NuPrime Evolution STA

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mresseguie

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NuPrime Evolution STA
« on: 17 Jan 2022, 04:48 pm »
Evolution STA $4995.00

The NuPrime Evolution STA offers a breakthrough in distortion reduction. We called that Only Distortion Cancellation (ODC) design, continued advancing the state-of-the-art Class-D for the past decade.

A typical feedback error correction design inverts the output signal for summation with the original input signal to derive the negative error signal, which adds to the next cycle of the input signal to form a more accurate output signal. Nonprime’s ODC Class-D design derives the error signal from MOSFET devices and the output filter circuit directly, significantly reducing the negative feedback signal, which resulted in a substantial reduction in distortion THD+N of 0.002% @1kHz(5W), and less than 0.005% THD+N at 1KHZ (2W-100W). This breakthrough improvement in Class-D design resulted in a natural and pure sound characteristic.


https://nuprimeaudio.com/product/evolution-sta/?v=7516fd43adaa

https://nuprimeaudio.com/product/evolution-sta/?v=7516fd43adaa
Specifications:
Power Output (RMS): 230W @ 8 Ohms , 310W @ 4 Ohms
Power Output (peak): 270W @ 8 Ohms , 360W @ 4 Ohms
Gain: x21
Sensitivity (to rated power): 2Vrms
Input Impedance: 47K Ohms
EVO STA WATT / THD / S/N (typical) : @5W (0.0025% ,95db) , @50W (0.007% , 105db) , @100W (0.01% , 110db)
Frequency Response: 10Hz to 50kHz (-3dB)
Trigger IN and OUT
Standby Power : 1.5W @ 115V outlet, 1.7W @ 230V outlet
Idle Power : 24W @ 115V outlet, 26W @ 230V outlet
Worldwide AC voltage: (115VAC / 230VAC) with Voltage Select Switch
AC Fuse : Slow blow , 7A , 250VAC
Dimension : 430mm x 372mm x 66.5mm
Weight : 10.5Kg
Package Dimension: 642mm x 594mm x 254mm
Package Weight : 14Kg
Color : Black or Silver

mresseguie

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Re: NuPrime Evolution STA
« Reply #1 on: 17 Jan 2022, 05:04 pm »
Jason,

Congratulations on your new baby! I'm guessing this amp must be pretty awesome sounding. Have you got anything more to say that's not already on the website?


rustydoglim

Re: NuPrime Evolution STA
« Reply #2 on: 18 Jan 2022, 11:03 pm »
Due to covid travel restrictions throughout Asia, I haven't been able to listen to Evo STA out of Taiwan factory.  But I don't need to listen to it for myself, I can rely on the chief engineer.  HiFi Advice has been reviewing our amps and we come close to challenge the reference CH A1.5 ($39,500). I think Evo STA has a shot at matching any class A reference amp.

John Casler

Re: NuPrime Evolution STA
« Reply #3 on: 18 Jan 2022, 11:30 pm »
Jason,

Congratulations on your new baby! I'm guessing this amp must be pretty awesome sounding. Have you got anything more to say that's not already on the website?

Hi Michael,

I think one is being built now, with your name on it. . .  :thumb:

mresseguie

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Re: NuPrime Evolution STA
« Reply #4 on: 19 Jan 2022, 01:25 am »
Hi Michael,

I think one is being built now, with your name on it. . .  :thumb:

 Go ahead...surprise me.  :thumb:

 :popcorn:

John Casler

Re: NuPrime Evolution STA
« Reply #5 on: 23 Jan 2022, 07:33 pm »
Well the surprise is the one with your name on it should be on its way next week.   8)

RonN5

Re: NuPrime Evolution STA
« Reply #6 on: 23 Jan 2022, 10:22 pm »
Rusty,  I saw this discussion, below, by Ralph Karsten over on Audiogon…. and I’m wondering if you guys generally agree with him about distortion and sound and how you would describe your new amps distortion profile?  Thanks.

“IMO/IME the most important measurements are distortion vs frequency and a spectral presentation of what the distortion signature looks like. If the distortion does not rise with frequency anywhere in the audio band, and if the distortion signature allows the lower ordered harmonics to mask the presence of the higher ordered harmonics, then the amp has a very good chance of sounding quite good.

