Solid-State Power Amp Adventures

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

  1. Forza AudioWorks

    Forza AudioWorks MOT: Forza AudioWorks

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    Fair points, yet when I see Goldmund's god tier (apologies, I couldn't help it) circuitry inside of a $499 deck, I somehow doubt that. So let's make it 'any' without this one example of fine engineering and we're good :eek:

    Fair enough:D?
     
  2. Forza AudioWorks

    Forza AudioWorks MOT: Forza AudioWorks

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    ...and inner minimalist in me likes the looks of new stuff more, but for several hundred bucks one can't have everything.
     
  3. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

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    Even completely unrestored it sounded better than most things under $2k. It simply costs a lot in 2017 to make a giant 35lb dual transformer MOSFET amplifier.

    I found another hobbyist that was local to me that restores his own stuff on Audiokarma, I asked him where to go locally and he offered to do it.
     
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  4. rlow

    rlow A happy woofer

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    This is very interesting stuff.

    Is there any kind of a list or site out there that would talk to some of the best "vintage" amps that might be worthy of restoring and that would significantly outperform a new amp in a similar or higher price range? I'm aware of the m22/25 but not really many/any others.
     
  5. yotacowboy

    yotacowboy McRibs Kind of Guy

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  6. winders

    winders Worst poster on SBAF (not a joke)

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    I really hate my my Pioneer M-22....really...no one should buy them. They suck!
     
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  7. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

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    Not really, at least nothing comprehensive, but it's easy enough to search for specs, service manual and some listening impressions online and figure out if it's a good canidate for restoration or not.
     
    Last edited: Dec 12, 2017
  8. murphythecat

    murphythecat Friend

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    yes, one must look the schematic.


    "For 1K I'd probably look for some of the late 80's early 90's
    Japanese integrated a bit below "flagship" level (flagships are
    overengineered and often do not sound as good as simpler mid-level units, with
    very simple circuitry. There are good example from many brands, to me Denon, Luxman,
    Onkyo and Sony stand out. But make sure to get the right models."

    Sony ta707/808, denon pma1560, luxman L-510/513 are good
    examples
     
  9. msommers

    msommers High on Epipens

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    Can someone confirm/deny this adage that higher/top quality SS amps will double-down power from 8->4 ohms. Is this a sign of the overall quality of the unit or one specific part of the amp and not really representative of its overall performance/quality?
     
  10. murphythecat

    murphythecat Friend

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    its bs
     
  11. Peter

    Peter Rando

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    Doubling down from 8 to 4 ohms is indicative of the quality of the power supply. The question you need to ask yourself is, so what?

    Are you running efficient 8 Ohms speakers? If so, then the power into 4 Ohms is irrelevant. You just need to make sure that the power into 8 Ohms is sufficient.

    Are you running power hungry speakers that are 4 Ohms or less? Then you should care, because you will easily hear it if your amp is not up to the task, the bass in particular will be weak. The sound quality will suffer in other respects, it will seem one dimensional and congested if your amplifier is struggling.

    To me a good power supply is really representative of overall quality, but feel free to disagree.
     
  12. Armaegis

    Armaegis Friend

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    If I had the dosh to throw around I'd be getting a Powersoft X8...
     
  13. Forza AudioWorks

    Forza AudioWorks MOT: Forza AudioWorks

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    Can't agree with that, sorry. Let's skip Class AB for a second. Class D is meant to be used where Class A can't be. The difference between the two is more than substantial not only sound wise but how they interact with given speakers. There's no comparison really.

    If, for example, you have thick, sluggish floorstanders of low sensitivity and harsh impedance, class D fits better in such scenario usually. Class A able to handle such speakers would be very hot, very heavy and very pricey if of quality, unless you go vintage/used stuff probably.

    I'm not a class D advocate, I adore class A, but the latter isn't a remedy to every audio pain there is. Unless one wants to boast in front of friends that his amp is huge and looks pro, but that's silly. And will it sound good in every situation? Nope, it won't. My point is that audio is a puzzle to solve. In order to get it done, one has to know what element fits where.

    Class D is getting better and better. For example, nCore modules are affordable and very good for what they are.
     
    Last edited: Dec 13, 2017
  14. Priidik

    Priidik Friend

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    ...
    You spelled my thoughts out yourself. NCORE modules for diy-ers + matching psu-s with enclosure cost much less than 2k.
    The real cost of producing those modules is a magnitude less. There are a few barely expensive parts in switching apparatus.
    I agree that NCore amp sounds good, but better than good class A-B? This needs some further investigation.
    And why should we forget about class A-B when assessing class-D? It's the closest competing tech, when not counting multi-rail amplifiers.

    edit:
    My angle in this is purely from technical perspective. I'm not biased for or against any of the classes of operation, maybe a little towards pure class A when I can use it.

