carver M-4.0T and M-1.5T hum on output at idle

[hifidoctor 0]

Hi All,

 

 

New to the group. I purchase a few Carver amps(M-4.0t and M-1.5T). Both of them have the same audio hum at idle with no input connected from the pre-amp. Each one is from different sides left and right. But once I hook up the patch cords from the pre-amp to the Carvers is goes away???????Any help would really be appreciated.

 

 

Thanks

Don

[loner_t 2,571]

Welcome to CS, HiFiDoctor!

 

My guess is something is not grounded properly. (but wait for other techs to chime in). 

[Ar9Jim 6,520]

 

 

Hi All,

 

 

New to the group. I purchase a few Carver amps(M-4.0t and M-1.5T). Both of them have the same audio hum at idle with no input connected from the pre-amp. Each one is from different sides left and right. But once I hook up the patch cords from the pre-amp to the Carvers is goes away???????Any help would really be appreciated.

 

 

Thanks

Don

Welcome hifidoctor.. I suspect it is normal to pick up noise on most amps when the inputs are not connected and the amps are under power.. It is always recommended to have the preamp connected and under power before turning on the amps, and when shutting down, turn the amps off before the preamp.. Open inputs on an amp connected to speakers and under power can be a bad thing and very noisy.. When you say audio hum, I am assuming the sound is coming through speakers and not transformer hum from the amp itself?