Nuforce STA200

Hey guys! I'm new on here and signed up just for the STA200. I've been lurking for a few months now and decided to get the STA200 based on everyone's amazing feedback on the amp. My amp is paired to Linn Kaber's (4 ohms, 87dB), and there is an audible hiss (without signal) when I bring my ears about a foot from the speakers. Is this normal for the amp? I'm still within the return/replace period of Amazon. Thanks!

Hi Mr. D,

My amp, without any input connected, produces somewhat of a white noise (shhh sound). Is this normal or do I have a defective amp? I will try connecting my amp to a set of floorstander NHT’s at 8 ohm tonight.

Thanks!

Hi Mr. D,

I apologize for not getting back to y'all earlier. I got caught up with some other stuff and just decided to order a Schiit SYS to see if that fixed the problem.

I was using a cheap FX Audio Tube pre-amp/buffer with the upgraded GE tubes. The tubes definitely produced a significant amount of noise once the volume knob hits the 9 o'clock mark, and the noise only increases from there on. I received my SYS yesterday and tried it out last night. With my chromecast audio and NEC cd player connected on the SYS, the noise on the speakers was cut down in maybe half. There is still a very faint shhh noise on the left speaker when I put my ear right next to the drivers, while the right speaker has a faint high pitched noise on top of the shhh noise. I'm only a beginner in audio stuff, so I would assume this would be what you call the noise floor of the amp, right? Now with the SYS, music is more detailed and has a very slightly wider soundstage compared to the FX Audio tube preamp. I tried connecting the chromecast audio to the FX Audio then routed the sound to the SYS before going into the amp, and the sound warmed up a tiny bit with a very minimal sacrifice in soundstage. So, based on the different combinations that I've done so far, the noise that I'm hearing is coming from, or caused by, the amp itself.

Last week, before ordering the SYS, I tried the amp plus FX Audio tube preamp on my daily system with NHT speakers. There was still that shhh noise and a slight high pitched noise (I don't exactly know the frequency of the noises). Although the noises that I'm hearing on my NHT's with the amp are similar to the noises that I'm hearing from my Pioneer stereo receivers and vintage integrated amps. I guess the noise floor is normal with such a high gain amp. Kindly correct me if I'm wrong.

Based on last night's listening session, I am happy with the amp. I will give it another go tonight to see if my thoughts change. Before getting this NuForce amp I had a Linn LK140 that I bought used, but decided to return it to seller because one channel was buzzing and when I opened it up there were signs of damage, repair, and a missing capacitor. That amp was quiet though, aside from the buzzing on one channel. My other amp option is to get another used Linn amp and hope I'd get lucky with a good example.

Thanks for your help, Mr. D, and to everyone on this forum! I really appreciate it.

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!

Okay guys, sorry for the super delayed response but I wanted to try every option I had before posting another reply to the thread. I tried switching out to different interconnects (both are cheap options but I know both of them are shielded), but the same noise is present (hiss in the tweeters and hum in the mid range driver). So I went ahead and ordered an Emotiva CMX-2, which I just received tonight. I plugged everything in and the same noise is present. About a week ago I went around the house and unplugged electronics to no avail, and we don’t have any dimmers in the house. So, I just requested for a replacement of the amp through amazon. I should be getting the replacement on the 31st. I’ll make an update once I get to plug that thing in. Thanks for everyone’s help! I really appreciate it.