Nuforce STA200

My STA200 was/is dead quiet.  I am told some systems could have a gain issue which from what I understand means that if you pair the STA200 which has a high gain with a preamp having high gain you can end up with the hiss you mention.  One fix for this is a Schitt Sys passive for $49 between the amp and preamp.  Its set once and forgotten.  Unfortunately it does not sound like you have time to work through all of this, and really may just have a "bad" amp and not an gain issue.  If I have this wrong someone please jump in and correct me.

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!

Mike, your making me laugh.  In the late 70's I answered a classified ad and purchased a used Sansui receiver and Cerwin Vega speakers, just for a back patio room. I just came to expect compliments on the sound of that low $ stereo, and never again on any other set-up, including some plus $20K systems.  I eventually gave it to a friend.

George, Yes in the old days (1970) I had a Sansui AU 555 integrated at the heart of my system. 30wpc. Currently I use a BEL 1001MK5. 50wpc. Course the BEL is in a different league entirely in its ability to drive speakers. Mike

Holding over a hundred amplifiers qualifies you as a collector (of decibels) lol. Would you kindly rank the STA 200 (or range, say within +-5)? Thanks!

Glad you happened by mrd, best to you and yours.  George

The poster of the blown amp might be a competitor ( or owns a competitors amp ) at or near the $499 price. You never know. I do know a few individuals who returned the STA 200 because it did not work in their system, but the majority of people who private message me are very happy, as some others here. BTW, it is a great little amp when used properly. However, I am currently rotating amps ( again ), as I will be cleaning out another closet full of amplifiers. When this started a few years ago, I had over 100 amplifiers in my collection. Just saying. Happy New Year to all. Enjoy ! MrD.

I have been on A'gon for a whole lot of years.  You will note that the poster with the blown amp has exactly one post on A'gon.  I have found throughout the years that people who post once or twice with something negative often have some beef somewhere down the line.  Not saying this is the case here about the poster, but I now think the risk of blowing an amp is pretty much the same as the risk of blowing any other amp lower powered amp.  By the way, in the old days SS amps often had much lower watts at all ohms than this unit.

Jetter, Thanks. I was not familiar with the Copland pre. Looks to be a fine unit.  

Aberyclark, Yes we need more info re the blown amp. So far no response to your previous post asking for clarification.

My speakers are so easy to drive (101db efficiency), a clock radio hooked to them will fill the room. As far as the amp blowing, there are so many variables it would be hard to figure out what happened with so little info. This is the first time of hearing of such happening with the STA200. Hopefully, the person purchased new with a reputable dealer

Thanks mesch for your clarification, truly appreciated.  From your earlier post I got the mistaken impression that you were saying that you knew of an identified amplifier design weakness that could result in possible serious amp failure.  I don't think this any longer.  These things do happen though, for example, I have a pair of Goertz alpha core speaker cables that without the use of zobel networks have resulted in some amps going into oscillation with not pretty results.

So blue skies on this end.

Well, I might just be overly cautious. I need to spend more time with my STA200. I certainly am happy with it's sonics and it seems compatible with my PS Audio Digital Link III via the SYS. In addition to the speakers I mentioned earlier, I also have a pair of Dali Zensor 1s which don't drop lower that 5ohms and are 88dB sensitive. I will try the amp with these as well. 

I purchased this amp for use with a passive pre in an attempt to build a low cost high quality system.  Though I don't believe specs tell the whole story, I do believe there are some that certainly help to insure electronic compatibility between components when putting together a system. I have learned much from this forum toward that end. I remain with much more to learn.

Happy New Year to all!

Mesch, I have two pairs of nominal 6 ohm speakers, both probably in the 85db range.  One is a 2&1/2 way with two 7 1/2" or so scanspeak mid/woofers.  I can run the unit all day, with the STA200, being fed by this tube preamp, http://www.divertech.com/coplandcta305.html and the amp never is even warm to the touch.  I have a Schitt sys, but honestly it is set to not reduce the output to the amp at all as it is not needed.  In other words, the volume control can be turned up far enough (high enough) from the zero position with the sys in or out of the system to not worry about the preamp volume control not being high enough to function fully.  I don't understand the impedance matching thing to know if I happen to have a more compatible preamp than normal or what.

