new GAN amplifier

 The $750 GaN amp from Premium Audio also uses these same GaN fets. GaNs will be everywhere soon.

Correct, I posted this amp up a month ago and they made a special intro price of just $650 for it then
https://premium-audio.com/mini-gan-5-balanced-power-amplifier.html

Cheers George

in the case of the Alexia where one just has to look at the frequency response/impedance curve to see it, often correct peaks (valleys) in the frequency response. It is like a built in equalizer :-)

You are **** ** *t , the OTL’s are fixing nothing, they just can’t drive those Alexia loads, (and are a tone control because of it), read carefully, they say it twice.:
Stereophile on Alexia
" The peak in the midbass is entirely due to the nearfield measurement technique."
" The broad peak in the midbass will be mostly due to the nearfield measurement technique"

More more you two try to gig your way out of this BS, the more ridiculous you look, with your comments made about OTL’s trying to drive speakers with horror loads like the Wilson Alexia’s ect ect.
Next I’ll put money on is you’ll drag out the (autoformer band-aid fix) solution.

Given that you have been and are repeatedly misusing the term EPDR

So you believe the atmasphere statement, that his OTL’s can do a nice job of driving the Wilson Alexia’s as well?? also delusional🤦‍♂️
Give it up you two, looks like your colluding, maybe your his new Class-D partner? Like tweak is with ricevs.

Since there's no quantization of the symbol widths his comparison to DSD or S-D DACs is totally meaningless.

Wonder if his mate Bruno Putzy (Hypex) put one on his chin after that, I think they're still mates. 

I think I just saw a pig fly over my house.

Thorsten’s chin going into orbit

👍

Are you 100% certain that low damping factor is always best?

Yes of course it is, unless I can think back to the 80’s when there was a speaker with purposely an over damped design, as Linn/Naim (Ivor Tifenbrun & Julian Veriker) in cahoots back then tried to do with the dual B139 Isobaric speaker which had no bass!! when driven by a Krell!! of of all amps.
That speaker to have bass needed an amp that was designed to have poor damping factor, hence Linn/Naim cornered the market with that little marketing duo, as anything else driving the Isobaric sounded wrong.

So the amplifier will not act as a "tone control"

Wrong, on the Alexia that OTL amp will have anything but a flat frequency response driving those speakers, to think otherwise remember Supertramp "Dreamer"

If you look at the amplitude response curve and impedance curve, you will notice throughout the base, they are somewhat inverted.

Now in effect your saying that, the OTL’s lack of bass drive current, and poor damping factor, will be a perfect match for the Alexia, and an amp like the Gryphon Antillion is not!!!!
I’ve never heard such a crock of **** I’m sure now you two are ******* in each others pockets.

arty_vandelay
If / when Halcro goes class D for their flagship amplifier, only then can it be said that class D is as good or better than AB.

You can put these into the same list.
(Except for Rowland they sold out to the Class-D$$$$.)

Bob Carver
"I built many of them right here in my own laboratory with the thought they could and would fulfill that final promise.... I was never able to build a Class D amplifier that sounded as good as a linear one."

John Curl (Parasound, CTC, Vendetta Research, Constellation)
"Some version of hybrid Class A/D looks like the future in optimum audio design."

Cyrill Hammer (Souloution)
"if you want to have your product performing at the cutting edge it is not possible with today’s known switching technologies. In order to come close to the performance of the best linear design we would need high-current semiconductors that provide switching frequencies of several MHz or even GHz."

Lew Johnson (Conrad Johnson)
"I tend to think that Class D circuit design is an approach best relegated to producing low-cost, physically manageable multichannel amplifiers—where one might accept some compromise in sound quality for the sake of squeezing five, six, or seven 100 watt channels into one moderate-sized package for a budget home-theater installation."

Vladimir Shushurin (Lamm)
"No, it is not. And I would like to respond to the second part of this question with an allegory. Any field of human activity defines a number of requirements which, when properly implemented, guarantee a positive outcome.

