I correct my own BS above. I do not know why this man does the cable thing. I hate that he does! But here is the thing. He does just about everything in the world but say "If your electronics fall within these parameters, they will sound just as good as mine" Now that my friends is commendable.
Mr Sanders: I see you have a bias toward planar speakers, nothing wrong with that. Hearing Quads is what got myself and millions of others here, that is great, that is fine. Your amps seem to me to be impeccable so why in the hell don't you preface that cable sales section with the truth and obvious disclaimer? Kudos to you for all but screaming: "If your amps do not clip, if they make the a to ab crossover point right, if they have that very low distortion less than 1% (I believe it may be somewhat lower for some) they *will* sound as good as the ones that I produce" What the hell, you can't ask for more truth than that can you? but 5k seems ridiculous.
Mr Sanders: I see you have a bias toward planar speakers, nothing wrong with that. Hearing Quads is what got myself and millions of others here, that is great, that is fine. Your amps seem to me to be impeccable so why in the hell don't you preface that cable sales section with the truth and obvious disclaimer? Kudos to you for all but screaming: "If your amps do not clip, if they make the a to ab crossover point right, if they have that very low distortion less than 1% (I believe it may be somewhat lower for some) they *will* sound as good as the ones that I produce" What the hell, you can't ask for more truth than that can you? but 5k seems ridiculous.
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So below after my comments, is what Mr. Sanders quoted in an interview. This is above and beyond reproach. Thank you Fas42 for pointing me toward his site. Beware asschole liars and crooks of the audio industry this guy ain't playing your bullschiit game and even better, hig ego is not making him obfuscate reality to sell his stuff. He needs not the BS.. His honesty has led me to some conclusions that are not even near the ones that are beneficial to his company ,other than that I will point to him as a real true, honest guiding light for all: Sanders:
"The truth is available, but the industry in general doesn't want audiophiles to know it. It is essential that confusion abound so that all sorts of false claims can be made to sell audio equipment and nobody will believe measurements or valid listening tests that prove that these claims are bogus. I find it utterly astonishing that audiophiles are so gullible and willing to believe all the voodoo science out there. They should demand proof of claims before dropping tens of thousands of dollars on equipment. This situation is an extremely sad and frustrating commentary on our industry"
Hear hear Mr. Sanders, hear hear.
"The truth is available, but the industry in general doesn't want audiophiles to know it. It is essential that confusion abound so that all sorts of false claims can be made to sell audio equipment and nobody will believe measurements or valid listening tests that prove that these claims are bogus. I find it utterly astonishing that audiophiles are so gullible and willing to believe all the voodoo science out there. They should demand proof of claims before dropping tens of thousands of dollars on equipment. This situation is an extremely sad and frustrating commentary on our industry"
Hear hear Mr. Sanders, hear hear.
I found a chink in his armor though. He refers to the xover he uses in his speakers as "the digital crossover" Hmmmm.... I know damn well what crossover he must be using. I also can guess that he doesn't want to get involved with defending some of Uli Behringer's earlier shenanigans. Most of us know that unit sounds superb "if" you are using digital in, but not as great if you are going analog to analog. That must be a sticky wicket. Probably his gear sounds very un-fatiguing even with those added conversions, but I would avoid them. Just mentioning if you do have that unit, get in there on the AES/EBU and at 96k for a number of reasons if you can.
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This is your man: Peter Walker of Quad. (no longer with us, unfortunately)
http://reocities.com/ResearchTriangle/Lab/6722/pwint1.txt
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The difference is one of damping, which is essentially EQ. The net result will be similar. In each case the desired tonal balance can be the goal.
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Listen to a good recording that fades out at the end (electrically) and slowly with the band playing a constant fullrange sound at their normal level throughout. Listen at normal levels. If there is anything unexpected about the sound that changes through the fade out, there are issues with your speakers.
Are we still talking about Fletcher Munson?
