Review and Measurements of NuForce STA-200 Power Amp

[Frank Dernie]

I looked at Job 225 specs/website before finishing this review. They show the same poor distortion metrics as I got/NuForce advertises. So they are no better in this regard.

I usually go by the old engineering metrology rule-of-thumb where the measuring device should be at least an order of magnitude better than the DUT.
I personally reckon that since few speakers have better than 0.2% distortion any electronics driving them will be a requestably good approximation to perfect if the distortion is less than 0.02%
On this measure pretty well all DACs are "perfect" pretty well all preamps are "perfect" but not all power amps. Record players are w-a-y far from perfect

 

[Frank Dernie]

I like the extremely low noise floor of the Devialet, as well as the SAM feature, which is wonderful for minimonitors in nearfield setups.

One of the reasons I originally bought the D-Premier was how good the phono stage was and how quiet and clear it was on all inputs.
The phono stage was downgraded noise-wise when they updated to the pro line IME, sadly. I part exchanged my 800 (updated from the 2 D-Premiers) I had for the Original d'Atelier for the colour. Many people tell me it sounds better but my aural memory is not good enough to confidently say myself.
Otherwise all inputs are very quiet and it is very versatile. There is no SAM profile for the speakers I normally use with it, but there is for the KEF LS50s (excellent with SAM) and the Yamaha NS1000M which I haven't tried yet.
The Job Pre/225 had no noticeable noise either though. I do vaguely remember one setup where I had hum with it but can't remember the detail. Old bloke syndrome...

 

[Frank Dernie]

I love the LS50s with SAM, but they are not in the same universe as the Dutch & Dutch 8Cs.

I did not buy the Expert Pro upgrade, and the Pro line was rolled out, to my annoyance, one month after I bought my Expert 120.

Despite problems with the AIR feature, I've been happy with the Devialet.

Too old for changing anything now, probably.
I like the 8Cs but I have given up on streaming and want a simple rotary volume control, so no good for me so far.

 

[Purité Audio]

Until D&D introduce their own break out box, I have been sending AES to mine via The RME ADI pro, which is capable of attenuation , no remote though.
Keith

 

[JJB70]

want a simple rotary volume control, so no good for me so far.

There is a lot to be said for good old fashioned simple rotary dials. Turn one way to make louder, turn the other way to make quieter, turn to select source etc. I hope I'm not an absolute luddite but one of the thins I like about my car is that the climate controls are still rotary dials and despite the mandatory screen MMI it still has old fashioned rotary dial short cuts for the stuff I actually use.

 

[restorer-john]

Taps, steering wheels, door handles, jars, bottles, screws, nuts etc. They all turn.

Rotary encoders are horrible. Slide controls, and up and down buttons are horrible. They always were, even when they were novel in the 1980s when every piece of HiFi had stupid up/down controls and flat panels for that 'high tech' look. I have many examples of failed ergonomics and overly complicated mechanical designs simply done to get 'feather-touch' up/down controls when a simple 270 degree rotary pot was better.

I love my car's heater, aircon controls as they are not buttons with dumbass icons like on our other car. If I want some air on my feet and some in my face, I put the dial in between the two settings- it mixes it. If I want some on the windscreen and the rest on my feet, same deal. The heater control is a gradual mix of cool air over the hot water and can be trimmed perfectly. I get putridly angry with the dual control BS with icons that make no sense on my partner's car. Every car I've ever had with so-called 'climate control' has been flawed. The systems are simply too dumb with too few sensors and no idea.

 

[Wombat]

I usually go by the old engineering metrology rule-of-thumb where the measuring device should be at least an order of magnitude better than the DUT.
I personally reckon that since few speakers have better than 0.2% distortion any electronics driving them will be a requestably good approximation to perfect if the distortion is less than 0.02%
On this measure pretty well all DACs are "perfect" pretty well all preamps are "perfect" but not all power amps. Record players are w-a-y far from perfect

Yes, indeed. Chasing higher level performance tends to be for-the-sake-of-it and not necessarily for any tangible audible benefit.

 

[graz_lag]

Hi there from France !
In 2014 I bought an AVR from Primare, Sweden, the SPA23 (now replaced by the SPA33).
Primare was claiming and still claims, to have designed the best class D amplifier in the industry ...
Here is the link that gives details abt. what they call the UFPD technology : https://www.primare.net/about-primare/technologies/
A couple of .pdf can also be downloaded from the page to get further explanations.
My decision process went thru listening sessions comparing the Primare SPA23 to Rotel, Pioneer and Emotive, although Primare was 2.5x more expensive, so I was certainly not comparing apple-to-apple.
However, at the end of the day the Primare was miles better and so I decided for it.
I am now "terrified" abt. the results of these measurements of some class D amplifiers, OK built for a totally different type of consumer than the Primare, but still I am afraid that the class D limitations "may" in some ways apply to my "much more expensive" UFPD technology from Primare ...
The Swedish are know for stuffs well done : Volvo, Saab, Ikea ... or for the Hi-Fi : Primare, Hegel, Electrocompaniet (the latter from Norway, but still Vikings in the DNA).
That was also considered in my decision process.
If someone of you guys wants to take some time in going thru this UFPD Technology and get back with comments / feedback ...
Merci !!!

