[minimus]

I spent most of a day -- far too long, really -- setting up a new system: a Manley Shrimp preamp into a Meridian G57 power amp driving Sehring 703 speakers.  I bought the Meridian G57 used on Audiogon.  The US dealer of my Sehring speakers recommended the G57, its retail price (~$5K) was way above my budget, and so I bought a used one.  (It was modded, with the stock speaker binding posts replaced with Eichmann binding posts by the seller.) 

Long story short, the Meridian cuts out every time I turn it on.  The actual sequence is I turn the amp on, a spark shoots out from the right speaker binding posts, the loudspeakers make a loud popping sound, and the Meridian's circuit breaker causes it to shut down.  The speakers don't appear to be the problem, as I got the same result when I hooked up some old Polk LSi9s I have in my apartment.  Also, the Sehring speakers worked fine when I tested them out with a cheap receiver that is much less powerful than the Meridian.

I also tested to see if the Manley Shrimp is the problem. I plugged my headphone amp into the Manley's RCA outs and the headphone amp worked perfectly.  Unfortunately, I don't have an alternative power amp on hand that would definitively let me test whether the Meridian is the root cause of the problem or not.

The bottom line is that I strongly suspect the Meridian amp I bought may be a lemon.

If anyone has any thoughts on what the problem might be or recommendations on what to do next, they would be much appreciated.

Thanks.

[WerTicus]

do you want to fix it or get your money back?

break out the multimeter and find the fault, sounds like a simple short to me - or ... follow the usual procedure for getting money back in this case....

if your not technically minded take it to a local hi fi electronics guy and have them diagnose it - could be a simple fault.

[BillB]

I am going to guess there is a problem where he modded it. Maybe he was sloppy and left some wire strands that finally got moved into shorting position with the shipping?

Wouldn't hurt to take her top off and take a peek would it? 

[Glen B]

Yes, maybe wire strands or even more likely, the replacement posts were not properly installed (esp. with the right insulating spacers) and one is now making contact with the chassis.  Using a multimeter set to resistance measurement, check for continuity between the post and chassis.

[*Scotty*]

 minimus, You might want to connect a multimeter to the right channel speaker binding posts with it set to read DC voltages less than 200volts. After connecting the multimeter to the binding posts turn the amp on while observing the meter and note the DC voltage read by the meter. Your reported symptoms and the activation of the amps protection circuitry lead me to suspect that the right channels output devices are blown and you are seeing the full DC power supply rail voltage at the binding posts of the right channel which could produce the fireworks you are seeing and the nasty noise from the speakers. You might check both sets of speakers you connected to the amp and verify that the tweeters are still alive.
Fried tweeters and crossover components can result from the presence of high DC voltage appearing at the output of the amp and the protection circuitry not activating quickly enough
to save the speaker.
Scotty