[rustydoglim]

I think it is an upgrade from STA-9 to Ref 18.

[benma]

Did anyone compare the Reference 20 mono blocks with ST-10M mono blocks?
Would it be wiser to get two second hand Reference 20 mono blocks in mint condition for the same money than two new ST-10M mono blocks?

[benma]

P.S.

I've auditioned the ST-10M mono blocks and in general I liked them. My only complaint is the lack of highest detail and dynamics in the treble area. Are the Reference 20s better in that?

My speakers: Dynaudio Contour 30

[rustydoglim]

The Reference 20 and the Evolution One are better than ST-10/10M.

[benma]

Thank you

[Arlequen]

The Reference 20 and the Evolution One are better than ST-10/10M.

Hello Rusty .. since I'm trying two new Reference 20 .. this is their first sounding week .. and I can choose for them or for the Evolution One .. could you tell me how much this new Evo is improving compared to the Ref. 20?
Well .. to be clearer .. I pay half price for the Ref. 20 (new but sold as demo units) while the new Evo is full price .. apart a little discount .. so I'm investigating about if the kinda double price is worthing
Thanks in advance for the reply

[rustydoglim]

Performance is subjective, especially at this high level.  All I can tell you is that Evo Amp is a newer design (for details please refer to the product page) and everything else is just better than Ref 20.
Keep in mind that Ref 20 is an incredible amp, and there is no particular weakness. So Evo Amp is just better in every way.
Is it worth the extra cost, that's subjective.

Some people drink away a few thousand $ a year in wine, take a vacation, or my online gaming pals spend a few thousand $ per year for the thrill of being the best, so it is a personal choice you have to make.

[Arlequen]

Keep in mind that Ref 20 is an incredible amp, and there is no particular weakness. So Evo Amp is just better in every way.

Thank you Rusty.
I quoted your sentence in an interesting part.
In your knowledge where and what I gain with the new Evo One?
By my small experience with the Ref. 20 I greatly appreciated the soundstage  a bit wider deepest and taller than the one obtained with my Parasound Halo JC1 and the Primare A32 I'm using from a year .. and the tonal neutrality... as good as from the other amps used.
The weird data is the power of the Ref. 20 compared to the Evo One .. in fact for the first NuForce says 200/8 and 400/4ohms .. for the second 240/8 but 330/4
Could this due to the new toroidal power stage compared to the previous switch module?

My rig .. Pass Labs X1 preamp .. TW Acustic Raven One TT with Graham Phantom II and Benz Micro LP cart. .. Whest Audio PS30RDT SE phono stage

Upgraded combo Philips CDD 882 Transport with Philips DAC 960 ..

Thiel CS 2.4 loudspeakers

Power Cords all Shunyata .. two Venom HC on amps and two Delta NR on pre and phono.

Cardas Golden Reference spkr. cables

Previous amp : Odyssey Audio Stratos .. than Parasound Halo JC1's .. and lately Primare A32

[rustydoglim]

The weird data is the power of the Ref. 20 compared to the Evo One .. in fact for the first NuForce says 200/8 and 400/4ohms .. for the second 240/8 but 330/4

Some basic about power, current and voltage
V = I * R
P = V * I = V square / R
So, the basic assumption is that  when the impedance R is half, then power is double. 
I think so far everyone understand this elementary math .
But in reality that's not always the case.

Let's use Ref 20 as the example:
200W at 8 Ohm is the spec for the amp.  400W @ 4 Ohm is the expected power if the power supply AND the amplifier are designed to scale up.  So far so good.   Now let's consider other alternatives.  What if we increase the capability of the amp to get more power at 8 Ohm.
Evolution One has 240W @ 8Ohm, better.  Could we have also increase the power of the amp and power supply to deliver 480W @ 4 Ohm ? Sure, but that would compromise the sound quality where we have to alter the design.   

Therefore, the overall power of Evo One has increased for most speakers (whose nominal impedance .  In all practical purpose, nobody really listen at max power, the typical listening power is less than 100W. 

[Arlequen]

Got it! .. Thanks
Theorically on my Thiel CS 2.4 the Ref. 20 works better than the Evo ..

This is what wrote a famous reviewer about my spkr:

"I estimated the Thiel CS2.4's voltage sensitivity to be slightly higher than both average and specification, at 88dB(B)/2.83V/m.
However, despite Wes Phillips' conjecture that this speaker is not too hard to drive, its impedance plot (fig.1) indicates that the CS2.4 demands a lot of current from amplifiers.
Not only does its impedance drop to 2.73 ohms at 600Hz, but it stays significantly below 4 ohms from 100Hz to 50kHz, and there is a difficult combination of 4.5 ohms magnitude and –45° electrical phase angle at 80Hz.
Thiel CS2.4 owners should make sure they have a good 4 ohm–rated amplifier to drive this speaker."

[rustydoglim]

Theorically on my Thiel CS 2.4 the Ref. 20 works better than the Evo ..

I disagreed.  We could be going in circle.  The max power is rather irrelevant as long as you have adequate power.  Anyway, I am happy regardless of what customers buy, as long as it is a NuPrime

[RafaPolit]

I could recognize JAs review anywhere! He is a genius, and his info is vital to a lot of us that can't hear first hand and need to rely in other people's opinions and measurements.

