JJ KT77 Matched Sets Premium Tested
The KT77 has been available from Genalex but it is now becoming very expensive.. JJ Electronic has revived this design with their version, the JJ KT77. It sounds similar to a 6L6 but features the heater current, maximum plate voltage, and output rating of an EL34. The JJ KT77 boasts specifications identical to the original Genalex ones. It includes pin 1 on the base, though it’s not connected to any internal component. The sound lies somewhere between an EL34 and a 6L6, offering a nice balance of bass, midrange, and treble tones. The breakup occurs earlier than with a 6L6 and has more compression, but not to the same extent as the EL34.
Unlike the EL34, this valve can be used as a replacement for a 6L6 in Fender amps with minimal modifications. Vintage Fender amps typically use pins 1 and 6 as tie-off points for input and screen grids, with resistors mounted on the socket. A standard EL34 can’t be used because the input grid would short to the suppressor grid via pin one. The KT77 avoids this issue. The main considerations are ensuring that your power transformer can supply an additional 500mA of heater current per tube and that the bias voltage adjustment range is correct. If you have a Marshall amp and find EL34s too compressed and 6550s too crunchy, the JJ KT77 might be the perfect solution.
We match your KT77 at 470 volts and we listen to them for noise and microphonics on our own custom tester. Check out our latest tester
Click here for the JJ KT77 data sheet
Valves made by JJ Electronic in Slovakia. We are official importers and distributors for JJ Electronic.
