Fiinally selling off a few projects that have been hanging around for a while.
First one is a phono preamp built using 4 pencil tubes (2X 6111 and 2X 6112) it's in the little grey box with input/output RCA's and a switch to select RIAA or NAB (tape EQ) - NAB position is NOT hooked up. It sits on top of a black box which houses a 12 volt battery, charger and HV inverter to supply the B+. The separate large wall wart plugs into the side of the black box and charges the battery. Just checked that a full charge supplies the preamp for around 4 hours. Gain is 40dB - fine for MM cartridges. Trace on the scope is a sweep from 20hz to 20Khz with the preamp fed from an inverse RIAA box. response is within 1/2dB over that range. Input impedance is 47K. Schematic included.
Selling as I don't have a TT anymore. Price $65 plus shipping.
THANKS
(hope the pic comes through - I'm new to this
![URL]](/community/proxy.php?image=http%3A%2F%2F%5BURL%3Dhttp%3A%2F%2Fimg413.imageshack.us%2Fi%2Fpenciltubepre.jpg%2F%5D%5BIMGDEAD%5Dhttp%3A%2F%2Fimg413.imageshack.us%2Fimg413%2F1268%2Fpenciltubepre.th.jpg%5B%2FIMGDEAD%5D%5B%2FURL%5D&hash=6f27e82fd6491c9ffb589a4796a67093)
First one is a phono preamp built using 4 pencil tubes (2X 6111 and 2X 6112) it's in the little grey box with input/output RCA's and a switch to select RIAA or NAB (tape EQ) - NAB position is NOT hooked up. It sits on top of a black box which houses a 12 volt battery, charger and HV inverter to supply the B+. The separate large wall wart plugs into the side of the black box and charges the battery. Just checked that a full charge supplies the preamp for around 4 hours. Gain is 40dB - fine for MM cartridges. Trace on the scope is a sweep from 20hz to 20Khz with the preamp fed from an inverse RIAA box. response is within 1/2dB over that range. Input impedance is 47K. Schematic included.
Selling as I don't have a TT anymore. Price $65 plus shipping.
THANKS
(hope the pic comes through - I'm new to this
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