A gentleman would accept when they are beaten rather than lower themselves to cheap insults. Or even try and learn something. Ah well we tried.
Far from it sunshine. Your the one stuck in Bruno Putzey "protection mode".
All I'm doing by starting this thread is showing something that looks very much to be what could be the future in audio amps is going to be, and for some reason you don't want it to happen. (a "coloured" vinyl junkie? they tend to think like this)
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And newer, therefore it MUST be better. Lol
And with audio it also always MUST be magic special voodoo, only being capable to be taimed by a couple of specially selected holy choosen ones.
It's only them who MUST be able to understand such magic and be able to create.
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It isn't really - but you seem to think these GAN devices require "no feedback" and a digital fornt end - they don't - they are just transistors... the architecture of an amp is much more important then individual component characteristics... no low hanging boutique fruits in sight - sorry..
//
From some owner's review "Nothing is lost, nothing is added. Whoever thinks that their dac/amp combinations is better has only that in their mind!"
Get over it, not when the distortion is .004% without it.
Ones that think lower distortion than that is even better are just measurment junkies and don't listen.
All that know, know that global feedback is a "necessary evil" in most amps. And that it should be used "as sparingly as psossible", if not fix the problems you are trying to camouflage with it.
That Tact Millenium was always touted as
Tact Millenium Sound | Wealth of detail and lack of hash or noise; "makes music as if it is being played right in front of you"; agile bass with excellent definition and speed, but "seems not to have the rock-solid bottom" of some other amps. The reason I'm loath to brand this as a weakness is that I also find the bass remarkably agile with excellent definition and speed. |
Trouble with it was apparenty, "that it had no balls" to get the bass right, it's current abillity into low impedance was said to be pathetic. GaN doesn't seem to have that issue as much, but I believe it's still limited like Mosfets are in Class-D's. Unlike BJT's in things like the big Gryphons and D'Agostino's etc etc that can almost double their wattage for each halfing of impedance down to 2ohms sometimes even 1ohm.
Cheers George
It comes down to practicality of design. It's tough to make all of the people happy all of the time. Someone's going to have the undrivable load. Perhaps a better product from the producer's view is an un-mountainous peachtree, which drives 98% of what's likely to be used as a speaker.
You can get any current you want from Mosfets, it's just that these transistors get harder to turn on and off, with the more current they are capable of passing. I'll guess GaN eases up on that difficulty, with the rest being the same.
Easier to turn on/off translates to faster speed more easily achievable, until that advantage approaches the realm of design difficulty again. With faster speed, you can use a smaller inductor, or even no inductor, which as a component in the speaker signal path adds its own limitation to the achievable current output.
If you look at a modern PC motherboard, you'll likely see rows of inductors. Each of those corresponds to a Mosfet pair and in parallel, it's one way to scale current output capability. The PWM cycle is split up across these; think several people driving a stake into the ground with hammers - the timing between each strike. While this works for a computer power supply, that technique may not be amenable to an audio amplifier. The PWM pulses are really small in CPU supplies, therefore there's lots of room in time for the other 6, 8 sections to hit in sequence, before the cycle wraps. About all I know in an audio PWM, is that it sits at 50% duty quiescent a value the computer power supply never goes anywhere near.
I've no doubt someone smarter than me could build an audio amp with lots of little parallel stages, that could deliver 1000A and use ordinary Mosfets. If I recall correctly an ordinary PC (I7-I9) power supply might give a 2V swing, 100+ amps with 8 bit resolution on the output voltage value, from the "VID" feature. The processor is always telling its powersupply to change the output voltage. "Just" extend the bit length to 24, the output voltage swing to 100...
Do you still believe that the Peachtrees are nor class-d?
A switching duty is something else than following a slow audio signal - right?
You do know how PWM works?
//
Of course they can but the " massive current ability" amps of like the ones I mention, the "bruisers" of the industry, all use complimentry BJT's to do it with for a reason. Because getting "Compimentry Mosfets" with that kind of continuous amperage is near non existent I believe.
Cheers George
^ Hi George - I'm trying to follow... your posts are informative, but I got lost.
First, are these "bruisers" the big Gryphon / D'Agostino amps you reference in #209? Are you specifically referring to Class A and Class A/B (depending on how one defines it) amplifiers and similar from those manufacturers or others?
