[geowak]

For all the technical minded- Give us a simple explanation or possible causes for the "hiss" sound coming from your speakers??

If you have a source (CD PLAYER) and run an analog RCA cable to a PREAMP , an analog cable to an
AMP in keeping with a simple CD-PREAMP-AMP audio system and you hear hiss at moderate volume when the CD player is not playing a cd, what is the most likely cause(s)?

THANKS

[WerTicus]

Its the noise floor of your system.

[WerTicus]

if its a hum then its likely a ground loop issue or unbalanced RCA's acting as antenna.

[Russell Dawkins]

You may be able to isolate the cause by turning everything off, then unplugging the preamp from the power amp.
Turn the power amp back on and listen.
Turn it off, then plug the pre back in, turn both on and listen again (with the CD player off).
Then turn the CDP on (while the input selector of the pre is set to another input) and select the CDP. This process of going methodically back "upstream" will isolate the source of the hiss.

If you had RCA "shorting plugs" you can get a truer picture of the potential performance of the preamp or amp under test, since these perform better with shorted inputs and sometimes hiss audibly with no load on the input.

Sometimes better performance from a preamp can be obtained by using shorting plugs on all unused inputs.

[twitch54]

Its the noise floor of your system.

Yes, relative anything and everything upstream from your speakers........cables,amp, pre-amp, source, tubes, etc.....lots of possibilities.

to start the isolation process begin at one end of the chain and work to the other till the culprit is found.

[Russell Dawkins]

cables? 

[Christopher Witmer]

A brood of vipers inside the enclosure? 

[miklorsmith]

Two things that caused loops in my system - Cable TV connection and having amps plugged into different outlets.  For the amps, I plugged them into the same strip which eliminated that hum and the CATV I unthreaded the wall connection and backed out the cable a millimeter.  I may get skewered here if this isn't safe.  There are loop-breaking connectors for CATV that you can buy that aren't too expensive.

Good luck!

[nodiak]

What pre and amp, and what condition are they in? I have an older receiver that has a hiss in one channel. It might be a solder joint, bad cap, etc.