Expanding questions about tubes in a preamp


Hello to all...

Started with a (helpful) discussion titled "How to select tubes for a line level preamp"... Expanding questions that have generated from that...

Have learned that hum/noise from tubes is a major consideration - now trying to figure cheap ways to address quieting the 12AX7s and the EF86s.

Would like to try "banding" the tubes with rubber ring washers - one?two?three per tube?

Where should the rings be on the tube: Top? Mid? Bot?

Can you over dampen a tube?

Knowledgeable tube users/ Masters input/suggestions please...

insearchofprat

Showing 2 responses by lowrider57

Using a tube damper will not quiet a noisy tube. Noise is usually inherent in the tube. Hum could mean the tube has a fault or it’s coming from elsewhere in the circuit.

Dampers can be used to reduce microphonics from a tube. They are often used to tighten up bass or reduce excessive overtones. And they will change the sound, so experimentation is necessary.

The only time I’ve used dampers is on a component with exposed tubes. Acoustic vibration from a speaker or vibration from the audio rack can be heard through some tubes.