LSA and Peachtree have been using the same GaN fet class d modules. No feedback and a very load dependent frequency response, just like the old Tripath class d amps from 25 years ago. Out of date design with the flavor of the month fet. Ask Peachtree for some frequency vs load data and compare to modern class d designs like Hypex, Purifi, etc., which are ruler flat...Pig with lipstick.
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@donnylovely
Due to the fact that all the other Peachtree GaN amps have had load dependent frequency response and the fact that class d amps without feedback have had the same issue, it's a very good bet this new product has it as well. Prove me wrong.
It's an issue that can be measured. No doubt Peachtree already knows.
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Not following your logic. Probably because there isn't any logic to your replies.
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@thespeakerdude
Call me crazy.
Crazy is thinking that someone who makes a living selling dreams will ever wake up to reality.
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In almost any class D circuit, the specs of the resistors, caps and inductors have to be examined to make sure they will work in the circuit.
Rather ironic isn't it that amplifiers are designed using components that are chosen on their specs yet if we likewise use the specs of the finished product to help judge it's performance we are ridiculed.
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Having a measurable effect is not the same as having an audible effect, much less an audible effect that is universally agreed to as being positive.
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All I need to know is in the design. Science doesn't care about opinions. It's normal to think what you buy is great. Doesn't make it true. It's called confirmation bias. I find independent, non-biased opinions much more useful and truthful.
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No real consensus, which should be no surprise:
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Baffle them with BS, a common disinformation technique used by those with nothing of substance to use in their support to deflect and obfuscate. Over and over, when challenged, we get the same guru double speak. Boring.
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@kitsap2
Science doesn't care about your opinion and I am not moved by your ad hominem attacks nor your arm chair psychology. If you, or anyone else, have anything germane to add to this discussion, by all means, feel free. Otherwise, your off topic, attack the messenger comments are simply just more noise.
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You must be fun at parties.... It’s a different module. Maybe just listen to it instead. Who cares about load data and rulers? It sounds amazing. Stay ignorant my friend
@donnylovely
Different module, still no feedback. Perhaps if you knew why load dependent frequency response is relevant you wouldn’t be making such ignorant and rude comments. Here’s why: when amps have load dependent frequency response, they don’t sound the same with varying loads. What that means is they can sound different not only across the frequency spectrum with one’s speakers, but can sound different when used with different speakers. There is thus no guarantee that they will sound "amazing" with any or every speaker, disregarding the differences in tastes amongst listeners. Therefore, one can take the impressions of listeners here with less than the usual grain of salt.
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@donnylovely
No, that isn't the case with every amp, only poorly designed ones. Most well designed amps don't change character with load.
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@donnylovely
Sorry, I have no interest in poorly designed products nor can I talk myself into enjoying their flaws. Get yourself a Sonos class d amp and save yourself $1500. Everyone says it sounds amazing so it must be spectacular!
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@donnylovely
I think I have as much right to post here as you do so if you don't like my take, ignore it.
@ricevs
More hype for your mods eh? The shilling never ceases.
We have 7 people commenting here that this thing sounds amazing on THEIR speakers.
OF COURSE it does! And there are 672 reviews on Amazon of the Sonos amp that say IT'S AMAZING! And it's ONLY $699! And you DON'T NEED a DAC! It's a TOTAL GAME CHANGER! 672 RAVE REVIEWS! It's revolutionary!
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@donnylovely
Those who think that comments about this amp's sound characteristics are applicable in their own systems are being fed a bunch of nonsense. I don't need to hear it to know that load dependent frequency response is undesirable in an amplifier. That isn't guessing and assuming, it's a fact.
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@donnylovely
That's what I am hearing. It has zero feedback which has been synonymous with load dependent frequency response in class d amps historically.
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Funny how they say nothing in their marketing copy about the load dependent frequency response. So 1980's class d. Most well designed class d amps have solved that issue. Nice concept, poor design.
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@donnylovely
That’s because it doesn’t have a load dependent frequency response.
