[logwed]

Someone please tell me if this doesn't work or doesn't make sense, but wouldn't putting a resistor between your amp and drivers eliminate current related hum by raising the resistance? (be kind, I'm only in Phys 1 and my knowledge of circuits is basic)

 

[Punnisher]

Yes this will work. I tried it using a 90 ohm adapter with my grados and my millett SS.

No difference in SQ fortunately.

 

[logwed]

So it doesn't eliminate any hum?

 

[boomy3555]

increasing impedence won't necessarily eliminate hiss. Hiss isn't always caused by low volumes. The only way to diagnose the issue is to put some sort of extra resistance between the amp and the cans. Even a good in-line volume control can help you find out if that is the problem. Some high end IEM's come with an impedence adapter such as the 50 ohm adapter that comes with the Ultimate Ears SF5. Most full sized cans have enough built in resitance to eliminate any low volume hiss from the source.

 

[NightOwl]

Increasing impedance can lessen hiss, but won't fix hum. Hum can be caused by EMI or RFI (requires relocation of components or better shielding of cables or components). It can be caused by dirty mains or a heavily utilised outlet or if connected to a surge suppressor/power bar (try connecting to a different wall outlet on a circuit that's lightly used). It can also be caused by a ground loop or poor grounding in your amp. It can be caused by running balanced connectors at one end and single-ended (e.g. rca) at the other. It can be caused by an oxidized (or faulty) volume pot or input selector switch. It can be caused by a faulty connector or jack.

 

[logwed]

Quote:

Originally Posted by NightOwl /img/forum/go_quote.gif Increasing impedance can lessen hiss, but won't fix hum. Hum can be caused by EMI or RFI (requires relocation of components or better shielding of cables or components). It can be caused by dirty mains or a heavily utilised outlet or if connected to a surge suppressor/power bar (try connecting to a different wall outlet on a circuit that's lightly used). It can also be caused by a ground loop or poor grounding in your amp. It can be caused by running balanced connectors at one end and single-ended (e.g. rca) at the other. It can be caused by an oxidized (or faulty) volume pot or input selector switch. It can be caused by a faulty connector or jack.

Thanks! So hum isn't a function of impedance?

 

[NightOwl]

No. Not in the way you mean it. There is shared or common impedance in a ground loop, but the problem causing the hum is the ground loop.