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. 

The hiss with the Nuforce should be louder than the Sony due to higher than normal gain. Do you have a friend’s house you can take the amp to and try there? Also, light dimmers have caused noises with my systems in other homes. Even if the dimmer is not in same room. 

I have my STA200 paired with a Parasound Zpre2 and both have been left on for about a year+ virtually without being switched off, if so, then only briefly turned off then turned straight back on.
Is it scare mongering, or should I be worried about the STA200 going pop? I find the sound quality excellent. I actually bought two, the other is still in its box unopened. For the money $499 they are really nice sounding power amps. Don't know or care about the power rating, they sure do go loud when required. These findings are to my ears. 

Had my amp for about a year now, no issues, great sound.  Current speakers (diy) are 89 dB.  Looking at a new design where efficiency would be 84dB.  Be interested in hearing from anyone that’s paired this amp with lower efficiency speakers.

You know, one person posted their amp had a problem, and that person never posted again when asked to.  Then an article came out that said the wattage at 8 and 4 ohms was the same and started some worry that this was a problem.  

I ran my amp for about 8 hours straight both days over the weekend.  My speakers are 85 db and nominal 6 ohms and the amp never got warm and has never been warm to the touch. At least with my amp there is no difference in temperature between on and off. 

Yes, one person who has never had a real presence on AG. I'm not saying the person is a troll, however, one must look at what is right in front of them. Even if the amp did "pop" it would not be the first time someone got a defective (assuming the cause was internal to the unit) component. Even the big boys gets returns due to defective units. My STA200 runs quite cool, however my speakers are rated at 101db. In fcat, I have had my amp on for hours upon hours playing at decent levels, no issues. 

With my current speakers at 89dB, it rarely ever gets even warm, and I can’t go beyond a quarter turn with my passive pre amp before it gets uncomfortably loud.  Not sure if that translates into having the headroom for a driver that’s 84dB.  I know that every 3dB increase in volume requires twice the power.  So this new driver at 84 dB could require nearly 4 times the power play at the same level.

Removed my last post because it was about another amplifier, rather than the STA 200. Sorry for not keeping the thread on track. Enjoy ! MrD.

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.

I wanted to thank you all for sharing your experiences with the STA-200. I am a new, happy owner of the amp and I would not be without the benefit of your experience.

I was a pretty serious budget-oriented audiophile once upon a time. But after decades of faithful service, I knew it was time to replace my Audible Illusions Modulus 2B. The volume pots, replaced once already, were now reliably noisy with any adjustment at all. After some research I brought home a Rogue Audio RP-1. It added a whole new layer of musical detail, but I noticed a layer of upper-midrange glare. I was prepared to look elsewhere.  

Then I realized the glare – which turned into some seriously bad distortion on a solo piano recording – was only in the left channel. I flipped the cables to my power amp and found that the distortion stayed on the left. It was not the pre-amp after all – the higher resolution of the RP-1 revealed a problem with my power amp!

So now I was faced with a larger upgrade, both the Modulus 2B and my (also ancient) Forte Audio 1A amp. Unfortunately my budget hadn’t grown! I went looking for a highly-regarded inexpensive power amp. And that lead me to the STA-200 and, ultimately, to this thread.

The discussion of the STA-200’s sensitivity, and aberyclark and jetter’s experience in solving the problem with pre-amp noise ended up being crucial. Because I had exactly that problem – when I first hooked up the RP-1 and the STA-200, the noise floor was, well, more like a noise ceiling. Tube hiss was clearly audible from my listening position and, although the music through the RP-1 and STA-200 sounded great (dynamic, rhythmic, detailed and supple) the hiss was there every time the music got quiet or silence appeared. Not only that, but any RP-1 volume setting above about 17 (60 being full gain) was too damn loud for my room.

I immediately bought a Schiit SYS, just like aberyclark and jetter. As soon as I popped it between the RP-1 and STA-200, and dialed down the gain to 12 o’clock, the hiss was gone. But not the music. I’m running the volume control at anywhere from 25 – 35 now, so I haven’t even begun to max out the RP-1’s gain. I am very, very satisfied.

So thank you for your contributions to this discussion, especially aberyclark and jetter. I greatly appreciate your help!

Hi deseldin, really nice that you are enjoying the STA-200, it is a fun amp, and its funny that I believe it is the only AB amp they made, the rest being class D (AFAIK).  For me, without mrdecibel's input I wouldn't have purchased this inexpensive little gem.  

The SYS is a fun little toy, the first of its sort I have had.  Have fun.

I love the SYS. I'm glad I could be of help. 

Yes, I have enjoyed the SYS using it as a stand alone passive pre with both the STA200 and Dynaco ST-70. I have not yet tried it as an attenuator between my Jolida  Fusion tube pre and the STA200. This I will do in the future and report back. The Jolida is mated to a BEL 1001 MK5 in my main system. 

The combination of the SYS with the STA200 when paired to the right speakers makes for clean and detailed sonics. One of the best deals in audio. 

