Too High Voltage on Preamp Tubes HELP

[GuitarZombie]

Building a 5f6a/jtm45 clone off of a Lafayett PA645. Have the amp built, but readings are showing my voltage to the PI, V1 & V2 as way too high.

I kept the power section off the amp the same as the original Lafayette, as when I took readings before I gutted everything from the PI to the Inputs, they where similar to what was being called for on the 5F6a Bassman schematic. Actually a bit lower, but not bad. Now, after the switching of everything from the PI-inputs, voltage readings are way higher. The plate and grid voltage isn't out of specs with the 6l6gt's, but after that, they don't really drop on the rail like they need/should.





My readings now on the 3rd cap read 440v as opposed to the 366v that I had before the frontend swap.

[sgelectric]

Are you taking these readings with all the tubes installed in the amp? Just checking................

SG

[soundguruman]

Building a 5f6a/jtm45 clone off of a Lafayett PA645. Have the amp built, but readings are showing my voltage to the PI, V1 & V2 as way too high.

I kept the power section off the amp the same as the original Lafayette, as when I took readings before I gutted everything from the PI to the Inputs, they where similar to what was being called for on the 5F6a Bassman schematic. Actually a bit lower, but not bad. Now, after the switching of everything from the PI-inputs, voltage readings are way higher. The plate and grid voltage isn't out of specs with the 6l6gt's, but after that, they don't really drop on the rail like they need/should.

[ATTACH=CONFIG]26692[/ATTACH]

[ATTACH=CONFIG]26693[/ATTACH]

My readings now on the 3rd cap read 440v as opposed to the 366v that I had before the frontend swap.

You need to bias the output tubes hot, and the voltage will drop. You do have a speaker (or load) connected?

[g1]

Pretty hard to tell anything without a schematic of what you actually have there. What you have built is no longer the lafayette schematic or the 5F6A, correct?
You need to draw exactly what you have built and show the voltages you measure at all the supply nodes and tubes.
It sounds like one or more preamp tubes is not conducting. Is the amp working properly or no sound?