T2K Posted April 8, 2001 Share Posted April 8, 2001 In other words if I read specs for say an AV reciever that says "100 watts per channel-all channels driven" then am I actually getting stated output as advertised? I understand there are standards in place for the rating of output for recievers,amplifiers,etc. but if I AB'ed lets say an AV reciever rated as above and a separate amp rated likewise,then more than likely I will get superior sound quality from the amplifier. Why? If both pieces were tested for output using the same 8 ohm resistive load,then would the difference be simply build quality?Any and all ideas and input appreciated. Keith Quote Link to comment Share on other sites More sharing options...
jwgorman Posted April 8, 2001 Share Posted April 8, 2001 Sadly, a watt is not a watt. Sort of like the Army issuing black berets to any rear eschelon nimrod, the term looses meaning. If you look at Mcintosh amps, they have large capacity power supplys (ie, big transformers, beacoup storage cap capability etc) I bought an old 20 watt per channel integrated sansui circa 1977 whose modest power supply equals many modern 100 watt per channel offerings. Unless you purchase from a company whose name is synonymous with solid engineering and quality construction you are probably not getting the real deal. Obviously there are other companies besides McIntosh but I happen to have some experience with them. You can always haunt garage sales and ebay looking for any Yamaha, Sansui, Luxman from about 1975-1980 and, providing they ar functioning properly, you won't go wrong. jwgomran Quote Link to comment Share on other sites More sharing options...
rowooo Posted April 8, 2001 Share Posted April 8, 2001 Nothing to do with the post but....Where's the U.S. buying all these new black berets for are fighting men and women...You guessed it, CHINA....nice... Quote Link to comment Share on other sites More sharing options...
boa12 Posted April 8, 2001 Share Posted April 8, 2001 right on i'd use my '75 kenwood kr-9600 as a power amp in a heartbeat, but this darn sony doesn't even have preouts or amp ins is there another way maybe of utilizing my kenwood monster? ------------------ Klipsch KLF-30 (front), KLF-C7, Cornwall I (rear) Velodyne HGS-18 sub woofer Monsterbass 400 sub interconnect & Monster Z-12 cable Sony STR-DE935 a/v receiver Sony DVP-C650D cd/dvd player Sony Trinitron 27" stereo tv Toshiba hi-fi stereo vcr Technics dual cassette deck Technics direct drive turntable Scientific Atlanta Explorer 2000 digital cable box 2nd room: Klipsch RF-3 (front), RC-3, cheap little Technics (rear) Kenwood KR-9600 AM/FM stereo receiver (vintage '75) Teac PD-D1200 5-disk cd player Sega Genesis game player Sub: None yet rock on! Quote Link to comment Share on other sites More sharing options...
T2K Posted April 8, 2001 Author Share Posted April 8, 2001 Yes, I understand all of the above.My question was this.If I build a reciever that I say delivers 100 watts per channel to all channels at 8 ohms and also that it is capable of driving 4 ohm loads with a rated output of 200 watts, as opposed to your product that you say delivers 100 watts per channel at 8 ohms-200 watts at 4 ohms, then why in almost all cases does your product(amp) outperform my hypothetical (AVreciever) product? Keith Quote Link to comment Share on other sites More sharing options...
JohnA Posted April 8, 2001 Share Posted April 8, 2001 Keith, A full explaination will get very esoteric, very quickly, and well beyond my understanding. However, .... If both amps are really capable of 100/200 watts, as stated (nothing is really that linear and the real output at clipping is more likely 100@8 and 192+@4, or 110@8 and 200@4), then they will likely get just as loud as one another pushing the same pair of speakers unless one has some extra power supply capacity and can produce a little more dynamic power. Nothing here has addressed sound quality. The quality of the components and their ability to pass and amplify a signal unmodified from its input will dramatically affect the sound of the amp. Even things like the operating temperature of the transistors affect their ability to accruately amplify the signal. Mosfets sound a lot different than the normal bipolar transistors. The arrangement of the transistors in the circuit (cascode, cascade?) and whether there are capacitors in the signal path will affect sound. The maximum frequency rating of the transistors and the circuit will, too, due to its effect on transients and slewing rates. What's better and what makes no difference is pretty much beyond me. I think good sounding amp designs are still a bit o' magic. John Quote Link to comment Share on other sites More sharing options...
boa12 Posted April 8, 2001 Share Posted April 8, 2001 sorry i'm too tired to review again, but did anyone give the formula for wattage? is amperage in there somewhere? thought I knew it once (probably high school electronics). md's #2 above i think is a good example of my sony (110WX5 on the spec sheet). can we use amperage when shopping? never see it on like the commercial receiver specs, but is it out there somewhere? the stereo shop teenager will usually just pick up an amp/receiver & say like "this thing weighs a ton" to make his point. & again md or someone, sorry to but in w/ a ? on mine, but speaking of heavy amps. could i possibly hook up the 2nd audio(remote) outs(L&R) on my sony(it has no main or preouts) to the power in of the kenwood kr-9600. or would it then play the mains only on stereo mode? maybe i'll try it. the sony manual's no help. thanks. ------------------ Klipsch KLF-30 (front), KLF-C7, Cornwall I (rear) Velodyne HGS-18 sub woofer Monsterbass 400 sub interconnect & Monster Z-12 cable Sony STR-DE935 a/v receiver Sony DVP-C650D cd/dvd player Sony Trinitron 27" stereo tv Toshiba hi-fi stereo vcr Technics dual cassette deck Technics direct drive turntable Scientific Atlanta Explorer 2000 digital cable box 2nd room: Klipsch RF-3 (front), RC-3, cheap little Technics (rear) Kenwood KR-9600 AM/FM stereo receiver (vintage '75) Teac PD-D1200 5-disk cd player Sega Genesis game player Sub: None yet rock on! Quote Link to comment Share on other sites More sharing options...
