Need a repair shop for tube amp Detrioit-Toledo

browse forums and see if you can rebiase yourself. there are also lots of reading material on troubleshooting and modifying amp for better reliability and performance.
did you audibly test your tubes by swapping between channels? how do you know you need rebias? search resources. please check also output tubes of your cd player by swapping with good ones before taking decision to send it to techie. shipping your amp to any decent repair facility may cost you over $100 for $350 amp + repair costs.

if you're given bias harness, than you should check bias with voltmeter or multi-meter at 600mV or .6V. check/correct bias on each pot. if the difference is large from .6V and you're not able to bring it there, than you have possibility of a bad tube. connection of probes to the most of multimeters as well as setting is self-explanatory and easy. adjust bias pot slow and constantly monitor tube and multi-meter.