Quite often, such as in the pages of Stereophile, the distortion is only measured at 100Hz. In a nutshell that's simply inadequate- so even though the distortion might seem quite low, that's not enough to know if the amp 'measures well'.

The ear uses the higher ordered harmonics to sense sound pressure and so is keenly sensitive to them (it has over a 120dB range)! A slight amount of audible higher ordered harmonics will cause the amp to sound brighter and harsher because the ear also assigns tonality to all forms of distortion. If there is enough of the 2nd and 3rd harmonics present they can mask the higher orders. This is why an SET, which has more higher ordered harmonic distortion than any other kind of amp, can sound so smooth, whereas most solid state amps with 2 or 3 orders of magnitude lower distortion and still sound harsh and bright”.

mresseguie

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Re: NuPrime Evolution STA
« Reply #7 on: 24 Jan 2022, 01:10 am »
Well the surprise is the one with your name on it should be on its way next week.   8)

Hot damn! I wonder how that happened?

I’ll burn it in for a few days before I give it a good listen.

Thanks, John!


mresseguie

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Re: NuPrime Evolution STA
« Reply #8 on: 27 Jan 2022, 02:23 am »
Hot damn! I wonder how that happened?

I’ll burn it in for a few days before I give it a good listen.

Thanks, John!

I lied. I plugged it in and just had to listen right away.

It was delivered about 2 hours ago. Outside temperature was about 40 F. When I pulled the amp out of the <awesome> packaging, the case felt as though it had sat in a fridge overnight. I know better than to make judgemental comments at this point because the amp is cold and <presumeably> needs a good 100 hours to wake up. It's just a baby.

This baby's got BASS!

 :popcorn:

Going on 8 hours....vanishingly low distortion....Last night, while I was listening to Natalie Merchant's Paradise is There, my wife commented on how loudly I was playing it. It hadn't seemed loud because there were no distortion cues to catch my attention.

I'll probably burn it in for another 4 or 5 hours on my main system before connecting it to my Omnia A300 for 'dedicated' burning in on my office system. I'll let it play for a couple days before bringing it back down for a listen.

 :popcorn:
« Last Edit: 27 Jan 2022, 03:04 pm by mresseguie »

rustydoglim

Re: NuPrime Evolution STA
« Reply #9 on: 1 Feb 2022, 05:40 pm »
Rusty,  I saw this discussion, below, by Ralph Karsten over on Audiogon…. and I’m wondering if you guys generally agree with him about distortion and sound and how you would describe your new amps distortion profile?  Thanks.

“IMO/IME the most important measurements are distortion vs frequency and a spectral presentation of what the distortion signature looks like. If the distortion does not rise with frequency anywhere in the audio band, and if the distortion signature allows the lower ordered harmonics to mask the presence of the higher ordered harmonics, then the amp has a very good chance of sounding quite good.

Quite often, such as in the pages of Stereophile, the distortion is only measured at 100Hz. In a nutshell that's simply inadequate- so even though the distortion might seem quite low, that's not enough to know if the amp 'measures well'.

The ear uses the higher ordered harmonics to sense sound pressure and so is keenly sensitive to them (it has over a 120dB range)! A slight amount of audible higher ordered harmonics will cause the amp to sound brighter and harsher because the ear also assigns tonality to all forms of distortion. If there is enough of the 2nd and 3rd harmonics present they can mask the higher orders. This is why an SET, which has more higher ordered harmonic distortion than any other kind of amp, can sound so smooth, whereas most solid state amps with 2 or 3 orders of magnitude lower distortion and still sound harsh and bright”.

That's true. But nowadays all the state of the art Class-D amps sounded very good with low distortion anyway, it wasn't like that 10 years ago. Nuprime amps across the board already have distortion that most people don't pay attention to the THD+N. Anything less than 0.1% is hardly noticeable. Some model such as STA-9 or AMG STA has Class A transistors circuit in the preamp stage with even-order harmonics not to mask off the harshness but to create more warmth. Fundamentally all existing Class-D amps use a certain way to do noise reduction:
A typical feedback error correction design inverts the output signal for summation with the original input signal to derive the negative error signal, which adds to the next cycle of the input signal to form a more accurate output signal.