WMcD Posted April 8, 2001 Share Posted April 8, 2001 I note a lot of the discussion about amps refers to their performance when they are being driven to near the upper limit. Usually 40 to 100 watts. Most of our listening is being done at well below one watt. With sensitivity ratings of some Klipsch speakers, I hazard a guess most of our listening is at the milliwatt level. That is 30 dB below one watt. If we have 104 dB sensitivity at one meter, one milliwatt gives 74 dB of sound. Granted, listening distances are bit greater than one meter. But we do have two speakers. In any event 10 mW is certainly a credible figure for average. If your talking about subtile sound, we're back to 1 mW, probably. The point is, we really don't see too many specs down at 1 to 10 mW. The few I've seen sometimes show an increase in distortion. I don't sign on the theory that all amps sound alike. I do believe the objective instrument tests are material. But I'd like to see those run at 1 to 10 mW. Then we might get some correlation. If the 1 - 10 mW test show something bad, it would be a figure of merit. This is the old, still valid, "What the world needs is a good 5 watt amp" lament. It is being extented to, "What we need is an amp known to be free from distortion at 5 mW." Gil Quote Link to comment Share on other sites More sharing options...
T2K Posted April 8, 2001 Author Share Posted April 8, 2001 boa12,to use your own words,I feel your pain. I know this is going to sound ridiculous and I hate to post here account laughter,but seems to me I read somewhere years ago of some device that would convert a high level signal to a low level signal.Otherwise,I have no idea personally how you can accomplish that which you are wanting to do. Good luck. And as far as the hypothetical goes: good answers.Just thought I'd pick everyone's brain and possibly learn something at the same time.I knew I could count on mdeneen!And yes John I too believe in magic. And I would like to add that I too have a Sony reciever that,unlike boa,I am terribly satisified with(GX900ES).Bought it in January 1995 along with an Acurus amp.Anyone considering an amp purchase owes it to themselves to audition Acurus.With my Klipsch speakers it makes magic. Keith Quote Link to comment Share on other sites More sharing options...
boa12 Posted April 9, 2001 Share Posted April 9, 2001 thanks for da comfort keith i'm very satisfied w/ my sony - as a preamp that is i know sooner than later i'll be getting nicer amplitude for the main sys. but now that i have the 2nd room goin w/ the old kenny, i'll still continue to search for a way to hook up the sony preamp front channels to a nice power amp, such as the kenny. it seems the only way is to use those 2nd audio (remote receiver) preout jacks (i'm using the tape monitor jacks for well a tape deck). & when looking for new/receiver amp, i wonder what other specs to look for besides wattage & thd. guess we don't have to worry so much about selectivity & sensitivity somebody got a spec checklist for a good amp? ------------------ Klipsch KLF-30 (front), KLF-C7, Cornwall I (rear) Velodyne HGS-18 sub woofer Monsterbass 400 sub interconnect & Monster Z-12 cable Sony STR-DE935 a/v receiver Sony DVP-C650D cd/dvd player Sony Trinitron 27" stereo tv Toshiba hi-fi stereo vcr Technics dual cassette deck Technics direct drive turntable Scientific Atlanta Explorer 2000 digital cable box 2nd room: Klipsch RF-3 (front), RC-3, cheap little Technics (rear) Kenwood KR-9600 AM/FM stereo receiver (vintage '75) Teac PD-D1200 5-disk cd player Sega Genesis game player Sub: None yet rock on! Quote Link to comment Share on other sites More sharing options...
boa12 Posted April 9, 2001 Share Posted April 9, 2001 md, thanks that's great info as always. my high school level electronics knowledge is now revived enough to make me quite dangerous. so when i shop for an amp out there in the jungle i'll just see how heavy they feel & how they sound. & yea & also the valuable opinions of others to some degree Quote Link to comment Share on other sites More sharing options...
djk Posted April 9, 2001 Share Posted April 9, 2001 >>So, it is not hard to see the problem. Comparing two "nominal 100W amplifiers", 3.5A might be easily handled by two transistors, but 14A will certainly require 12 or so.<< Let's see....if one pair will handle 3.5A then two pair will handle 7A and four pair would handle 14A so four pair must equal 12? >>A power transformer will grow EXPONENTIALLY in size and weight as the power demand doubles. For 3.5 amps of current, the transformer might weigh 2 pounds, at 14A it could easily come out to 25 pounds of steel and copper! << A transformer rated at 4X the current is always less than 4X the weight.Efficency improves in transformers at higher power up to about 1KVA then levels out.From the spec sheets we see that a 320VA transformer is about 55VA/LB and a 1KVA ransformer is about 59VA/LB.Most 100W solid state amps would use about 38V X2 for the transformer rating.Run in amps per LB or VA the relationship is essentially LINEAR. http://www.toroid.com/solidamps.htm Quote Link to comment Share on other sites More sharing options...
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