Another 'problem' the Tact Millennium had (since you don't specifically say the MKII version) was output impedance. That topic has been beaten to death. I'm not trying to bring it back up, but... that could contribute to its <cough> eunichness with some speakers. I've never seen one. I'm just piling speculation upon another speculation. Who said the things re: its current ability into low impedance loads? Did they publish, or is this all hearsay?
What do you mean by ..."<sic> Complimentary Mosfets" with that kind of continuous amperage? What do you mean by "massive current ability"? Could you elaborate, please.
Are you saying/implying that the Tact Millennium would likely have less current capability or is less massively current capable than one of those "bruisers" at a particular power output into a particular load? Do you associate current delivery and/or Iq (what I think you mean by continuous amperage) with "balls" => better bass?
--------
In general to the group. <climbs onto non-existent soapbox>. This thread has almost become lounge-worthy, IMO... so.
Current delivery / ability... <sigh>
EVERY voltage amplifier will double its power output when shifting from an 8 ohm load to a 4 ohm load and double it again into a 2 ohm load (up to a point). Why do (some) people think this is magic associated with some rarified type of amplifier? <somewhat rhetorical... and I'll answer myself>
IMO, marketing people and maybe a clever engineer or two decided that it was important to show that the maximum power output would double / quadruple with those loads. Don't get me wrong, I'm a big fan of truth in advertising, and some amplifiers really will do that. However, the necessity for them to accomplish such feats is ... for me ... and dare I say for most ... minimal. With that said, if it's important to some, then it's wonderful that some amplifiers will do it. I hope the choice is made based on the speakers' impedance curves, sensitivity, and owner's listening levels vs. some impression of "balls". Heck, even if the choice isn't made for those reasons, I hope it's an informed choice. Very few of my choices are founded in science, but I know why I made them.
Let's take a hypothetical 'properly-rated, 25W' amplifier. Typically 25W means 25Wrms into 8ohms at some agreed level of performance. So, I'll go with that.
By definition, that means that it can output 14.14Vrms/40Vpp and source ~1A8rms of current with a current envelope of ~5A (assuming I did the math correctly, and I understand the terms. I may not have, and I may not). Let's assume that the amplifier designer (because it's the industry norm) designed for advertising power output at 8R. That may even be regulated in some countries. I truly am not sure. Let's further assume that the amplifier can source absolutely no more than 1A8rms, because that was how it was designed.
That amplifier is going to 'double the power' output from 8ohms to 4 and again from 4 to 2. THAT'S THE WAY IT WORKS. It's just going to stop doing that once the output reaches 6.25W at 2R. The $hitty part (for marketers) is that it would now be a 6.25W amplifier if we had to advertise maximum power output into 2 ohms, or if we defined an amplifier by its rms power into 2R as the norm. Gosh, 6.25 Watts sounds just pitiful.
We want... NO, WE NEEEEEED 100W into 2R and any decent "25W" amplifier should do that. Well, fine... I'd tell people to put a continuous sine of 3V6rms through the speaker of choice at various frequencies and see how they feel about it when standing at a chosen distance. Then, they can adjust their amplifier expectations accordingly.
Again... some people may want ... and a rare few may even need 100W into 2R, but I'd bet not many. Those that care, are likely thinking about transients at 20Vp, and I assume those are going to be 'down low', and some speakers dip to 2R 'down low' ... sure... So, they rightfully care about that 100W at 2R...
Now... if the sacred evaluators of the cajones of amplifiers (lets call them the cardinals of the industry) must check the relative size of amplifier cajones at particular SPLs with particularly 'hard to drive' speakers, they should pick appropriate amplifiers. They can give each amp the old turn your head and cough evaluation. However, they should stop the BS around this "current capability" drivel. More current => Higher SPL at a given load. More current =/= "tighter" or "better" or "whatever" bass.
One more time with feeling, more current DOES NOT mean that the 'Bass is better'. That (to me) is: nonsense, rubbish, poppycock, balderdash, hogwash... AND... baloney.
Wouldn't it be comical if some ad-guy was reading my nonsense and decided... this guy's really onto something... We've been slaughtered... so, let's flip it... Next week in all the rags.
NEW AWESOMENESS OF AWESOME AMPLIFIER!
Doubles maximum output power from 2 to 4 ohms and again from 4 to 8 ohms!
Up to QUADRUPLE the maximum power through more impedance!!!!! Massive voltage capability that will curl your hair!!!
C'Mon down to Lucky Bob's Amplifier Emporium and try yours TODAY!
