2. tech-talk
  3. 1234645601

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?
licoricepizza

Showing 3 responses by newbee

newbee
4,812 posts
 
It can be, but often a hum can be caused by a phono stage, one that is in the pre-amp, or an outboard one, that is too close to transformers, especially in amps, and the cables from the TT to the phono stage must also be placed carefully so they do not come close to a transformer or PC. If you haven't already tried that, be sure to do so before you buy an outboard unit. Often just getting space (as much as possible) between the phono pre and or cables from other electronics will do the job. You probably already knew that and eliminated these possibilities. So....

If you can get one that will match your cartridge and have a return privilege, why not - the ones you mention are inexpensive enuf.
newbee
4,812 posts
 
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
4,812 posts
 
Well I see I came late to your 'party'.

At the end of your other post you seemed to have solved your problem which you traced to an interaction between the amp and the pre-amp. -You referred to RF if I recall - I've a very short memory :-).

Going back to my original post - you seem to have seperated your amp and pre-amp in a quest to correct your problem. To what extreme have you taken this? When possible and necessary I try to keep the amp and phonostage (of what ever kind) at least 6ft apart. A couple of my pre-amps with phono stages come with seperate power supplies with long cords to allow a distant seperation to avoid hums - and it makes a difference believe me. Long winded way of saying, get some 6ft long IC's (cheap variety will do) and put your amp as far away from the pre-amp as possible. BTW, I don't think you are dealing with stray RF from anything, I think you are dealing with magnetic fields - I think.

May not work but gives you something to do! :-)
More to discover