Hafler DH-101 hum & crackle

[Zach Nelson]

I have recently acquired a Hafler DH-101. It sat on a shelf at a local store for a while, so I'm sure it needs a good cleaning to start. Last night, I noticed the right channel sounding crackly/distorted. Not terrible, but enough to break up the treble. I walked into a different room for a while and returned to find the left channel had no sound at all coming out of it. I powered everything down and could not get this to happen again. The channel is still slightly distorted. I also noticed that if I touch the face of the preamp while on, it has a low hum. Almost the sound of a turntable that is not grounded. What is going on here?

 

[cobbears]

Get yourself some proper switch cleaner and clean all the switches and pots - notorious for it - it is almost 40 years old after all

 

[icenine]

Does each speaker output have a fuse on that model?

 

[Zach Nelson]

Does each speaker output have a fuse on that model?

No....This is a preamp. I think the only fuse in it is for the power supply.

 

[cobbears]

No....This is a preamp. I think the only fuse in it is for the power supply.

Yep - just psu fuse.

 

[rickl]

i wonder if this will help your hum.

 

[Zach Nelson]

i wonder if this will help your hum.

Interesting. I might give it a try! Thanks Rick

 

[rickl]

we have had the 'hum' discussion before. I recall even pulling the lid off my pre to check for hum. Found none. I did this update a long time ago and my pre is pretty quiet.