May Queen Booster

[toby]

Hi. ive built the mayqueen booster and have been tying it out with my burns red special. there is the overdrive sound i expected but you only get it if you play really hard. also, the notes decay really quickly. they just stay for a few seconds and fizzle away! the voltage reading for the middle transistor (2n3904) should say 2volts but on mine it was about 0.2volts. Could this be why it isnt making the right sound as it doesn't sound exactly like the sound clips? any advice would be apprreciated

[markm]

that's a VERY good reason why, Mis-Biased Tranny.

[BrianJ]

I built the the May Queen last month.  I can't troubleshoot yours for you but, if it helps, I had to increase the size of the 220K feedback resistor to about 1meg to bias Q2 properly.   That resistor and the bias on Q2 were very interactive with the JFET and its bias resistors so be ready for a little complication when you get started.  At first mine was biased like the schematic at ROG shows, but I had trouble with some crackly breakup as the note sustains.  I tweaked some values to get the collector values closer the 1/2Vcc.  It changed the tone but I find it more usable now. 


Good luck