For example, the basic requirement in the army and sports is an able-bodied individual. So, it would be quite natural to concentrate on searching for such an individual (especially as we know where to find him).

However, out of the blue we decide to choose a feeble-bodied person who, on top of that, is encumbered by various diseases. Having made this decision (which is a priori improper) we start justifying it to ourselves and others by citing the great state of our medicine, which is capable of curing many ailments."

Fumio Ohashi (BAlabo)
"No. Class D can’t really be considered for super-high-end performance in its present stage of development, although it can be fine for mid-market products."

Nelson Pass (Threshold, Passlabs)
"Does a $10 bottle of wine compete with a $100 bottle? Of course it does, and it often wins based on price. Right at the moment Class D designers seem to be still focusing on the objectively measured performance of their amplifiers. I expect that at some point the economics of the marketplace will encourage them to pay more attention to the subjective qualities, and then they will probably play a greater role in the high end."

Jürgen Reiss (MBL)
"I have worked a lot lately with Class D. Ninety-nine percent of Class D circuits are not competitive with linear circuits.
Most Class D sounds sterile. It’s tricky to figure out what to do to compensate for that."

Jeff Rowland
"I consider Class D to be highly competitive in the present, and to offer an evolutionary pathway of audio design that may produce even more astonishing results in the future."

Thorsten Loesch
I have yet to hear a pure class D Amp I’d rate above "below average for solid state" (which is not very high performance).
In a little update of my classic "Valve Analogue Stages for DAC’s #" I wrote:
"Perhaps more crucially, so called Class D Amplifiers, which have in recent times sprouted up like mushrooms after a warm rain, continue to use the straight two or three level modulation scheme described above. And thus they still require the use of heavy handed noise shaping to attain anything like acceptable 16 Bit Audio performance.
The clock frequencies for these amplifiers are usually at 300 KHz to 1MHz in the best cases. That is 3,000 to 10,000 times lower than what is required to attain 16 Bit / 44.1 KHz performance without noise shaping and
other forms of signal manipulation!
And again, one is baffled and perplexed by the rave reviews many Class D amplifiers receive, as baffled as one was about the late 90’s reviews of timeslicing dac’s. The best of breed I have auditioned were certainly not bad; however in direct comparison to the best available valve and solid state amplifiers they do not produce a very good sound. Well, at least they offer novelty and the reviewers something to write about other than another (however good sounding) 8 Watt valve amp.
Incidentally, the best sounding Class D amps tend to be really low power single chip devices (putting out little more than the 8 watt valve amps), presumably because they are faster AND because they always work near what one might call “full scaleâ€, if they would be dac’s. On second thought, they of COURSE are DA Converters and where a Class D amplifier accepts analogue input directly it is an A2D converter followed by a power D2A converter!
What an insight!?"
Mark Levinsons interleaving of multiple Class D Amplifiers is potentially a step in the right direction, but does not go far enough.
Personally I think that the best option would be something that combines a Class D Amplifier for the heavy lifting with something Class A for fine detail. Probably implemented in the style I did for AMR’s AM-77 "Jikoda$" Style. In this case both of the circuits involved can operate fully open loop.
In many ways the problems in Class D Amplifiers are analogous (but not identical to) those in Class B Amplifiers (but without an option to implement Class AB or Class A) so similar solutions apply.


Thorsten Loesch
All Class D amplifiers are essentially delta-sigma DAC’s.
If the input is not digital PWM signals (aka "DSD") but analogue audio then it is also a Delta Sigma Analogue to digital converter...
Now DSD (aka SACD) which to my ears fails to come close, never mind equal true PCM CD Replay in most aspects of sound quality, operates at 2.8MHz switching, or around 10 times as fast as common Class D Amplifiers...
Why anyone would want to listen through an A2D followed by an D2A Converter that are around 10 times worse than single speed DSD is beyond me.
But with enough hype and snazzy naming it cannot help but sell high and wide.

