Ideas for a tube that heavily distorts ?

[jim]

Hi,

I would like to know if there are special types of tube that
heavily distort a signal instead of being linear.
This because I'd like to build a distortion-effect with tubes but
something different than overdriven 12AX7/ECC83.
Thermionic Culture for instance uses a 6AS6 tube.
Any suggestions ?

Thanks,
Jim

[Giaime]

Some remote cutoff tube? You can find them cheap.

[jlsem]

Any tetrode.


John

[smoking-amp]

dual control tubes: 7 pin: 6GY6, 6GX6, 6HZ6, 6AS6, 6DB6, 6DT6, 5725, 6187, 6954

9 pin: 6LE8, 6BU8, 6KF8, 6MK8, 6GS8, 6HS8 (these have dual plates too)

octal: 6888

[pmillett]

Look at the 6BN6...

http://www.pmillett.com/etf_sod.htm

Pete

[hagtech]

Try playing games with a pentode (or tetrode like the other guy suggested). Maybe a EF86 or something simple. 6AU6? Maybe drive the screen with signal instead of grid. Or tie screen with a high value resistor such that it gets sucked down for long sustain.

Don't limit yourself to triodes. How about a vari-mu tube?

jh

[ray_moth]

You could have real fun experimenting with a frequency-changer lke a triode-hexode.

[jim]

dual control tubes: 7 pin: 6GY6, 6GX6, 6HZ6, 6AS6, 6DB6, 6DT6, 5725, 6187, 6954

What do you think is the best way to hook them up ?
Signal to grid and changing screen-grid voltage for less or more
distortion ?
Feeding signal in both control-grid and suppressor grid ?

Originally posted by ray_moth
You could have real fun experimenting with a frequency-changer lke a triode-hexode.

How could I use those ?

Greetings,
Jim

[tubelab.com]

I was experimenting with an old Fender Champ (5C1 series) several years ago when I came across an interesting discovery. The old (really old) Champs used a 6SJ7 pentode (sharp cutoff pentode) for the voltage amplifier tube. If you plug in a 6SK7 (remote cutoff pentode) instead the amp works normally when the guitar signal is low (volume knob on the guitar on 5 or less) as the drive is increased the distortion increases. Driving the amp with a fuzz box set on its cleanest setting produced a unique sound. This sound went away when I put the 6SJ7 back. I never got around to experimenting with that sound.

More recently I was testing out boxes full of tubes trying to find out which types were suitable for clean, undistorted voltage gain. I made a similar discovery. I found that a 6AU6 can be used for clean gain but the similar remote cutoff pentode, 6BA6 would not deliver more than a few millivolts without distorting no matter how much I tried. It may be possible to use this phenomenon to an advantage in a distortion effects unit. The distortion is dependent on the tube current and the screen voltage.