Solid-State Power Amp Adventures

Discussion in 'Power Amps' started by purr1n, Jan 24, 2017.

  1. pechelman

    pechelman Acquaintance

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    In addition to the fully loaded rag above, there's stuff like a bluesound power node, ps audio sprout, and the naim uniti atom, but that last one is over budget even when used most likely.
     
  2. artur9

    artur9 Facebook Friend

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    @msommers I recently acquired a used T+A Cala for around your price point. If it's powerful enough for you the clarity it delivers is outstanding. The speakers it is driving aren't capable of much bass so I cannot comment as to that.
     
  3. neogeosnk

    neogeosnk Friend

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    I picked up a Yamaha a-s3200 recently.. It's a mosfet amp but to me is quite resolving, plenty of power and very refined sound to it. Wife liked the aesthetics (sigh) thus why I picked it up but, damn it's a great all in one and the phonostage is better than expected.
     
  4. mkozlows

    mkozlows Friend

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    Hopefully this isn't too off-topic for this thread, but I've been looking for a decent, not-too-expensive five-channel amp for home theater purposes. "Three Vidars" would actually be a not terrible option, except that I couldn't easily find a place to put three of them, and it'd be more involved getting them set up without a 12v trigger.

    So the ATI-built Monolith amp mentioned here -- $1500 for the five channel version -- seems like a plausible choice. Thoughts on that, or other suggestions? Emotiva? Something else?
     
  5. ogodei

    ogodei MOT: Austin AudioWorks

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    Monoliths run super hot in my experience.

    I have Emotiva running 11 channels for home-theater purposes, no complaints at all. I've heard their prices have been creeping up tho.
     
  6. SineDave

    SineDave Friend

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    I'd personally pick the Monolith over Emotiva at the moment - just based on value and a more over-engineered design. Emotiva has been charging more due to tariffs as their stuff is mostly sourced in China, and their quality is not quite what it used to be based on recent reports.

    I would avoid Outlaw audio like the plague given recent issues with service.

    On the home theater front, I like ATI, D-Sonic (this is what I own), Emotiva (quality issues lately so be somewhat cautious), Anthem, Marantz and Wyred4Sound. If you're looking for a budget option that is getting buzz lately, check out the amps from OSD Audio.
     
  7. M3NTAL

    M3NTAL Friend

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    I am running a very old Emotiva MPS-1 (the big guy with the full 7 channel big cards) and it's being fed from the XMC-1 - I only do 4K and 5.1 audio - so it's not needed to go with the crazy RMC or XMC-2 even. But my 2-Chan is the same. RSP-1 / RPA-1. I was caught up in the whole Mark Schifter stuff and bought into the Onix and AV123 stuff. I actually still enjoy all of it and have no desires to change anything.

    Oh - @SineDave - The CX finally showed up with Robert this week. I've got 2 more weeks added for the calibration!
     
  8. monacelli

    monacelli Friend

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    Thoughts on the QSC RMX 850

    I picked up a QSC RMX 850 a while back as a stopgap while I re-cap my Adcom 535, or potentially shift gears toward Aegir. I've had it in my system for long enough that I feel like I understand its character, so I figured I would share some impressions. For background the RMX 850 is a pro amp that does about 200 WPC into 8 ohms. It's a Class AB design, but don't let that fool you. It does not sound like an old school Class AB amplifier. It also has a noisy fan that must be replaced for home use (pretty cheap and easy to do).

