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Hello All, Just got this beautiful re-issue Fender tweed bandmaster on my bench and as I was going through it I noticed someone at some point split the 1st stage cathode. One side at 1.5k/25uf and the other side 3.3k/22uf. Also, this reissue came with a 4.1meg feedback resistor instead of 10meg as per schematic. Any idea why anyone would split the cathode? Different voicing? Also, any options on those signal caps? Crap? Should I upgrade them while I'm at it? Thanks... See attached...
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Yes, splitting the cathodes gives more options in detailing the voicing of the amp. Same with the feedback. Feel free to tweak values of the coupling caps, but as far as "upgrading," I wouldn't worry about that unless you can prove that they are actually BAD.
Justin"Wow it's red! That doesn't look like the standard Marshall red. It's more like hooker lipstick/clown nose/poodle pecker red." - Chuck H. -
"Of course that means playing **LOUD** , best but useless solution to modern sissy snowflake players." - J.M. Fahey -
"All I ever managed to do with that amp was... kill small rodents within a 50 yard radius of my practice building." - Tone Meister - -
I guess the point was to get more gain or create a brighter channel. It's a pretty chime amp as is.Comment
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Just had one of these in. Gotta agree with Justin. The interstage/eq caps are metallized polypropylene, perfectly good stuff.
My customer had me alter the power switch to a progressive one, and changed out the standby switch for a triode mode. Sounds schweet either way. Triode mode cuts the power to about one third and rounds off the hi end, makes it a bit mellow, good for small-room gigs. He's a happy camper.This isn't the future I signed up for.Comment
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here is a shot of the preamp section. i don't see many gut shots of the 57 bandmaster RI on the web. You can see the 4.1meg feed back resistor as well as the modified V1 to split cathode. Someone replaced the original 100k plate resistor with an oversized metal film one. Doesn't one usually match a 3.3k cathode resistor to a 220k plate? 3.3k/100k gives a tad less gain? Right?Comment
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Just took some voltage readings (tubes in at idle). Wondering if these look high for a Bandmaster. With 126VAC coming in, this is what I measured:
V1a=289VDC, Vb=265, V2a=241, V2b=361, V3a=273, V3b=338, V4=497, V5=497, Vrec=500 Grid Voltage V4/V5=-51.7VDC
Do these sound high? I have no reference but that is some high plate voltage.Comment
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Yes it is, but Fender designed it that way. That doesn't mean you're stuck with it. Hi preamp plate voltages tend to make for a taut, bright tone. You could replace the dropping resistor to the node of the power supply that powers the preamp plates. Use a higher value resistor there to decrease the voltage to whatever sounds good to you. Can't give you an exact value because it's a matter of dialing it in to your personal taste.Originally posted by cluster View PostThis isn't the future I signed up for.Comment
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thanks... i'll tinker with it to hear how it sounds first. i was just surprised at the plate voltage. The RI bandmaster must put out more wattage than the originals at this plate voltage.Originally posted by Leo_Gnardo View PostComment
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I'm sure this reissue is plenty more powerful than the original. The one I had here clocked 55 watts to 2.7 ohms at clip. In triode mode, 20 watts.Originally posted by cluster View PostThis isn't the future I signed up for.Comment
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