I finally purchased the STA 200 amp and it is only 3 hours into listening—I enjoy the soundstage, imaging and sonic bandwidth. The price is fantastic and may be a used amplifier killer up to $2000 used / $4000 new. I’m comparing it to three other amps and will post my impressions later. 
The only issue is the limited space for connecting my speaker cable for bi-wiring. 

To both jetter and abery ( and anyone else ). Although I am not using my pair of STA 200s in my main system, I do believe it is an amazing little amplifier. I also believe I have as much, if not more, experience than most, in using the amp with several different combinations since my acquisition of the first sample almost 2 years ago. The amp was designed with a passive pre to go before it, and for a year now, this is how I have been listening. Not just with the STA 200, but with other amplifiers. Without naming names, I owned 2 top tier preamps, that were quite excellent, but ultimately, determined they were coloring, and robbing my system of details in the music. I would suggest both of you to take your preamps out of your systems, and run only through the SYS, for about a week. There will be an adjustment your ears will make, as I know you will not like everything you hear at first. But if you really appreciate your recordings for what they truly are, and can be, given time, you, like me, will stay passive. This is especially true with the input sensitivity, and gain, of the STA 200. No preamp, one less pair of interconnect, and I am telling you, your preamps are not needed. My Luminous unit is incredible. Silent, reliable, and offers me remote volume, which I never had before in my main 2 channel system. My Dac is quite amazing as well, and it is an older type ( modified Adcom GDA 700 ), and drives any of my amplifiers with ease. And if I am wrong, after about a week, all you need to do is go back to your preamps with an extra set of interconnects, and, enjoy ! So, there you have it. Enjoy ! MrD.

Thanks for suggestion. I will try "sys only" this weekend. Now, I did use my Prebox S2 as a pre while my RP-5 was getting repaired and it performed outstanding. Finding a passive pre with all the features, inputs and remote as the rp-5 would be quite difficult.

Looking forward to your thoughts on the SYS/STA200 direct into your Zu speakers. 

I haven't read this whole thread, and maybe it was mentioned, but does the Sys have a remote control?  Thanks,

No remote on the Sys.  It about as basic as you can get, but it works well.

The first thing to do would connect the Sys, direct, play music of all types that you often listen to ( I do say give it about a weeks time ), and determine if you like it, better, or not. My Luminous ( $1250 ) is quite a bit " cleaner " than the Sys, but, it should still give you more of a sense of " straight wire ". Passive is not new, but sources have gotten better and beefier in the output stages. Just give it a try, be patient, and see if your ears are good with it. If you like it, then, you can shop for a unit that has what you want and need. Again, if you don't, well, now you know. Enjoy ! MrD.

I'm looking forward to trying. Just curious, I wonder who makes a passive pre with all the bells and whistles?

I agree with mrdecibel, the SYS is a good way to explore the merits of using a passive. I would probably upgrade from it in my main system. 

The SYS is not the most basic as it allows two inputs.

Busy now, but agree it will be fun to use the little SYS as a standalone pre in the near future to gain that experience.  Thanks for the thought MrD.

The Sys is so cheap that I went ahead and bought a second to have both a dual mono setup and also to be able to control the balance.  It really widened and opened the soundstage up using two instead of one.

I've got a Saga too, but as hard as I try to prefer the Saga, I actually think the Sys sounds better.

If anyone is interested ( and this applies to anything ), you can open up, go inside of the sys, and Dynamat the circuit board and some of the chassis, as you will hear a significant improvement in detail and resolution. It will also add some weight to the chassis. Always need to be careful when pressing down on the boards, as you do not want to break the " traces " ( Sorry, been doing these mods for 50 years, and they work well ).

mrD, your post made me laugh. Why would you want to add more weight to the SYS unit? According to the Schitt website it already weighs in at a heavy 1 lb. I’m guessing they rounded up to get there.

Its been out a few yrs. How does the STA200 stack up to newer budget amps, Emotiva monoblocks, Nuprime, TPA3255 based etc?

What cables - RCA and speaker - are you guys using with your STA200?  I've got a mish-mash of old high-end and cheap new (Monoprice) cables connecting my DAC, preamp, SYS, amp and speakers. 

I want to upgrade, but at a reasonably low price.  

Thoughts?

I originally had Blue jeans interconnects and they sounded fine. I am in the process of building my own cables. 

I use Blue Jeans LC-1 interconnects between source-SYS-STA200 as the LC-1 has very low capacitance.  

So, has anyone new tried passive ? Even with a Parasound A21, as it works with amps that have normal gain.

@daseldin - Currently using VH Audio Pulsar Cu RCA Interconnects. Vampire Wire also makes good reasonably priced interconnects.

Thanks guys. 

I got myself Audioquest Cinnamons (from the digital sources to the DAC) Golden Gates (from the DAC to the pre-amp to the SYS) and Red Rivers (from the SYS to the STA200).

I stuck with my ancient FMS Blacks to the speakers.

The sound is warmer but the details are still there.  I'm happy.

Can anyone compare the STA 200 to the Mytek Brooklyn AMP?

