Case No. 1) Canary Audio CA-160 Mono Blocks Amplifier

A customer brought in a pair of Canary Audio CA160 with an excessive idling hum.  He had been told a reasonable amount of "hum" is normal due to the number tubes employed in the design.

We diagnosed the problem and made several changes to the circuit:

• Re-configured the filament voltage source of the inputs tubes

• Re-adjusted the filament voltage from 5.6V to a proper 6.3V

• Adjusted the input sensitivity from 0.5Vpp to 1.0Vpp.

Results from out bench test show figures which exceeded factory specification, with noted improvements in the signal to noise ratio.  The idling hum was reduced to inaudible levels.

Estimated Repair Cost: $ 400.00       

Actual Repair Cost: $ 350.00

Turnaround time: 2 days.

"Thank you Excelstereo, you can do what the factory couldn't." Greg, Toronto