NuPrime STA-9 Power Amplifier Mini Review

Discussion in 'Power Amps' started by purr1n, Feb 14, 2017.

  1. purr1n

    purr1n Finding his inner redneck

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    NuPrime STA-9 Power Amplifier Mini Review

    I was going to take some pictures of the amp myself, but I figure I'll link to the manufacturer provided ones or others on the Internet. Thanks for @beemerphile for sending this in.

    [​IMG]

    The amp is diminutive in size, being only 235mm or 9.25 inches in width. It's not super heavy at 4.75kg or around 10 lbs, but heavy enough to support decent sized audiophile speaker cables without the chassis doing a backflip. Despite the small dimensions, the speaker posts, input jacks, switches, and IEC power jack are smartly laid out. The staggered diagonal pattern of the speaker posts actually allows me to use spade connectors, provided the amp is elevated to allow room for the cables to dangle down from the spades. Otherwise, banana plugs will work in a jiffy. Both balanced and unbalanced inputs are provided and placed well away from the speaker posts. No spaghetti here. Parasound should learn from these NuPrime guys.

    [​IMG]


    http://www.fairaudio.de/img/test/nuprime/sta-9/innen2.jpg
    [​IMG]

    The transformer in the front provides good weight distribution and counterbalances speaker and line level cables connected to the back. There's a little heatsink in the middle of the chassis, a little bit toward the back. This area of the chassis gets warm to the touch when the amp is in operation.

    The STA-9 when cold, or at least when first out of the box, sounds terrible. The sound is thin, grating, grainy, and raspy. Think of it as the combination of the worst qualities of Wolfson, Analog Devices and ESS delta-sigma DAC chips. It's basically a digital product, so I let the thing warm up for about two days and came back to it.

    The sound of the STA-9 was much better after this warm up period and consistent with what we've heard on the Internets regarding its "tube like" sound. First of all, regarding the "tube" sound: I don't know WTF the Internets is talking about in regards to this. The STA-9 sounds nothing like tubes other than offering a warmish (and smooth) sound, which not all tube implementations do. Tubes (properly implemented) to me might mean bloom, harmonic richness, huge deep staging, microdynamics, microdetail, or immediacy. The STA-9 posses none of these qualities.

    The presentation of the STA-9 doesn't do anything outright wrong. There are no solid-state needles or glare. There seems to be plenty of power with an ease to the presentation. The price seems decent. However, the STA-9 is rather uninspiring sounding. Perhaps the word I am looking for is insipid. I actually didn't know what this word meant. In closing, I will leave you with the definition of the word insipid:

    in·sip·id
    adjective
    1. lacking flavor.
      "mugs of insipid coffee"
      synonyms: tasteless, flavorless, bland, weak, wishy-washy; unappetizing, unpalatable "insipid coffee"
     
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    Last edited: Aug 30, 2017
  2. Armaegis

    Armaegis Friend

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    I find this is true of most Nuforce/Nuprime products that I've tried. Maybe their chief designer works in an oven controlled environment or something.
     
  3. Riotvan

    Riotvan Got lost for three weeks at Delft City Hall

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    Sounds like you described a typical class d amp. Technically solid but lacking soul has been my experience, did you test with Freya in tube mode? That's something i have been contemplating, tube pre with class d power.
     
  4. purr1n

    purr1n Finding his inner redneck

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    Yes, I tested with Freya in toob mode. Toob goodness didn't translate. Class D killed the toob star.
     
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  5. purr1n

    purr1n Finding his inner redneck

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    Is NuPrime related to NuForce? And does Nu Metal have anything to do with them?
     
  6. Riotvan

    Riotvan Got lost for three weeks at Delft City Hall

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    Awwww :(
     
  7. beemerphile

    beemerphile Friend

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    Second that question. My use for it was to be as a speaker amp for the HE-6. I will run it from the pre in my Liquid Glass and that, I was hoping, would dampen the "Typical Class D" effect if its built-in "2nd order tubeyness" was insufficient. It would be a lot easier to build a system that works if all of the "character" could be injected by one component with everything else just playing it straight. All I wanted out of it was gain.
     
  8. beemerphile

    beemerphile Friend

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    NuPrime bought the high-end business from NuForce.
     
  9. Armaegis

    Armaegis Friend

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    The NuForce brand and intellectual property was bought by Optoma (the projector company). As best as I can tell, the original Nuforce company spread themselves too thin trying to do too many things at once (their head guy is super passionate and believes in his products, but I think tries too hard to please everybody and every single comment or complaint or request that comes in) and the company stumbled until the buyout.

    NuPrime was founded shortly afterwards with a group of the original guys and engineers (including the founder of NuForce, Jason Lim). They reacquired their high-end products through some means, though I don't know the exact details. Their product lineup started off modest, but again they are branching out with a lot of similar looking products so I hope they don't glut themselves again.

    I have no idea about NuMetal, unless you're talking about Linkin Park or something.
     
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  10. TheIceman93

    TheIceman93 El pato-zorro

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    I have been curious about the quality of their dedicated headphone amp, the HPA 9. It sounds like the STA 9's pitfalls might be due to the fact that it is a Class D amp. However, the HPA 9 is Class A so maybe it is a better implementation of the "tubey" NuPrime house sound.
     
  11. Big D Design

    Big D Design I've got stereo junk in my trunk.

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    Ok. Now here we go with something different than the Marvey review. I just hooked up a broken-in Vincent SP-331 that I just bought. I have had the NuPrime STA-9 as my amp for about 2 months now. I have been trying to finish off my system that I had in limbo for 5 years. All I had was a Quinpu 16 watt amp driving my Martin Logan ESLs and a Martin Logan Dynamo 1000 sub for the low end. I searched for a solution for years that was cost effective to finish the damn thing.

