SWL Posted March 6, 2008 Share Posted March 6, 2008 I've read from different sources that amps do not have a particular sound quality.........that it solely depends on the preamp and other equipment upstream from the power amp. I have a hard time believing that the amp is completely neutral in determining what comes out of the speakers. I've had five different amplifiers in my house in the last few years hooked up to the same preamp, cdp etc. and they were all not the same. I understand that a 500 watt amp may sound different than a 100 watt amp because of the power/voltage difference etc. An example would be the Crown XLS series vs. the XTI series. The XLS 802d and the XTI 2000 are similar power ratings but the XTI's offer much, much better sound quality hooked up to the same preamp, cdp etc. in my house. Now, I'm always reading how guys are describing their amplifier's sound qualities............so the guys stating otherwise, what would back up their claim that amps are not a factor in determining the resulting sound characteristics in a given stereo system? Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted March 7, 2008 Share Posted March 7, 2008 well, yes, and no .. I'd present that the Power amp, makes the least difference in the signal chain .. but as you have seen .. a cheap amp like the XL series .. sounds, well ... Cheep ... diminished sound stage, perhaps, some grain .. say, otherwise .. who would buy the x-pensive amp ..?? Quote Link to comment Share on other sites More sharing options...
oscarsear Posted March 7, 2008 Share Posted March 7, 2008 Scott-- In electrical terms, not HiFi terms, an "amplifier" has a broad meaning that encompasses any method of increasing voltage or current in an AC signal. An audio preamplifier is an "amplifier", and an audio power amplifier is an "amplifier" and there are amplifiers in your FM tuner, and there are amplifiers in your CD player, and in your DVD player and so on. "Amplifiers" - - are everywhere. And, when that definition is applied, they all have some common characteristics: -They have distortion -They have noise -They have a transfer function (each interacts with its inputs and outputs in a unique way) -They don't have infinite gain, infinite, bandwidth or infinite power - i.e. they are are LIMITED from the ideal This holds true for ANY AND ALL kinds of amplifiers from audio preamps to 50kW FM transmitters. Therefore, the design of any specific amplifier will yield specific characteristics of noise, distortion, bandwidth, transfer function, power, gain, and so on. These entirely TOGETHER will form a kind of signature. When the amplifier is an audio type (meaning in the audio sound spectrum) this signature can often be heard, and distinguished from other signatures. To use a common example, a Dynaco MKIII Tubed Power amp, will have a distinguishably different sonic signature than a Dynaco ST120 Power Amplifier. Each is a power amplifier, each designer would probably sayhis amp is both "accurate" and "neutral," and yet the sonic results are clear. Two amplifiers with very close and similar designs, and sharing very similar specifications, might also sound extremely similar. As the design methods and specs diverge, so usually does the sound. When it comes to audio power amplifiers the case is exacerbated by the speaker itself which is a non-linear load being applied, while a randomly changing signal (music) is applied to the input. Since "frequency" is a circuit variable throughout the entire amplifier including it's output, the non-linear speaker load means each design of amplifier will interact slightly differently with this load (depending on the input source) and thus make different sounds. This effect of non-linear load is much, much less in preamplifiers, tuners, CD players. Believe your ears. What a wonderfully lucid explanation. Well done. Quote Link to comment Share on other sites More sharing options...
mas Posted March 7, 2008 Share Posted March 7, 2008 And then there is the small task of matching the proper tool for the job. If you consider an amp designed for limited duty 'public address' system use the same as a 'full range' amp designed for a greater duty cycle and broader response, allot of responsibility needs to be taken off of the amplifier and borne by the person choosing it! Gee, it sure it taking a long time to cut this redwood with my super duper deluxe titanium custom made Swiss Army knife designed to produce world class tooth picks... As Duke said: "I'd present that the Power amp, makes the least difference in the signal chain .."... with the speaker along with its acoustic interaction with the room being the most significant. Quote Link to comment Share on other sites More sharing options...
pzannucci Posted March 7, 2008 Share Posted March 7, 2008 The least impact by the amplifier but I would say that last 10% that can be changed by the amplifier can be very significant and rewarding. Quote Link to comment Share on other sites More sharing options...
mas Posted March 7, 2008 Share Posted March 7, 2008 I would say that last 10% I would steadfastly maintain a percentage of not more than 2.375638652%, allowing for a fundamental limitation in the measurement equipment and reiterative rounding error... [] Quote Link to comment Share on other sites More sharing options...
