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Completed install of VRM in Trinity Tweed and there was a lot more hiss (at high volume and when the tone control is turned up) than before (some, but not objectionable) . VRM was installed per layout with 1M resistors on pin 2 and 7 of V1. Also there is a 1M resistor on each of the inputs per layout. Sooo, 1) Are the 1M's necessary/required in both positions (inputs and V1)? 2) What do the 1M's do on V1?

Also read in documentation that replacing carbon comp resistors w/ Metal Film will help tame the hiss. I don't want to go overboard with the MF resistors. Should I replace the 820R cathode(?) or the 2 100K plate(?) resistors or all three? And will Carbon Film's do the trick (have those in 100K; the 820R will need to be ordered if needed)?

Thanks for any additional information provided.

Edit: Reread the VRM docs and it answered most questions. The 8-16 uF 450V capacitor is added between HVIN terminal and power ground, this is correct? And regarding the resistors to the plate, good/bad idea?

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"The only problem with being retired is you never get a day off"

My install was on a TC-15 so maybe different but...
I did take the resistors off of the input jacks.
My instructions said something like "move the 1M resistors from the input jacks to the grid."
And I do believe Stephen said something to me about a hum if you don't make this move
So I don't have the 1M resistors in both places.

Thanks for the reply! PS Were you on the AX84 forums? I joined AX84 ,but haven't kept up for about 10 years. Work interfered, but retired now. Back to fun!

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"The only problem with being retired is you never get a day off"

1M should be on the tube if you have a VRM installed. Not in both places.

Read the section called "Introduction to Vacuum Tubes and Common Terms" in our manual. It will tell you what the resistors do.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Stephen, thanks for the definitive reply on my VRM question! I built the Tweed first and added the VRM after the Tweed was running and playing REALLY well. Will make a note in build docs so I won't repeat this mistake again.

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"The only problem with being retired is you never get a day off"