Power Amplifier Quad 606

Hi, 
I am the new member of this forum. I have a question regarding Quad 606 MKI. I had purchase this power amp from India. First time when i connected the amp with power notice that a humming sound come from it. If it's a real problem please let me know how can i resolve this. Further, My question if I upgrade it MK II it will performance better compared to earlier version.

Determine whether the hum is mechanical or due to ground loop. If you don't hear the hum from the speakers and if the hum is beyond the noise floor of the room then I wouldn't worry to much about it. 

Another cause of the hum is due to your electricity supply. Check the voltage. I do not have the actual reasoning but I noticed that I get the hum when the voltage was very high. 

If it is ground loop then isolate the offending equipment. You could try to google on groundloop troubleshooting.

Thanx for your co-operation. The humming sound comes from inside the system. I think from the capacitor. It's come only from the amp. I didn't get any sound distortion from the speaker. I have checked it to my friends house too, same problem occurred.

Looks like mechanical hum. How loud was it?  There are a number of people facing similar problem with the Quads. Some say, the older Quad requires ground cable to be connect to your preamp. Some say, there is D.C. In the power supply. Sometimes, large capacitors will hum. Do you see any silicon or damping material on the capacitor? Check whether they are intact.

I think large capacitor will hum. I didn't see any silicon or dumping material on the capacitor. 
The sound is very low.

soumyajit.basu wrote:I think large capacitor will hum. I didn't see any silicon or dumping material on the capacitor. 
The sound is very low.

I have a 606 but there is non of the humming from the unit or from speakers

STC wrote:Looks like mechanical hum. How loud was it?  There are a number of people facing similar problem with the Quads. Some say, the older Quad requires ground cable to be connect to your preamp. Some say, there is D.C. In the power supply. Sometimes, large capacitors will hum. Do you see any silicon or damping material on the capacitor? Check whether they are intact.

I contact with the mechanics regarding this humming sound, he told me that due to powers supply has been damage. Need to change power supply system.