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In Reply to: RE: armchair electrical engineers posted by bullethead on September 26, 2015 at 08:30:37
Victor Khomenko, John Curl, Charles Hansen are quailifed EEs who know
whereof they speak. There are others whose names escape me at the moment. If one of them says something, I give it a lot of credence.
Follow Ups:
"If one of them says something, I give it a lot of credence."
"Victor Khomenko, John Curl, Charles Hansen are quailifed EEs who know
whereof they speak. ... If one of them says something, I give it a lot of credence."
Me too!
And in terms of experiential results... I also give great credence to AA posts. But when it comes to explanations, well, they are best taken with a grain of salt.
And that makes perfect sense to me: Very few posters have a clue about specifying, designing, producing or measuring electronic products, and why should they? This is our hobby, not our jobs! But, we all know and how stuff should sound, and we care...
I happen to have been lucky? enough to have spent my working life in the Electronics industry (yes, the USA did once have one) and I've been on all sides of the various fences. The biggest thing I notice here is that users usually don't clearly understand the roles and limitations of product and engineering specifications and the inevitable instance variations in production. And why should they, shoot, most of the marketing people don't either! Sorry, couldn't resist...
Anyway, let me tell you from extensive experience that it's virtually impossible to nail down the performance specifications and tolerances tight enough for anything that is tightly coupled to our senses, especially sight and sound from my experience (but I bet our local vintners would plump for taste and smell), to the point that two instances of the same product will be indistinguishable, let alone equally desirable. That's life, we are sensitive creatures. Sniff...
It really doesn't take golden ears or an epicurean palate to hear, taste or smell the differences although not all differences will be sensible to all people. Just the luck of the genes and life history. But do they matter? Ah, that's the rub. Speaking of music and wine, a $12 bottle of wine will probably improve the sound of a fairly decent system more than any other tweak. And listening to pleasurable music will likely enhance the enjoyment of good spirits. AND having the right person next to you on the couch? Perhaps the best tweak of them all...
Rick
each of those designers along with Nelson Pass employ a number of Brad's criteria where possible in their amplifiers. Class A operation using zero feedback is quite typical with line sources. My ARC preamp is designed that way.
-Class A operation
-Zero or little corrective feedback
-Single ended operation
-Large transformer (if necessary)
Both Victor and John praise the linearity of triodes. Victor uses them for both line level and power output (6H30 "super tube" and 6C33, respectively) while John uses them as a goal post. Both employ low levels of feedback with their amps and zero with their preamps using discrete components.
Charles Hansen uses zero feedback with his MK-R and KX-R designs.
It is true that it isn't practical to make single ended amplifiers with higher than flea power. Consequently, most all are push pull. Nelson Pass' SIT-1 meets all of Brad's criteria but is limited to 10 watts output. On the other hand, the 300 watt Xs300 is Class A with "small" amounts of feedback and uses a single ended front end. He gets as much goodness as possible with a high powered design modeled after what he considers the "striking" performance of the SIT-1.
Which Brad are we talking about , x-spectral ..?
from an earlier post.
that there is no one right way to build an amp.
Comments from poster Burrows on diyaudio.com on his Pass amp:
"A colored amp can easily hide a problem source, for example, as the NC-400 is really just a clear window on the rest of the system. I directly compared my NC-400 amp to my PASS X150.5, for example, and heard more detail (more finely structured low level harmonics, better timbre) and better control over the speakers for more finely detailed bass. I heard this differences throughout the entire frequency range. No synthetic sound in my system whatsoever. This is why I use NC-400, as I build DIY DACs, and like to hear what they really sound like, rather than the sound of a cloudy colored amp."
From an audioasylum review of the same Pass amp by "the analog kid":
"The final characteristic of this amp that merits mention is the naturalness of tone. It is an EXTREMELY realistic and natural sounding amp - warm, clean, clear, and transparent. But it is NOT high on the liquidity scale. For those seeking that "drip from the walls" sound, this amp will strike you as comparatively sterile. However, I find it the closest sound to "the real thing" I've yet experienced, and it is the PERFECT mate for the Forests, which perform SO far beyond the envelope now it's frightening."
try it! you know you want to!