And Thorsten Losch is one of Bruno Putzty's (hypex) best mates, bit of a slap in the face.

Cheers George

No it’s quite, but at least there not too much voodoo there like here, lots of snake oil peddlers here, a bit of undercover shilling going on for small manufacturers, their threads can eventually get removed or closed.

Cheers George

Slumming it  abraxalito?, did you got bored over at the other place?

Cheers George

Like the Halcro Eclipse with its incredible specs ; 110kg/250 pounds, 135,000$

We had a friend that knew Bruce Candy and had the DM88 monoblocks, he used them with Wilson 6, 7 and 8’s, they were "nice and transparent" and could go loud, but a bit ho-hum, kinda boring, no life to the music, nothing that grabbed your attention and or emotions.

Cheers George

arty_vandelay

Yes, if the Wilson Alexia didn’t have a negative phase shift of -45’ degree in the bass causing an EPDR of 0.9ohm, then it would be an easier load for the amp to drive, but still it would be 1.8ohm and still needing an amp with good current delivery. Definatly not OTL or P/P tube or even most complimentary n & p channel Mosfets, unless they are push pull N channel only, then those can get some current going, like the Solution amps (or similar) I believe.

Cheers George

Sorry, just a correction there @arty_vandelay it’s EPDR (Equivalent Peak Dissipation Resistance.) for those who want to know the complete title.

Here is a snippet from the measuring labs used by HiFi News and Record Review, also used I believe Absolute Sounds use as well. And Stereophile’s John Atkinson also mentions it from time to time when things get into the hairy load area.
https://ibb.co/qxjtkn7

https://www.stereophile.com/content/heavy-load-how-loudspeakers-torture-amplifiers-page-2

Cheers George

Your the best mate!!! (in your own mind) "No more responses to anymore ** you say."
Now go back to the Misc Forum spruiking about voodoo snake oil along with your SR "fuser" mates geoffkait, uberwaltz, oregonpapa ect ect, or how OLT tubes can drive Alexia’s

I’m not the one idolizing a reviewer

No but you rubbished him, and that in many eyes makes you a total loser. JA of Stereophile gives more to the audio industry in his little bench testing finger that you ever could.

Like I said if I’m parroting, it’s because of continuing false statements like you make, "that OTL’s can drive Wilson Alexia’s to what they’re capable of doing".

Go back to spruiking and telling OTL tube owners, their amps are great for speaker loads like Wilson Alexia’s ect ect , your good at that kind of false statements.

It is no different than with epdr which you continuously referenced even though it had absolutely nothing to do with class D amplifiers.

And EPDR (impedance + -phase angle) loading that the amp sees is fact, your the only one who says it’s not.

🤦‍♂️

There you go, big noting yourself again, putting **** on John Atkinson (Stereophile) is a real good way to get reco.
Go back to shilling that OTL’s can drive Alexia’s, that made more sense.

I am going to guess I have far more experience with AP equipment and getting the most out of it than the average Stereophile writer who is a casual user.

Yes your the best, and yes your a"Dreamer".

JA (John Atkinson) would have so many more hours than you on AP test gear it’s not funny. That all he does all day every day, is measure everything Stereophile reviews and subcontracts out as well.

Stop "trying" to big note your self, and go back to saying how good OTL amps are for driving bad speaker loads like the Alexia’s, that only made you look half as bad, we can’t follow two ridiculous claims at once.

I’m talking about the Audio Precision’s auxiliary AUX-Filter which goes between the Class-D and the AP Analyser, it’s a 52db per octave passive low-pass filter and can only take low power, it eliminates the Class-D’s switching noise for testing purposes only can’t be used for real music levels, even Stereophile state they can only put low power wave forms through it with it in use.

