Preamp output question (cathode follower)

[pdf64]

'should a 2M or 10M pot work better'
No they would be worse.
A 250k or 100k pot would be better.
It would be beneficial for you to get your head around why that is the case. However, trying to construct an explanation is making my headache worse, so I'll try later.
Why not use the lowZ output, why do you need the high Z output?

[bluemonk]

trying to construct an explanation is making my headache worse

I guess there's a math. And there are my eventual difficulties with English.
But finally I had some time to spend checking the theories.

Here are "empirical data" for my diy Alembic preamp with:
- 1M pot in place of 1M output resistor
- "stock" Hi-Z output
- Lo-Z output from CF (one triode, no gain) in series with Hi-Z output through a 47k resistor.
Power amp: diy Hiwatt Dr504's Main Input (placed at master volume pot just before PI) connected by 1,5 m cable.

Here are the tonal differences IMVHO.
Output Pot at max = no differences (perhaps very subtle?) between Hi-Z and Lo-Z outs.

Output Pot at mid position = Lo-Z out is much brighter, punchier and louder.

It seems that output pot actually affects tone heavily when dimmed.
On the other hand I can't see any issue with Lo-Z output.

Why not use the lowZ output, why do you need the high Z output?

I suspect my blind faith in branded schematic!
But your words sounds like a good conclusion for my little experiment

[Steve Conner]

i've never heard the SVT. I'm sure it's good amp.

The rehearsal rooms around here have a couple, mostly the rackmount versions with the tubes all squashed together in the back. I love them, but I once played bass in a band with a frontman who hated the things. He called it a "f***in' giant hamster fart".

Output Pot at mid position = Lo-Z out is much brighter, punchier and louder.

Good, this is exactly what should have happened

[bluemonk]

It seems that output pot actually affects tone heavily when dimmed.

Tried to replace 1M pot with 820K resistor in series with 100k pot. That makes Hi-Z out far more similar to Lo-Z in terms of tone (without the need to add a triode for CF).