I am curious about the Nuforce STA200 amplifier If anyone has experience with the amp it would be appreciated if you would share your listening impressions, both good and bad. Some of the descriptions I have read classify it as a class AB amp and others a class D amp. I am not technical savvy about these things, can a single amplifier be both? Thanks George
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.
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 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. :)
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.
+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.
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.
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?
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.
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.
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.
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
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.
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 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.
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.
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.
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.
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.
I was going to mention that my STA200 doesn't even get warm on my 89db, 6ohm speakers. But just the same, I am a bit surprised it didn't play well with you Elacs.
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.
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...
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 :)
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.
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?
jetter, I did try some 10db attenuators and did not like them. I also borrowed an inexpensive passive unit to go between my pre and amp. Did not like it either, with a 2'ndary volume control and an additional set of cables. Tried the cheap passive direct, and found it better in some ways to the preamp. So bit the bullet and am enjoying high end passive. I am glad, after a year, you bit the bullet, purchased, and are enjoying your STA200. Enjoy ! MrD.
mrdecibel, I purchased a STA200 about a month ago when Audio Advisor received them back in inventory again. As was discussed previously, the amps high gain resulted in me only being able to turn up the volume on my tube preamp about 1/3 of usual. At someone's recommendation, I purchased the Schitt Sys passive for less than $60 including shipping and put it between my pre out and amp, and that did the trick perfectly. I have had only tube amps for a long time, but I am enjoying the STA200 quite a lot. At $499 I am quite happy.
I purchased a Luminous Audio Walker Mod, single ended, 3 in, 2 out remote unit about a month ago, and all I can say is, I will never use a preamp again. And, the STA 200 is amazing, and such a joy to listen through. Enjoy ! MrD.
I picked up the NuForce a couple weeks ago and was planning to have my CEntrance dacmini modded to variable outs. When that was a no go, I ordered a Luminous Audio Axiom ii passive preamp. Luminous Audio takes the specs on your amp and speakers (as well as the dac) and designs the preamp accordingly. Put it all together today, and even tho it’s just a few hours out of the box I’m pretty blown away. Excellent soundstage and imaging, bass is tight, excellent midrange and the background is dead quiet. I highly recommend the Axiom—about $220.00 with the upgraded Caddock Resistor.
@aberyclark Thanks for the recommendation. I will try the attenuators when they arrive, and allow them break in time. Hopefully, they do not smear the sound much. If they do not work out, I will see what to do next. Thx.
Just do what i did. I have a tube pre amp and the high gain causes the hiss to become louder thAn normal. I have zu 101 db speakers. Order the Schiit $49 passive preamp and place between pre and nuforce. Adjust the schiit volume to an accepttable level where hum is not heard at sitting position. Very transparent and better than attenuators. I tried attenuators and the sound was slightly smeared. No noticable sound quality reduction with the Schiit.
Ordered a pair of Goldenjacks 10 db attenuators. Will see if it reduces the hum, without affecting the sonics ( doubtful ). If this does not work, might need to go back to passive ( never liked ), change to a lower gain preamp, or a different amp ( although I do like the STA 200 ). I gave up on tubes a while ago.
@erik_squires My understanding about the STA 200, is, it is a conventional AB design, taken from a circuit developed by Goldmund, also used in the Job 225. But yes, Nuforce ( Nuprime ) does use designs in other models in which you speak of.
NuForce uses a hybrid approach, very similar to Carver's idea, and << cough >> borrowed by Yamaha in the EEEngine design. Not sure if Yamaha ever licensed it or waited for patents to expire.
The voltage + and - rails are Class D, and they swing up and down. In between the rails is a Class A or A/B (not sure) linear amplifier.
It's quite clever. By keeping the voltage rails from deviating too much from each other, the power dissipation in between is always limited to a few watts compared to a linear power amp of the same output.
For instance, a 120 W amplifier might have +- 50 V rails. The amp between has to dissipate a lot of heat as a result of the 100V difference. But if the voltage between the two rails is kept small, say 30V, then the heat and size of the amplifier can be made much smaller, with much less wasted power.
Purchased one in April of ’17, for shits and giggles. Sold many of my " expensive " amps, because after a few months of this little guy breaking in, it bettered many of them. My only negative issue, because of it’s high gain, I do get a small amount of hum from my 104 db sensitive speakers, which was bothersome at some point. Hum is at constant level, does not increase with volume. Have not even done my AVM mod to it yet ( which I do to almost everything ). An amazing amplifier.
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