Musical Fidelity Tube Amplifier Kit - 2.0 / Stereo Tube Amp with 5.5x2.5 Power Interface Plug

This kit is not for beginners--you have to know how to read resistor codes, and how to solder. No instructions are provided, the PCB is silk screened with the component reference designator and the value--so you have to follow the PCB closely. The schematic is not provided either, but it can be found online in several places, search for "6J1 preamp".Great value--2 tubes and 2x ceramic tube sockets plus diodes, resistors, etc.Important to note: the power is 12V AC, not DC; amps will not work with DC supply.The amp has two independent channels each with a voltage gain of about 7.5. You can connect the channels in series to get a gain of about 50 which is pretty useful.The plate voltage is around 62V because the 12VAC supply is boosted with what looks like a tripler circuit.This voltage is still pretty safe but high enough to get reasonable gain.I used it as a boost pedal for a guitar amp. It starts to distort on a single channel with about 1.6V peak-peak input, and at 2.5V p-p it starts to clip due to plate cutoff which gives the sound more crunch.If the channels are series connected, distortion is noticeable at about 0.2V p-p.I rewired the grid stopper resistor to the correct place, connected between grid and the grid leak resistor. This makes grid limiting kick in which add some more distortion--what is desired in a guitar pedal but not for a headphone amp for example.Nice low cost platform for modifying to produce guitar pedals.

You will spend 4 times the price and it still hums. I did every mod I could find. Unless you have some very inefficient speakers.

Should have trusted the reviews!!! I have tried and tried to get this AMP to work and like many others it just does not function. Soldering is good, assembly good, just does not produce the specified voltages.