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Hi, I finished building my amp on friday and i've been playing through the amp for a few days now without a problem. Today its started to cause the speaker to pop loudly whenever standby is switched on & there's a big drop in volume. I took a few measurements and here's what I got.

B+ 355v
Plates: V1=127v; V2=171v(pin1), 274V(pin6); V3=178v(pins1&6); V4&5=371v;

Cathodes V1=1.3v; V2=1.2V(pin3), 171v(pin8); V3=120v(pins3&8); V4&5=7.5v;
The plate voltages on V3 are much lower than whats indicated on the layout & the cathode voltages are considerably higher.
I've tried swapping the tube with no change.
I think I may have a capacitor problem here but I'm not sure, any help would be great

All valves are in place, guitar plugged in but producing weak sound when measurements were taken.
Measured capacitance of 22uF 450V caps all measure between 24uF & 27uF. DC resistance in the megaohms.

Both channels not sounding correct?

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

At full volume on channel2
it's about tv volume. Channel1 is louder
But not by much

Were the PI values close to spec before? Now: V3=178v(pins1&6) (250 spec) ; V3=120v(pins3&8) (70 spec);

Measure all Resistor values again and touch up ground connection as well. Touch up the pin solder joints as well.

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

Problem solved
Removed board and found a tiny piece of fine wire underneath about where the plate resistors for V3 would have been.
It was an off cut probably from the shielded cable I used for the input wiring. Used compressed air to blow out the chassis of the amp in case I'd missed anything else. Sounding sweet again! Plate voltages back up at 252 & 247 V.
I should have been more careful during the cleanup!
Thanks for your help & for a fantastic amp!

Excellent!! nothing like a Post-Build chassis cleaning. I use a air gun / compressor.
Post-Build chassis cleaning. Good advice for all.

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

I just had the same problem with the VRM install regarding wire strands causing some trouble. Some small wire strand poked a hole through the sila pad. Removed wire cleaned everything, tested all values and everything was in line. and she sounds fantastic!