• 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.

Electrolytic capacitor vs extra triode stage

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
That certainly worth a shot.

Btw, what value of trimpot should I go for? 1k? And, do I want to bypass the TL431+trimpot with a small film cap?

Sorry, I have never used a regulator. :D

The small 10 to 25 turn trimpots have a power rating of 50 milliwatts typically. I don't know your 6H30 bias voltage but if it's 3 or 4 volts then 1K would give you 9-16 milliwatts. 2K or 5K depending on your target voltage would be better IMO to reduce the power dissipation to < 10 mW. You can also use a pair of fixed resistors if you don't need adjustability.
 
... do I want to bypass the TL431+trimpot with a small film cap?

In my experience these cause no stability problem even with high gm tubes and they have plenty Gain*BandWidth for this use.

If there is oscillation in the 200KHz-2MHz region (the GBW limited region), one could certainly try bypassing between a and k pins as a solution.

My personal bias is to only add components when there is a specific need or significant performance enhancement.
 

Attachments

  • tl431dynimp.png
    tl431dynimp.png
    49.6 KB · Views: 80
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.