parallel triodes & CF

[tubenit]

Out of curiousity ...............................

Anybody tried a parallel triode followed by a cathode follower?   And if so what values did you use?

Not sure if this would work or not?   

Anybody have a guess as to what the cathode resistor value would be here in this example?

With respect, Tubenit

[tubeswell]

If paralleling a triode, the RoT is to halve the plate and cathode resistors' resistance to achieve the comparable operating point with twice the tube current that you'd get from a single stage.

When halving the Rk, the 'other' RoT is that you approximately want to double any (Ck or Cp) bypass that's there in order to get the same ballpark 3dB rolloff (as a single stage). Having noted this, other things happening in a paralleled tube (the reduced plate resistance and inter-electrode capacitance and reduced output impedance etc) will impact on the freq rolloff you get at the end of the day, but as far as I'm concerned the RoT still holds 'true' more or less.

[sluckey]

Anybody have a guess as to what the cathode resistor value would be here in this example?

I'd think 50K to 100K would be fine.

the RoT is

What's RoT?

[PRR]

> What's RoT?

Republic of Texas
Rule of Thumb
Reign of Terror
Right on Time
Restraint of Trade
Rate of Turn
Radar-Only Tactic

Probably he means Reign of Terror.

Tubenit- it's a distortion stage. You don't want "maximum gain and clean output". You might want minimum output in distortion so you don't have to cut-down so much later. Ordinary optimizations don't apply to Distortion stages.

Actually what you want is "interesting flavor". There's no good rules. A "safe flavor" might be 2 small onions and one small garlic. An "interesting! flavor" might be ten garlics. Or four onions and a big slug of cinnamon.

Open all your resistor drawers, warm the iron and the guitar, try anything.

[jazbo8]

Does the configuration provide a lot of current drive capability? Does the PI benefit greatly from it? Or is it just for getting a different flavor as PRR said?

Jaz

[tubeswell]

RoT is what you make of it ;-)

[6G6]

In my neck of the woods, that's definately Republic of Texas.

I think I would start with each triode using thier own Rp Rc and bypass cap of the original value as the single triode,
then season to taste.