4 ohms from 100 to 50K is the entire frequency range! Are you sure you copied that correctly? If that is true, these are certainly < 4 Ohm speakers! 600Hz is the very MIDDLE of everything you will be hearing, and that is 2.7Ohms.  Ouch!

Still, let's say all this is true (which I am sure it is, JA knows his stuf better that anyone else I have read in the industry).  You would still be getting 340 W from the Evos, which is probably more than you would usually need.  Would more be better? Sure, but only if everything else is equal.  So, let's say you had the same exact sound (not possible, lets just theorize for a minute) and you could get a 400 instead of 340.  Then yes, for sure it would be better.

But if the sound is less rich, or less detailed, or a bit more colored, or ... you get where I'm going at.  Perhaps it's better to have 340 great sounding Watts, instead of less good 400 W. 

So if there is any chance for you to try them out and judge for yourself, that'd be great.  Still, at double the price, I can assure you they won't be twice as good.  No where near that much in fact.  So if you are happy as is, you could save a lot of money and have both the amps and the $ wine Jason is talking about (or the PC games if you are into that! )

Best,
Rafa.

[Arlequen]

Are you sure you copied that correctly? If that is true, these are certainly < 4 Ohm speakers! 600Hz is the very MIDDLE of everything you will be hearing, and that is 2.7Ohms.  Ouch!
Rafa.

https://www.stereophile.com/content/thiel-cs24-loudspeaker-measurements

[Mystic Dragon]

SHOULD I BUY STA-10 OR STA-10M?

I am looking for a power amplification solution for a stereo system which currently uses a Chord Hugo as a DAC and pre-amp.

This amplification solution needs to power my current Focal Aria 938 floor-standing speakers as well as my future speakers which are likely to be a product along the line of Focal Sopra 2 or Goldenear Triton Reference. 

One question that I have not been able to answer is whether to purchase a stereo amplifier (e.g. ST-10) or two mono amplifiers (e.g. ST-10M). I have not bought any NuPrime products before but am very interested.

I hold myself accountable for buying intelligently and might not be able to forgive myself spending twice the amount of money to obtain only a 10% improvement in performance.

Please advise. Thanks.

[seikosha]

SHOULD I BUY STA-10 OR STA-10M?

I am looking for a power amplification solution for a stereo system which currently uses a Chord Hugo as a DAC and pre-amp.

This amplification solution needs to power my current Focal Aria 938 floor-standing speakers as well as my future speakers which are likely to be a product along the line of Focal Sopra 2 or Goldenear Triton Reference. 

One question that I have not been able to answer is whether to purchase a stereo amplifier (e.g. ST-10) or two mono amplifiers (e.g. ST-10M). I have not bought any NuPrime products before but am very interested.

I hold myself accountable for buying intelligently and might not be able to forgive myself spending twice the amount of money to obtain only a 10% improvement in performance.

Please advise. Thanks.

I hate to tell you, but (unless you own a really difficult to drive speaker) I don't think there is more than a 10% difference with just about any amp once you pass a few hundred dollars.  Don't get me wrong, there are certainly improvements out there, but I'd argue that they aren't really much more than 10% if that.  The high end is all about chasing that last 1-10% of improvements.

[rustydoglim]

the difference is relative.  I am a coffee drinker, I buy only Jamaica Blue Mountain Coffee bean for drinking at home and to me, the difference between top tier coffee and "regular" coffee is day and night.  Same for sound quality.
I do agree that the difference between ST-10 and ST-10M is 10% or less unless you have a difficult to drive speaker.
BUT, we can't generalise that for the other NuPrime amps.  The difference between Evolution One and STA-9 would be huge in all aspects of sound characteristic.  And there are much smaller differences in quality (for example, comparing resolution) between similar range of amps (ST-10 and new AMG) but they differ in sound characteristic.

According to our chief engineer, he designed these amps and their desire characteristic through extensive computer simulation of circuit and devices during the design stage, not via trial and error. The sound characteristic is achieved by crafting class-A transistors preamp stage of the Class D power stage.

Sure, if you use these amps to drive a $2 speaker, they are going to sound the same.

[rustydoglim]

@Mystic Dragon

I recommend that you go with ST-10.  You will be happy with ST-10.
And later if you upgrade your speaker, and want something much better, then trade in (I am sure your dealer will be glad to take one ST-10 at full price) for a pair of Evolution One later.

[Mystic Dragon]

Thank you seikosha and rustydoglim for the very useful advice.

NUPRIME SALES CHANNELS

I live in Australia and hope NuPrime would establish brick and mortar or online sales channels that serves this market. 

While I would be satisfied to place an order for a ST-10 without having first listened to it, I cannot see myself doing the same when I consider buying a product priced at the Evolution One level.

It would be good to be able to buy MCX-2 type products from eBay or Amazon.

Class D amplifiers with Class A

[rustydoglim]

Please contact http://www.mcleans.info
He has been active with NuPrime lately and bought quite a few items.
I will add his contact to Nuprime website.

[Mystic Dragon]

Please contact http://www.mcleans.info
He has been active with NuPrime lately and bought quite a few items.
I will add his contact to Nuprime website.

I have just place an order for a ST-10 with McLeans in Australia. Look forward to hearing how it sounds.