Well that sucks. I don't see how I could have overdriven the center though. I've only had the amp for about 6 months. But before that, I was using a Denon 2805 to run my system. I did briefly have my crossover set at 60Hz, but for the last 6 months or so, I've had the whole system crossed over at 80Hz, specifically because the center is rated down to 65Hz, but my rears are only rated to 80Hz, so I figured 60Hz was too low of a crossover point.
Do you know ballpark what it might cost to replace the drivers? If it's more than $100 or so, I might as well buy a new center channel speaker.
Thanks for all the help so far.
I have had one other thought. I'm sorry I don't think as fast on my feet as I used to. You have to have your tech do some further tests, and feel free to show him this communication. There may still be a problem with the amp.
Modern transistor amps are direct coupled. That is to say the power transistors are directly connected to the load. There is no output cap like in early transistor designs.
Now as power transistors fail they develop a DC offset voltage. This in an amp as powerful as yours could be close to 100 volts DC. This is presented to the woofers and is a voice coil fryer. Usually the fuse does not act fast enough to save the driver if the amp protection does not work.
Now obviously this really upsets people. Now when direct coupling came out in the mid seventies there was a rash of speaker fry ups. The Crown DC300 A was a particular offender. I lost a line source of eight expensive midrange drivers to a Crown 300 A in an installation in a large auditorium.
When all these speaker fry ups occurred protection circuits where developed.
These are DC sensing circuits. The commonest is a TRIAC and thyristor that makes a clamp circuit that shorts the speaker output under conditions of DC offset. This sacrifices the output transistors but they are usually done anyway. Other types rapidly cut the rail voltage, and there are circuits that disconnect the speakers.
Occasionally you still run into a rogue design that has no protection.
Now have your tech check that your amp has speaker protection and that it is working.
Now have him disconnect or by pass the circuit, and drive the amp hard into a large dummy load resistor. Have him continuously monitor the output for DC offset. If DC offset occurs he needs to do the appropriate repairs.
I have had cases where there was no speaker protection or were the protection was not functioning, and huge DC offsets occurred as the amp was progressively driven. This is a well known issue in solid state amp service, so your tech should understand.
I know this is technical but if you don't understand it all your tech should.
In my experience an amp line fuse never blows for no reason. The question as to whether the speaker or the amp primarily caused this failure has to be definitively answered, other wise you will likely be very unhappy.
Interestingly I have a friend who has just bought a new McIntosh 400 watt per channel amp. I was stunned to find it has output transformers! I suppose if the tube fanatics can't hear transformer hysteresis distortion the solid state owners won't either. There is no possibility of frying speakers from DC offset with this amp. They say they did it to perfectly match the amp to the loudspeaker impedance. Just like a tube amp! I think they just wanted to make sure they never had to buy a customer an expensive pair of speakers. It eats into the profits you know.
By the way I don't think I know what your speakers are. But if it comes to that your best bet is to contact Orange County speaker repair or the manufacturer.
http://www.speakerrepair.com/
Good luck and keep us posted.
