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  • Power amp- no Difference in sound ?

    I asked this years ago:

    1)When all wattages output being equal....will 1 power amp sound different from another in sound quality?

    All those who responded said - No. An Amp is to amplify the signal from the mixer. It does not have its own 'sound'...so any amp will sound the same.

    I find it hard to believe. That being said...a high end Crown amp will sound the same as a low cost Peavey Amp?

  • #2
    Damping factor alone can make a difference in sound when using a speaker system in a home stereo that is ported. Changing the bias setting on one of two identical amps can make them sound different. My Phase Linear 400 sounds quite different than my Dynaco ST70. My Dynaco ST35, MKllls and Fisher amps all have a different sound as well.
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    • #3
      I'm no expert - but some of the things that can make 2 amps with 'identical' wattage sound different are:
      - Actual vs. Rated power. Not all manufacturers are honest about their spec sheets (I know, right?)
      - Slew Rate. This is a measure of how fast the amp can respond to fast transients
      - Clipping characteristics. Some amps have a 'smooth' clip and others are more square wave and consequently more audible when driven into clipping.
      - Damping factor. Especially when driving long cables. Higher damping gives a tighter, more controlled sound.

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      • #4
        Generally yes, all amps driven within thier specs will act and sound the same. When the amps are driven to thier limit and beyond is when you'll hear differences. But really there should be no reason to do this. When choosing an amp it isn't about sound: what other amps are there in the system (it's good to use amps in the same family, i.e. QSC PLX series, crown XTi series etc)? What types of speaker loads will be used? Are you driving 1 or many boxes? Is it for full range or band pass? How about the racking and truck pack? Any DSP needed? What type of inputs/outputs?

        many questions...
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        • #5
          Some folks claim they can tell the difference on the high end between a class "D" and "analog" amps so use "analog" amps on the HF drivers. In a "live" situation with lots of background noise I doubt it makes enough difference to matter to any except the most OCD "audiophile" :freak: .

          "We Have Met the Enemy and He is Us" - Walt Kelly​

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          • #6
            Amplifiers don't really have a "sound" when they are used in their linear mode. What you hear as a sound is the result of what happens when you drive the amp beyond it's limits (which does happen frequently). What you are hearing at this point is the sound of the limiting and the sound of the power supply's ability to refresh itself. In this respect there is some difference.

            A comparison between a 60's Dynaco 60W tube amp and a more modern solid state amp with 4x the power is hardly an fair comparison. But a test between a Peavey and a Crown (of similar power ratings) will likely be so close as that no one can tell the difference (with their ears).

            A few years back Bink Knowles ran a pretty comprehensive test http://srforums.prosoundweb.com/index.php/mv/msg/884/0/0/0/
            As I recall only 2 out of the 60 or so listeners could tell the difference in A/B/X listening tests and this was under pretty great listening conditions.
            Don Boomer

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            • #7
              I've run my system through QSC plx, rmx,Peavey ipr and Carvin. Reliability difference was huge,(Carvin :facepalm sound difference-------I couldn't hear one. Many, many years ago I recall an audiophile article where it was stated about the sonic superiority of McIntosh amps vs. everything else. Don't know for myself. Biggest difference I've seen is with mics and speakers.

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              • #8
                Let me understand this from you folks. If pushed too hard...then an amp will sound different? Well...I think I know that already.
                So, say a chinese made amp is 1000w at 4 ohms...while a Crown is 600w at 4 ohms. When pushed hard...the Crown will sound bad...while the Chinese amp will sound better cos it has higher headroom?

                Pls teach me.

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                • #9
                  A few years back Bink Knowles ran a pretty comprehensive test http://srforums.prosoundweb.com/index.php/mv/msg/884/0/0/0/
                  As I recall only 2 out of the 60 or so listeners could tell the difference in A/B/X listening tests and this was under pretty great listening conditions.


                  Well... yes and no concerning the listening conditions. It could be argued that conditions of the listening tests portion of that amp shoot-out were basically ideal for not being able to tell the difference in sound from one amp and another, although I don't believe that was the intent for how the listening tests were conducted. It's been quite a few years back, and I don't recall most of the details of the listening tests, but as I recall here's possibly some of the details:

                  1) As I recall, the program source was possibly CD recordings... I don't recall any live program source... and there certainly wasn't a live band involved. As I vaguely recall, the program material varied throughout the listening tests... so it was difficult to compare how "this" amp sounded vs. "that" amp with different program material. I'm pretty sure the same music sample wasn't played over & over.

