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In Reply to: RE: Judging by the comments on current thread there on negative feedback, posted by kuribo on September 18, 2015 at 17:24:34
his SIT amps were specifically designed to meet all of Brad's criteria:
"The SIT-1 is the first of a new generation of power amplifiers using Static Induction Transistors (SIT) in single-stage, single-ended Class A circuits delivering superlative sound without feedback or degeneration."
Follow Ups:
Here is a Pass quote:"As I said at the beginning, this has been an interesting amplifier to develop,largely because it has contributed to my depth of knowledge as to what techniques make for a good sounding amplifier. Of course this is a subjective thing, and no amplifier is the best for all listeners and situations."
Oh, and he does indeed espouse the use of negative feedback. If you had bothered to read the thread you would know that, LOL....
try it! you know you want to!
Edits: 09/21/15
If you had followed my link, you wouldn't have put your foot in your mouth. Pass is not a liar, despite your weak attempt to make him one.
You are referring to the F6 amplifier where you'll find the quoted text. Hint: that's another link. :)
Because he understands well what I have been saying, in fact, has even said "this is a subjective thing, and no amplifier is the best for all listeners and situations."And he does believe in using negative feedback, again, if you had read the thread I linked on diyaudio.com, you would know that.
His SIT amps are just another flavor, perhaps meant to cater to those who prescribe to the no feedback dogma. He is a businessman, after all, who also happens to have mind open to experimentation and different approaches.
try it! you know you want to!
Edits: 09/21/15
"His SIT amps are just another flavor, perhaps meant to cater to those who prescribe to the no feedback dogma. He is a businessman, after all, who also happens to have mind open to experimentation and different approaches."-No, it isn't another flavor, he is striving for a benchmark that hasn't been met or exceeded by anything SS.
That is why he is experimenting with virtually unobtainable exotic transistors in hopes to achieve some of the traits of the triode.
He posts quite regularly at DIYAudio, perhaps you should ask him yourself."He is a businessman, after all"
-Just like the folks at Hypex, who aren't the first to exploit the ignorant masses with misleading advertising specifications.
This has been going on since the dawn of SS with the power wars. More this, less that...
It got so bad that the federal government had to step in and apply a power testing regiment for 2 channel amps and fined manufacturers who weren't truthful about their power ratings.On a side note, I have a 2000 watt home theater in a box for sale, you interested?
The sad reality Kirby, is that pulse width modulating amplifiers reproducing low frequencies will compromise high frequency reproduction and are extremely sensitive to speaker loads.
I am not aware of any SS amp out there that can reproduce consonants the way the old triode can, all of them ruin the sibilance.
Once you are aware of this, it becomes the elephant in the room, the triode will completely ruin any further SS experience. You will hear the high order distortions on every "S" sound.Maybe somebody has a nice SS amp out there somewhere, but I can guarantee it won't be a Class D amplifier, lol! and it won't be cheap or practical compared to a little SET that need only cost a couple a grand tops.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Edits: 09/21/15
"The sad reality Kirby, is that pulse width modulating amplifiers reproducing low frequencies will compromise high frequency reproduction and are extremely sensitive to speaker loads."
Extremely sensitive to speaker loads? Surely you mean SET's because ncore, a class d amp, had you taken the time to look at the specs, and understood them, is about as load independent an amp as there is.
Your ignorance of this topic continues to astound me. There is no point in discussing this with you further because you lack a basic understanding of the topic. Do me, and yourself, a favor, and educate yourself by reading through the ncore specs and documentation. Then, if you want to discuss it, by all means have at it. Until then, it is pointless and a waste of everyone's time.
try it! you know you want to!
A good SS amp, hilarious.Amps dont work in vacuums, if the pursuit is SOTA level hi-fi , no SET type amp with flea power is going to do it , well, unless you have a horn behemoth spanning 12 ft in width , you can forget about it. SOTA speakers are large for a reason , the amplification to drive them is too, very few SOTA systems will have tooby amps,( unless 12 ft horns) you guys need to get off this, tooby microphonic halo BS and stop reviewing amplifiers in a vacuum.
SS amplfiers can and do deliver, just like toobs , they are not all equal, most of the bad sound most hear is coming from the monkey coffins/ room interface in front of them ..
Regards.
Edits: 09/21/15 09/21/15
A good SS amp, hilarious.
Yeah they are a bit of joke if you want truly good sound...
OK, so no SS , give me a list of your top 5 Toobs ....
No, you give me your top 5 SS amps and why then you might get a list from me. Then your top 5 livable tube amps and I will give you the SS amps I might be able to allow in my home.
Best tooby , there is only one .....
Edits: 09/22/15
Well, those are something alright...but are they push/pull...tsk tsk ;-).
