2-channel power amp recommendations?

Discussion in 'Computer Audio' started by Commander Shepard, May 14, 2019.

  1. Zarathustra[H]

    Zarathustra[H] Official Forum Curmudgeon

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    Well, yeah, it depends on who you ask,

    There are certainly those who believe subwoofers ruin the neutral response they are looking for.

    I think if you tune the crossover right, you can have the best of both worlds, though I am struggling a little bit with this setup. It seems to vary so much based on volume output and on the track I am playing.

    I'll dial in the crossover and gain on the subwoofer to perfection, and then I'll turn the volume knob up or down, or the next track will come on and it either feels empty on the bottom, or way too boomy.

    I guess so much is mix dependent, but this setup feels a little bit more finicky than others I have played with in the past. Either that, or I have become pickier in my old age.
     
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  2. Nenu

    Nenu [H]ardened

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    I always had this issue and when young I knew exactly where to dial the bass control on my hifi for every song.
    No such luxury these days, its all digital with no dials.

    There is a lot of old music that lacks oomph. ie Early Abba, U2, Floyd ...
    So I use the Electri-Q VST EQ in Foobar to switch in more bass when needed by setting it up optimally then turning it on/off with an icon on the taskbar.
     
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  3. Zarathustra[H]

    Zarathustra[H] Official Forum Curmudgeon

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    I may just have to pick up an equalizer so I don't have to keep bending under my desk to adjust the sub.
     
  4. Zarathustra[H]

    Zarathustra[H] Official Forum Curmudgeon

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    This little Schiit actually looks pretty appealing and inexpensive...

    loki-mini-front-1920.jpg
     
  5. Nenu

    Nenu [H]ardened

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    Looks like a sweet little device.
    I cannot take this route after doing an experiment which you would be wise to do.
    (I can see this getting controversial ;))


    I considered putting a passive analogue volume control on my DAC so it could always be running at full bitrate (ie not using the digital volume control in Foobar [my DAC has no internal volume control]).
    This was to be a switched resistor network not a potentiometer, but before I went the whole hog I wanted to see what difference adding more interconnects and connections to the signal path would make.

    I took a gold plated QED RCA volume control box and shorted the volume controller out so the connections were straight through and connected it in my system with 2 short silver RCA leads. (to be clear, this makes it just a box of RCA connections, no volume)
    I compared this to a direct silver RCA lead and found a surprising amount of fine micro detail was muted with more connections!

    I also needed to compare Foobar controlling the volume on my DAC to an analogue volume controller, so soldered a high quality resistor to give a pleasing volume level.
    There was definitely more detail lost going through the resistor volume unfortunately. This was beyond any potential volume level difference.
    I tried the same using HQPlayer instead of Foobar and the loss was even greater. (HQPlayer drags even more detail out of music with extreme quality upsampling, its quite something. It has its own digital volume controller)


    So you have to choose the best of 2 evils, analogue or digital volume/tone control.
    The result might be different on your equipment.
    if you cant tell the difference, why not get an analogue volume/tone controller?
    Bear in mind, if you later upgrade your equipment you might find the component limiting you the most is the analogue volume controller and/or its connections!
    Note: loss of detail will be larger passing through more circuits such as filters for bass/treble etc.

    I figured having selected my hifi components very carefully and spent a lot to get this micro detail, I wasnt prepared to lose it.
    So that took the analogue volume controller out of the equation.

    fyi
    This test was carried out using silver RCA leads throughout with Silver Bullet RCA plugs.
    IRL I use silver wire balanced XLR direct from my DAC to the amp, that would have been more trouble to test.
    I was after a proof of concept, RCA served well.


    I thought I would be better served using a very high quality switched analogue volume controller with the DAC at 100% output.
    Oh well.
     
    Last edited: Nov 4, 2019
  6. Zarathustra[H]

    Zarathustra[H] Official Forum Curmudgeon

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    Interesting.

    I've never noticed a difference, but I've also never really listened for it.

    I wonder if your short may have not made perfect contact?

    I'll have to test it with and without if I ever get around to getting it.
     
  7. Nenu

    Nenu [H]ardened

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    Yeah, the leads buzzed out ok, and there was no imbalance between the channels so the joints were good.


    It depends what you want from your sound system, and as you say, you might not notice or care anyway.
    Its worth considering if you intend to go high end at some point.

