Nuforce STA200

Hi, anyone have one of these amps shut down for overheating? Do they have thermal protection circuits? Mine cut out--was pretty hot. Let it cool down and it came back on. Driving Elac Uni-fi UB5 speakers--4 ohm. Very little info about these amps online. Are they okay with 4 ohm speakers?

Haven’t had any issues with mine playing 4-6 hrs at a time, actually gets only mildly warm, but I’m running 8 Ohm speakers.

Even the Job 225 on which this amp is based does not like speakers that dip below 4 ohms. The problem is the speaker not the amp. Elac recommends amps with 140 wpc and 4 ohm stable.  That is the problem with these "marvel" Elac speakers and before them the Pioneers that Andrew created.  The speakers themselves are cheap but the amplifier requirements are not.  

I run Salk SongTowers which are 4/6 ohms...can run all day without issue...have never found any ratings or measurements for STA200 except 8 ohms...

Thanks. I suspect it's the speakers. No problems with a Cambridge CXA 80 driving them but the Nuforce runs pretty hot. I also have it in a cabinet without enough ventilation and was really running it when it happened.  Going to add ventilation and swap in some 8ohm speakers and see how it runs.

The Elacs do sound really good, esp. since I got them on sale for $350.  Maybe I'll buy another amp and run two :)

The TA Premium PC came yesterday, quite an improvement over the less expensive  TA PC that preceded it.  I’m running AQ dbs Jaguar IC’s from my pre to the amp- I think that’s the next upgrade...

I have run my STA200 on several types of speakers, and it has had no problem running them to levels I am happy with. It runs slightly warm, and I leave it on 24 / 7, unless I am out of town overnight or longer. It has become my main amp for my Lascalas. Enjoy ! MrD.

Quick follow up: swapped in Monitor Bronze 2 speakers (8ohm, 90db). Amp is hardly breaking a sweat. Really think it does not like the Elacs...

Why are surprised as we are talking about a speaker with a stated efficiency of 85 db and impedance of 3.4 ohms and that is just stated not measured.  I am sure measurements by JA or Soundstage would find that both are overstated. The is the same as with the Pioneers and is a common characteristic of all recent Andrew Jones speakers. 

Not necessarily surprised, just wondering if anyone had similar experiences. My Cambridge CXA80, also 80 watts, handles the Elac's easily. There's just no info out there about how the Nuforce handles 4 ohm speakers. 

The Nuforce has been fine with the Elacs. I had it cranked up, it was hot out, and the doors on my cabinet were shut. I think I just managed to overheat it enough to shut it down.

I had the Job 225 amp for several years and now have the Nuforce which is a scaled down version in my office system.  Neither amp is by nature fond of difficult loads.  They have both easily handled speakers easier to drive up to almost $20k with no issues but give them a difficult load like the Jones speakers and they bog down.  I suspect the Cambridge has a bigger power supply and transformer.  The main difference between the Nuforce/Job amps and the similar Goldmund Telos is the transformers and capacitors.  Those amps would have no issues.  And sure shutting it up in a cabinet probably didn't help either.

The Elacs really sound better with this amp than the Monitor Audios. The Monitors are really bright, almost harsh and grainy. Had to swap them back out. 

Well if you give the Nuforce the room it needs to breath hopefully it will hang in.  If you really like the Nuforce you might want to start looking for a more compatible speaker though. 

As much as I like the Nuforce, I would not look for a speaker it can drive. I would pick the speaker, and find the suitable amp to drive it. This has always been my approach. Enjoy ! MrD.

Well, I just ordered another from Audio Advisor, as, I do not know how long these will be available. I wish I was excellent with words, because I would give this amp a tremendously positive review. It really possesses all of the great attributes of so many amplifiers I have owned, and have listened to, in all of my years. Is it perfect ? Are my ears perfect, or my speakers, or my room, or my sources, or my recordings ? No, But, it is just so musical and embracing, and allows me to enjoy all of my music. And, for the money ? Enjoy ! MrD.

Anyone have any thoughts on using this amp with a tube pre amp. I have a few tube pres that id like to try with it, but really dont want to insert a passive/attenuation in between...

concerned it will generate a lot of noise..particularity if i use one of my vintage tube pres...thanks for any info

I had a relatively high end tube preamp, which resulted in a hum through my 104 db efficient speakers, with this amp. The combo was fine with less efficient speakers. Same occurrence with a ss preamp, in both cases. Because of it’s high gain, it is a possibility noise can be a problem. The noise is not from the amp, as it is dead quiet. The other thing would be a very small amount of adjustment via the pre’s volume control. I love the amp though, and went passive. Some folks added a volume control ( a simple passive unit, something you said you did not want to do ) between their pre and the amp, to cut back the gain, and are quite happy. Enjoy ! MrD.

