From the product literature of my friend Arty of ErectoSond:
Here as ErectoSond we have always been cognizant of the fact not every man is blessed with or even has the ability to house large horn units.
This was the very soul and inspiration for our acclaimed Phallo series ultra high wattage power amps. Rest assured that our new Phallo series can swing enough current to push even mini sized drivers to satisfaction. I am using two in my own system.
Thank you,
Arty Toupe,
ErectoSond
Here as ErectoSond we have always been cognizant of the fact not every man is blessed with or even has the ability to house large horn units.
This was the very soul and inspiration for our acclaimed Phallo series ultra high wattage power amps. Rest assured that our new Phallo series can swing enough current to push even mini sized drivers to satisfaction. I am using two in my own system.
Thank you,
Arty Toupe,
ErectoSond
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Yes it is. Double stack them, and it sorts the men from the boys.
That it sounds better. In the worst of all audiophile clichés - a veil was lifted. Except in this case it was no veil, more like a couple of heavy velour curtains were lifted. At the end of the day, you have to pick the amp that you want to live with, no matter what the marketing department or the specs tell you.
That 'veil' is everywhere, the audio scene is riddled with the sound of "sad" amps - the recent audio show demonstrated that there are a few exceptions these days, it's better than it used to be ...
Even though some people can't believe it possible,, the shock, the memory of the first time you hear nothing speakers pump out intense, clear, dynamic sound - just like the real thing, in other words - stays a long time with one ...
Even though some people can't believe it possible,
, the shock, the memory of the first time you hear nothing speakers pump out intense, clear, dynamic sound - just like the real thing, in other words - stays a long time with one ...But is it the 'correct' sound? Are the exemplary distortion and stability specs misleading? On real music does the amp fall apart?
People may think they don't like these amps in sighted, or (mythical?) unsighted tests, but is that because they are distortion-free and therefore not as "musical" as another? In the long run are they going to be less fatiguing?
Edit: Is what people prefer (or say they prefer) in listening tests, a red herring? Given a choice between two amps, may some people actually 'prefer' the one with a bit of distortion and dodgy frequency response, especially if that's what they're used to? Given time, however, maybe they could learn to love the neutral, objectively-correct system, which would be good for their ears in the long run. No one ever seems to suggest that people actually need to learn how to listen to an audio system, rather than the instant gratification of a 'musical' EQ.
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Every speaker I've built has been crappier than the next one, and I'd say I've had this kind of experience.. after building a 200W pentode AB amp, and by the way converting to mosfets was not too dissimilar.Everyone in audio deserves to have at least one experience in their lifetime, of having a really "crappy, useless" speaker driven by a totally competent, massive headroom amplifier, to ear deafening levels - to just 'slightly' disturb those rigid, core beliefs ...
A class A amp ought to sound effortless when done properly and they do.. in a neutral, or passive kind of way. I did see the big amps as imparting effortlessness but there was a kink in it (like the effortlessness was wandering a little off track in a non-linear kind of way (IIRC)).
A good class AB amp has a good power supply as you've said. I don't much care for one with a bank of capacitors trying to hide an undersized transformer.
There is another kind of effortlessness and it's purely speaker related. I wouldn't be surprised if the amplifier output impedance characteristic was modulating the speaker current in a fortunate way (though I'm not going to try to demonstrate it).
Dependent relationships (the optional ones) aren't my favourite way to do things especially when they are tricky to 'dial in' and need re-tuning whenever I make actual improvements to something I'm not yet happy with on its own.
For this reason I've since tried to limit any voluntary amplifier contributions to small amounts of low order harmonic distortion.
That is certainly what I've found in extended A/B tests. The 303 and 405 didn't make that cut, tho.
That implies that you know they're not objectively correct, and this was confirmed in your listening tests. But what is it that tells you whether an amp is objectively correct?
??
me said:
to which you replied
pano said:
which I translate as "I have found that in extended A/B tests, neutral objectively-correct systems sound best. However, the 303 and 405 didn't meet this requirement i.e. they weren't objectively-correct."
But how do you know they weren't objectively correct?
This reminds me of my penchant for small paper full range drivers, when appropriate. I'm not sure what to make of plastic cone tweeters though.
With mine I decided to settle on it possibly being the emitter-driven single-ended stage (IIRC) or the output coupling caps. These aren't all that bad and they seem to have some 'magic', which made it seem all the more disappointing to have to pack them away.
IME the best amp QUAD ever made is the 520.
It is a 606 with a pair of output transistors missing. In return it got a substantially bigger PSU.
I read an interview with Peter Walker once in which he said that the last two digits of his amp designations refer to the PSU size, he was fairly pleased with the super stiff 520 PSU.
He was also quite proud of the 520s optional transformer balanced input modules.
QUAD were nice enough to send me 4 of those for free when I tried to buy two for my own 520. Mind you it did coincide with QUADs new chinese owners moving the UK customer service centre to smaller premisses so I probably got the last four remaining ones.
Lastly it is generally accepted even amongst QUAD fanboys that the 303 and 405 are somewhat dull sounding. Might have something to do with the inrush limiter they feature. This was necessary for the amps to be stable when driving ESLs (BGW 750 famously start to emit smoke rather than sound when driving ESLs) but the 520 was never meant to drive those so no limiters there. It was meant to be a PA amp and the large sound hire company which shared premisses with my past employer used a lot of 520s for treble duties.
It is a 606 with a pair of output transistors missing. In return it got a substantially bigger PSU.
I read an interview with Peter Walker once in which he said that the last two digits of his amp designations refer to the PSU size, he was fairly pleased with the super stiff 520 PSU.
He was also quite proud of the 520s optional transformer balanced input modules.