I said it years ago if you have a look in their comments, when Stereophile first started using this AP AUX switching noise filter, I complained they weren’t showing us anymore what is representative of what comes out of the speaker terminal of Class-D with this AP filter in between the Class-D’s output and the AP Distortion Analyser, especially the screen shots of the 10khz square waves.

As you can see years back Stereophile used to show with (top) and without the AP low pass filter, and it’s always used at very low power.
Today they never show the square wave "without" the filter in line (bottom), which is not representative what’s coming out of the speaker terminals.
https://ibb.co/MnK3mcm

The above was explained ad nauseam

No it wan’t explained why a screen shot of a 10khz square wave couldn’t be shown direct from the Purifi 1ET400A speaker terminals, as the speakers see it, as Stereophile shows a few years ago here https://ibb.co/MnK3mcm (top pic) but now Stereophile also don’t show it without the external filter, because it’s not a good look for their advertisers to show that kind of barely recognizable square wave. 

Instead the screen shot that is shown, had been extensively cleaned up after it had gone through an A.P. AUX external -52db LP testing filter (bottom pic), fooling readers/viewers into thinking that it comes out this clean from the Purifi 1ET400A speaker terminals. A hoax in my view.

purify look good but keep in mind those IMD measurements conducted at relatively low power and with a LPF in line.

Not just low power Arty, but "very low" power, as the testing equipment used, the Audio Precision in line external Class-D switching noise filter has a LP slope of 52db per octave, and any more than a few watts through it would burn it out a flash.
Would be very nice if you could listen to normal power music through this AP filter, as then everyone would love Class-D (even me), virtually no switching noise or phase shift in the audio band, no heat, light weight, low power and cheap, what could be better

Cheers George

in the case of the Alexia where one just has to look at the frequency response/impedance curve to see it, often correct peaks (valleys) in the frequency response. It is like a built in equalizer :-)

You are both "Dreamer’s", the OTL’s are NOT fixing/correcting anything, as there’s nothing to fix on the Alexia’s.
They can’t drive those Alexia loads, because of "lousy damping factor" and "minuscule current delivery" (and are a tone control because of it) not "equalizing" as you say, read carefully, Stereophile say it twice.
Stereophile on Alexia:
" The peak in the midbass is entirely due to the nearfield measurement technique."
" The broad peak in the midbass will be mostly due to the nearfield measurement technique"

The more you both try to dig your way out of this nonsense, the more ridiculous you look. With your comments made about OTL’s and them trying to drive speakers like these Wilson Alexia’s ect ect that have horror loads.

Next I’ll put money on is you’ll drag out the (autoformer band-aid fix) solution.

There’s a Supertramp track, that fit’s this claim of "doing a nice job" of that amp driving the Wilson Alexia’s, it’s called "DREAMER"

With serious lack of damping factor, and far less current than an 80’s NAD 3020 integrated can give.
This thing on the Wilson Alexia’s would become the worlds most expensive monoblock tone control, in the worst possible way.
Might work if it just drove the mids and highs.
https://www.stereophile.com/images/1213Walexfig01.jpg

atmasphere7,771 posts09-18-2019 6:50amOur OTLs do a nice job on the Alexia

This one statement among others, shows just that your not of this planet anymore.
To say your OTL’s can drive the Wilson Alexia!!!!. is just so ?? words fail me.
One of the hardest speakers ever to drive correctly, yet one of the most accurate that I and others have ever heard, when driven with amps with big current that can do them justice.

The only thing you two are succeeding in doing, is keeping this post recent until someone adds something useful.

Totally agree.

This is simply not a matter of debate.

Keep believing this in the "wrong context you are saying it in" and your cred will suffer for hiend audio, just like your statement.

    atmasphere   Our OTLs do a nice job on the Alexia

Post removed Nov 20, 2019

I agree, not worth the effort, what a Class-D w****r.

