Blow OT?

[WillSync]

I got my 69-73 Metro kit right before George got out of the kit business. Wow what an amp. It's a beast.

Or it was.. Xmas 2012. I played at a family party and got ready to play, no sound. The impedance selector switch got moved somehow to in between the 4/8 ohm position. I was able to play that day and everything seemed to be OK.

About 3 weeks ago I was playing at my son's house and I heard a static noise and the amp shut off.

I thought I blew a tube. New glass in it now and everything sounds weak and fuzzy. It gets worse as I turn it up. I could only get 24ma on the tubes with the bias turned to the max.

I have a bad feeling about this. I can still play through it but man.. the god like power and punch is gone.

what a bummer. How can I test the OT to be sure that's the problem. Thanks. Will

[ampSnob]

I would test your bias supply a bunch first. What voltage is it giving you with respect to ground? Is that voltage getting all the way to power tube grids with no guitar plugged in?

As far as testing the OT. You can do it with a 9v battery and a ne-2 (very common cheap neon indicator thingy) The principal is nice and simple, it relies on the flyback voltage that occurs when you remove the 9v from the circuit which will send a a bunch of volts across the ne-2 causing it to flash if everything is working correctly. If it doesn't do that, you probably have a short or something and the OT is dead.

Read here for details:

http://www.premierguitar.com/Magazine/I ... ester.aspx

or here

http://www.ehow.com/how_7775846_check-o ... ifier.html

I could swear there was even a post here on Metro about it too. BTW, If you don't have an ne-2 in your junk drawer you can probably get one out of a wall voltage tester things and use that. I have one with a few different lights that shows if I have 120 up to 600 volts-- has 3 ne-2 bulbs inside it, very simple - pretty cheap.