    My system:
    • Speakers: Tekton Lore Reference (I will post thoughts eventually. These offer stellar price/performance, but you have to be *super* patient in dealing with Tekton directly)
    • Amp: QSC RMX 850 (compared to Adcom 535)
    • Sources: Audirvana => JDS OL DAC USB Edition (AK4990), Modded AT-LP120 => AT-150E cart
    • Preamp: Freya S, usually in Nexus mode (X4)
    Overall impression: The QSC RMX 850 is best viewed as a tool for reproducing audio in live sound applications. It offers ample clean power at an affordable price. Its presentation skews toward the clinical/analytical/slightly sterile side of things. If you're a fan of the Benchmark sound, or the measurements-first audio philosophy, you will probably love it. If you prioritize tonal and harmonic richness, and tend to prefer designs that don't use much global feedback, this is not the amp for you.
    • The RMX uses 5532 opamps for summing/buffering and voltage amplification, with a discrete output stage on the back end. Unfortunately, instead of using a local loop in the voltage amplification stage, the designers elected for 70+ dB of global feedback instead (makes the spec sheet look better at the expense of engagement).
    • I rolled the 5532's, which frankly kind of suck. The OPA2134 is better across the board, but doesn't transform the overall presentation of the amplifier. Stay away from the OPA1662 in this circuit; I tried it and ran into stability problems.
    • The best way I can describe the sound of the RMX is like a Class D amp with improved coherency (lack of digititus). It's linear, neutral, decently resolving but ultimately not a ton of fun to listen to.
    • My Adcom 535 is sort of the polar opposite. It's derived from a Nelson Pass design, so the output stage runs mostly in open loop. It's got kind of an incandescent glow, mellow and tastefully dark. Skews warm but not too much, a bit of bloom in the bass.
    • In comparison to the 535, the RMX is more resolving, more neutral, clearer, but the engagement factor is missing. Listening to music on the RMX is sort of like inspecting it under the light in a doctor's office. You can see everything, but it's not always pretty.
    • The RMX offers improved bass control. I prefer the low end on the Adcom, but it is tighter and cleaner with the RMX. Now that I've heard both, I want the best of both worlds. The resolution and control of the RMX, but the tonality and engagement of the Adcom.
    I don't want to exaggerate the coldness and slightly sterile nature of the RMX. It's not horribad, I just don't really want to listen to it. I will say, if you have colored sounding speakers that skew toward warmth on their own, then the RMX may be a better match. But I strongly recommend against pairing the RMX with neutral/uncolored (or bright) speakers. I suspect it would turn into a cheese grater with RP-600M's or the new LS50 Meta's. Having owned Class D amps in the past, it's striking how close QSC was able to make a Class AB amp sound to Class D (mostly without digititus or solid-state nasties, provided that you roll in something like the OPA2134). Whether or not that's a compliment depends on your own personal preferences.
     
    Last edited: Oct 31, 2020
  9. uncola

    uncola Friend

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    so I've had a few class d amplifiers in my time.. ucd, iceedge, ti3255, digital amplifier company maraschino.. just got some Orchard Audio monoblocks that use gan transistors. large step up from all of the previous ones and the first that close the gap with my class ab kismet monoblocks.. just wanted to give them a thumbs up in case anyone was shopping for class d
     
  10. Metro

    Metro Friend

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    I'm curious about the ATC P1 Pro amplifier. Anybody have experience with it? It is a hefty 150W/ch AB amp made in the UK by ATC and recommended for driving their passive monitors. It is about half the price of Hegel H20 and I wonder if it has similar level of performance. The consumer (non-Pro) version has the same specs and was Stereophile Recommended Class A in 2015.
     
  11. Armaegis

    Armaegis Friend

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    Paging @Psalmanazar ...
     
  12. Psalmanazar

    Psalmanazar Most improved member; A+

    Pyrate Slaytanic Cliff Clavin
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    ATC is awesome. The amps are awesome but a ton of money and they look like two of the plate amps in a nice case. The 300w one is even juicier. I mean how can you go wrong with the amp unless you hate MOSFETs?
     
  13. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

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    So much money, who makes a reasonably priced dual mono MOSFET amp these days?
     
  14. dBel84

    dBel84 Friend

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    Not terribly priced for a commercial product of this quality.

    [​IMG]

    Looks like good solid construction but not overly complex.