Cheers George

Not sure what all this has to do with a new GAN amplifier, but the Wilson Alexia

BJT's and their ability to drive into these kinds of loads, and the BS statement that OTL can do it too🤣

Absolute Sounds test report Quote:
With the combined EPDR of impedance and - phase angle the Wilson Alexia presents a scary 0.9ohm load to the amp 

https://www.absolutesounds.com/pdf/main/press/WA%20Alexia%20HFN%200313-4web.pdf

Less efficient speakers also tend to be less dynamic due to voice coil heating.

This statement is more false, as the drivers are built far more exactly to meet their operational parameters

A secondary reason is the harder any amplifier is made to work to drive a speaker, the more distortion it makes

This statement is even more false, as the purpose built amps that can double their wattage’s down to 2ohm and that can drive them and have far less distortions than your OTL's, you are just in product protection mode because OTL’s can only drive certain speakers without distorting and those speakers usually have far more coloration/distortions as well. 

I am done with this particular conversation

Ditto, there’s no reasoning with Klipsch Lascala owners, beaten only by JBL owners. 
Remember I owned them, and the Forte, the Forte were a far more musical speaker, but still colored and midfi.

See that’s the difference between us, you can handle the Klipsch Lascala’s horn and box coloration’s, and no deep bass, I can’t.
I want to get the signal from the source to the speakers the purest way possible full range with no limitations on wattage or current or frequency, because the speakers also have to be least colored most dynamic you can get, unfortunately that usually means they’re hard to drive.
And to putting that "Peavy Thing" in the signal path goes against all of this.
Cheers George

This in my signal path, no chance, not ever!
https://assets.peavey.com/images/large/118741_33943.jpg

Cheers George

Post removed Nov 19, 2019

That was too strong for him could have caused him mental damage, it wasn’t going to help.

Yes, lets get back to the OPs topic which you side-tracked ...

 🤦‍♂️ whatever

I also believe, hard to drive speakers, are ridiculous

Your opinion Mr D.
This is where we differ big time, I would not call Klipch Lascala speakers or Hafler amps state of the art audio devices,having owned the Lascala’s and repaired a couple of Haflers.

I’ve found the most "uncolored full range" speakers, usually to be among the very hardest to drive, due to all the work that goes into them to make them full range, uncolored, and using the drivers in their most linear range with complex xover do do it. This all adds up to an inefficient speaker, with very low impedance dips and nasty - phase angles.  

Cheers George

Give it a rest sunshine it’s doable, and not as complicated as you make out, your full of it, I would estimate a days or less work for a good tech, with the components and schematic of the donor mosfet amp at hand.

Now lets get back onto the OP’s topic.

It's a different amplifier.

Sorry, same amp with different output/driver stage and bias change.That allows one to directly compare same amount of Mosfet devices to the same amount of BJT devices

Can you even buy TO3 transistors any more

Of course you can don't be an *****, and they're still cheap and plentiful,  just look around.https://www.ebay.com/itm/1pairs-OR-2PCS-Transistor-MOTOROLA-TO-3-MJ15003-MJ15004-100-Genuine-Origina...

End of story, no more on this as it's not about the title "new GaN Amplifiers" 

Its highly unlikely that anyone ever did a mod like this unless the amp was gutting for its chassis and power supply.

Include to the the complete chassis, transformer/s, power supply, the heatsinks and input stage to that, which is around 80% of the amp.

What’s left is the driver/output stage and bias mods. So yes I see it as doable, as he said he’s doing, but I think it would be limited to T03 case substitutions, otherwise would get messy.
And yes two different amps one Mosfet the other BJT using the same 80% above components.

You can’t just swap out the output FETs for the BJTs

Please don’t say I said this sunshine, because I didn’t.
I said there’s a member who converts Mosfet amps into a BJT amps, and of course there’s more to it than just changing the output devices only a fool would think or suggest otherwise.

You can do it, if you had any half decent tech knowledge you would understand, end of story.