Prove it.
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The proof is right there in the ad copy above- it's run open loop. Show me an open loop amp without a load dependent frequency response.
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@donnylovely
You have proved my point. NO FEEDBACK = open loop. Now you have learned something. You are welcome. Your turn to show how an open loop amp can avoid load dependent frequency response. Good luck.
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@donnylovely
If you read the op’s copy and paste ad copy and understood what open loop means you would have your proof. Ball is in your court to show otherwise. I won't be holding my breath as it is clear you are technically in the dark on class d amps.
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It's clear that the meaning and implications of load dependent frequency response are over the heads of many here. It's of no use debating with those who don't even understand the issue at hand, yet argue any way. Pure ignorance.
And, lol, no, power at a given impedance is not the same as frequency response at varying impedance. But you do keep proving my point that many here have no understanding of the technical underpinnings of these amps yet argue on and on without a clue what they are arguing. Bravo.
Still waiting for an example of an open loop amp without a load dependent frequency response, or any proof whatsoever that this Peachtree GaN amp is such.
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Who's delusional- the guy talking facts or the guy in denial who literally bought the koolaid, too dense to understand the technical explanation? Ever heard the word "bias" before?
I can see I am talking science to a zealot. I would have to be deluded to continue. I'm not wasting anymore time. Enjoy your 1980's amp.
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@art_boston
Seriously? This is certainly something to care about, if you have any clue about amps.
He is clueless, don’t waste your time. The FACT is open loop (zero feedback) amps are load dependent - the output filter interacts with the load, that is one reason why modern designs use feedback after the output filter. Simple physics which can't be ignored, as much as one tries.
@singintheblues
Back on topic, any ideas on what type of speakers work best with this amp?
That’s the gist of the problem, isn’t it, with amps that have load dependency? For modern designs which avoid that issue it isn’t a thing. Try something with a flat impedance curve that is basically a resistive load. Good luck.
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@donnylovely
Maybe this will help...
From:
https://sound-au.com/articles/pwm.htm
Class D Audio Amplifiers - Theory and Design
6 - Output Filter Design
The output filter is one of the most important parts of the circuit, as the overall efficiency, reliability and audio performance depends on it. As previously stated, a LC filter is the common approach, as it is (theoretically) lossless and has a -40dB/decade slope, allowing for a reasonable rejection of the carrier if the parameters of the filter and the switching frequency itself are properly designed.
The first thing to do is to design the transfer function for the filter. Usually, a Butterworth or similar frequency response is chosen, with a cutoff frequency slightly above the audio band (30-60KHz). Have in mind that one of the design parameters is the termination load, that is, the speaker impedance. Usually, a typical 4 or 8 ohm resistor is assumed, but that would produce variations in the measured frequency response in presence of different speakers. That must be compensated for by means of proper feedback network design. Some manufacturers simply leave it that way so the response is strongly dependent on the load. Surely a non-desirable thing.
7 - Feedback
As I have stated previously, timing errors can lead to increased distortion and noise. This cannot be skipped and the more precise it is kept, the better the design will perform. Open loop Class-D amplifiers are not likely to satisfy demanding specifications, so negative feedback is almost mandatory.
And there you have it...
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Speaker loads are rarely purely resistive nor are they flat.
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@atmasphere
Gentlemen. I see that @kuribo has entered this thread. I've crossed swords with him in the past, but on this point of load dependent frequency response he is correct.
Nice to see we agree on something.
To properly evaluate the performance, a simple constant, purely resistive load is not going to do it. Few speakers present such a simple load.
Additionally, without post filter feedback, there are other issues besides load dependent frequency response that can be present.
In all, it's a poor design in comparison to other currently available class d amps that have orders of magnitude better performance. Just more marketing, all aboard the GaN train!
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@donnylovely
Old tech, this is class d circa 1985. Without any actual understanding or knowledge of class d, that doesn't mean anything to you. The technology has matured and is now capable of much better than out of date designs without post filter feedback. But ignorance is bliss. Enjoy!
