considering octal fatness build with 6sj7 pentode preamp

[andrew]

Hi, I would like to try the Bean stack but could you wire it as a cathode follower tone stack instead of a plate driven tone stack? If so how would you change it? Thanks.

[xtian]

Hi, I would like to try the Bean stack but could you wire it as a cathode follower tone stack instead of a plate driven tone stack? If so how would you change it? Thanks.

In this thread:

http://www.ax84.com/bbs/dm.php?thread=394074

author Stevel describes his implementation (see post from Fri, Jan 08th, 2010 @ 00:22). This is for the AX84 SEL, which has, as you requested, the tone stack following the cathode follower stage.

I'm planning to build this, actually, and will post my revised schematic next week.

[andrew]

Got it Xtian - Thanks

[Andy Le Blanc]

Its a single freq. notch, your better off varying R and selecting C.

The pot in the middle gets you a tilt and sweep but the range is limited
with out properly selecting C.

Its not a practical mid sweep like you might expect on a mixing surface.

[flood]

oooooooooooooh

GO FOR IT - that's all i can say. the 6SJ7 preamp i built in this amp for a friend - see:

http://ampgarage.com/forum/viewtopic.ph ... ght=#84690

...made for one of the fattest, punchiest, most complex and articulate amps i've ever played, i hope i can build a better amp than this one someday. the updated schematics are on page 2. and the skwish! control - switching between 0 ohm and 500k ohm from screen grid to ground - is fantabulous.

i'm thinking about trying out something new with 6SJ7s, i want to try to make use of the suppressor grid as well somehow for some serious waveshaping/lo-fi/dissonance.