    I suppose what I am saying is: if you dont mind a little inconvenience turning on/off a high quality digital EQ, there is no extra expense and it works extremely well.
    Foobar has its own EQ built in which is easy enough to use but once you untick it, the next time you start Foobar it resets the bloody graph. You can load your saved presets easy enough but its not a quick button click.
    No doubt there are better EQ plugins, I went straight for audio gold standard with the Electri-Q VST free demo version. (you cant buy it any more, he closed shop)
     
  8. IdiotInCharge

    IdiotInCharge [H]ardForum Junkie

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    Equalizer APO?

    Needs... balance :)
     
  9. Zarathustra[H]

    Zarathustra[H] Official Forum Curmudgeon

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    Why?

    Wouldn't you set that up in your initial setup and then leave it fixed?

    I feel like I can handle that with the gain knobs on the back of the amp.
     
  10. IdiotInCharge

    IdiotInCharge [H]ardForum Junkie

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    Yes -- but I'm referring to having XLR interconnects with differential signals for noise rejection ;).
     
  11. Nenu

    Nenu [H]ardened

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    Last time I tried this it would only work with the Windows mixer, Wasapi etc bypass it.
    Has this changed?
     
  12. IdiotInCharge

    IdiotInCharge [H]ardForum Junkie

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    Unknown, to be honest. I haven't felt the need to use WASAPI drivers, just Foobar if I'm going to be playing something local versus streaming Spotify etc.
     
  13. Nenu

    Nenu [H]ardened

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    OK thanks.
     
  14. Arcygenical

    Arcygenical Will Watercool for Crack

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    Monoprice has a balanced/unbalanced rackmount 31 band EQ for around 100$, I use it, and love it. Adjusts from 25hz to 16khz, switches for 6db/13db.
     
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  15. IdiotInCharge

    IdiotInCharge [H]ardForum Junkie

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  16. Lastan010

    Lastan010 Limp Gawd

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    don't listen to them, speakers need a lot of power even when companies give your their recommended power ratings, those are minimum ratings so they can sell their speakers without scaring you into how much you really need to power their speakers.

    Tweeters don't need a lot of power, 5-10w at most, but the mid/woofer drivers need a lot of power, more the better, this is where damping factor comes in, a lot of people don't know what damping factor is from speaker amps.

    If you want something really good, I would get Anthem or Parasound amps, they are very high quality amps at very good price. If you want to hack the price to perf ratio, I would get the Emotiva BasX A-5175 amp, it is a 5 channel amp that is rated 120w for each, but in Stereo mode with 2 speakers it does 175w of pure high and dynamic sound into 8ohms and 250w into 4ohms, I think it costs $850.

    Also, if you want an end game for those LS50's, get this: https://www.amazon.com/Vincent-Audi...?srs=8441293011&ie=UTF8&qid=1573243194&sr=8-4

    that unit will make them LS50's turn into something else that you never thought possible, the damping factor from that unit is at least 10 times than standard speaker amps, it rivals amps from very expensive brand called Regel, and Macintosh.

    Stay in the class A/B speaker amp section, the person who linked you that class d amp on 1st page made me chuckle, do not buy a class D amp for any speaker unless you have a passive subwoofer that needs an amp, then you go with class D.
     
    Last edited: Nov 8, 2019
  17. Commander Shepard

    Commander Shepard 2[H]4U

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    We think along the same lines. I went with a pair of these: Outlaw 2200 monoblocks
     
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  18. Zarathustra[H]

    Zarathustra[H] Official Forum Curmudgeon

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    I personally don't see the point of having a oversized amp just to only utilize 20% of it.

    My philosophy is that as long as you aren't clipping, you have sufficient power.

    I take your point though about damping. A lot of cheap amps are under-damped, but as long as you do your homework you don't have to over do it power wise to get a good damping factor.

    I used to use an older NAD amp rated at ~40w and it was more than enough for my RBH 41se's. (50-100w amp recommended by manufacturer). I didn't even crank it up anywhere near the max.

    For a while I used a Emotiva UPA-2, but now I have a Parasound Z275 v2, rated at 95w into 8ohm. It is plenty.
     
  19. IdiotInCharge

    IdiotInCharge [H]ardForum Junkie

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    That's cool. Cool is bad for the wallet...
     
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  20. Nenu

    Nenu [H]ardened

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    As an average it doesnt sound so bad.
    But music is very dynamic, the music peaks momentarily use a lot more than the 20%.
    If you dont have enough power it compresses the peaks, and can become shrill.
    It depends what you want I suppose.
     
  21. Lastan010

    Lastan010 Limp Gawd

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    nice, mono blocks sound very nice and have a very good resale value down the road, they can last for a very long time. And you can pretty much power any speaker with those.
     