By the way, the measurements are out there. Get off your hind end and find if you actually have any interest in intelligently discussing this amps shortcomings. Otherwise you, like your amp, are just distortion boxes.
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@donnylovely
1db is more of a non-issue than an issue. Sorry we can’t all afford to buy the best preforming amps in the world, that’s more of a non-issue also, always going to be something that preforms better.
Now you actually admit the frequency response is load dependent after denying it time and again?
The actual performance into a real world varying reactive load is almost certainly materially worse than than 1dB, which is into a best case, non-reactive, constant resistive load.
We can't all afford to buy the most expensive amps but those who can afford the $1500 GaN 1 can certainly do better for the same or less money. There are plenty of better engineered and performing amps available - Ncore, Purifi, and Orchard, etc. are all much better performing and better engineered without riding the GaN marketing coat tails.
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@donnylovely
Your GaN measures poorly compared to Hypex, Purifi, Orchard, etc. That's a fact. You say the GaN sounds great, that's just your opinion. I know people who think their computer speakers sound great. So what. Opinions mean nothing. Try again.
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The module was measured at different impedances:
16 ohm......up .15 db at 20K
8 ohm ......flat at 20K
4 ohm........minus 1 db at 20K (quarter db down at 10K)
2 ohm.......minus 2 db at 20K. (half db down at 10K)
So the output filter was designed for a simple 8ohm resistive load. How does it perform with complex loads?
Have you seen the distortion versus power and distortion versus frequency? Poor by current standards.
Just like the 1980’s Tripath. Old tech. Yuck.
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@donnylovely
They’re too scared to actually listen to it. What if they actually like it? Their brain might melt.
Scared? Of what? Lol, I've read a lot of bs here but that sets a new standard.
Is there some logical reason that an amp can't both measure and sound good? Great, you like it! Doesn't mean it isn't poorly designed and falls drastically short compared to other cheaper amps. The only thing scary here is the ignorance.
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@donnylovely
Come back after you have learned something about class d. I have made the issues with this amp abundantly clear to anyone with a minimum of technical knowledge about class d amp design. You can find the data sheets on Mauser, and there is all you need to know about class d amp design and theory at the link I posted below. It's not worth my time to continue this one sided discussion.
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@donnylovely
You obviously haven’t looked at the design to tell if that's true or not. . Where are these mythical measurements of yours?
I have looked at the design and the data sheets while you clearly haven't. Nor do you understand what an output filter is, nor what the implications are of open loop (zero feedback) design. The more you shoot your mouth off the more obvious it is that you have no idea of the issues.
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Maybe why some think so, but certainly not a sign of good design. Lots of people liked the old 1980's open loop Tripath class d amps too. And lots didn't.
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My opinion is that the top end is definitely rolled off.
That's what happens with open loop class d amps...
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another owner heard but it went away after more hours.
It's called acclimation.
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I know it will be better than stock from the mods.
That’s called confirmation bias. Confirmation bias is the tendency to search for, interpret, favor, and recall information in a way that confirms or supports one’s prior beliefs or values.
Can you name one thing he will do that has any hope of altering this amp’s performance in a way that can be proven to be an improvement? Can he? No. All you will get is a meaningless spiel about how everything changes the sound and you can’t measure any of it. That’s ok, your confirmation bias has already made up your mind- he could literally do nothing and you will swear it sounds better. Chaching....
However, the rolled off quality maybe still be there if it does not disappear after more burn-in. Ric could also address that with his mods.
Really? He’s going to redesign the circuit and add an output filter? Lol, it’s people like you who keep people like him in business. Enjoy your kool-aid.
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@dolfan
I know there are shortcomings in everything but for us regular folk the sound quality and simplicity we get for less and less money spent is incredible.
True, but there are much better products out there for the money than this poorly designed amp.
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@kitsap2
Like I said, science doesn't care about your opinions and neither do I.
