6SJ7 Pentode 18 watt Lite...Formerly the ABSOLUTE Minimum

[Cyberhorse]

Can I please get the schematic for this amp. Sounds very interesting.

[Daviedawg]

It is likely that you will have to join Wattkins.com (link on left) and search for it or ask for it. Lots of useful other stuff there.

Dd

[LeifH]

Only because reviving the old threads are so much fun.
I built a version of this using a Filmosound 179, full octal tubes. 6SJ7, 6SL7, a pair of 6V6 and a 5Y3.

I have sound, it's nowhere near what it should be. If I crank the volume up full I have bedroom volume, but it sounds like preamp gain, a master volume set really low.

Voltages are
V1 6SJ7
Plate 202
Grid 3 1.92
Screen 37.86
Control Grid .0.002
Cathode 1.92

V2 6SL7
Plate A 188
Grid B 25.88
Cathode 34
Plate B 186
Grid B 26.44

V3 6V6
Plate 332
Screen 297
Grid .013
Cathode 19.09

V4 6V6
Plate 331
Screen 297
Grid .028

In the PI, I've used 470K for the grids, 47K on the tail and 820 on the cathode.

I've checked the connections, path and as I built it, it confirmed the component values. I've rechecked the soldering and the path of the wiring. I've tried a couple sets of tubes, without any change.

Because this is a bit of a MacGyver build, and I haven't been able to really find 6SL7's in a LTP to compare it to, to set the resistor values, but a lot of what I've seen, everyone seems to use the same values for 12AX7 with 6SL7's and voltages I'm a bit stuck.

Any thoughts where should I look first?

Thanks,

Leif