Deang Posted March 7, 2008 Share Posted March 7, 2008 Every component, down to the wire and caps -- can make or break a system. Quote Link to comment Share on other sites More sharing options...
Klipsched with Yamahas Posted March 7, 2008 Share Posted March 7, 2008 You guys continue to amaze me with your explanations, and I commend you! In terms, even I can understand. Receivers and separates that I have owned all had a unique signature, and even those that I demo'd. Quote Link to comment Share on other sites More sharing options...
Don Richard Posted March 7, 2008 Share Posted March 7, 2008 SWL - you are correct. Power amps with the same or similar specs can sound completely different. I used a Crown XLS-402 full range, and it sounded good. Then I got an XTI-1000 (same power, close specs) and it sounded much better. I feel that the way negative feedback is implemented within power amplifier circuits has a lot to do with the way an amp sounds. So did Paul Klipsch, as described in an old Dope From Hope newsletter in the 70's. BTW, whatever happened to The Dope From Hope? Are these archived anywhere on this website? Don Quote Link to comment Share on other sites More sharing options...
SWL Posted March 7, 2008 Author Share Posted March 7, 2008 SWL - you are correct. Power amps with the same or similar specs can sound completely different. I used a Crown XLS-402 full range, and it sounded good. Then I got an XTI-1000 (same power, close specs) and it sounded much better. I feel that the way negative feedback is implemented within power amplifier circuits has a lot to do with the way an amp sounds. So did Paul Klipsch, as described in an old Dope From Hope newsletter in the 70's. BTW, whatever happened to The Dope From Hope? Are these archived anywhere on this website? Don XLS 802d = Clean but grainy, edgy and fatiguing. Used with JM Peach...........crap sound.XTI 2000= natural sounding to my ears, non-fatiguing. Used with JM Peach...............worked well together. Getting equipment that is compatible with each other seems like half the battle.............then the room etc.[] Quote Link to comment Share on other sites More sharing options...
joshnich Posted March 7, 2008 Share Posted March 7, 2008 I would say that last 10% I would steadfastly maintain a percentage of not more than 2.375638652%, allowing for a fundamental limitation in the measurement equipment and reiterative rounding error... I feel special that I can hear the 2.37% Quote Link to comment Share on other sites More sharing options...
SWL Posted March 8, 2008 Author Share Posted March 8, 2008 Getting equipment that is compatible with each other seems like half the battle.............then the room etc. And, it's a good part of the fun. You are hearing notable differences in amps that are of relatively similar design. Now project the differences onto entirely different topologies, different design goals, principles etc., and you can see just how big the world is. 10-4 that.[] Quote Link to comment Share on other sites More sharing options...
Deang Posted March 8, 2008 Share Posted March 8, 2008 XLS 802d = Clean but grainy, edgy and fatiguing. If it's "grainy, edgy and fatiquing" -- it's not "clean". Quote Link to comment Share on other sites More sharing options...
SWL Posted March 9, 2008 Author Share Posted March 9, 2008 XLS 802d = Clean but grainy, edgy and fatiguing. If it's "grainy, edgy and fatiquing" -- it's not "clean". Edgy........no doubt.[N]Fatiguing.........depends on how many beers. Grainy...........depends on how much crap is in my ears after work.[] Like I said........it just ain't clean man!! LOL[] Quote Link to comment Share on other sites More sharing options...
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