People should go into a purchase with their eyes wide open. This amp is not what is being advertised, as I have explained. Some people appreciate an honest opinion, rather than hear only the self interested claims of someone looking to take your money by praying on ignorance and insecurity. There is too much fraud, deceit, and dishonesty in audio. Wake up.
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@yyzsantabarbara
Not that you would let science get in the way but be aware that nothing being done to mod your amp will make it perform better. You might have convinced yourself it is better, but like putting your cd's in the freezer improves the sound, or other such nonsense, it is all in your head.
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Yeah, just ignore science and reason and keep sending money.
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I wasn't giving advice, I was stating facts. You and others chose to dispute and argue with those facts. If speaking the truth is "raining on your parade", maybe you need to get an umbrella.
Your post was deleted because it was abusive and off topic, as has been most of the response given here to those who have pointed out the lack of technical knowledge and blindness to science exhibited here by the kool-aid crowd. It is indeed a hobby, not a matter of life of death, so take your own advice and skip the personal attacks.
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@donnylovely
I see you still haven't bothered to find them for yourself even though I told you where to look. Seek and ye shall find.
I don't have to eat excrement to know I don't like the taste.
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You appear to not be very skilled at searching or you would have found them. Call the manufacturer (no, it isn't Peachtree).
I may not know everything about this amp but I surely know more about it's design and performance than you do...
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@donnylovely
There are much better amps and amp designers out there, like Hypex and Purifi, such that I don't need to design my own amp, I only need to understand and recognize superior design, technology, and value. You can either educate yourself or be at the mercy of ignorance and others. Somehow you don't seem the type to actually take the time to learn or you would have already found out what I have shared here to be true and stopped your immature taunts and personal attacks.
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Always the go to fallacy: "people who criticize don’t listen"...just another deflection.
Who are you to decree that just because people trust science, logic, and reason rather than your self serving, self interested fairy tales, they don’t listen? Maybe many have and the issue is in fact that there is nothing to hear amongst the unsubstantiated, unproven-or should I say disproven?- claims you make (and make money of off)? Who are you tell everyone that your hack jobs will universally improve the sound of an amp? Even if your "tweaks" actually improved the performance of an amp, there are sure to be people who don’t think they improve the sound- tastes differ. Talk about fantasy...
It’s not slander to call out the truth. First, prove your "tweaks" actually do something other than degrade the performance of an amp, then prove that whatever you’ve done is universally accepted as an improvement. You can’t prove or verify your claims, yet you are a non-stop ad machine always sneaking in your services here on this hobbyist board, always spewing the same unsubstantiated claims. Audio is full of charlatans always ready to fleece the unknowledgeable and insecure. You might fool 90% of those on this forum but you won’t fool everyone.
Of course your disagree with Ralph- what could someone who actually designs and sells equipment possible know, compared to someone who makes a living off of other people's work, jumping on every new amp with fantastic claims of "improvement"? To actually think that some solder gun jockey could actually somehow know better than the designers of these products really is beyond the pale. Kind of like some 6th grade kid with a watch teaching Stephen Hawking about time...
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@jetter
And I think that anyone implying that the vast majority of audio engineers, scientists and other professionals in the field do not listen to their creations as much or more as anyone else is truly moronic and not worthy of being printed. Yes, there always will be an outlier.
Well said. It would be funny if it wasn't such a despicable scam.
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@arafiq
Exactly.
Many of these "tweaks" have been shot down by amp designers as more likely to degrade performance rather than offer any concrete improvements. Others have been called outright hazardous from a safety standpoint. None have any basis in science. Sure, there are those who make claims that their modded product went to an 11, but as we all (should) know, not only do we not all share subjective taste, our ears are easily influenced by biases. Without any objective data, it’s all sideshow liver pills.
And why we are continuously subjected here in this non-commercial forum to these blatant commercial ads is sickening. This same behavior has resulted in removal from other sites.
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@tweak1
the thread could return to its' intended purpose
What's that exactly? To discuss the Peachtree GaN amp or to be spammed by a snake oil salesman?
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