Forgive the rant and long post... I'm in a mood. I'll find Cal's thread to lighten it.
*Everything assumes that the operators (these skilled reviewers) are not driving the hypothetical amplifier to clipping at low frequencies and that the hypothetical amplifier is 'stable' and performing normally at the evaluated outputs into all loads.
<hops off soapbox>
First, are these "bruisers" the big Gryphon / D'Agostino amps you reference in #209? Are you specifically referring to Class A and Class A/B (depending on how one defines it) amplifiers and similar from those manufacturers or others?
Another 'problem' the Tact Millennium had (since you don't specifically say the MKII version) was output impedance. That topic has been beaten to death. I'm not trying to bring it back up, but... that could contribute to its <cough> eunichness with some speakers. I've never seen one. I'm just piling speculation upon another speculation. Who said the things re: its current ability into low impedance loads? Did they publish, or is this all hearsay?
What do you mean by ..."<sic> Complimentary Mosfets" with that kind of continuous amperage? What do you mean by "massive current ability"? Could you elaborate, please.
Are you saying/implying that the Tact Millennium would likely have less current capability or is less massively current capable than one of those "bruisers" at a particular power output into a particular load? Do you associate current delivery and/or Iq (what I think you mean by continuous amperage) with "balls" => better bass?
--------
In general to the group. <climbs onto non-existent soapbox>. This thread has almost become lounge-worthy, IMO... so.
Current delivery / ability... <sigh>
EVERY voltage amplifier will double its power output when shifting from an 8 ohm load to a 4 ohm load and double it again into a 2 ohm load (up to a point). Why do (some) people think this is magic associated with some rarified type of amplifier? <somewhat rhetorical... and I'll answer myself>
IMO, marketing people and maybe a clever engineer or two decided that it was important to show that the maximum power output would double / quadruple with those loads. Don't get me wrong, I'm a big fan of truth in advertising, and some amplifiers really will do that. However, the necessity for them to accomplish such feats is ... for me ... and dare I say for most ... minimal. With that said, if it's important to some, then it's wonderful that some amplifiers will do it. I hope the choice is made based on the speakers' impedance curves, sensitivity, and owner's listening levels vs. some impression of "balls". Heck, even if the choice isn't made for those reasons, I hope it's an informed choice. Very few of my choices are founded in science, but I know why I made them.
Let's take a hypothetical 'properly-rated, 25W' amplifier. Typically 25W means 25Wrms into 8ohms at some agreed level of performance. So, I'll go with that.
By definition, that means that it can output 14.14Vrms/40Vpp and source ~1A8rms of current with a current envelope of ~5A (assuming I did the math correctly, and I understand the terms. I may not have, and I may not). Let's assume that the amplifier designer (because it's the industry norm) designed for advertising power output at 8R. That may even be regulated in some countries. I truly am not sure. Let's further assume that the amplifier can source absolutely no more than 1A8rms, because that was how it was designed.
That amplifier is going to 'double the power' output from 8ohms to 4 and again from 4 to 2. THAT'S THE WAY IT WORKS. It's just going to stop doing that once the output reaches 6.25W at 2R. The $hitty part (for marketers) is that it would now be a 6.25W amplifier if we had to advertise maximum power output into 2 ohms, or if we defined an amplifier by its rms power into 2R as the norm. Gosh, 6.25 Watts sounds just pitiful.
We want... NO, WE NEEEEEED 100W into 2R and any decent "25W" amplifier should do that. Well, fine... I'd tell people to put a continuous sine of 3V6rms through the speaker of choice at various frequencies and see how they feel about it when standing at a chosen distance. Then, they can adjust their amplifier expectations accordingly.
Again... some people may want ... and a rare few may even need 100W into 2R, but I'd bet not many. Those that care, are likely thinking about transients at 20Vp, and I assume those are going to be 'down low', and some speakers dip to 2R 'down low' ... sure... So, they rightfully care about that 100W at 2R...
Now... if the sacred evaluators of the cajones of amplifiers (lets call them the cardinals of the industry) must check the relative size of amplifier cajones at particular SPLs with particularly 'hard to drive' speakers, they should pick appropriate amplifiers. They can give each amp the old turn your head and cough evaluation. However, they should stop the BS around this "current capability" drivel. More current => Higher SPL at a given load. More current =/= "tighter" or "better" or "whatever" bass.
One more time with feeling, more current DOES NOT mean that the 'Bass is better'. That (to me) is: nonsense, rubbish, poppycock, balderdash, hogwash... AND... baloney.