    So Freya and Saga came along. Oh yes, a preamp that has tubes and remote control. Check.

    Went for the Freya. Then NuPrime came out with the STA-9 and I bought a Demo for $579. What a great combo, but with the NuPrime having a balanced input, the Martin Logan sub didn't have enough gain thru the SE inputs. I had it turned up all the way and it just needed a hair more. At the time I didn't try to send the signal from the Freya to the SE input of the NuPrime amp. I just loved the thought of having finally a preamp to amp balanced.

    So I bought a refreshed REL S3 sub for $1,400 and used the speaker outs and the speakon input with the sub. Wow. We were getting a sound that was as good as I had heard in systems costing thousands and thousands of dollars more. The NuPrime and Freya brought instruments as real as it gets. It just doesn't get any better. Dynamics could get better.

    So today..... I hook up the Vincent SP-331. It only offers SE inputs. Using AudioQuest Evergreen cables from Modi Multibit to Freya and same cable from Freya to Vincent. What do I get. NOTHING WORTH TEN GRAND. Must be the tubes in the amp destroying the transparency. It's always been a rule of mine anyway that you put the tubes on the preamp and the solid state on the amp. The whole presentation on the Vincent fell apart in terms of that last bit of realism. The tubes have ruined all the money spent in a heartbeat. Can I fix this with cables? Don't know. But whatever Marvey is using for speaker setups is not anywhere near what can be revealed with some high end speaker setups like planar speakers. The NuPrime and Freya at this point is miles ahead with all the things pertinent in good sound staging and timbre with my Martin Logans. Just for reference: Tidal sounds different compared to my FLAC rips. I can tell the difference right away with the same tracks.

    Sound comes from matching things properly. I have new cable from a company that arrived yesterday that may help the Vincent. But I sincerely doubt that they can help the amp at all with my Martin Logans. These speakers are a pain in the ass. All they want is mostly perfect Class A with a little bit of tube in the preamp. I can only imagine what a set of Krell Monoblock Class A amps would sound like with the Freya. I bet much, much better than my NuPrime.

    All I can say is....... Don't underestimate the NuPrime STA-9. It's a little thing. But the sound of the guitar, piano, violin, vocals, are so real with certain speakers and is just as good as I have ever heard. There is more dynamics and a wider soundstage to be had with 10 times more money, but to me, realism is key and I more than likely will be selling my Vincent and keeping the NuPrime. The amp just sounds so, and mean so much better and just sounds right. Sorry Marvey on this one. Just gotta speak out. Dennis
     
    Last edited: Feb 14, 2017
  12. purr1n

    purr1n Finding his inner redneck

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    No biggie. I can't think of two very different speaker setups. I don't think the SP-331 is even rated into 2 ohms. The MLs are an extremely difficult load and actually go under 2 ohms in certain spots. The strength of the Class D amps has always been current / power into near short circuit loads. The BLHs and the Altec horns I'm running are 92db and 100db respectively where the first few milliwatts matter most.
     
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    Last edited: Feb 14, 2017
  13. Big D Design

    Big D Design I've got stereo junk in my trunk.

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    I'm leaving the Vincent amp on all night long. Hopefully it will sound a little better. I forgot to mention that I bought another REL S3 sub for the system to balance everything out. Wow. What a difference the REL subs make. They add to the whole spectrum. Everybody's sleeping and I will go to back to back testing tommorow again with new cables that I got in the mail. Shame..... the Vincent looks good sitting there. Maybe it just needs to warm up, but I doubt it.
     
  14. Big D Design

    Big D Design I've got stereo junk in my trunk.

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    @Marvey
    Yes. the Vincent is stable at 2ohm loads. It's those damn tubes ruining the transparency. Even the JFET can't get me the sound that the NuPrime does with the instruments and the vocals.
     
  15. purr1n

    purr1n Finding his inner redneck

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    Try the JFET buffer for Freya too. As I stated, the combination of Freya tube and Vincent tube was too much for me at times.

    (posted after your last post)
     
  16. Big D Design

    Big D Design I've got stereo junk in my trunk.

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    I wanted so much for this to be the end game for me. The lower registers is better, but timbre is way off.
     
  17. purr1n

    purr1n Finding his inner redneck

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    Well, stable doesn't mean necessarily mean good sounding...

    But it's good we are trying with different gear.
     
  18. Big D Design

    Big D Design I've got stereo junk in my trunk.

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    Just set it up tonight. Only warmed up for 80 minutes and 2 hours of listening. It's this veil, just like on Tidal. Clarity is missing in spades. It's possible that time will heal some of the downfall of the amp. But it seems fruitless to me that the clarity would open up as much as needed. That's what I always liked about Class A. That clarity is something that makes instruments sound real. Going back to the vinyl days.... I would go into the salon in San Diego and try to find what speaker was playing. It was just memorizing. Sound was in the air. I was hearing that in my home. Then came the Vincent. The veil is back.
     
  19. purr1n

    purr1n Finding his inner redneck

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    Interesting. With the HE speakers I'm running, the Vincent had a marked edge in clarity. The tube like second order harmonics of the STA-9 actually got in the way - veiled. Maybe in your case, too much tube bloom. Well, the Vincent I have is going out on loaner. I believe other folks have much more difficult speaker loads than I do. In time, I'll grab some lower efficiency planars to get a more comprehensive picture of things. All my current speakers are best served by 3-6W SET amps, so not really an idea test of these power amps.
     
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  20. Big D Design

    Big D Design I've got stereo junk in my trunk.

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    Great working with SBAF on the pursuit of best sound for money spent. Cheers.
     
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