The ergonomic & non-slip rubber grip handle gives you total control & comfort. The contoured head design fits virtually all tuning pegs both big & small, & its narrow profile keeps you from hitting close-fitted pegs on electric guitars. The innovative rubber-lined head smoothly & silently slips over your tuning pegs for a scratch-free & clank-free operation compared to traditional plastic peg winders. No feature is overlooked, starting with the precision bearing design they invented in 2016 that makes turning the handle effortless, silent & super fast. Presence, Bass, Treble, Volume (Instument Channel), Volume (Mic Channel)ĭistinctive 3x10" configuration with Fender Special Design P10R-F speakers by Jensen®. The Bandmaster amp's harmonically rich clean tones are perfect for vintage rock, blues and country styles, and its naturally touch-sensitive overdrive tone sounds electrifying-especially when cranked up. ![]() They faithfully reproduced the classic 5E7 circuit, which pumps about 26 watts through three 10" alnico-magnet speakers, and enlisted Jensen to help create the P10R-F driver (a Fender exclusive), which is voiced for warm, sensitive response. The new '57 Bandmaster amp now joins Fender's prestigious Custom series, with all-tube hand-wired circuitry and premium components. Hailed as one of the true holy-grail amps among guitarists and collectors, vintage examples are rare and highly sought after. I've attached a couple pictures of my bias probe readings as well as the schematic and layout for my bias circuit.Scottsdale, AZ (January 16, 2013) - The late-'50s tweed-covered Fender Bandmaster guitar amplifier combined great looks with sweet tone and powerful performance. So something's wrong with the power supply or the bias circuit. The tubes are still biased cold and I'd need to replace my 3.3k bias range resistor to get more adjustment. If I adjust the bias pot all the way down (minimum resistance) I get ~52 mA but the plate voltage drops down to 315V, way below where it ought to be. I see 348V on the plates (should be closer to 415V) and my bias probe shows ~40 mA of current, resulting in 13-14 watts plate dissipation. I wanted to solve the noise issue first, but maybe these are related. Apologies for not mentioning this sooner. Regarding amp operation: the thing that's puzzling me is that the amp doesn't seem to want to bias correctly. The junction of the two 270k and 4.7M resistors seems the most sensitive (it's very loud) but pin 2 and the wire joining those two points all produce a lot of noise when touched. I've also tried swapping V2 for a new 12AX7. Tapping V2 does not induce much noise tapping pin 2 directly does. ![]() Regarding sensitivity: the tube does not appear to be microphonic. Have you tried tapping on the tubes to see if they are just as sensitive (or more so) than that junction? ![]() The loud thump could be a microphonic preamp tube. It's amplifying a (roughly) 100mV signal up to over 40W!!! Even vintage amps could be considered very high gain by other types of amplifier standards and that can make some very high sensitivity. Even with a chopstick sometimes, as recently noted by one of our other posters.Īssuming your cathode voltage is correct (which I believe it is) what problem are you having with the amp in operation? I suppose with that V2 lead being so sensitive I might use a shielded cable for it. Is the sensitivity on this V2 lead causing some instability in the amp in operation? Hum when touching a lead is normal. ![]() Notice that the following stage has a higher supply voltage, the same plate resistor value and the same cathode resistor value but only shows 1.7V for the cathode voltage. Typo on the 2.2V spec for the cathode in the schematic.
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