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  22. Zarathustra[H]

    Zarathustra[H] Official Forum Curmudgeon

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    I'd argue that as long as you aren't clipping at those dynamic highpoints, you have enough power.

    It should be fairly obvious if you do.

    The followers of the golden-eared audiophile nonsense like to speak of subtleties in audio quality, but in my experience this is rarely true. Either it works and it is sufficient, or it doesn't and it isn't.
     
  23. Lastan010

    Lastan010 Limp Gawd

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    don't forget, less heat and stress on the amp section and longevity is prolonged by miles, this is why their resale value stays strong.
    You mind as well get a powered Bose speaker and call it quits.
     
  24. Nenu

    Nenu [H]ardened

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    My comment stands as stated.
    Take it as you will, I dont see any point furthering this with you.
     
  25. Zarathustra[H]

    Zarathustra[H] Official Forum Curmudgeon

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    Meh. You have to at least be open to the fact that placebo effect has an impact here, just like it does in 100% of all aspects of human perception.

    My setup sounds much better than any Bose system I've ever heard, and very little of that has to do with amplification. 90% of audio quality is in the transducer.

    If an amp doesn't have enough power to support a speaker, it clips. If it has enough power it doesn't clip. There is no in between. If an amp is clipping it should be extremely obvious. If it is not clipping, it has sufficient power.

    There are ways in which amps can sound bad that have absolutely nothing to do with how much power is available though, but from a power availability perspective, if it isn't clipping, at a fixed sound output level, no amount of added power will make it sound any better.

    I'm not one of the objective measurement extremists. I am open to there being things we don't know to measure yet that may have an impact on sound quality, but in general I trust my old electrical engineer colleagues who cut their chops designing amps from scratch, more than I do audiophiles, especially since the audiophile hobby is the poster child for misguided spending based on placebo effect :p

    But if you want to keep justifying your spending on car-priced audio jewelry, be my guest :p
     
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  26. B00nie

    B00nie [H]ardness Supreme

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    Listening tests and measurements show that listeners cannot perceive amp damping factor very critically. A damping factor of 1 is seen as the practical minimum after which critical damping is achieved to the signal.
    Amp damping factor is only theoretical value for anything but active speakers because the bigger the damping factor an amp has, the easier it gets destroyed by even the slightest speaker wire impedance. If you put a 10 foot long speaker cable between your speaker and the amp, the damping factor of the circuit gets annihilated. Usually from 200ish to around 10 or less.

    Also the comment on the 'tweeters need for power' is false in the sense that tweeters do not need power, they have rated power handling. Tweeters are typically rated to around 5 watts RMS and they burn out if this gets exceeded. That's why crossovers are required to limit the power input only to the high frequencies which contain very little music information. Tweeters are also usually very sensitive so they produce a lot of sound using few watts.
     
  27. Lastan010

    Lastan010 Limp Gawd

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    nobody here said that tweeters need a lot of power, the opposite was said here, it was said that mid and woofer drivers need the power, so please read peoples posts more correctly.
     
  28. Lastan010

    Lastan010 Limp Gawd

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    if you had the chance to take a home a real high end amp you wouldn't be saying this garbage, good luck with your $50 amp from Amazon that does 300000 billion watts.
     
  29. Zarathustra[H]

    Zarathustra[H] Official Forum Curmudgeon

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    I have a Parasound Halo A31 in my livingroom.

    It's a little overkill for my application, but my livingroom speakers are a little harder to drive than the ones in my office, and my listening distance is quite a bit longer.

    What do you use?
     
    Last edited: Nov 11, 2019
  30. Lastan010

    Lastan010 Limp Gawd

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    so why don't you use a low end amp with enough amps for the speakers and you will see that even if speakers are getting enough power they can still sound like shit with shitty amps.

    amp you have is decent enough, I have Anthem MCA 225 amp being fed by Hegel P20 Preamp, and the Hegel is being fed with latest ESS Sabre 9038 Pro DAC.
     
  31. Zarathustra[H]

    Zarathustra[H] Official Forum Curmudgeon

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    I actually used to use an old Emotiva UPA-2 to drive the same speakers. I replaced it because I was driving the center channel straight off of my receiver at the time, and I thought I could pick up a tiny bit of distortion on it, so I wanted to move everything to dedicated amps. Due to space constraints I wound up going with the A31 for my front three channels, and keeping the surrounds straight off the receiver, as they barely matter anyway.

    I had a few options in the 3 channel world, but I wanted to err on the side of safety, because I didn't know what things would sound like when I got it, so I went with the A31 which has reviewed favorably when compared to Mark Levinson and Krell Evolution amps that retail for over $10k

    When I first got the Parasound amp, I did a bunch of critical listening of 2 channel favorites back and forth between it and the much lower end UPA2 I bought used for $200 and could not tell the slightest difference between them.