Sort of a newbie question:  I’m thinking of buying a second STA-200 in case I decide to add a second system to my house. In the meantime, is there a way to use both amps as monoblocks?  I could rebuild the x-overs on my diy speakers to biwire and run one amp for tweeters and another for woofers, but I’m not sure how I might run one amp per channel.

The STA 200 is not bridgeable, meaning you cannot combine both channels to make a single higher wattage amp ( usually impedance capability changes with the amp when you do this ). However, when you separate the crossover of the speaker, as you suggest, you can either horizontally biamp ( passively ), or vertically biamp ( again passively ), with 2 amps. Your example would be horizonal passive biamping. Each of 1 amps channels running the woofers, the other amps channels running the rest. Vertical ( which I prefer, based on my own listening ), would be each amplifier " dedicated " to 1 speaker, 1 channel to woofer, 1 channel to rest of speaker. This all works well when both stereo amps are the same. I hope this helps. Enjoy ! MrD.

Thanks MrD.  With vertical bi-amping, what happens (if anything) to stereo imaging if both R and L channels are powering the drivers in one speaker?

?

Maybe I’m overthinking this-  if one amp’s R and L channel play thru one speaker, and the other amp does the same thing thru the other speaker, do you get the same stereo separation as if you were using one amp?

It doesn't make any difference as your perception of "imaging" is coming from the speakers.  If it makes you feel better then try it both vertical and horizontal and see if you hear any difference.  If you speakers don't need the extra muscle then don't bother.

+1 about imaging from the speakers (including the Xovers). If you might be looking to try to go as "dual mono" as possible for the best theoretical stereo separation with a pair of stereo amps then biamping vertically would be the way to go.. do that first but really best if you try it both ways as recommended by jackd.

The only possible disadvantage is that any variations in gain (unlikely) between the 2 amps will make one side slightly louder and may skew the soundstage when you vertically biamp.

kbuzz, this may be too late, but I saw your post about using a tube preamp. I bought the STA200 and had an old Audible Illusions tube preamp and there was a lot of noise. I bought a Rogue RP1 preamp which I picked partly because it has a low gain of 7 db, and that combination worked well.

Anyone have any thoughts on how this would compare to a Schiit Vidar?

Thanks

I just bought one from Audio Advisor, and shortly after, the listing changed to "Demo" model for $400. Looks like I might have got their last "non demo" one. :)

this morning they have new ones for $499

Oh well, still happy to get one. 

A purchaser of this amp, from early in 2017, stated " Conrad Johnson meets Krell ". I have owned a few CJ amps ( 2 tube, 2 ss ), and a few Krells ( but am familiar with many Krell amps ), and I have to say, this amp definitely has many " high end " characteristics. What I like about it, particularly, is how " tuneful " it is. With a better pc, it truly follows the bass and rhythm of whatever music I am listening to, and I cannot say many of my amps ( and believe me, there have been 100s ) have done so well in this area. The transients are fast, and the dynamics are incredible ( keep in mind my Lascala’s are quite dynamic ). The tone mimics the music, and the spatial presentation is high, wide and deep. A killer at $499., and of course, with the right loudspeakers. It is a very musical and enjoyable amplifier. Enjoy ! MrD.

I had to sell my Mark Levinson #331 a few days ago (I needed the cash...) To "replace" it, I bought a like new Vincent SP-331 off CL for $600 and this, I am going to sell whichever one I like less. 

I have been running the Vincent since yesterday, it is nice, but I am really missing my ML  :(  

If the NuForce is as good as you say, hopefully it will be closer to the ML...

If neither do it for me, I may sell them both and look at the new Class A amp from Schiit when it comes out. 

I am running a pair of Tekton Lore-S speakers and have a Schiit Freya pre.

I purchased the STA200 a few months ago based on feedback from users of this forum. Speakers that I've used with the amp are PMC OB1 (6 ohm, 87db) and Alta Rhea (4 ohm, 87.5 db) and the amp barely gets warm with either.

For $500 it is a ridiculous value. I love the fact it doesn't turn into a space heater and doesn't take up a ton of space. At the price point, there probably aren't many amps that can compete with it.

Those are certainly some nice speakers, if it was "good enough" for those, I will probably be happy :)

The amp takes well to an upgraded power cord. Enjoy ! MrD.

Have one on order from Signal Cable. Reviewed very well for under $100 PC. 

