old Fender schematics and not study what was actually used in the amp from the factory back in 1959. And the Pro 5E5A schematic shows a 10K resistor from the PT to the Sel Rectifier but the Pro Amps have the 6.8k just like the Super and Bandmaster. All the 5E5A Pro and 5F4 Super amps have the 4.7Meg Feedback resistor which is close enough to the 5 Meg value. Both the Pro and the Super have the 4.7 Meg resistor even though the Pro 5E5A schematic shows a 5 Meg resistor. The only change on the Bandmaster is the 10 Meg Feedback Resistor. The Pro 5E5A and Super 5F4 are exactly the same amp right down to the resistor values. They never mentioned the Bandmaster 5E7, Super 5F4 and Pro 5E5A are all the same amp circuit, it would have explained to people the size of the amp. The old stock bias cap was a 100uF/25v and you can use the 100uF/100v cap for replacement. ![]() When they say they installed larger filter caps they probably used 20 or 22uF in place of the 16uF Filter Caps. They did not mention or show what speakers they were using, or did I miss something I really hate soldering on those wax dipped SF boards and they have all those dammed wires with the "melt on sight" insulation running all over the place.As far as these re-issue amps go, there is nothing like the real amps. I've gotta do a 76 SFTR and I think I'll try the add a pot thing because I can leave the pase inverter as is. Doesn't matter how they look or test even with the right metter they're junk waiting to blowup or shortout at this point. You really can't check an electrolytic cap with an ohms meter but a real low reading is bad.īut i'd just replace them all they're junk anyway. Since this has old filter caps (make sure they're good and drained) check them with an ohms meter for shorts. Or you can keep the balance pot and add a bias voltage pot. You can rewire the stock pot and change a few things on the board in the phase inverter to be like a blackface. ![]() Then mod the bias supply so you can set bias. So if you want to use this thing plugged in change out all of those white Mallorys plus all the ones under the "dog house". Plus the electrolytics from that era suck anyway. Now if you pull say a filiment heater wire and the light dims start looking at filiment wiring.Īlso the worst thing for electrolytics is sitting unused for about 40 years. If you get all them off and it's still bright order a new power transformer.Īssuming of course the power cord and primary wireing isn't shorted. If it's still bright start pulling secondary wires from the power transformer. If the light stays bright keep pulling tubes. Now if the light bulb gets real bright pull the tube from that socket and see if it dims down. Yeah use a light bulb tester it might save a bunch of fuses.
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