The Evo STA uses a new design to perform error correction and noise reduction.
Nonprime’s ODC Class-D design derives the error signal from MOSFET devices and the output filter circuit directly, significantly reducing the negative feedback signal, which resulted in a substantial reduction in distortion THD+N of 0.002% @1kHz(5W), and less than 0.005% THD+N at 1KHZ (2W-100W). This breakthrough improvement in Class-D design resulted in a natural and pure sound characteristic.

I have stated earlier that any noise reduction with THD+N below 0.1 is hardly noticeable, so why does it matter for Evo STA to further reduce the noise? Apparently, the new design of deriving error signals from the devices directly is very hard to do (never heard of anyone else doing this), and it changes the perception of sound than we can quantify it (THD+N is the only measurable spec but there are other improvements going on here).

mresseguie

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Re: NuPrime Evolution STA
« Reply #10 on: 1 Feb 2022, 11:18 pm »
Jason,

Approximately how many hours of burn in is needed before the Evolution STA amp is considered fully burned in?

Edit:

For crying out loud! Isn’t there some way to burn in an amp more quickly than 24 hrs/day? Just kidding.  My Evo STA is only up to about 70 hours <though I’m not counting very closely> because it’s in my main system with my tube pre, and I won’t run it 24/7. [Ignore me. I’m just grumpy.]

When the amp had burned in for about 20 hours, it made acoustic guitar sound all goofy like it was being played in a big toilet. I’ve noticed this effect in two other pieces of audio gear during the early burn in phase. I assume it has something to do with capacitors, but I’m only guessing.

Carry on.
« Last Edit: 10 Feb 2022, 06:00 pm by mresseguie »

Sutts

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Re: NuPrime Evolution STA
« Reply #11 on: 3 Feb 2022, 07:43 pm »
I have owned TDSS-modded Ref 20 mono amps and also heard Evo mono amps (very similar).  *Question- I'm interested in the the new Evo STA amp however unless I am missing something, it appears to have been designed as a STEREO amp- why were monoblocks not considered??  Pardon the pun, but it would seem the natural 'evolution' to the Evo monos to have Evo 'STA' monos, and not only a stereo offering...  Confused.  Thx

mresseguie

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Re: NuPrime Evolution STA
« Reply #12 on: 3 Feb 2022, 11:58 pm »
It’s described on the website:

“It is a stereo amplifier with a dual-mono configuration.”


rustydoglim

Re: NuPrime Evolution STA
« Reply #13 on: 4 Feb 2022, 09:00 am »
I have owned TDSS-modded Ref 20 mono amps and also heard Evo mono amps (very similar).  *Question- I'm interested in the the new Evo STA amp however unless I am missing something, it appears to have been designed as a STEREO amp- why were monoblocks not considered??  Pardon the pun, but it would seem the natural 'evolution' to the Evo monos to have Evo 'STA' monos, and not only a stereo offering...  Confused.  Thx

It was designed as two mono amp in a box, sharing the same power supply.  It is possible that we can make pure mono version if there is sufficient demand.

Sutts

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Re: NuPrime Evolution STA
« Reply #14 on: 4 Feb 2022, 06:54 pm »
So then regular Evo mono amps (given the advantages of separate power supplies; etc.) will still operate at a higher performance level then the new STA stereo version?

rustydoglim

Re: NuPrime Evolution STA
« Reply #15 on: 10 Feb 2022, 05:26 pm »
So then regular Evo mono amps (given the advantages of separate power supplies; etc.) will still operate at a higher performance level than the new STA stereo version?

Evo One mono amp has a slight advantage with more power and being a mono amp. The sound quality is similar but if the power requirement is the same, Evo STA has an advantage.

If you are stepping up from ST-10, STA-9, AMG STA etc, then Evo STA is a clear choice.
If you are looking for a super high-end system and since Evo One is not available, Evo STA is a clear choice.