                  2) As I recall, the monitor speakers for the listening tests were possibly Meyer UPA's over 750's. I don't recall if Meyer processors for the system were employed and if they were, how they were involved, or if the crossover(s) was active or passive... and how all that was handled. I suspect the tested amps were driving stereo 8 ohm loads. I don't believe any of the amps were pushed to clip during the listening tests. I've reviewed a picture I took of some portion of the hook-up... I dunno...



                  3) As I recall, for each amplifier a couple minutes of CD recording music was played, then the amp was changed to the other amp we were A-Bing, and the sound clip was run again. As I recall there was some passage of time involved with the change-over between the first and second amp being listening tested in each of the multitude of amps going through the listening tests. This made it seemingly difficult (for myself at least) to recall what the previous amp sounded like awhile ago... and the length and compexity of the program material added to the confusion in my brain.

                  Anyhoo: I'm convinced the listening tests yielded basically statistically insignificant differences in the tested amps. I'm unconvinced if this was a result of the amps used in the test or was the result of the testing procedure. In other-words: I

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                  • #10
                    So, say a chinese made amp is 1000w at 4 ohms...while a Crown is 600w at 4 ohms. When pushed hard...the Crown will sound bad...while the Chinese amp will sound better cos it has higher headroom?

                    What does it matter? There are a lot of things to consider when buying an amplifier, but it's "sound" isn't one of them.

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                    • #11
                      I have heard differences in switching amps in certain conditions. My iTech on subs sounds much better than my XTI does. Some folks talk about damping but I think rail reserves have a lot more to do with it.

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                      • #12
                        It has been my experiance that, as stated, all things being equal, there is very little difference from power amp to power amp. We did a test many years ago at a pro audio shop I worked for. We were VERY careful about getting the same spl from amp to amp (just a single db will skew you perception a lot even though you don't really percieve much volume difference). I believe I could hear a difference (mostly in the bottom end) but it was minimal (extremely minimal). The blind test process was repeted several times and I picked the same amp every time. My ears were a lot better then (acuity not training).

                        I'll agree that most of the difference is firstly how reliable are the mfg's specs and secondly how does that amplifier handle being overdriven or current limited (if it's intigrated into the amp). This is where the differences become apparent. Since almost every SR sub amp I've seen gets run up and beyond to it's rated output at some point in it's service life (in a perfect world.........Oh I forgot we're talking about SR here :-). IMHO this is still a valuable thing to know when choosing an amp.
                        J.R. Previously jrble

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                        • #13
                          What does it matter? There are a lot of things to consider when buying an amplifier, but it's "sound" isn't one of them.


                          Spot on. The "sound" is a pretty small factor when making a choice. Real world power delivery, efficiency and dependability are more important by far.
                          J.R. Previously jrble

                          See my Dog Of The Hair studio at: http://www.dogoth.com/studio/

                          Quote from someone: Flat response? Get out the jack and change the tire.

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                          • #14
                            Spot on. The "sound" is a pretty small factor when making a choice. Real world power delivery, efficiency and dependability are more important by far.

                            Yup.

                            I gained some fairly good insight at Bink's amp shoot-out, as I repackaged all of the amplifiers that needed repackaging after the shoot-out (which was most of the sampled amps). It was amazing to see the wide variety of build quality in the sample amplifiers, including the differences in structural quality, acoutriments, packing material and included documentation... even a wide difference in the power cables. Generally the higher priced amps were noticably better built, better thought out, better packaged, and included better documentation.

                            A side note: I generally noticed that the amplifiers with the weakest chassis also weren't equipped with rear support bracket considerations. IOW: The amplifiers that probably most needed rear support brackets didn't have ready means to incorporate said brackets. A fuctional amplifier generally sounds better than a broken amplifier... a functional cable generally sounds better than a broken cable.

                            Personally, I focus way more on how speakers and microphones "sound" than how amplifiers "sound", because speakers and microphones are transducers (which convert SPL to electrical power or visa-versa) where-as amplifiers simply "amplify" a signal.

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                            • #15
                              As an amp designer, it's my opinion that any REASONABLY well designed amp will sound virtually identical when driven within it's linear region. Amps can sound sifferently when driven outside the linear region, because different designs operate or function differently when clipped, or limited, as the global feedback loop is opened.

                              There are, however, large differences in reliability and durabilty between different amp designs, as well as different manufacturers of very similar (or even identical) designs.

                              So, you need consider ALL of the variables when stating that one amp "sounds" better... I don't believe one amp sounds better than another but I do believe there is a BIG difference in reliability and performance. Also, your same power comment would have to mean that the amps are rated using the same method. Marketing folks can manipulate numbers in impressive ways.

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