[dollar99]

Whatever I do, I cannot seem to get rid of the hum coming from the left channel. Here is what I've tried
-Ground loop isolator between the source
-2 prong adapter
-Unplugging the source still gives me the hum so its not source related.
-Lowering the volume to 0 has no effect
-Tried different power outlets around my house, tried plugging into a computer UPS, and home theater power conditioner. Nadda.

I've noticed that when I first turn on the amp, it starts to hum after 5-10 seconds. If I gently tap the power supply the hum goes away. The hum will come back anywhere between 10 seconds up to 2 hours. After the amp is nice and hot after listening for a while, the hum does not go away at all.

Oh, and sometimes if I unplug the phones(AKG 701) and plug them back in it stops the humming for a couple of seconds, then it returns.

Could it be that I have a faulty tube?

I am not happy with this amp.

 

[sword_yang]

Quote:

Originally Posted by dollar99 /img/forum/go_quote.gif Whatever I do, I cannot seem to get rid of the hum coming from the left channel. Here is what I've tried -Ground loop isolator between the source -2 prong adapter -Unplugging the source still gives me the hum so its not source related. -Lowering the volume to 0 has no effect -Tried different power outlets around my house, tried plugging into a computer UPS, and home theater power conditioner. Nadda. I've noticed that when I first turn on the amp, it starts to hum after 5-10 seconds. If I gently tap the power supply the hum goes away. The hum will come back anywhere between 10 seconds up to 2 hours. After the amp is nice and hot after listening for a while, the hum does not go away at all. Oh, and sometimes if I unplug the phones(AKG 701) and plug them back in it stops the humming for a couple of seconds, then it returns. Could it be that I have a faulty tube? I am not happy with this amp.

This is perhaps the tubes "microphone" effects, please contact your supplier, we sent you to replace the tubes.

 

[Agent Kang]

Have you tried switching the tubes around to see if the hum transfers to the right channel?

 

[dollar99]

Quote:

Originally Posted by Agent Kang /img/forum/go_quote.gif Have you tried switching the tubes around to see if the hum transfers to the right channel?

Yeah, I'll try that, how do you remove the tubes? My first tube amp.

 

[dollar99]

Quote:

Originally Posted by dollar99 /img/forum/go_quote.gif Yeah, I'll try that, how do you remove the tubes? My first tube amp.

Cool, they just pop right off. So I switched the driver tubes around, and now the hum is in the right channel. So now the question is, what type of tubes should I replace them with? Should I also replace the power tubes?

 

[sword_yang]

Quote:

Originally Posted by dollar99 /img/forum/go_quote.gif Cool, they just pop right off. So I switched the driver tubes around, and now the hum is in the right channel. So now the question is, what type of tubes should I replace them with? Should I also replace the power tubes?

No replacement the power tubes.

 

[vcoheda]

sounds like something is wrong. try to work it out with little dot. i'm sure they will help you to fix the problem.

 

[whatisthematrixx]

seems to me like you have a faulty tube. i would contact little dot for a replacement. i think you only need one replacement tube, the one that is causing the humming in the left channel and when switched the right channel, but i am not very experienced in tube amps either. little dot has great customer service so i would definitely recommend contacting them.