    Working on the low side of industry standard, I suspect. 5x markup. You could make something similar from a classic AB mosfet design

    AB100

    Ultimate 100

    Griddle amp

    USSA series

    There are many designs floating about that have stood the test of time and are highly regarded. The 100W designation is typically determined by rail voltage and most of these designs can be scaled with minimal additional cost. This should be DIYable for close to $700. Depending on how you build and where you source the chassis
     
  15. pechelman

    pechelman Acquaintance

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    Depending on how much power you need for your speakers and if you are willing to solder, you can build one of Nelson Pass' amps using pcbs and a chassis from diyaudiostore for under 1k no problem, even with full dual mono. Handful of pages back is an aleph j done this way.
     
  16. Psalmanazar

    Psalmanazar Most improved member; A+

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    ATC specs out their products either very honestly or super conservatively. The amps can hit 100w and 300w RMS at the advertised super low distortion. They have competition but none of its cheap.
     
  17. Collusion

    Collusion Friend

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    Quick n' Dirty impressions of a couple of amps. Impressions are mostly based on listening to them with Quad Z3 floorstanding speakers (some listening have been done with Raal SR1a's too).

    First, some impressions of the Quad's for those who are interested:
    The Quad's have a sound signature which I'd describe as slightly bright, perhaps a tad dry on the upper band and slightly warm on the midrange (and lower frequencies) There's plenty of plankton in the treble with a miniscule amount of peakyness - stating this because experience tells me peakyness gets more audible with more revealing amplifiers and in this case it might be relevant. I've detected similar treble in many Mark&Daniel speakers (like in Maximus Monitor and Ruby, especially in the AMT models) but as a whole the Quad's sound more even in the treble and also more coherent between treble and midrange. Timbre overall is pretty good - Quad's have a pleasant texture on the midrange, sounding slighty like good paper cones but slighty more vibrant, if this makes any sense. A feature of glass fiber drivers? Otherwise the overall tone is very British, midrange is slightly dipped or less prominent than you'd find in a "studio neutral" speaker. This yields a sound stage that doesn't really pop out of the speakers, but more like renders between them or maybe even slightly behind them. Tend to work better the louder you play them. B&W-esque, one might say.

    Hegel H200:
    - Bright sounding amplifier and I'm not talking only about the treble - everything starting from the male vocal range seems to be slightly pronounced or more forward that I'm used to - but in a more broad and even way you might think. As such the brightness is not a completely undesirable quality. There's almost an impeccable sense of clarity and/or purity and perhaps of all the amps I've ever properly tested, Hegel has the airiest sound stage. Switching back to Hegel after auditioning the Moon Neo Ace my two first observations were: 1. Wow, the soundstage really pops out of the speakers! 2. Bass is now much more prominent. So, is this the amp of my dreams? When listening to Hegel more closely, I discovered the clarity comes at the expense of microdetail and pure/natural timbre. Dynamically Hegel is very capable, in both micro and macro realms and from top to bottom. Bass has good heft and speed, though it might sound just a little too round. Ultimately it just doesn't have that much detail to play with. There also a very subtle yet discernible metallic kind of quality to the overall sound in the upper midrange, which robs some naturalness from the presentation, though one could still describe the sound having some liquidness. Very distinct and non-neutral sounding amplifier. This must be the DM CV-2 of the amplifier world, try before buy.

    Random observations/thoughts:
    - Perfectly capable of driving Raal's, but the presentation is too much in your face (or in this case to be more exact, 'in your head') and the aforementioned shortcomings are (clearly) audible
    - Some intermittent transformer hum, might be related to other interference sources on my power grid

    SPL Performer S800 power amp (+ Phonitor 2 as pre)
    Preface: Having owned the Phonitor 2 for a year and a half, I finally decided to bite the bullet and blindly purchase an s800 power amp for Raal SR1a's hoping it would sound just like the Phonitor 2, but just in power amplifier form. Those of you who don't know how the Phonitor 2/X/E series sounds, read here: https://www.superbestaudiofriends.org/index.php?threads/spl-phonitor-x-e.3574/page-4#post-219127

    Okay, to put it bluntly: You get something and lose something. The neutrality associated with the Phonitor series is present on pretty much all fronts. Tone seems pretty even, neutral and certainly not thin sounding. Dynamically everything is okay, s800 doesn't overshoot transients nor sound laid back, but isn't state-of-the art either. Soundstage has adequate depth. Sound doesn't really have any sweetness or 'glow', but s800 still manages to sound non-clinical or mostly non-sterilizing of the upstream components. So, what gives?