Kalali, if my understanding is correct, because the voltage required to reach max output is low, sensitivity is high.  Given the output voltage of most sources today, the sensitivity and gain of this amp would call for judicious use of the volume control of any preamp. I have not yet approached 11 o-clock with my SYS passive.

Jetter, not knowing any more about the specifics of aysancorluham's situation it is hard to guess at why his amp 'blew up'. I would be cautious about using this amp with any speaker not known to be easily driven by an amplifier. To me that mean a speaker that doesn't dip below 6 ohms across the frequency range, and having a sensitivity of 87dB or higher depending on the size of the room in which the system is to be used.  

Finding such a speaker, one I feel fits into a budget commensurate to a $500 amplifier and $50 passive, is the difficult part. I am still looking.  

"At 51K ohms input impedance and the high input sensitivity a good candidate for a passive..."

The 0.45V input sensitivity is not much of an issue, its actually relatively low, but the 35dB gain is more of a concern. A passive with a low output impedance may work depending on the output voltage of the source.

Here's a bump to mesch, or anyone else.  We have a first time poster declaring his amp blew up, and mesch stating he will use his amp with caution.  I am not savvy enough to understand or otherwise translate from above what "the degree of attenuation becomes too low overdriving the input stage" means or how it creates a situation that can be hazardous to the amplifier.  Since it has been brought up as a potential danger, lets hear what the danger is?  There are not that many posts on A'gon where using an amplifier for its stated purpose can create a potentially dangerous situation, that perhaps an amplifier has been built without normal protections built in, since this has now been brought up, lets hear the background behind it and potential danger.  Thanks in advance.

mesch, in layman’s terms, please explain exactly what are you being cautious about? Are you worried about the amp being driven into oscillation?  How does the fact that the amp produces the same power at 8 and 4 amps create a potential problem? If neither of these are the concern, what is the worry? Thanks in advance.

This amp produces no more power into 4 ohms than into 8 ohms.
Sensitivity is 0.45V for full output.
Gain is 35dB.

Very sensitive to source voltage and speaker load. At 51K ohms input impedance and the high input sensitivity a good candidate for a passive. Maybe try to set a stop on the passive pre so that volume can't be turned such that the degree of attenuation becomes too low overdriving the input stage. 

I will be using my STA200 with caution!

aysancorluhan,, I already have the STA200, and the truth is worrying about it blowing up is the last thing I am doing.  I have not popped the hood to look myself, but it sounds like you are saying it is not fuse protected, which seems unusual.
 
While I am not currently thinking about new hard to drive speakers, I was really wanting someone to provide their input (thank you jl35) regarding the sound quality differences between the STA200 and a Parasound A21.  For example, does one image better than the other, better separation of instruments, anything else at all you can relate.

Out of warranty?

My STA200 blew up and cannot be repaired. Stay away at any price.

I'm so sorry to hear this. I have one and asking for my personal info:

1.Just blew with normal use I assume?

2. Did it just not turn on? Or did it actually pop and go dead?

3. was it after the amp was on a while or when you first turned it on?

4. Where did you purchase?

STA200 is an AB amp. My listening experience was very good. I understand the Chinese imitated the Goldmund amp without care for protection circuits. My STA200 blew up and cannot be repaired. Stay away at any price.

It obviously would provide greater options if one was wanting to make a change in speakers. Are you looking to make changes in your current system?

You should be able to find a used A21 and if you don’t like it lose very little on resale. But at that price there are the Odyssey amps and the...

jl35, thank you for your response, decisions, decisions.

I don't think the Parasound A21 would better within power limits, but it has 3X the power into 8 Ohms and 5X into 4 which could make a big difference not only in volume but also dynamics and openness...I have experience with both but only own the Nuforce...