    An amp with NC500 oem modules thrown in with some swichers psu-s and 'custom' input stage is not genius engineering (apart from knowledge what Bruno has put in to the underlying mode of operation), there are no real expensive parts inside it, apart from potentiometer, if there is one. The chassis can be small, no big heatsinks are required. Where do these amp makers suck out the prices like 5k$, 8k$.. or even more?
    It could be done for cheap; for no loss in sound quality, and there are offerings that are reasonably priced, too, only usually in shadow of the stupidly expensive ones.
    This is like the smartphone business, the greediness pisses me off.
    Forgive my apparent grumpy tone, I'm a cheap diy nut, who values every cent I could get ripped off.
     
    Last edited: Dec 13, 2017
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  15. bengo

    bengo Friend

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    I would assume that bi-amping with class D (big Watts for big inefficient woofers) + class A (small, high-quality Watts) would be one solution. Bi-amping by itself has advantages, and the downsides of class D sound quality hopefully are much less noticeable on the lower end. I don't have much practical experience here (yet... my car is all class D, but considering an outboard class A amp for tweeters).
     
  16. Forza AudioWorks

    Forza AudioWorks MOT: Forza AudioWorks

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    There are loads which will fare far better with sub $2k class D than $2k or slightly upwards class AB. It all depends on a given floorstanders. I use such a product daily. In most cases Class AB will prolly sound better, but each scenario is different and should be scoped individually, that's what I'm sayin'..

    True that. One post earlier I was merely addressing the D vs A matter, class AB is a different thing.
     
  17. Peter

    Peter Rando

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    I have had a few amplifiers over the years. One of the best I ever tried was a NAD 2200. Wow, that was really something, it made my small bookshelf JBL speakers rock. A great listen.

    [​IMG]

    [​IMG]

    I was so impressed that I later purchased a NAD 208. My thinking was that the 208 was bigger, so it must be better. Well, wrong. To me the 208 always sounded a bit lazy, and boring. I guess it was built for power, not sound quality. I think it was biased to run at a very low idle power. It was pretty much always cold to the touch, no matter what.

    [​IMG]

    I can recommend a 2200 sound wise, but apparently they commonly have issues like failing relays. If you can get a restored 2200 with upgraded relays you will have something good.
     
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  18. iFi audio

    iFi audio MOT iFi Audio

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    Oldie but goldie. Some people in our company still remember vintage NAD products with tears in their eyes..
     
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  19. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

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    Any impressions to share with SBAF now that it's been a month?
     
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  20. yotacowboy

    yotacowboy McRibs Kind of Guy

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    I've had mine up and running since November. All impressions are compared to my Cayin EL34 integrated running pass-thru w/Freya preamp (using both tube (preferred) and JFET stages; didn't spend much time using passive output)*:
    • Great bass definition, good punch and power (aside: I had to turn my subs down about 30% and crossed them over @ 40hz, down from 80hz, after adding the NuForce)
    • A little cool in the upper midrange, but lower midrange (and a bit into the upper bass) is more palpable
    • Better instrument/image specificity and separation
    • Soundstage is less wide, but much better depth - no "crazy imaging outside of the speakers" **
    • Better air/sense of space around instruments and voices
    • Macro dynamics are better, less "tubey-syrup" softening transients
    • Lacks a little of the tube magic with tone/harmonics and body, but a good set of tubes in Freya brings this back into play
    • Overall, compared to my old integrated, the NuForce highlights great bass pitch definition and heft, and really opens up the upper end of the treble without sounding strident or forced
    • I'm still playing with minor tweaks; cheap footers, 6db inline attenuators (93dB/w speakers + Freya tube stage = hisss), cables, etc., but there's no way I'd go back to the EL34 integrated at this point
    Hope that helps!

    * I spent 3 listening sessions comparing the amps directly. After about 5 hours total listening between the two, farting around with cables and wires and moving things around, I'd had enough.
    ** I've read some thoughts that "crazy imaging outside the speakers" on tracks that don't use any phase tomfoolery is actually a sign that there are some phase issues with the speakers themselves, but I'd like to hear more thoughts from folks who know more about this than I do. In other words, listening to something like Cowboy Junkies The Trinity Session isn't some shock-and-awe HIFI hyper-real event (like I was kind of expecting given the better detail and treble response); but instead, it's much more believable or authentic.
     
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