FWIW, $700 for a good condition MC7100 is very reasonable. If you trust the seller and have the spare cash, you should strongly consider buying it. Especially if it's a late model with the balanced inputs.
That said, Erik has passed along good advice. I'd add fooling around with speaker position and double-checking all electrical connections. Those are always less costly than changing gear.
Good luck and happy listening!
That said, Erik has passed along good advice. I'd add fooling around with speaker position and double-checking all electrical connections. Those are always less costly than changing gear.
Good luck and happy listening!