 

[andreasmaaan]

I am now "terrified" abt. the results of these measurements of some class D amplifiers, OK built for a totally different type of consumer than the Primare, but still I am afraid that the class D limitations "may" in some ways apply to my "much more expensive" UFPD technology from Primare

I don’t know about the Primare, but I wouldn’t worry based on these results if I were you. Class D amps are capable of excellent performance - just not these few measured here.

Primare’s technical document doesn’t seem to suggest there’s anything particularly unique about their UFPD technology though. The way they describe it is very vague and could apply to any class D amp really.

 

[amirm]

Primare was claiming and still claims, to have designed the best class D amplifier in the industry ...

Welcome to the forum. You just reminded me that I have a Primare integrated amplifier! I have to tear it out of my system but I will do that and measure it.

 

[Dialectic]

Welcome to the forum. You just reminded me that I have a Primare integrated amplifier! I have to tear it out of my system but I will do that and measure it.

Using it in a second system?

 

[amirm]

Using it in a second system?

No it is in my primary system! I use its pre-amp only so had forgotten about it being a class-d power amp.

 

[graz_lag]

Welcome to the forum. You just reminded me that I have a Primare integrated amplifier! I have to tear it out of my system but I will do that and measure it.

Great !
Double check the model and year of manufacturing of your integrated amp : Primare went from the A-B design to the class D abt. 10 years ago, or so.
i.e. Primare I30 (2004) was an A-B; Primare I32 (2011) is a class D.
Congratulations @amirm : this is a great forum, indeed !

 

[graz_lag]

I don’t know about the Primare, but I wouldn’t worry based on these results if I were you. Class D amps are capable of excellent performance - just not these few measured here.

Primare’s technical document doesn’t seem to suggest there’s anything particularly unique about their UFPD technology though. The way they describe it is very vague and could apply to any class D amp really.

Thanks !
Yeah the tech documents contain the usual blah-blah marketing, not a lot in fact.
Primare is the same company that has taken the already extremely good Oppo universal players to a higher level by means of several upgrades especially in the analog audio section, first with the BD32 (based on the 105 platform), then with the BD32 MKII (based on the 205 platform).
However, these are non available any more as Oppo has stopped the assembling line.

 

[amirm]

Primare I30 (2004) was an A-B; Primare I32 (2011) is a class D.

Ah, it is an I30 so class AB?

 

[graz_lag]

Yes, an A-B; the replacement, the I32 was a class D ...
The I30 was and still more valued by the enthusiasts, the I32 was not as good ...
Who knows if the swift to the class D has had an impact with that poorer performance vs. the I30 ...
I attach the specs page for the I30 just in case you did not keep the user guide ... perhaps you feel you want to test it anyway ...
OK I do not want you to push off-road ...

 

[amirm]

I attach the specs page for the I30 just in case you did not keep the user guide ... perhaps you feel you want to test it anyway ...

Thanks and yes, I will test it in the future.

 

[GanAinm]

Hello,
I just got an STA 200 to replace an 80's FET boat anchor (recapped Nikko) into Rega speakers. It is smaller, prettier, runs cooler and sounds better to me so for 500 bucks mission accomplished. Assuming it lasts. But am intrigued, and not shocked (or "insulted") by measurements. Appreciate the work. Is a schematic available yet for tinkerers? (Although I would likely wait a year to keep warranty) Any thoughts or measurements on simple AC noise reduction like ferrites on the line cord or othe basic pre filtering?

Anyway. Thanks for a forum for audiophiles with good ears AND undertstanding of, or interest in, electronics and physics. Reasonable people can differ on audibility/importance of certain measurements. Inventing "new physics" for easily explained psychoacoutic and listening space phenomena, less comvincing to me.

 

[graz_lag]

Here in the old Europe we have a bunch of companies, especially from the UK and the Netherlands, that are in the growing process of proliferating myths about the technical contents of power cords, audio interconnects, and - obviously, speaker cables.
I have been caught in the net, in several occasions.
I would like to report some of my experiences and understandings.

#1. The power cords to the gears add only 2 meters or 6 feet, or so, so this is a small fraction of the entire path to the outlet
#2. Shielding a power cable is not a good idea, as it will add much more capacitance to the cable vs. minimal positive benefits
#3. Ferrites to stop RF being picked-up by power cords and other audio cables : these will significantly round-off the high-frequency content
#4. In my installation, I have run a dedicated power line, two in parallel actually, each one made from 2-conductors, 12 gauges twisted solid copper, to the A/V system outlets. (My gears are all class 2 double isolation chassis with no provision for the earth wire.)
#5. These dedicated lines end up on outlets with above-standard high copper content as well as with silver plated contacts
#6. I now build all my power cords from 12 gauges solid copper, 2-conductors, twisted. (You need to accept the fact that you need to bent it to route it to the gear.)

However, and ultimately, the biggest role is played by the gear built in power supplies : do they have enough low inductance energy storage and enough fast response times to provide current to the electronics ? If the answer is yes, very minor advantages will be noticed, if any, by replacing the standard $2 / tons FOB Shenzhen black cords that are supplied with the gears with esoteric or DIY power cords.

 

[GanAinm]

Thank you. I certainly was not thinking about high end cords, just rational and affordable ways to keep noise out of amps. I womder why ferrites on an AC cord would dampen audio signals?