Before anyone askes, yes I do realize there is a large price difference.

mrdecibel or anyone else who may have heard both amps.  I noticed that Audio Advisor is blowing out their Parasound A21's due to the new model A21+.  If I purchase the A21, what and where do you believe would be the level of improvement over my STA200?  Two pairs of speakers are both 6 ohm, one pair being 85db and the other 86db.  I am using pair of SVS subs.  Volume is currently not a problem in my listening area. Thanks in advance for any input.

I am a fan of 2-way monitors. Most rated at 6-8ohms that I am familiar with have an impedance dip below 4ohms somewhere usually at bass frequencies. I can't help thinking some caution need be applied when using a amp that provides 80wpc at 8ohms and same into a 4ohm load.

Currently I can use my STA200 with B&W 685s, Focal 706s, and the Esoteric MG-10s. All possess the aforementioned impedance dip. I will get back to all after I have more experience with this amp.

There was a question on an earlier post about using the WDC200 with the STA 200.  I purchased the WDC200 about 3 months ago to pair with my two STA 200’s which I use to bi-amp Martin Logan SL3 electrostats.  I was especially interested in the fiber optic feature to use on a reference Marantz CD player I have.  The fiber optic was a big step up from RCA, which should not be a surprise.  It sounds very good to my ear.  I purchased it on sale for about 200 from Hi FI Heaven in Green Bay, don’t know if they have any more.  The wireless is decent, I use Apple Air play to stream from my I-pad air two.  I feel it is very close to my Dragonfly Red DAC which uses the lightning outlet of the IPad for a better quality signal.  The flexibility to run wireless is convenient.  The only complaint on the WDC 200 is the volume control is super finite, meaning it takes many turns to crank the gain.  But SQ is very good to my ear, again especially its fiber optic.  For 200 getting a fiber optic operational was worth the price.

Without ever using the stock cord, the STA200 always sounded musical, grainless, and airy to me.

Some amps will measure great but don't sound *right*. Lots of negative feedback will do that. Trust your ears and how you feel when music plays through the gear.

Into my 4ohm Maggie 1.6s, music or TV *always* satisfied. It never clipped even with room correction low bass boost (TV optical only) using a deq2496. Only with crazy or clipped blu-ray effects would it clip and clip HARD (quakes, explosions, choppers closeby etc). Never while playing DTS or Dolby demo tracks tho.

I swapped in a 650W @ 4 ohm Crown Drivecore 2 instead and the same conditions would also cause clipping, but gave me more headroom.

I miss using it but love the power the xls2002 delivers. I'll find use for the STA200 somehow, it sounds so right, sweet, coherent, in or outside the room. Maybe bi-amp with the Nuforce on top (assuming I can match  gain) but will see first how my new vintage Soundstream DA1 does full range with the maggies.

Wishing musical nirvana to all.

Audio Advisor has demo’s on sale for 399.

I'm running the STA200 with PMC OB1 (87db 6 ohm) with a NAD M51 as the frontend and have no complaints. The amp will drive the speakers louder than my neighbors would be willing to stand.

Thanks for the comments guys I am looking to power 86 dB proacs and had started to think maybe the amp wouldn’t be able to power them sufficiently. I am considering an nad m51 as a pre.

I have had no problem powering either my 6 ohm 89db or 6owhm 85db speakers, but neither are crazy loads.  Also, not sure if its because I have a tube preamp or not, but no obvious gain problems.  Maybe just lucky.

Just received my STA200 and am playing it via a Schiit SYS. As to my earlier post today, my only concern was about power output not sound quality. My amp is a demo unit, however I have no idea about the number of hours use it has taken. Out of the box it sounds quite nice, my impression is that at $500 it is a high value amplifier which requires careful pairing to regarding signal strength and speaker load. 

