Hi, got this from estate sale in RDU, NC area several months ago. Unable to find any info on this amp except that the 300B driver circuit is a classic Alan Kimmel mu-stage driver identical to the Welborne Labs Laurel monoblock amps. Compared to the Laurel, the builder added an additional preamp stage, (I'm using 6SN7 but could use 6SL7's), a regulated DCV for filaments of the 6SN7, 6SL7 and 6AG7 preamp tubes and a DCV regulated bias supply for the 300B tubes. Waiting for some 300B to arrive to find out how well this amp works. Date codes on nearly components where I can see a date code are from 1998-99. See hand drawn schematic of one channel and the PS.
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Looks to me that you have the PS filter choke in the wrong place,
should be in the 300B plate supply.
Which part of the cct is Alan Kimmel, just a boot strapped pentode at the top.
Find this in many text books from the 40s & 50s.🙂
should be in the 300B plate supply.
Which part of the cct is Alan Kimmel, just a boot strapped pentode at the top.
Find this in many text books from the 40s & 50s.🙂
Hi, oops, good catch, I drew 300B plate wire to wrong spot in schematic. Replaced schematic with updated version. See attached picture of Alan Kimmel mu stage schematic from a Welborne Laurel SET monoblock amp. that is 99% the same as what traced out from the wiring to the schematic. He also designed one using the 6AC7 tube as in other attachment. I did not build this amp, I bought it as is from estate sale.
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Hi, shown is a picture of it operational with full complement of tubes. Starting from the front corners going inward diagonally, are the 6SN7, 6SL7, 6AK7 (black metal), then 300B. The two tubes in the front center are the 5Y3 rectifiers tubes. Front left hand 1/4 jack is an selectable input, the right hand is for headphone.