Wouldn't it be comical if some ad-guy was reading my nonsense and decided... this guy's really onto something... We've been slaughtered... so, let's flip it... Next week in all the rags.
NEW AWESOMENESS OF AWESOME AMPLIFIER!
Doubles maximum output power from 2 to 4 ohms and again from 4 to 8 ohms!
Up to QUADRUPLE the maximum power through more impedance!!!!! Massive voltage capability that will curl your hair!!!
C'Mon down to Lucky Bob's Amplifier Emporium and try yours TODAY!
Forgive the rant and long post... I'm in a mood. I'll find Cal's thread to lighten it.
*Everything assumes that the operators (these skilled reviewers) are not driving the hypothetical amplifier to clipping at low frequencies and that the hypothetical amplifier is 'stable' and performing normally at the evaluated outputs into all loads.
<hops off soapbox>
You need help, as your avatar shows your aware of.
(As all know, the simple test for an amp that dosen't strain and limit it's current ability into those hard to drive types of speakers like the Wilson Alexia with an EPDR of .9ohm load at 110hz, is to be able to try to double it's rms wattage from 8 to 4 to 2ohms loads, even 1ohm if possible, The only one I knew of that could do that all the way down to 1ohm was the old old Mark Levinson ML2 25w monoblocks (sure their distortion figures were average at best), it was said they could do 25w at 8ohm, 50w at 4ohm, close to 100w at 2ohm, and almost 200w at 1ohm. A friend heard a pair on those Alexia's above and said the sound while not quite loud enough (only 25w) for him, it was "biblical".
Cheers George
(As all know, the simple test for an amp that dosen't strain and limit it's current ability into those hard to drive types of speakers like the Wilson Alexia with an EPDR of .9ohm load at 110hz, is to be able to try to double it's rms wattage from 8 to 4 to 2ohms loads, even 1ohm if possible, The only one I knew of that could do that all the way down to 1ohm was the old old Mark Levinson ML2 25w monoblocks (sure their distortion figures were average at best), it was said they could do 25w at 8ohm, 50w at 4ohm, close to 100w at 2ohm, and almost 200w at 1ohm. A friend heard a pair on those Alexia's above and said the sound while not quite loud enough (only 25w) for him, it was "biblical".
Cheers George
Well, there certainly is diminishing returns on damping factor. The ordinary woofer VC only has so much force-coupling to the magnetic structure that even with a copper bar short across the terminals, the cone will still move some due to a force acting upon it. Which means regardless of amplifier, there's going to be some "slip" between what the cone is actually doing and the signal's intent.
Beyond some point, other mechanisms dominate and one could pound the amplifier output impedance all the way to zero and those other mechanisms simply wouldnt respond in kind, showing a "so what" or "and?" attitude.
Now, if the woofer cone / amplifier has position control feedback to where it's going to go to that position or blow the fuses trying, that's a different story ;')
I got a Nuforce DDA100 and DDA120. No analog inputs (well the 120 has one, an ADC )... it's all truly digital as it creates PWM from the data. (I run them via USB in our home offices ).
BTW, whatever happened to @jean-paul ? He was looking at this topic years ago.
We did that back in the 70's include the speaker and it's VC itself into the global FB network, BUT!! it needed a third wire and resistor from memory (50 years ago) to the speaker, but the real downer was it had to be a fullrange driver with no xover, worked very very good, turned a cheap 6" full ranger into something you didn't think possible, but as you can imagine the bass wattage power handling was very low, as it forced that little 6"er to behave flat to behave like a John Holmes 12" at 20hz.
Cheers George
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This is true for the modulator. The output stage doesn't work digitally (i.e. it doesn't deliver numbers or logic states, but voltage and current). So an amp like this is actually a power DAC and therefore a mixed-signal device. There will never ever be a digital amplifier.
regards
Charles
^ well... if you put it that way, yes, at some point the PWM needs be integrated into an analog waveform. Hence the output filter.
Now, I must say I have not looked in detail into the output stage, but given the size, cool running and pedigree of the brand, I believe it is a home grown class D type... the 100 has no input ADC, the 120 provides on analog input which goes through an ADC.
Now, I must say I have not looked in detail into the output stage, but given the size, cool running and pedigree of the brand, I believe it is a home grown class D type... the 100 has no input ADC, the 120 provides on analog input which goes through an ADC.
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