Let's (correctly) attribute his comments, shall we?
These quotes are from Audio Distortion and Feedback
" Negative feedback can reduce the total quantity of distortion, but it adds new components on its own, and tempts the designer to use more cascaded gain stages in search of better numbers, accompanied by greater feedback frequency stability issues.
The resulting complexity creates distortion which is unlike the simple harmonics associated with musical instruments, and we see that these complex waves can gather to create the occasional tsunami of distortion, peaking at values far above those imagined by the distortion specifications. "
nt
try it! you know you want to!
He uses feedback...
Not surprisingly, nuance eludes you in multiple areas.
What he uses is "small" amounts for stability. There is quite a difference between small amounts and heroic (80 db) used by your hero. Let's follow more of his thinking, shall we?
This is from the Xs brochure . (Yes, Virginia that is another link!)
" They found the sound of the [zero feedback] SIT to have truly remarkable properties and it was quickly decided 'Whatever this is, we need a way to bottle it'. Not only did we need to bottle it, but we needed to put it around a much bigger bottle.
In a subjective area where engineering has limitations , it is extremely useful if you can recognize what you want when you hear it. It you have an example of the sound you are looking for, there is great advantage.
Because the sonic quality was so striking , it became easier to discover what modifications to the circuit would make it go away, and by the process of varying the design and listening to the result ...A small amount of feedback was employed around the output stage
nt
try it! you know you want to!
and have done so several times in the past month or so - I'll leave you with his take on switching amps . BTW, the pic is one he built. :)
As with my previous four posts, I'm linking to the source to eliminate confusion (on your part). Let's review his thoughts:
" Class D amplifiers are switches with tons of feedback.
It's amazing they work as well as they do. "
But nice straw man.....we already know he believes in feedback and that amp choice is subjective....
The ncore will be there when you tire of your distortion....
try it! you know you want to!
I don't know about that one Kirby, Putzeys hasn't done anything besides switching amps since he got out of school.Pass on the other hand has a much more diverse and successful background. He is a cult legend for a reason.
Class D isn't black magic, heck, even I could cobble one together, as mentioned before it is nothing new or exotic.
It is challenging, in the sense that it sucks for audio.Back on topic, which believe it or not is not Kirby's class D amp...
Here are some interesting quotes from Pass's wikpedia page:"The SIT chip combines a square-law input character with a low impedance output to form the only solid-state gain device, which Pass claims, "behaves like a triode tube.""
"The point of the SIT is that it behaves like a triode but at lower voltages and higher currents, so it doesn't need a matching transformer to deliver power to 8 Ohms. "
"SITs have a curve which looks a lot like a triode vacuum tube; low at first and climbs steadily. The distortion curve is similar, a steady rise instead of a valley with high distortion at both ends." (Which is what Morricab stated when he said SS made more distortion at low volumes.)
So, I would consider Pass's SIT amps as "SOTA", not to be confused however with the "pinnacle" which was developed by De Forest over 100 years ago.
Everything since then, has been a compromise in one way or another.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Edits: 09/22/15
Putseys started designing and building tube amps. He has moved on with spectacular success.
Pass' products are all ss as far as I know. He once tried a class d amp but couldn't get it to perform well.
And yes, building a class d amp is not hard. Building a good one is. Just ask those who have tried.
try it! you know you want to!
Well maybe you know more about Putseys then is public record?"Early life
He graduated cum laude at the National Technical School for Radio and Film on the subject of power stages for switching audio amplifiers. Worked for 10 years at the Philips Applied Technologies Lab in Leuven, Belgium, where he developed various digitally and analogue controlled class D amplifiers, noise shapers and modulation methods, and invented among others the "UcD" class D circuit."
"Career
In 2005 he left Philips to divide his time between Grimm Audio and Hypex. Current activities include designing high-performance discrete AD/DA converters and analogue signal processing circuits, DSP algorithms, class D power amplifiers and switch-mode power supplies. He holds several patents in the fields of digital audio and power conversion and has published extensively in these and related domains."
It doesn't say anything about tube amps...
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Edits: 09/22/15
Here's one
He dabbled briefly as a teenager.
Well, you got me.
I guess Putzey has the same pedigree as hundreds of others over at DIYAudio after-all.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
the section about his music collection:
"Along another wall in the living room are shelves with an eclectic mix of a couple of hundred CDs..."
Makes perfect sense that analog and high resolution are absent.
How many CD's in your collection ..... ?
along with another 600 vinyl and several dozen high rez albums.
I have heard the Grimm active speaker system now several times here in Switzerland and each time it is totally clear and precise and STERILE and UNmusical like hell. I can't stand more than a few minutes in the room with such an utterly unmusical "mr. Spock" like sound. Grimm indeed...
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