    To be fair though, I use powered subwoofers for all the low frequencies, so I likely don't give the Parasound A31 much of a workout.
     
  32. Lastan010

    Lastan010 Limp Gawd

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    I assume you are using AV receiver pre outs to the A31?

    If so, then you are limiting what your amp is capable of by miles, I went that road long time ago, never again.

    If I could lend you my Hegel preamp to try it on your A31 you would be blown away.

    AV brands output very low and limited signal to the amps from preout section for safety reasons, so people dont blow their speakers and blame it on the AV brand.

    Now if you get a pre processor then you would have a proper setup.

    So if you are running AV receivers preouts to A31 I strongly suggest to get rid of that setup, that A31 is a beautiful amp, it deserves better.
     
    Last edited: Nov 11, 2019
  33. Zarathustra[H]

    Zarathustra[H] Official Forum Curmudgeon

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    I'm well aware. It's a stepping stone to a more appropriate pre-amp.

    There is only so much audio hardware I can buy at once without being relegated to sleeping on the couch :p

    Ideally I'd like a home theater processor with balanced outputs for movie nights, and some sort of switch for when I want to do two channel listening, but I haven't gotten there yet ...
     
  34. Lastan010

    Lastan010 Limp Gawd

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    This would wake the A31 up from long hibernation https://www.safeandsoundhq.com/prod...YA5IsRjTcKIkXKWhgthQ5TTs-jGdDy4xoCEoQQAvD_BwE
     
  35. B00nie

    B00nie [H]ardness Supreme

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    Well, you could also read my post correctly. I said tweeters have no 'need for power' they have rated thermal maximum power. The amount of power that goes to the tweeter depends entirely on the type of the tweeter. A hifi tweeter is typically rated only for a few watts where a professional constant directivity tweeter may be rated for 200+ watts. Then again a tweeter in a small speaker may play only the range of 5000-40000hz where a horn loaded compression tweeter may play from 300hz upwards.

    The amount of power needed depends entirely on the sensitivity of the speaker driver (note the use of generic driver without limiting to tweeters) versus the SPL required. A highly sensitive speaker can play adequately at 1-2 watts where a typical hifi speaker needs 10-1000 times the power to produce the same sound levels.
     
  36. Arcygenical

    Arcygenical Will Watercool for Crack

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    Definitely discontinued on monoprice... Damn, I think I paid 115$ shipped (to Canada, mind you) about 5 years ago. It's finally starting to fail on me, with one RCA input shorting to ground every so often.

    I'm re-building my desk - and therefore my audio rack... I'll open the damn thing when the rest of the rack/PA's/crossovers come in, I was happy enough with it to track down the OEM... And no curious fingers ever sent 350wrms to a single speaker, despite many, many "failed attempts" - a step up from ebay/Aliexpress EQ's that let anything through.

    And, in the market for new rackmount PA's... I'm terrified of what these D-class PA's could do to my speakers/neighbours...
     
    Last edited: Nov 13, 2019
  37. B00nie

    B00nie [H]ardness Supreme

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    Some of them are very good, especially for the price. If you want a really good D-class go for Hypex Ncore. They sell also consumer kits if you don't have an OEM account like me :)

    Ncore can be found in many high-end amps but the price is 10-40 times higher then...
     
  38. Arcygenical

    Arcygenical Will Watercool for Crack

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    Stop showing me things in the 1.5k+ price point :). I only need 6 amped channels, 3 way xovers... about 100 speakon/XLR connectors, 10km of 12g wire... And a USB/wifi DSP to control it all. Fuck me, right. Oh, and the rack. That's the thing about flood damage... It takes pretty much everything. Silver linings I suppose!

    And yes, the SPL @ 1w/m for a 1" diameter AMT tweeter, properly crossed - say, 3200hz - is in the 95dba range. Ouch.
     
  39. B00nie

    B00nie [H]ardness Supreme

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    The Ncore 500 consumer kit is IIRC 400 bucks. Granted if you want to build 6 channels with active XO you will have to pay thousands using Hypex.
     
  40. Arcygenical

    Arcygenical Will Watercool for Crack

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    can you link me?

    I can do the xovers myself, just basically need a stereo amp (250wrms each side into 4ohm) and a mono capable of 350w into... uhhh, either 2 or 4 ohms (woofers are in parallel). The last stereo amp is to push music to my active crossovers/tactile transducers in the adjacent bedroom.