You should be able to determine what is causing the hum through an organized trial and error. Don't live with it. Isolate it and fix it.
Live with A Hum vs. Buy An Outboard Phono Stage
It appears that I have an airborne hum that I can't seem to track down. I've done all the usual things (use cheater plugs, shorted ICs, etc.). Now, I am wondering if I should just ditch the whole effort, and buy an outboard phono amp, ala Bellari, Creek, and such. The turntable I have won't set the world on fire, but it does a more than adequate job if given the chance.
So, opinions please. Is it worth getting a phono stage, and plugging it into a dead-silent input, or will it suffer from the same thing?
So, opinions please. Is it worth getting a phono stage, and plugging it into a dead-silent input, or will it suffer from the same thing?
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- 17 posts total
Lee -- Towards the end of your original thread about this problem the hum disappeared, returned, and disappeared again as you did various things (reversing plug polarities, separating and shielding components, etc). Obviously it has now returned once more. Therefore, what I'm thinking is that it may be an intermittency in the phono stage of the preamp, which happened to not be occurring when you shorted the inputs. So ruling out the preamp on the basis of that experiment may not have really been conclusive. If it is an intermittency in the preamp, my suspicion would be that a capacitor may be on the edge of failure, as you were led to believe way back at the beginning of that other thread. Does the problem seem to be temperature or warmup sensitive? If you are not sure, try putting the preamp in either a cold basement or a warm attic for a while, and see what happens. Beyond that, I agree with Newbee's suggestion to try to get a separate phono stage with return privileges. Regards, -- Al |
I thought that the problem may be thermal, that's why it lessens to a degree when the preamp/combo are left on for a while. Now, I have the preamp on a separate shelf. The amp can no longer provide a measure of heat. Maybe a heating pad on the preamp will goose it along. If I want to get the preamp really cold, all I have to do is put it outside. |
What kind of pre-amp are you using? If it has tubes in the phono stage you could be getting hum from them. I'm not sure I understand what you mean by shorted interconnects - are you saying that you in essence shorted the phono inputs by using IC's and the noise went away? Or are you saying that you connected the TT IC's to a line input and there was no hum. How did you short the IC's - I've never seen female shorting plugs. Interesting, anyway........ |
Newbee -- Here's his original thread: http://forum.audiogon.com/cgi-bin/fr.pl?htech&1233446646 His preamp is a NAD 1155, which I assume is solid state. I think he shorted the phono inputs by connecting interconnect cables to them, and at the other end of the cables putting a piece of foil between the center pin and the ground of the male rca. The hum was not present when he did that. Regards, -- Al |
- 17 posts total