QUAD were nice enough to send me 4 of those for free when I tried to buy two for my own 520. Mind you it did coincide with QUADs new chinese owners moving the UK customer service centre to smaller premisses so I probably got the last four remaining ones.
Lastly it is generally accepted even amongst QUAD fanboys that the 303 and 405 are somewhat dull sounding. Might have something to do with the inrush limiter they feature. This was necessary for the amps to be stable when driving ESLs (BGW 750 famously start to emit smoke rather than sound when driving ESLs) but the 520 was never meant to drive those so no limiters there. It was meant to be a PA amp and the large sound hire company which shared premisses with my past employer used a lot of 520s for treble duties.
Gosh. Must have touched a nerve or something. Thought I was being very friendly and just trying to tease out what you meant.
Never mind!
Edit: it's that technical forum thing again: whereas a person could just say "You've misunderstood me. What I really meant was ...." but they don't. They just leave us all in suspense. All you have to do is to correct my 'translation' in the earlier post rather than making me feel as though I've mortally offended you. (If I have, I'm sorry. I didn't think I was being too rude and unpleasant).
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I believe that as we become familiar with increasing layers of that onion we call reproduction, what those unfamiliar with see as one layer, others better versed see as completely separate, isolated effects.
When one side questions multiple implications as a single event, those better versed respond not realizing we need to explain what those layers are first, in order to find the exact question being asked. Better (and far more fatiguing) is to attempt to forward think what the answer is to the real question being asked while clarifying the difference between those layers. Often the best advice is required reading, mixed in with listening tests. Hopefully this would lead to self discovery of what each of these layers are for the best conceptual understanding.
When I was little my Grandmother would say something like... to be wise like Mr. Owl, look and listen, but do not speak. The answers you seek will be discovered soon enough, without a peep.
confused, I am
When one side questions multiple implications as a single event, those better versed respond not realizing we need to explain what those layers are first, in order to find the exact question being asked. Better (and far more fatiguing) is to attempt to forward think what the answer is to the real question being asked while clarifying the difference between those layers. Often the best advice is required reading, mixed in with listening tests. Hopefully this would lead to self discovery of what each of these layers are for the best conceptual understanding.
When I was little my Grandmother would say something like... to be wise like Mr. Owl, look and listen, but do not speak. The answers you seek will be discovered soon enough, without a peep.
confused, I am
Amplifiers are a compromise, like most things in audio.
Class A is just a better way to design, but who wants an amp that runs red hot with no signal?
Sugden A21ai Series 2 integrated amplifier | Stereophile.com
Well, I do, but those Sugden Class A amps cost a LOT, and need some cooling!
Class AB is severely compromised on the first watt. The output impedance is high with a transistor that is almost switched off. It gets better as you get louder.
I really don't want to spend time on amplifier design right now, but another aspect is Common Mode rejection. That's a hard one to deal with, but some very simple transformer MOSFET designs get a grip on it:
Some designs have a very high output impedance like this other Class A MOSFET design which is quite SET valve like:
I'm prepared to agree that with the right speaker, both can sound good. I would expect great detailed sound.
FWIW, my first system engineering job was with 20 MHz transatlantic frequency division multiplexing telephone systems where we would string together 600 (5 FET) amplifiers (repeaters) and 600 3 mile polyethylene cables and hope to get a good output at the end. That took some understanding of this whole business of impedance matching and group delay and common mode.
What made it manageable was that we had control of every element, rather than the fairly random collection of components that make up most audio systems.
Class A is just a better way to design, but who wants an amp that runs red hot with no signal?
Sugden A21ai Series 2 integrated amplifier | Stereophile.com
Well, I do, but those Sugden Class A amps cost a LOT, and need some cooling!
Class AB is severely compromised on the first watt. The output impedance is high with a transistor that is almost switched off. It gets better as you get louder.
I really don't want to spend time on amplifier design right now, but another aspect is Common Mode rejection. That's a hard one to deal with, but some very simple transformer MOSFET designs get a grip on it:
An externally hosted image should be here but it was not working when we last tested it.
Some designs have a very high output impedance like this other Class A MOSFET design which is quite SET valve like:
An externally hosted image should be here but it was not working when we last tested it.
I'm prepared to agree that with the right speaker, both can sound good. I would expect great detailed sound.
FWIW, my first system engineering job was with 20 MHz transatlantic frequency division multiplexing telephone systems where we would string together 600 (5 FET) amplifiers (repeaters) and 600 3 mile polyethylene cables and hope to get a good output at the end. That took some understanding of this whole business of impedance matching and group delay and common mode.
What made it manageable was that we had control of every element, rather than the fairly random collection of components that make up most audio systems.
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Steve,
what about class AB amps which run in A until much higher than 1W?
ATC does or used to claim that their amps run in class A until they exceed 2/3 of rated output on their site.
I once had a chat with one of the designers of my amps (MC2 Audio) on the phone and while he wouldn't be drawn on a precise figure it was fairly clear that the amps run in class A to somewhere more than 30W.
Are there any disadvantages to that other than reduced thermal efficiency in home use?
If there are keep it simple as I only have a rough grasp (if that) of electronics. ;-)
Cheers
what about class AB amps which run in A until much higher than 1W?
ATC does or used to claim that their amps run in class A until they exceed 2/3 of rated output on their site.
I once had a chat with one of the designers of my amps (MC2 Audio) on the phone and while he wouldn't be drawn on a precise figure it was fairly clear that the amps run in class A to somewhere more than 30W.
Are there any disadvantages to that other than reduced thermal efficiency in home use?
If there are keep it simple as I only have a rough grasp (if that) of electronics. ;-)
Cheers
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