[maty]

[Polish] NUPRIME DAC-10H+ST-10 by Radosław Łabanowski

https://audio.com.pl/testy/stereo/wzmacniacze-stereo/2901-nuprime-dac-10h-st-10

to English with Google:

https://translate.google.com/translate?sl=pl&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Faudio.com.pl%2Ftesty%2Fstereo%2Fwzmacniacze-stereo%2F2901-nuprime-dac-10h-st-10&edit-text=&act=url


NUPRIME DAC-10H, inside

NUPRIME ST-10 power amplifier, inside

Fig. 1. NuPrime DAC-10H + ST-10 - frequency response.

Fig. 2. NuPrime DAC-10H + ST-10 - THD + N / power.

Fig. 2. NuPrime DAC-10H + ST-10 - harmonic distortion.

    Rated power (1% THD + N, 1 kHz) [W] 8 Ω, 2x 173
    Rated power (1% THD + N, 1 kHz) [W] 4 Ω, 2x 161
    Sensitivity (for maximum power) [V] 1x 0.52
    Signal-to-noise ratio (A-weighted filter, with reference to 1W) [dB] 80
    Dynamics [dB] 104
    Damping factor (relative to 4 Ω) 62

Even from a small impulse amplifier, we can expect a large dose of watts, as well as a clear increase in watts with lower load impedance. Meanwhile, NuPrime decides on a rather unusual configuration, in which a similar maximum power is maintained for both 8 and 4 Ω; according to the specification, it has to be 2 x 150 W.

However, in our laboratory we start from checking the potential of a single channel (then only the power supply works for it), and hence the results much higher - 231 W at 8 Ω, although in fact not much more, because 240 W at 4 Ω. The results in the stereo system are close to company announcements, but the linear power supply "does not keep up with the possibilities (and demand) of the impulse terminals, at 8 Ω we have 2 x 173 W, and at 4 Ω - 2 x 161 W.

The preamplifier allows different configurations of sensitivity, even in the factory setting (L - low sensitivity), this parameter is 0.5 V, which is still a very universal value.

As a rule, impulse amplifiers suffer from high noise (high frequency, but appearing in the measurement results), NuPrime DAC-10H / ST-10 does quite well, S / N is 80 dB, and the dynamics is 104 dB. An easy test for this type of construction is also the measurement of transmission characteristics (Fig.1). Raise at 30 kHz, however, does not exceed the acceptable value of 1.5 dB.

A more serious problem is the level of distortion (Figure 2). The strongest second lies at -67 dB high, the third at -79 dB, and above -90 dB are next; to the ninth inclusive. [maty: the small problem is the H6 at -80dB]

Distortion THD + N (figure 3) lower than 0.1% can be obtained for an output power exceeding 0.8 W at 8 Ω and 1.3 W at 4 Ω. The characteristics quite quickly reach their minima, in which the DAC-10H / ST-10 resembles a tube amplifier somewhat.

[TheSpaghetto]

This numbers are far from specs available on the NuPrime website.
I think that NuPrime should take the chance to add these technicalities to their product pages.

I love the fact that the website is very clear on the NuPrime philosophy, something that I don't understand at all on other websites, but it could be much more clear on numbers. Other manufacturers usually have better specs in a more readable and comprehensive table..

Having measurements similar to the ones published by Soundstage and Stereophile would be the top!
https://www.soundstage.com/index.php?option=com_content&view=article&id=17&Itemid=141

[slash71]

the numbers are so far but my hear are so close to a well structured and  musical aware sounds comes from my st-10 and dac-10h pile. classical ++++ soft rock++

[TheSpaghetto]

They do sound great!

but with OEM modules suppliers going so strong, such as Hypex, I think they are raising the bar in providing fully spec'd sheets.
I never heard Hypex ncore and Nuprime in the same room, and I think most of us didn't, so numbers are what we are left with.

But I am an engineer, so maybe I am biased by my job!

Anyway I would be curious to know what Nuprime guys think about releasing all the specs or just making them more organized...

[maty]

Also Volkswagen and other brands go well by road but ...

https://www.nytimes.com/interactive/2015/business/international/vw-diesel-emissions-scandal-explained.html

And the frequency response is more typical of cheap class D amplifiers that I have criticized so much in other circle threads, for example with the studio monitor JBL LSR 305.