Of course there are different drive conditions and they are all addressable in changing over mosfets to bjt, you just choose not to believe it. 🤦‍♂️ 

And I'll post once again the pro's for going bi-polar

"BJTs tend to have better, more linear gain characteristics…and can give you a lot higher voltage gain than MOSFETs.…They're also able to handle higher output currents…and have a lower output impedance.…That gives BJTs a huge advantage over MOSFETs…for building amplifier circuits…that need to provide a significant amount of output power…and or drive loads that have low input impedance.…MOSFETs are going to have a harder time…driving a low impedance load…because they have a higher output impedance.…"

 

How can you know "what to listen for"

There’s a post a member put up a couple of weeks ago (go find it), who does mods for his customers, where he takes a Mosfet amp removes the complimentary N/P channel Mosfet output stage and replaces it with complimentary NPN/PNP Bi-Polar (BJT), and he and his customers say it all in their description of the sound change.

That’s why I said if you live with the two for a while you will hear the difference.

If you read what was said at the seminar, you can apply that to what you might hear, again especially on the harder to drive speakers.

I hear Mosfets into my hard to drive speakers as "polite" but a bit of a "yawn" that lack that punch, drive, boogie factor, and an openness that BJT’s have that can also be detrimental with bad recordings.
Some call it "Mosfet Mist" other call it "Tube’ish" I think maybe it’s because they aren’t as linear as BJT’s just like tubes with with 2HD as outlined in the seminar.

Cheers George

what you wrote below, I cannot just accept on the face as factual.

That's your opinion, it is, and if your are a tech you'll know that it's very possible to do this to the driver/output stage.
Cheers George

Maybe, if those listeners don't know what to listen for.
But for those same listeners short term living with each amp, listening to many albums over a few days you eventually would pick it, especially if the speakers are hard to drive.

Cheers George

Also note this difference between the two taken from a seminar on Mosfet V Bi-Polar (BJT), which to me gels with what I notice/hear.

"BJTs tend to have better, more linear gain characteristics…and can give you a lot higher voltage gain than MOSFETs.…They're also able to handle higher output currents…and have a lower output impedance.…That gives BJTs a huge advantage over MOSFETs…for building amplifier circuits…that need to provide a significant amount of output power…and or drive loads that have low input impedance.…MOSFETs are going to have a harder time…driving a low impedance load…because they have a higher output impedance.…"

Cheers George

Many (me included) just don't like Mosfet sound. 
 Listen to some older Threshold Pass amps that used bi-polars, you'll change your mind.

Cheers George

The larger Bryston 4B SST2 puts out 300 at 8 ohms, 500 at 4 ohms, and the tech estimated 600-700 at 2 ohms. Definitely better, but unfortunately all this doesn’t correlate with the sound.

Yes you are correct Viber, I myself never liked the Bryston sound, and I put that down to just one of the things that I've never liked and that is that they use an excessive amount of global feedback, to get their specs.

I myself prefer much less feedback (so long as the amp still achieves good measurements) and also if the design allows the use of just local feedback (again so long as the amp has good measurements).
EG: my ME amps, Gryphon’s, Agostino, early Pass ect ect
https://ibb.co/kGJMXcr
https://ibb.co/0hTPp6f
https://ibb.co/N94rSTt

Back to the 2 ohm thing, hey George.

Yes MrD, and they are needed if one has some of the very best speakers around which dive to 2ohms or even lower, and you wish to get the very best out of them with no compromises.


Cheers George

The doubling of output from 8 to 4 ohms suggests a good power supply.

Most Class-D can double from 8 to 4ohms
It's when test bench measured independently, from 4ohms to 2ohms is where they usually *** themselves, many actually go backwards instead of doubling or even increasing.

Cheers George 

It’s good for it to have it’s own thread, new amp using the new GaN technology.
So long as the claims are kept real, and BS is not posted.

Wasn’t it this one or another (Nuprime) that claimed to have "super fast 500,000hz!!! switching frequency" which is just 500khz like most others?
BS No. 1 if it was.

Cheers George