• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

6V6 line preamp

Say 12R pass 0,15 A which is not impossible if a tube draws 0,5 or some more even. 0,15 times 6,3 is 0,95 W so I SHOULD be within margins but its close.

Thing is, we dont really know how each and every tube acts when CSS fed. All I know thay acted very differently. I start with ZMs circuit and collect some data.
 
Almost there:D:D:D

Freakin smallfingerjob;)

Anyways its homework and kiddo g'night story story tonight so we'll see
 

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Say 12R pass 0,15 A which is not impossible if a tube draws 0,5 or some more even. 0,15 times 6,3 is 0,95 W so I SHOULD be within margins but its close.

Thing is, we dont really know how each and every tube acts when CSS fed. All I know thay acted very differently. I start with ZMs circuit and collect some data.

If you burn the Colverns i can supply the bigbrother.

They´re in the 3W range.

Next size bigger won´t fit the box :D.
 
Hello insect lovers

The bug is now up and running and I have been running some samples. The schema is ZMs except for 10R pots and 18R series (R3).

I first ran it on 13R5 dummies and got between
5,82-5,93 and 5,84-5,95 volts (ch 1 and 2) by min/max on pot.

Then I dropped in a pair of RCA clearglass
5,86-6,09 and 5,98-6,14

RCA Black Anodes
5,43-5,61 and 5,51-5,68

Philips
6,01-6,23 and 5,71-5,91

Russian 6P6S
6,12-6,32 and 5,90-6,08

Well, what do we get out of that. At least I would like to be able to run different tubes in the same amp without having to open it and solder, so if running CSS on filaments I definately need a variable one.

Second I need a wider variation span. Almost 0,7 volts in difference between tubes is (only those few tested yet) is going to affect the sound to much for being acceptable for me.

The way to go might be to drop R2. That will put more current over the pot but make it more variable in current (and voltage).

Any suggestions/comments before I tear things apart?
 

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I will give it a try and sort out the breadboard a little so I can first go over some more tubes and then go on with the audio circuit testing.

Is the distance between CSS and filaments of any importance in this kind of application or can I just place it anywhere?

Current is the same through the entire circuit so not the problems you have with voltage regulation.

So not sensitive to cable lenght.
 
Big dog from Japan seems to like BAs' Idea of damper diode after SS.

6moons audio reviews: Leben CS660P

"Hyodo San used a silicon diode instead of rectifier tube for its "high speed, large capacity, small consumption and small size". However, because the diode supplies a large voltage immediately after turning on power, a 6CJ3 "dumper tube" provides delayed ramp-up of the output tube voltages to warm the pentodes up gently and extend their operational life."
 
I was posting that more as a comment on Bas' idea of SS rectification with damper tube to slow ramp up. I think that is all the tube is for. T was intersting to me that I happened across it in a review of a well regarded amp. As i said earlier, I preferred SS, but being new to the game, I take that with a grain of salt. It is reasonable to believe that each has its merits. I do not know, just learning.