Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Bantam on April 05, 2020, 01:21:29 am
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Couple questions, please. The heater wires look very thin but is that because it's such a small string I've seen that question asked about other makers amps and the 1 I was reading about
was also 3-12 a_7's, and 2-6L6's...although no tube recto, which mine does.
Amp is stock, orig. Filter caps, no leaks, well no visual leaks, no hum, runs high voltage wxt 6l6s. Only mod is what looks like negative feedback lift. It was throwing me off because that's only the second switch I've ever come in contact with that when the bat was thrown the connection went that way usually when the switch is thrown one way the connection goes the opposite. The switch does make a contact but I don't hear any difference and by looking at it can anyone tell me anything about it or any experience and I don't mind trying some different values I remember on the blues Meister it was really tunable with the negative feedback but that was also Distortion amp and this is just a clean one you know per se. As usual thanks for all the help.
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I tried to attach the schematic for the Bantam Bass with update on switch placement
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The jacket of the wire is thin but that doesn't mean the gauge of wire itself is under rated.
Can't seen the switch very well and if I blow it up it is out of focus.
My guess is stock NFB resistor on board and another resister across the terminals on the switch to increase NFB.
Mark
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I've seen that heater wiring many times in SF Fenders from 68/69. It was one of the trials as they tried to get away from cloth wiring. Better than what they ended up with.
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thanks for replies. think notifications are off. yeah that camera sucks. it looks to me that switch is meant to lift nfb, looks to sever connection from ext. spkr jack to 820r 100r Gnd. they remain grounded from 100r, but just disconnect from 2nd/ext jack. I don't hear or feel any difference when switching.
I've generally liked nfb lifts, or at least versatility, would it maybe be installed wrong, or maybe different values, or in conjunction w/pot cap?
besides planned 12'' 10'' baffle mod, will test tone stack lift, as I generally like those also, but beyond that very pleased with sound, and will probably keep close to stock.
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Heater wire look good to me.
Not sure ? Read heater voltage at power transformer (6.3 ?) and read at the end of the wire line/ last tube.
Same voltage = wire gauge ok