Did my preamp short kill my Mark Levinson amps and Infinity Beta servo ?

OK, a 'short' means that somehow the preamp leaked DC voltage into the Infinity crossover/servo box and the power amp? But if the Infinity is a Low Pass/High Pass setup, which I think it is, the high pass section would block DC from the HP output feeding your Hafler, wouldn't it?

I'm just trying to understand.

Maybe the short was in the power supply of the preamp and DC or worse, a rectifier diode failed, and it was AC that got on the chassis ground? In that case it may have fried the ground traces off the circuit boards in both down stream devices. That's not really fixable, and you'd be looking at replacements. Either way, bummers, Best of luck with your repairs.

Update: I replaced a fuse in the Hafler and it came back to life.  I hooked up one of the ML No23....the one that was not connected to the servo crossover...to another system and that is working (I did not realize the switch has a "reset" protection circuit).  My second ML...the one hooked to the servo unit is not alive, but was told it might be an "internal fuse" issue.

So I am thinking the servo unit is the damaged bad actor after reading other posts with similar problem  ( massively loud "bark" once servo turns on with two different amps...very scarey loud).

My pre-amp was repaired for under $700 and is on its way back to me.

I am contacting PS Audio for help with the servo as recomended here.  Thanks to all for all the help.  I really want to save those IRS Betas.

Update on saving the betas:     PS Audio no longer works on the IRS Servo controller, however "magicmarksy"  (ebay name) is someone to contact for work on this unit....and by the looks of what he has refurbished and lists for sale, a definite high end vintge Infinity system go-to guy.

I currently added in two NHT SW3 passive subs with seperate amp and crossover to use along with the midrange and tweeter ribbons columns and it sounds OK, but really want to save those woofer columns and servo unit.

I 

jerry_b2

... I am thinking the servo unit is the damaged bad actor ... massively loud "bark" once servo turns on with two different amps...

That is normal. The servo should be powered up (and the servo circuit synced) before the amplifiers are powered on.

Tried that....with two different power amps, once of which had a volume control i could slowly turned up output before trouble.   Same loud ...and I mean weapon of mass destruction loud...even blew off the dust cap on the servo wired woofer....with same results.

I had both sequentially....and simultaneously.....  turned on the servo unit and amp for 25 years and nothing like this ever happened.   Infinity warns of this horrible output if the servo feedback not working properly.

I will get the servo fixed as well has hopefully find someone to test the active woofers before hooking it all back together.