    Perhaps the first time I came into realization of a shortcoming s800 has was when I was comparing it to the Hegel H200. Hegel has this almost liquidlike quality which in contrast made the s800 sound very slightly sibilant. In defence, this was something I wasn't able to discern that easily in isolation. Whereas Hegel may be described as having slightly glossed over or polished type of sound, there's none of that here. S800 just plainly puts out everything it cans and calls it a day, without putting lipstick on a pig. Perhaps due to this the absolute resolution leaves something to be desired. It might just edge out the Hegel, or this might be my interpretation of the situation due to more neutral type of delivery otherwise. To put it on a scale, we a talking a 'good' level of performance here, instead of excellent (or mediocre). Regardless, the SPL combination gets more listening hours and is still in my equipment rack, when Hegel has already changed ownership. Is S800 worth 3k$+? Audition one and decide for yourself.

    Random observations/thoughts:
    - Even if there are some shortcomings with the sound, I've managed to live quite long with this one without that much griping

    Moon Neo Ace MiND 1 (same dac/amplifier section as in Neo 240i)
    My impulse buy, which I thought could replace a Hegel H200 + Bifrost 2 + Bluesound Node 2i stack in my small living room. As the familiar story goes, the one that dreams of an all-in-one solution trumping a set of carefully selected separates soon gets a reality check.

    Using the internal MiND streaming solution, for example with Tidal as a source, you get a warmish, slightly laid-back type of sound without that much of air. I'd even dare to say there has been clearly a goal to achieve a certain type of smooth and coherent type of rendering here, as telling this one and something that truly aims to be 'neutral' apart from each other is quite elementary. I do have to admit I still found this configuration slightly dull and lifeless, not really evoking any kind of emotions regardless of the type of music playing, even if I could appreciate some aspects of the chosen tuning. There was also some 'squareness' evident and perhaps the treble was very slightly glarey in some parts, but as a whole it was mostly listenable. In terms of resolution it was surprisingly acceptable. However, in the end it failed to make my foot tap. (BTW: the internal dac is based on ESS ES9010K2M chipset, it seems).

    Forgetting the internal streaming solution and DAC, and substituting them with Bifrost 2 and Bluesound Node 2i made things to turn for the better. Although the overall tonal balance stayed mostly the same, Bifrost 2 managed to blow some life into the presantation. There was now some sweetness or 'musicality', if you will, and both micro and macrodynamics took a step up. The squareness went away and what was before a slightly glarey treble is now more smooth and even. Soundstage also gained an additional layer of depth. With Soekris dac2541 as a dac I was actually able to confirm that the Moon Neo Ace is more detailed than the aforementioned SPL s800 power amplifier the upper we proceed on the frequency range. Where it loses though, is the impactfulness on the bottom end and other technicalities, such as dynamics. As an amplifier only this thing is very capable of rendering enjoyable and easy-going sound and I thought for a some time about keeping it. In the end, I decided it would be better to replace it with an all-analogue model from Moon.

    Randoms observations/thoughts:
    - Was able to drive Raal SR1a's better than I anticipated based on the specifications (50 @8ohm, 85@4ohm), but sometimes sounded slightly shouty / 'hard' with some bass heavy music
    - Overall resolution quite good with a revealing external dac
    - As a whole does not represent good value (IMO)
     
  18. gepardcv

    gepardcv Almost "Made"

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    @Psalmanazar: What’s your take on the ATC SIA2-150 integrated? Or do you just like ATC’s pro stuff?
     
  19. Psalmanazar

    Psalmanazar Most improved member; A+

    Pyrate Slaytanic Cliff Clavin
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    Never heard it. The pro stuff is brilliant. It’s probably fine.
     
  20. Abhishek Chowdhary

    Abhishek Chowdhary Friend

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    [​IMG]

    Effortless, explosive, depth,timing,immense power and control....what an amp!
     

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