• 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.

Salas SSHV2 + Moglia hybrid mu-follower

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The LF bandwidth is unnecessarily low, not worth going under 10Hz with "linear" section.

The R6 also "horn in" the low frequency behaviour.

Try to use lower R6, much lower C2, possibly with other operating point.
5687 is happy at higher current.
 

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Hi Felipe
the gyrator doesn't change with "warm-up" time. It's pretty stable from a tempco point of view. I have not noticed any changes over time am afraid.
Perhaps is something else in your system. I'd also suggest trying without the cathode bypass capacitor, it will sound better in my view....
Cheers
Ale

Ale the Russian teflon caps were new when the lack of bass, now both hybrid mu-followers are sounding with high SQ. The cathode bypass capacitor adds bass so more clear without cap (I tried) thanks.

Sorry Ale, I had to say teflon capacitor "break in" not warm-up.
 
No worries Felipe. I think you may want to be a bit more careful and perform more research and tests before drawing to a conclusion that the 2 components “sound bad”. It gives the wrong impression which frankly isn’t useful when the issues could be anywhere in your system.

If you want lower gain, the 71a is a great valve to look for.
Cheers
Ale
 
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You have a fundamental fallacy.

Two individually good module (NOT component!) cooperation depends on good planning and implementation.

It's not "plug and play", it's requiring proper planning.
Each module output has an impact to other input, thus can change its operation, and vice versa, the parameters changing reacts module components.

If you look a gyrator as "module" and tube as "module", not cooperating component conglomerations, the final operation may be uncertain.
 
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