We decided to discontinue Evo One when Evo STA is out because 2 x Evo One (MSRP almost $8000) is not going to offer a significant advantage over the new Evo STA (MSRP $4995).  We didn't make the Evo STA mono because we are concerned that $9000 a pair will not have a significant advantage over Evo STA.  Therefore Evo STA in a box offers the best price/performance for the super high-end series. In fact, we think that it will be able to match the CH Precision A1.5 (ST-10M and AMG STA were reviewed by HiFi Advice and compared to A1.5).

mresseguie

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Re: NuPrime Evolution STA
« Reply #16 on: 11 Feb 2022, 12:59 am »
Sutts,

If I may add...

I've never heard the Ref 20 amps nor the Evo One mono amps, so I cannot offer any sort of comparison. However, this Evolution STA dual-mono amplifer sounds excellent in my system. It has burned in for ~130 hours now, and I'm very happy with how it sounds. Hopefully, I'll be able to set time aside for critical listening in the next week or so. In the meantime, I'm really enjoying all the music I've thrown its way - no complaints.

Michael

Sutts

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Re: NuPrime Evolution STA
« Reply #17 on: 14 Feb 2022, 03:54 am »
Michael- thank you- very positive endorsement indeed re: the Evo STA amp.  However (and regardless of Jason's opinion) I have yet to hear a stereo amp from a high end manufacturer that beats the mono block version of that same amp.  Would be fascinating to compare side by side my previous TDSS Ref 20 or Evo monos to the new Evo STA- 'the proof is in the pudding' as they say- if possible I will find some way to hear the new EVO STA and report my findings. 

By the way- I have also found that a very good tube pre can elevate the Nuprime amps to amazing levels.  My Absolare Passion (single-ended) preamp with the mono blocks was spooky good, so much so that if I acquire an Evo STA I will keep that same pairing (likely with an Evo dac, of which I have owned as well and am a big fan of).  The amps I had after that I felt that eclipsed the TDSS Ref 20 monos were the GAN-based Class D Merrill Element 116's- should never have sold them  :(  Bass deeper then Nuprime, and low level detail superb.  I will say thought that I am in full agreement with Jason that his Engineer has nailed the proper tonality with the Nuprime amps- superb in this area for Class D, or regardless of topology- hope this is maintained/furthered with the new STA version.

rustydoglim

Re: NuPrime Evolution STA
« Reply #18 on: 14 Feb 2022, 05:16 pm »
Our chief engineer designed Ref 20. TDSS mod is a very minor improvement over the standard Ref 20.
Since then we have ST-10 and then Evo One was a big evolutionary design (could have called it revolution) change from the old Nuforce designs (Ref 20 was the last generation).
AMG was a baby Evo One with its own differences.
So we can confirm that Evo STA has a very noticeable improvement over Ref 20.

mresseguie

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Re: NuPrime Evolution STA
« Reply #19 on: 14 Feb 2022, 07:16 pm »
Michael- thank you- very positive endorsement indeed re: the Evo STA amp.  However (and regardless of Jason's opinion) I have yet to hear a stereo amp from a high end manufacturer that beats the mono block version of that same amp.  Would be fascinating to compare side by side my previous TDSS Ref 20 or Evo monos to the new Evo STA- 'the proof is in the pudding' as they say- if possible I will find some way to hear the new EVO STA and report my findings. 

By the way- I have also found that a very good tube pre can elevate the Nuprime amps to amazing levels.  My Absolare Passion (single-ended) preamp with the mono blocks was spooky good, so much so that if I acquire an Evo STA I will keep that same pairing (likely with an Evo dac, of which I have owned as well and am a big fan of).  The amps I had after that I felt that eclipsed the TDSS Ref 20 monos were the GAN-based Class D Merrill Element 116's- should never have sold them  :(  Bass deeper then Nuprime, and low level detail superb.  I will say thought that I am in full agreement with Jason that his Engineer has nailed the proper tonality with the Nuprime amps- superb in this area for Class D, or regardless of topology- hope this is maintained/furthered with the new STA version.

I absolutely agree with you wrt tube preamps. While I have never heard an Absolare pre, I imagine it must be very nice. I’m using a Don Sachs 6SN7 Model 2 pre which I am very happy with.

I’m still debating whether I want to try the Evolution DAC.

Michael