[slash71]

Also Volkswagen and other brands go well by road but ...

https://www.nytimes.com/interactive/2015/business/international/vw-diesel-emissions-scandal-explained.html

And the frequency response is more typical of cheap class D amplifiers that I have criticized so much in other circle threads, for example with the studio monitor JBL LSR 305.

ya, but pollution kill people , THD or SNR not yet ..

[slash71]

They do sound great!

but with OEM modules suppliers going so strong, such as Hypex, I think they are raising the bar in providing fully spec'd sheets.
I never heard Hypex ncore and Nuprime in the same room, and I think most of us didn't, so numbers are what we are left with.

But I am an engineer, so maybe I am biased by my job!

Anyway I would be curious to know what Nuprime guys think about releasing all the specs or just making them more organized...

specifications are part of game , imho people plays music and the HW for these outsiders is only a commodity ..
in a recent audition I've heard some piece of HW , one of these is 'THE BOX' from QHW audio. A 'simple' opamp +6db on gain that improve the sound? yes .. connected between my amp/preamp  setup it reveal detail and bring music to another level of audition.. difference is notable on large number of devices and configuration , devices with very high published specs...

[maty]

Well, the harmonics profile is very important too.

A very beautifulll profile in this new DIY class A 20 watts.

Aksa Lender P-mos Hybrid Aleph (ALPHA) Amplifier

http://www.diyaudio.com/forums/solid-state/318102-aksa-lender-mos-hybrid-aleph-alpha-amplifier.html

Problems to load image 

http://maty.galeon.com/WP-imagenes/hum/xrk971-Alpha-20-2.87vrms-8ohms-FFT.png


NUPRIME ST-10

If I am not wrong, measured with 8 watts.

[RafaPolit]

Nice link Maty! I would really love to venture into that sort of DIY would it not be that components here are very hard to come by.  I grew up watching my father do boards like that, and really love the feeling of having something you did with your own hands.

Maybe at some point.  Right now, I just bought another RPi3 to link to the uDSD and see how that turns out.

Best regards,
Rafa.

Edit: According to the nuPrime graph, there is equal amount of odd order harmonics than even order harmonics, is that correct?

[maty]

The preamp has very good specs. Harmonic profile too.

AKSA's Lender Preamp with 40Vpp Output

http://www.diyaudio.com/forums/analog-line-level/314563-aksas-lender-preamp-40vpp-output.html

Systems with H2 predominance sound with more emotion, more credible, more natural. Like tubes but without noise and others nasty harmonics.

Usually SS amps are H3 predominance -> the sound is more analytic, less emotion.

ALPHA has the H3 12 dB below from H2, very good thing.

Nuprime ST-10 is H2 predominance.

The problem with this class A are the watts. 20 watts or 50 watts the Big Boy (toooo much heat for now). You need speakers with high sensitivity and/or high impedance curve that no is the case of my loved cheap tweaked KEF Q100 coaxial speakers 

[amarsicola]

Even a 500€ nCore based amp would destroy it, let alone a 300€ nad 320BEE that i owned before purchasing this, based on positive reviews from TNT-audio. Check audiosciencereview with your eyes.
My largest error in hi-fi purchases after the PMC loudspeakers. What a fool giving away 1400€ for such a poor measured performance

[jonbee]

I never heard Hypex ncore and Nuprime in the same room, and I think most of us didn't, so numbers are what we are left with.

I've owned and compared DAC10H, ST-10, Hypex NC-400s, and several DAC Cherry amps.
I replaced the Hypex with Nuprime; the ST-10 amp simply sounded better, more like music within its limits. The DAC10Hs sounded superb with all, imo.
The Cherry Maraschinos sounded better yet, for more $.
That said, I've simplified my systems and am very pleased with the IDA-16 in a difficult to drive hi-rez system, with a modded IDA-8 in a second system. Not as good as the cherrys, but the IDA-16 is still very satisfying musically, and a great value for what it offers.
Numbers never tell the same story as our "ears", and probably never will, due the the wide variations of listeners, systems, rooms, etc.

[rustydoglim]

In the early days of class D amps, manufacturers struggled with improving THD+N, power and the curve.
I don't know about others, Nuprime is able achieve exactly what we want now, so we stop paying attention to the measurement.
It is now more important to achieve the sound characteristic that we want, than to decide whether to have 0.05 or 0.01% THD+N. Other aspect of the designs make that irrelevant. For example, using class-A transistors in the preamp stage add warmth but increase THD.