The STA200 doesn’t have specs provided for 4 ohm output because the transformer limits the power output, plain and simple. The same thing goes for the Job 225 which the STA200 is based on. The output into 4 ohms cannot double with either amp because the transformers cannot supply enough power, hence the 4 ohm output is nearly identical to 8 ohm output.

This can be verified by reading one of the Job 225 reviews on the net (I forget which one exactly).


Also, as others have mentioned, I listen and judge with my ears, not my eyes. You will find numerous people who bash REL subwoofers because of their poor measurements, but ask folks who actually own and use REL subwoofers and they will tell you they are the bees knees.

Nine months ago purchased a pair of the STA-200’s to bi-amp Martin Logan SL3 electrostats.  Very satisfied.  After about 200 hours of break in time can verify the good results reported by others.  Liked them so much purchased a 3’rd and sent it to my son (at $499 from AA a steal).  Ditto results.  The only issue, as reported, is the high gain.  They do not distort even when pushed hard, but it limits out on my system at 11 o clock (too loud), more like 9:30 for normal listening.  I use a DB hand held meter to preserve my hearing.  The only issue is the amp does induce a slight hum from my tube phono section in neutral..  Have a Schiit passive on order and expecting it any day.  Based on reports here I’ll try an upgrade to the PC.  Thanks for the recommendations.

I tend to not put much stock in reviews when people take a fantastically reviewed piece of equipment, and say, "but look at these measurements I came up with"..... Especially when it is a lone voice.

aberyclark +1 

Test or not at $499...the amp sounds terrific. 

The test was done into a 4 ohm load. Rated output was measured as 76wpc. Seems to me one might consider this amp as a 40wpc at 8ohm supplier. Did I miss something?

Read the link quoted above.  I don’t pretend to understand all of the amp’s measurements, but I know from speaker building that some that measure well don’t sound particularly good, and vice versa.  My speakers have a good 5dB peak from 10 kHz to 20 kHz; they don’t measure flat.  But that steadily increasing response has a lot to do with the air and detail I hear in the treble section.  I could control for that peak, by filtering it out and up with a dull and lifeless response that measures flat. With the STA-200, I’m letting my ears be the judge, and apparently others are doing the same.

I had been considering giving this amp a shot but my interest is starting to wane after reading this

https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-nuforce-sta-20...

I thought about the Pro-ject Prebox, but this where it gets a little complicated.....I’ve had this system together only 1 year, started from ground zero, and now I have upgrade-itis.  Deciding what to upgrade next is tough.  With the STA-200 as the mainstay of the system, I think maybe the CEntrance is good enough, for now.  My diy speakers are excellent, as are my diy cables.  However, I bought the basic Luminous Audio passive pre-amp, and I’m thinking the upgrade to the Walker Mod might be the biggest bang for the buck right now.

Pro-Ject Prebox s2 (using only as a DAC..not preamp)

Too much gaib is never good, and I always try to not Thonk too hard...  ;)

Laughing at my last post. Don't know what gaib is, and don't know how to Thonk. Any help?

Thanks for the heads-up Devilboy! I have a Jolida Fusion preamp. Likely too much gaib for the 200. Won't even try it now. Have other use for the amp. Thonking of using it with a DAC/Pre of passive, currently a Schiit SYS but considering the Lightspeed. 

@jl35 I can’t really comment on how the three compare because I changed my system around so much. However, both times I had the Job 225 and the one time for the INTegrated they were all very dynamic, fast, open and clean sounding with very nice bass control and surprisingly "warmish" mids. I’ve had all of them on three different Metrum DACs.

Funny thing though... One of my best systems was a Metrum Hex, Tortuga LDR passive and the Job 225. That said, I inserted the INTegrated in there and missed nothing. I then sold the Hex, Tortuga and 225. I just couldn’t justify the price difference.

I also had the Lightspeed Attenuator in there with great results.

Be aware using tube preamps with the Job though. No DC protection so if any gets passed on from a tube amp the 225 will pass it on to your speakers. So for those of you using a tube preamp with your STA 200, this is something to be mindful of.