Nuforce STA200

Hi Japol, I hope Mr. D posts here quick to help you out as I don’t have enough experience with gain issues, so these are just random thoughts until the voice of experience chimes in. My first thought would be that to determine if you have a gain issue you should just hook up the Sys with the amp, and the amp to your speakers and with no sources connected see if there is a "hiss" caused by too much gain or the if there is still the "high pitched noise". If not, I would think, but may be corrected, that the noise issue is being generated by your sources, wiring or a ground loop.

If you determine that in fact these noises are the result of the amp I would not think twice of exchanging it for another one or if you choose a refund. If it was a noise floor thing I would think the "hiss" would be the same level from both speakers, and no matter what there should be no "high pitched noise". But again, wait for Mr. D.

Hey Jetter, Japol and all you other audio gents. Japol, if your STA is causing a hiss through your speakers, without anything connected to the amp's inputs, I would say this is not normal. Either the amp is defective, and / or, the amp, or the speaker wire, is picking up stray electrical noises from somewhere ( see my earlier post ). If you like the amp, I might suggest you contact the seller and arrange for a replacement. If the replacement does the same as the 1st, I would assume the amp does not work in your environment ( again, the sensitivity and gain situations ). Keep in mind, things such as under cabinet kitchen lights, ceiling fans with remotes, florescent bulbs, and many other things, can be picked up by amplifiers, which could be the situation. Did you try your other set of speakers ? Keep us posted. Always, and Enjoy ! MrD.

The Nuforce should be dead quiet with Just the sys. When I had my RP-5 in for warranty work, I used my Pro-Ject s2 Pre Dac as a preamp. Dead quiet. I mean dead quiet!!! My Zu's are rated at 101 db. Slight tube hiss is normal (ear against speaker) for the rp-5. The Nuforce has such high gain, along with my efficient speakers, I needed the SYS between the pre and amp to pull things back. 

Hi Mr. D, jetter, and aberyclark, and everybody on here! So tonight I went ahead and did an experiment. I bought a grounding adapter to isolate (disconnect) the ground from the 3 prong plug from Lowe's. That did not eliminate the problem. I also tried plugging in the amp straight to the wall outlet, but still the same problem. So, I went ahead and used a different speaker wire... problem still there. Then, I tried using my Sony TA-F500es just to see if it produced similar hum/hiss... they're still present but it is more quiet compared to the nuforce. Now, I'm not sure what's wrong with my system. 

I also tried connecting my nuforce to my NHT floorstanders and the noise is present, only louder. 

All these tests were with the sys connected to the nuforce, except the test with the Sony integrated. The hum is isolated to the mid-range driver and the hiss (sounds less of a hiss and sounds more like electricity buzzing) is isolated to the tweeter. I tried recording the noises on my phone but it is difficult to be discerned from ambient noise. 

I feel like I can live with the hum and hiss/buzz, but I also wouldn't want to be keeping a defective amp. Tough call.

Thanks again, guys!

Hi japol, if I understand your post above you have a hum with both the nuforce and with your sony integrated.  So you are not sure if you have two amps with a problem or the problem lies elsewhere in your system.  You have already determined that your speaker wires are ok. 

I only have a couple of thoughts.  One is are you using shielded interconnects and if shielded you are sure they are functioning properly?  The other is that I have the TV cable box connected to my preamp and this resulted in a hum through my speakers.  I had to purchase a cable tv ground loop isolator which eliminated it.