Makes sense. I'll make the change. Thanks

Huh didn't know that. It definitely works there however may work better up front. Thanks

Up and running strong. Installed behind the rear seat back of my f150. Also running an audio control line driver for the 2500. These amplifiers were so worth the time and money spent to get running. Sound quality of these amps are incredible. Thanks everyone for the great information on fixing these.

Thanks so much!

That would be awesome, the button works great just missing the cap. My address is 4061 Brian avenue Duncansville PA 16635.
John Zenobia

bought off ebay as is not working. was definitely beat hard replaced 8 caps in the power supply and raised the uf to 3300 at 50 volts,repaired broken trace under the on large cap and replaced all the mosfet outputs. All that's left to do is get it warmed up on the bench and check the bias voltage. P...

Just bought an XS2500 that I am planning on rebuilding. New caps , new output stage,etc. I loved the sound that XS4600 and wanted a little more power to the sub so I will be running both amps .I remember selling these amps when I worked at a local stereo shop back in the late 90's. Will keep updates...

Sitting in my truck now listening to it! It's like a whole new audio system arrived! Unbelievably awesome ☺

UPDATE !!! So excited got it working. Thank you so much for the all the information it was a great help. changed all the mosfet outputs,all the transistor drivers,8 cap0s in the power supply,4 caps in the xover section that were leaky and swelled and numerous cold solder joints. The sound on the ben...

Thanks for the great information. Yes I ordered the IRF540. Do you know what the bias voltage and where it's measured at. I know sometimes you check it at the emitter resistors.. Thanks waiting on parts from digikey.

Update. Got the amp running for 30 seconds before blowing out IRF540 mosfet drivers. I replaced 12 caps throughout the amp and some cold solder joints.

Either front or rear channels have the same issue . I am guessing that only half of the power supply is firing on and not powering up the preamp board. I still have more checking to do. Thanks so much for the great advice and information.

Update. Seeing 28 volts on half of the power supply caps

Both channels thumb when selecting the 24 db crossover and when pushing the hp/lp button the squeal starts and stops. thanks

Yes the noise is stopped if the x-over is bypassed.

I didn't check if both channels are affected but after re-check on the outputs the transistor I thought was bad was a diode so I think the outputs are fine. Need to do some more work on it this week when I get home from work.

Ok thanks for the quick reply and the information. Do you think anything could be wrong in the preamp section of the board? The squealing noise seems to be slightly affected by pushing the crossover button in and out.

So i bought this Phoenix Gold xs4600 off ebay. Description said pristine condition, well it was fair condition to say the least. Got it hooked up and getting a squealing sound coming out of the speakers. Opened it up to see the main power supply caps were bulged and leaking. Ordered 10,000 uf at 25 ...