Recent content by Scott MacKenzie

Ok, thank you.

Hey Agedhorse. No disrespect taken. I work on a lot of tube amps but this is a bit above my head. I assumed that the rails should be balanced but opposite polarities. With the AC voltage coming in fairly equal, but directly after the rectification the voltages become unbalanced, I thought...

Hi All. Hope this is in the correct section. I'm repairing a BX4500. Power amp (P3000) has a big difference in the voltages of the power rails. I've re-flowed solder to all caps and transistors, checked all diodes, measured caps with an ESR meter. I'm about to throw it against a wall. Anyone...

Hey All. Thanks for all the input. So, to summarise, I was a dumbarse....I tried balancing the tubes using the hum pot. Once I connecter 2 DMM's to both sides of the tubes could I balance the tubes correctly. Then, using Wasnex' info, I connected 2 DMM's across the pair of tubes I was...

Thanks for the replies. It is an unusual circuit.

Hello all New member here. I have been repairing tube amps for some time and understand the dangers and safety issues involved with working with high B+ voltages. My question here is how to bias the 400PS correctly. I have been following the Ed Jahns 30 point setup The Fender 400-PS Updates...