I know this is an old thread and I am a new member, but I have a question about the STA200 for which I cannot for the life of me find an answer.  Is it stable driving a capacitive load?  I have Vandersteen 2ce Sigs that I want to vertically biamp with a pair of STA200s.  However, Mr. Vandersteen warns that many solid state amps are unstable driving the capacitive load when vertically biamping.  I tried calling Optoma to ask, but their tech support is dedicated to their projectors, not their audio stuff.  Please help?!

dengief, welcome.....I am not sure what Mr. V is indicating....I am running my pair of STA 200s in a vertical biamp situation ( something I have been recommending for a while now, given having two identical stereo amps, or of the same, 4 monoblocs ), and I am having no issues to speak of. The speakers I am using are a pair of Signet floor standing towers ( I was a rep when I got them ), and they sound very good being driven this way, and of course, with the NF amplifiers. I have used professional Yamaha amps, Hafler amps, Citation amps, and some others ( I had a s---load of power amps at one time ), with the same configuration, with excellent results. I owned 2c’s, and later 2ci’s ( in the past ), and have had clients with them, and never an issue, and vertically biamped them, too. Unless Mr. V. is doing something different with the latest incarnation of the model 2s, I do not see a problem. I have always preferred, is sq, vertical biamping vs horizontal, and I have done so with Martin Logan, B&W, Kef, Klipsch, Legacy, and others, that had the passive biamp ability, without issues. I would encourage you to read the manual of the Vandys. I hope this helps, but if it does not, I do understand.....my best, and Enjoy ! MrD.

Mated my Nuforce STA-200 with a Schiit Saga, was very good with my Zu Omen's. Used a Sillnote cord for $100.00 and opened up well.

Hi Mr.D.  I was hoping to hear from you.  Your comments about this amp are largely why I decided to buy a pair.  Apparently, RV used to recommend vertical biamping in his manuals, mine included.  He now recommends against it on his website and his newer manuals.  Here is a quote from RV himself on the “Ask Richard” section of his website:

”VERTICAL BI-AMPLIFING IS NOT RECOMMENDED AS MANY AMPS OSCILLATE WHEN NOT HAVING A GROUND RETURN DRIVING THE TOP END OF THE SPEAKER. THIS PART OF THE CROSS-OVER IS CAP COUPLED FOR BOTH THE MID-RANGE AND TWEETER THIS COULD CAUSE THE AMP TO OSCILLATE AT VERY HIGH FREQUENCIES. THIS COULD BE A PROBLEM AND DAMAGE THE TWEETER.”

This has me scared to try.  I wonder if this phenomenon is unique to his first order crossovers.  I have had my 2ce Sigs vertically biamped with Rotel for the past 13-14 years.  But I’m still scared of damaging something if I do the same with the STA200 I just ordered.  Thanks!

RV would certainly know best...give the company a call about your specific system

The NF STA 200 has a much wider bandwidth than the Rotels. What this means, I am not really sure, technically, because musically, the high frequencies on the NF are musically capable of reproducing much higher frequencies, with music signals. I still do not know what he has done differently, than 10 years ago. There must have been some folks ( likely just a handfull ), who had some issues, as it only takes one issue to raise a white flag. Same happened many years ago with a particular speaker wire, by Polk, that caused some amps to oscillate. I had these cables, and never experienced an issue. I know the STA 200 does not do well below 4 ohms, but this oscillation thing is completely different. If it were me, I would try it, as I have had very good luck, without things oscillating during my many audio years. But, this is me..........you can always replace tweeters, lol.....Seriously, I feel the STA200, based on all of the circuit research I did, would not go into oscillatio; The Vandys, as much experience I have had with them, never caused a problem to any amp I am aware of, except for a clipping issue, which is different than oscillation. It is your call. Could create a new purchase of a pair of tweeters. The Nuforce will likely be better, in sq, than the older Rotels. Like I said, if it were me......You, are not me....Enjoy ! MrD.

Thanks JL35 and Mr.D.  I think I’ll see if RV knows about the NF amp.  I might even ask, in a diplomatic way, whether his retraction was an overreaction to a minute number of incidents.  Thanks again!

I wanted to report back that I have now tried a pair of the STA200s vertically bi-amping my Vandersteen’s.  No oscillating!  Phew!  The amps sound great, but they’re still breaking in.

Thank you for the feedback. What changed your mind about trying them this way, except time ? 

RV said to listen for extra brightness when bi-amped.  I had time, so I compared and found no additional brightness.  I didn’t want to go through the hassle of returning one of them.  I really like the sound staging and imaging from the amps.  Bass seems a little lean, but it’s fast and articulate.  Hopefully the amps will bloom a little more after breaking in.  I’m using a brand new Parasound P7 all analog preamp with it, so maybe that needs some break in time too.  New power cords too.  I’m incredibly impressed with how dead quiet the amps are, however.

I encourage you to leave everything on, 24 / 7, with music playing through the system. It will take, ime, a few hundred hours, for them ( the preamp, too ), for things to gel ( lean bass, as an example ). They should be better, in sq, over the Rotels, in every area, but with a new preamp, you might not attribute all of these changes to the amps themselves.......And yes, they are very quiet....Anyone who experienced them to be noisy, was experiencing the high gain of them, amplifying noise earlier on, in the signal chain. Thank you for the feedback.....Enjoy ! MrD.