By definition (of the Fletcher Munson curves), if the EQ is flat and the volume level is not 'realistic', you will perceive a different tonal balance from that which you would have perceived 'live' at the mic position. An electrical fade-out of a constant tone should cause you to hear a change of timbre, and should not sound natural as such. Whether you count it as "unexpected" depends on whether you listen to electrical fade-outs a lot.
Worth commenting on Peter Walker's statement, I think:
The two big problems with transistor amps are slew rate limiting and crossover distortion. BOTH manifest themselves as an inability to supply clean current to a low or difficult impedance. You crossover designers will do yoursleves a favour by making big efforts to keep impedance high and reactance low. Then the amp behaves as advertised. This is why I favour Zobel circuits on tweeters, rather than attenuators after the LC filter.
It is also worthwhile knowing how to calculate the root L/C impedance of a treble filter. 4.7uF and 0.2mH comes out as about 6 ohms, for instance. So with an efficient zobelled 6 ohm tweeter and a 6 ohm input attenuating resistance, everything works out rather nicely.
You must then line up the phase between the drivers as accurately as you can. Cone breakup from the woofer is much less noticeable if you do this. I favour Lynn Olson's approach:
Every midwoofer requires a differnt notch, but the 6" bass is particularly straightforward around 4-5kHz. The last piece of the puzzle with a two way is to ditch the awful soft dome. These really stink in terms of spit and sizzle as Robin Marshall explains:
You might try a zingy metal dome, but my current weapon of choice is the cone tweeter:
That's about it really.
The two big problems with transistor amps are slew rate limiting and crossover distortion. BOTH manifest themselves as an inability to supply clean current to a low or difficult impedance. You crossover designers will do yoursleves a favour by making big efforts to keep impedance high and reactance low. Then the amp behaves as advertised. This is why I favour Zobel circuits on tweeters, rather than attenuators after the LC filter.
It is also worthwhile knowing how to calculate the root L/C impedance of a treble filter. 4.7uF and 0.2mH comes out as about 6 ohms, for instance. So with an efficient zobelled 6 ohm tweeter and a 6 ohm input attenuating resistance, everything works out rather nicely.
You must then line up the phase between the drivers as accurately as you can. Cone breakup from the woofer is much less noticeable if you do this. I favour Lynn Olson's approach:
Every midwoofer requires a differnt notch, but the 6" bass is particularly straightforward around 4-5kHz. The last piece of the puzzle with a two way is to ditch the awful soft dome. These really stink in terms of spit and sizzle as Robin Marshall explains:
You might try a zingy metal dome, but my current weapon of choice is the cone tweeter:
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That's about it really.
Too bad Mr. Walker and crew didn't listen to some music on the 303 and 405 after all the testing. If they had, they might have built a better amp!
Now we're getting down to the nitty gritty. The Quad amps measure very well, and a large number of people think they sound good (if the 303/405/306/606/707/909 resale values are anything to go by).
What is it that makes you say they aren't any good?
I was trying to address how to make a speaker amplifier friendly. The Quad ESL was a hideous capacitative load that would give most amps kittens. I'd take it for granted that expensive, power consuming Class A is better than Class A/B and its inherent crossover distortion, so what's your point?
We could consider valve amps a separate topic. There are ways to make a speaker valve amp friendly, usually involving larger than usual closed box and impedance correction.
Reference please!
No, CopperTop, don't allow us to become hoplessly sidetracked!
I happen to have studied Quad amplifier schematics, and there is a lot to like including Class A preamplifier stages, and correctly biased electrolytics on a single power rail, which are better than modern designs with op-amps really, a la John Linsley-Hood, but at heart, even with the current dumper output stage of the 405, they are Class AB output stages, which are much of a muchness IMO.
It's a characteristic sound. The best you can do with them is design your speakers to be easy to drive. This is more fruitful than an argument about the merits of different amplifiers.
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