I've mounted a moving magnet (MM) cartridge (cart) on the Garrard Autoslim turntable in my Allegro. It sounds so much better than the ceramic cart that was in there. Of course a MM cart requires a preamp. I built a preamp from a kit that requires 8 tubes. I'm all ready to try it out, but there are connection requirements that have me stumped. How do I find these connection points in an Allegro (or any) Fisher amplifier? ... 12VDC heater power supply. Is this point a socket pin for the heater(s) of one of the tubes? Two 12VDC connections are required, one for each channel. Connect to 2 pins? ... B+ power supply. Anywhere between +200VDC to +300VDC is required. There is a spot on the schematic that displays 250V which is at pin 1 of one of the 12AX7 tubes and 300V at pins 3 and 8 on a 6HU8 tube just before going into a transformer that powers the speakers. The schematic PDF file is too large to post. Can I simply connect to those pins? There is also 330V and 280V early in the circuitry, at resistors attached to the pins of a can capacitor. Also, the tubes I'm using are twin cathode, dual triodes e.g. 12AT7. They can be wired in parallel or series. The preamp board has jumpers among the tubes so I can wire them in series. I guess parallel is the default. According to the 12AT7 data sheet the heater voltage is 12.6V when run in series, 6.3V when run in parallel. Are there advantages and disadvantages of each configuration? PS - Did I really title this thread "Hot to..." when I meant "How to"? Geez.