[Wig]

 Guys,

 I have always had hissing coming from my system, but have minimized it in the past by lifting one of the ground on a pre or amp. I now have a Torus CS-15 and thought it would eliminate most of the hiss. How should I go about finding and minimizing this noice and should I use a cheater plug on my CD player or pre?

 Thanks,
 Wig

[Wayner]

Do you have a hiss problem or a hum problem. Lifting the ground won't stop hissing.

Wayner

[low.pfile]

Is "lifting the ground" the same as using a cheater plug? if it is, how else is it possible to lift the ground?

[Wig]

 It is a hissing issue. Cheater plug was the lifting mechanism.

 Thanks,
 Wig

[ctviggen]

Remove everything from your system except your amp (with no input connections) and your speakers.  Turn on the amp.  Any hiss?  Connect your preamp to your amp (turn off your amp before doing this, obviously).  The preamp should have no connections into it other than power.  Turn on the preamp and amp.  Any hiss?  Add one source component to this system.  (Turning the system off before adding any source) Any hiss?  Keep doing this until you add the component that causes the hiss. 

Once the component is isolated, try hooking it up only (that it, as the only source) to the preamp.  Is there any hiss?  If not, there's an issue with interaction between components/interconnects.

I did this and realized that interconnects between one of my components was the culprit.

[Wayner]

Hissing issues are usually the result of mis-matched input and output impedance of amps and preamps. Or it could be the result of poor circuit designs. And I think there is a distinction between "hiss" and "noise". Hiss, by my interpretation is like a tire with a hole in it, leaking air and making a "hiss" sound. Noise is anything not part of the amplified musical event.

Wayner

[Wig]

 I'll try this tonight and let you know the results!

 Thanks,
 Wig

[Wig]

 Amp with cables only produce a tiny buzz but the pre-amp is the culprit and where the hiss is coming from, not loud but present. I changed several brand of cable and all produced the same amount of hiss, I guess my pre is noiser than others but it sounds wonderful. Are there any other step to minimize this further?

 Thanks,
 Wig

[avahifi]

How loud is the hiss?  Can you hear it at your listening position?  Can you hear it when music is playing? Do you have to have your ears very near the speakers to hear it?

Hiss from a preamp can originate for essentially three reasons.  If it is a vacuum tube preamp the most likely cause is more noise than normal from one or more tubes.  The fix is replace tube(s).  Either solid state or tube preamps may have excess thermal noise from active components, or from noisy plate resistors in tube equipment.  Hiss can also be an indication of low level very high frequency (out of hearing range) oscillations from the preamp.  Either case two or three requires the attention of a good repair shot to troubleshoot and repair.

Best regards,

Frank Van Alstine