Hi guys!
I'm having problems with my band mates bass amp head.
It stopped working one day.
I found that one of the driver transistors was dead (it was not short circuited but hFe could not be measured) so I changed that. The fuses were blown and some 0R resistors as well (they are used as jumpers on the PA pcb).
This far it was straight forward but now the frustrating part comes.
If I turn it on (with a light bulb in series with 220VAC cable) without any speaker load and attach speakers later - it works fine. If I turn it on with speaker connected - it trys to jump to positive rail voltage (the light bulb limiter does not allow it to do that). Judging from the burned 0R resistors it has been run with only one rail connected for a while. All the trannies are fine now (desoldered and measured hFe for all of them).
Has anyone expirenced such a strange PA behaviour?

Hello everyone!
Just wanted to show my new creature.
I have made a Meatball clone for a friend of mine (McMeat layout) and he was interested in Z.Wex Ooh wah. I thought it would be much more useful to make just the "LFO" generator and feed it into Meatball. This gives more features than regular Ooh wah.
Here's a little sample video. I have to admit - no guitar sounds in this video. Sound is created by a distortion pedal with feedback (the signal line is      MT2-->TU2 -->Meatball  while bypass output from TU2 goes to input of MT2)
http://www.youtube.com/watch?v=4WKh_BytKuY

Hi everyone!
I'm thinking if any one has an idea where to get these really small potentiometers. For example like some of Z.Vex pedals use

Does anyone have drawings of a guitar amp head?

Hi!
I'm looking for an adjustable tube amp power attenuator build. The problem is - I can't find any adjustable attenuator schematic.
May be some of you guys have seen them somewhere...
Thanx.