I also picked up a Proceed BPA2 (on its way) I really miss the ML and I am hoping it will be a somewhat close match. Between the 2 amps, I am sure I will be happy :)

mrdecibel, what is the item that is on the stock STA200 power cord just below where the cord attaches to the amp?  I assume it doesn't impact ones choice of power cord? Thanks

Jetter, I believe you are speaking of the magnet ( ferrite choke ). Look up " what are the bumps at the end of computer cables ", as you will get your answer. These are sold everywhere, and have been for ages, in different sizes, by many manufacturers. Enjoy! MrD.

Thanks mrdecibel, I have seen them often, but I never knew that they were all basically the same device inside the cover, performing the same function. Live and learn.

OK, installed and running, just a couple hours on it...

WOW, for $500 this is incredibly good. Everything above that was said about this amp is true. 

I need time to really sit back an assess it, and I want to let it burn in a bit  before that. But initial impressions, great bass extension (much better than the Vincent SP-331 I tried, and better than my B&K reference 200.2 from my other system) unbelievably transparent, fantastic imaging. Deep sound stage.

Running with upgrade but generic 14 gauge PC currently.

:) :) :)

A few weeks from now you might be convinced there's nothing at $500 that can compare. It is an amazing value.

It is a great amp, and it found a home in my 3rd system running a pair of Wharfedales Emerald 97 mk IVs, but it was beat out by the Proceed BPA2 for this system. 

The amp originally retailed for $1200. I believe NuForce was discontinuing the amp (from what I was told). Nuforce manufacturing produced new batches to run out parts inventory at facility. However, the word got out and the amp has new life with more manufacturing runs. 

I'll be honest, if the sound of the amp with your speaker combination is what you like, you'll be find to find anything better even at $1200. Like I said earlier, I purchased the amp as a "go between" until more funds became available (my old amp blew). I decided to upgrade other components because I am so happy. After the NuForce, I purchased a Rogue tube RP-5, combo is amazing. 

I feel a little embarrassed to ask this question, and I will explain why. Simply, in my 50 plus years at this ( as an audio professional and consumer / hobbyist ), I have opened every amp I have every owned, to do a mod or 2 of some kind ( everything can be modded, for improved sq ). Has anyone been under the hood of the STA 200, as I have a few mods I would like to do. Removing the 4 philips screws from the rear side walls, I would think you spread the side walls, from the rear where the screws were removed, to loosen the top. I have tried, very gently, but they did not budge. I did not want to use excessive force. Nuforce has not answered my emails, as I suppose they do not want me in there. I would appreciate any response. BTW, as I have said before, this amp does so much right, musically, that although some amps might be better in 1 or 2 ways ( through a particular set of speakers, due to efficiency / impedance ), this little amp is quite the beast. I have owned AR, Krell, CJ, Threshold, Bedini, Ampzilla, you name it. Amp sounds best on a non resonant shelf, being left on continuously with signal playing through it ( a few hundred hours ), an after market power cord, and a 1-2 lb weight on the top center ( I use a thinking man statue over a padded piece of 4 in. X 4 in. piece of granite. Enjoy ! and Happy Holidays. MrD.

Can't help you open the case.

My purchase of the amp was necessitated when one of my monoblock amps blew out. I was looking for something that was relatively inexpensive that would hold me over until I could figure out whether I was going to purchase something in the price range of a Bryston 3BSST, Simaudio W3/W5, etc. To my surprise the damn thing sounds as good as others have commented and with my modest apartment it drives speakers as loud as my neighbors can stand.

I bought one of these probably about a year ago. Haven't tried it yet. I bought a Schiit Sage preamp to go with it. Has anyone tried the Saga with it? I've been wondering if the gains will match each other.

The Saga and STA 200 work well together. The input gain on the amp will easily allow you to use the Saga in passive mode, which I prefer over the tube stage. It is of course personal, and you might like the added color and roundness of the tube sound. Note : It also has to do with your source's voltage output and power supply design, when using it in passive mode. Enjoy ! MrD.

Thanks, MrD!


I probably won't use my system until I have the room ready. And that could be a while yet. But it sounds like this STA 200 is really a nice sounding amp, regardless of price. I have a Freya on my main system, and love the adjustability of the Schitt preamps with the passive and tube choice. Some songs on my main system sounds more transparent and detailed with the passive, even though I use the tube section of the Freya more.

Hi MrD-

Are you using a dac with the STA-200?  If so, which one?  I think we’re both using the same passive pre amp.  I’m using a CEntrance dac mini, but thinking of upgrading.