Since there's no such thing in exsitence, that bit simply shows the author's lack of experience - and nothing else.
Unless you left out a continuation, where he goes on to explain what the trade-offs are - IOW, what's wrong with that amp otherwise.
This post was made to simply show how opinions, even about the same equipment, can differ.
Do you have experience with the ncore? Or is this a kettle/black thing?
try it! you know you want to!
a company like Semi-South (which unfortunately is no longer in business) could fabricate a 150-200 watt static induction transistor? Now, that would be a game changer! A two hundred watt single transistor amp.
It could bridge the gap between what those guys know about making the best sounding amplifier and the current limitations of output device technology.
I would definitely try it out! My adventure with single ended MOSFET output left me not completely satisfied (100 watt SE(T=Mosfet) hybrid...NAT Symbiosis SE) even though it was very very very good overall. Based on the SIT descriptions by Srajan (if those are in some way to be trusted...I have personal experience to doubt the man's reports) it would still miss some things but I will one day hopefully get to the hear the 10 watter.
If the SIT has a more linear transfer function than a MOSFET then I guess it has great potential...especially as it doesn't need another stage or output transformer.
You are right that they all try something getting some of the ideas in place but in the end they bow to the market desire for power and then go to push pull and or Class A/B...which ultimately screws up the harmonic distortion pattern.
they bow to the market desire for power and then go to push pull and or Class A/B
It's not the market that caused me to purchase a push-pull AB amp. It was the speakers. :)
I have never heard electrostats sound better than with top notch SETs...
.
Mine too, at least the more desireable models...
Forget WAVAC , Hypex fits your Budget, try 3 , you know you want to ...
ROFLMAO :)
Edits: 09/29/15
I actually have tried Hypex...UcD.
Morri , Attach some names to them bones , top Notch SET ..?
We've already been down this road, A. Wayne...no need to do it again...
Is this the "one" ...? JJ 322 parallel SET
Is this the one what? Yes, it is one of the amps I own. The others are a pair of Wall Audio M50s and the last is a Pure Sound A30 for the TV system.
There used to be a good review on the internet in Polish that had nice measurements but it seems to be now deactivated (it was from about 2000 or 2001). I wish now I had downloaded the .pdf and saved it. The amp makes it to 15 watts (in either 4 or 8 ohm tap when load is matched) with 1% THD. The frequency response was flat to 20Khz and down 3db at 35Khz. The harmonic pattern at 1 watt and 1Khz looks quite good as well with decreasing distortion with increasing harmonic number with nothing much beyond 6th.
A greek magazine has some basic measurements like THD and frequency response that agree with the Polish magazine.
The amp made a lot of noise in 2000, winning a major design award, but like all things time passes on and people tend to forget. It is a very good sounding amp, well designed and using very good parts...especially the output transformers. Is it SOTA? No, but it is getting close for reasonable money.
Ever heard Walcot ..? Audio Art in your neck of the woods is a dealer ...
Edits: 09/29/15 09/29/15
Never heard them but interestingly they use some form of POSITIVE feedback...supposedly great with electrostats but otherwise??? Plus, its push/pull...so you know...conceptually wrong.
Yeah but SET's as you know are conceptually wrong and cant drive bat poop, but some like them ... :)
I like what he has done with those Walcotts, no where to hear them thou, Audio Arts is in Switzerland are they still around..?
Edits: 09/30/15
I use amps to drive loudspeakers and you seem to use them to drive bat poop...I guess that goes a long way towards explaining our different points of view ;-).
No idea where Audio Arts is located...I know Switzerland is not big but it is not that small!
Hofwiesenstr.
267 CH-8050
Zürich Switzerland
Drive this with an SET .....
Edits: 09/30/15
I lived 10 years near that location (I lived in the same postcode) and I never heard of this company. I thought I knew all shops/manufacturers in my area so probably they have been out of business for a long time.
nt
try it! you know you want to!
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