BASH amplifier problem

[lightlinked]

this is a BASH based plate amp from an Athena AS-P6000 subwoofer and it basically seems like the power supply has some kind of problem. instead of music i get a buzzing, i would describe it as PWM at 120 hz proportional to the audio input level. based on what i have have heard about the power supply stage of these, for some reason it is not switching at the normal high frequency. nothing on the board looks toasted, and none of the joints look cold so i'm not sure what to do about it. the crossover has power, +- 15 volts. any suggestions on how to fix this? is it possible to rip out the fancy follower smps deal and throw a linear supply on this thing since it is really just AB? it seems like such a waste to throw it away and get a new/used, different/better amplifier

[planet10]

I'm interested in following this. I have a smoked bash amp (Daniel -- boy genius next door -- says he could fix it if he had a schemo)

dave

[lightlinked]

here is a scope shot,
CH1 is the signal i am giving it, it is some music through a subwoofer crossover, yes that is going into the crossover built into the amp, double crossover, oh my gawd, so bright, so vivid

CH2 is the speaker output. not very musical

i might try to cut the power rails between the SMPS and amp and power it with a linear psu

[dave_gerecke]

Hello Gentlemen, this is for a different brand of equipment (Klipsch), but they used the BASH technology in the amps. Here's a link to a reverse engineering job that was done on the Klipsch Promedia. They also have some good information about what seems to be a common failure, at least in the Klipsch design.

Klipsch Promedia V.2-400, V4.1, V2.1, And V5.1 Amplifier Repair

Peace,

Dave

P.S. I believe that at least one of the two individuals involved in the website and/or reverse engineering is a member here.