5B2 question

[Madison]

The .01 cap after the input jacks.
1. What is it for?
2. Can it be eliminated and just go with a standard "hi" single input with the 68K and 1M resistors?

[FYL]

The 5B2 uses grid leak bias, with a large resistor between grid and ground - 4M7 if I remember correctly. The coupling cap isolates the input from the DC bias current.

You can't just use the standard 68K/1M combination without adding a suitable cathode bias section to V1a. But it won't be a 5B2 anymore...

[Madison]

>>But it won't be a 5B2 anymore...
No prob.
I am more interested in fiddling with octal.

Can I just wire up the 6SL7 V1 like a 5C2?
I realize the pin outs are different for the V-1s but bus cathodes on a 6SL7?
Just seems simplified.

[FYL]

A grid leak stage uses a grounded cathode, hence no cathode resistor + bypass cap.

You may use the usual 1K5 + 22µ cathode and 82K to 220K plate R if you want a standard 6SL7 stage; or keep the 5B2 grid leak stage w/ an input coupling cap, 4M7 grid to ground, 220K to 250K plate - large plate R's are a must in order to limit current - and no cathode R.

Grid leak stages have an interesting sound of their own with a lot of gain, smooth compression and very little dynamic range. They sound best when playing with old-style single coils and no effects.

[Madison]

Excellent.
Thanks for all the advice!
I'm going to get to work and report later.