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Yes, I am aware that impedance varies with frequency. The only thing I was saying is that these impedance swings shouldn’t be so severe that a good amplifier, of adequate power, should handle those swings. Amplifiers that can’t do so will distort, especially at high output…and eventually shut* down or give up the ghost. Whether those frequency abbreviations (you brought up) are audible or not is another topic, but is applicable to people’s subjective opinions. This information is what I’m most interested in.That said, I’m sorry that you find my search for subjective opinions on class D a waste of time. As I already stated, if I only cared about objective performance I would buy whatever amplifier is at the top of ASR’s list and wouldn’t have started this thread. I currently own 5 of Nelson Pass’s creations, which I love for their various audible qualities. The only thing I don’t like is their heat dissipation in the summer. In my original post I stated that this is the core reason for my class D search. However we all know that different amps perform differently, including class D amps. So…if someone has experience with class D with speakers that I am familiar with and maybe even has a similar room size, then it would be great to hear from those people (in my case) wouldn’t it? Regardless, I am open to learning from anyone who wishes to contribute to my search.* edited by admin on request of author
Yes, I am aware that impedance varies with frequency. The only thing I was saying is that these impedance swings shouldn’t be so severe that a good amplifier, of adequate power, should handle those swings. Amplifiers that can’t do so will distort, especially at high output…and eventually shut* down or give up the ghost. Whether those frequency abbreviations (you brought up) are audible or not is another topic, but is applicable to people’s subjective opinions. This information is what I’m most interested in.
That said, I’m sorry that you find my search for subjective opinions on class D a waste of time. As I already stated, if I only cared about objective performance I would buy whatever amplifier is at the top of ASR’s list and wouldn’t have started this thread. I currently own 5 of Nelson Pass’s creations, which I love for their various audible qualities. The only thing I don’t like is their heat dissipation in the summer. In my original post I stated that this is the core reason for my class D search. However we all know that different amps perform differently, including class D amps. So…if someone has experience with class D with speakers that I am familiar with and maybe even has a similar room size, then it would be great to hear from those people (in my case) wouldn’t it? Regardless, I am open to learning from anyone who wishes to contribute to my search.* edited by admin on request of author
AGD or is it ADG, I can never rememeber? I have their least expensive amp called Tempo. It is outstanding. My previous two amps were the class D NAD 290 a Purifi amp, and Son of Ampzilla II, a A-AB amp that was outstanding. I fell for the hype about the Purifi and bought it to replace the SOA II, but after using it for a few months, on a whim I put the SOA II back in the system. It sounded a lot better than the NAD Pufifi. Eventually sold them both for the ADG which blows both of them away for overall sound quality.
I too was quite intrigued by what I'd read about AGD amplifiers. Over the past year Audiophile Power Amplifier Reviews has taken a hard look at how current releases in Class D stack up against each other, I found it very interesting:https://futureaudiophile.com/orchard-audio-starkrimson-mono-premium-amps-reviewed/The AGD Productions Tempo di Gan for $5,700 (read the review) is a close comp in terms of performance for the Orchard Audio Starkrimson Premium Mono amps, but costs literally twice the price. I’ve had this amp in my system and it was impressive, but not any more sonically than the Orchard Audio Starkrimson Premium Mono amps. The AGD’s form factor is a little bit more luxurious, but not anywhere close to justifying the huge difference in cost.Again, if the criteria is bang for the buck, there are a lot of choices out there
The author of the Orchard amp cited above lost all credibility with this statement:"GaN amps provide big power from a small semiconductor form factor that flies in the face of everything that we know about top-performing audiophile amps. They produce a sound that is analogous to Class-A amps, but use close to no power and create, in effect, no heat. GaN amps don’t cost a fortune, but they have changed the amp game."Fets don't produce a "sound". They of course use power and create heat, though slightly more efficient than silicon. Judging by AGD's products, they can indeed cost a fortune. Most of the GaN amps today use old, outdated designed and lack a load independent frequency response. Orchard's GaN products are one of the few with a modern design and don't have this flaw. None of the GaN amps have the performance of the Hypex and Purifi amps, which use plain silicon fet devices. Designers at Purifi have stated that while GaN fet devices have advantages over standard fets in certain applications, audio amps aren't one of them. Purifi's performance backs this up. Using GaN fets with outdated designs is more of a marketing gimmick than anything else.
It isn't that the amplifier "can't handle the impedance swings" and will shut down, the issue is the amplifier will not accurately reproduce the signal due to its frequency response varying with the varying impedance of the speaker.An amplifier with load varying frequency response will reproduce the signal differently with different speakers, meaning that it may or may not perform for you and your speakers as it does for someone else with their speakers. Assuming you share tastes with someone else (a rather large assumption that you have no way of actually knowing), you have no way to know if the amp will perform for you and your speakers the way it does for someone else and theirs.A proper amp doesn't have a "sound", rather, it make the input signal larger, adding or subtracting nothing. If you love their various audible quantities, what you are really saying is you love their varying distortion profiles. As said earlier, assuming other's tastes and preferences will match your own is a very large assumption. I never said to buy strictly by objective parameters, of course one must ultimately enjoy according to own's own personal, subjective preferences. Isn't it logical to first order a a good steak and then add one's own preferred amount of salt and pepper, rather than have someone else season it for you? Purifi and Hypex class d amps are basically wires with gain- they have no "sound". Far better to add your distortion profile preferences through dsp to your taste than buy an amp effects box that has someone else's distortion preferences already built in, right?
Thanks for posting. I hadn't seen this review and it should be very helpful for RDavidson. There is also a less expensive pair of Orchard Audion monos called the Starkrimson 25 Mono Premium and on sale for $1,095 per mono for May iirc. There's a tour on that pair and I signed up for it. One of the appealing things about the Orchard class d amps is the purity of the sound.
Your approach to all this is reasonable, but it isn’t the only way. How am I to know “what a good steak” is when my experience is limited (with the more recent advances in class D)? Where does one start? THAT’s what I’m trying to wrap my head around. You find my imploring for experience / advice (to point me in a direction) pointless. As such, why keep at it? Are you suggesting I buy a buffet of Class D amps and figure all of this out on my own? That’d be ideal. Practical? Uh…no.
Yes, I am aware that different amps will distort differently and thus produce different audible and phase related qualities into varying loads. I’m not new to this. I disagree that Hypex and Purifi are straight wires with gain. It has been repeated many times, by many people, that they have audible differences. At minimum, there will be insertion losses. Same with cables. Cables aren’t additive to the signal. The best simply do the least harm. Ideally an amplifier wouldn’t exist and we’d be able to drive speakers directly from the source’s output voltage. DSP is another topic and is indeed another valid approach. That’s not what I’m looking for, however.
Is this what you are referring to, Randy?
I had the Purifi enabled by NAD. I eventually came to the conclusion that it had a dry, sterile sound, and no life, so I dumped it. All amps have a "sound," good, bad, or ugly, or they have nothing at all. The Tempo, whatever you think of the price, is outstanding.
Your subjective opinion. The fact is it simply outputs what is input. Read the data sheet, see the test results. Many people like and are conditioned to hearing a certain amount of distortion which colors the sound. Hypex and Purifi were designed and engineered to eliminate audible distortion. What you subjectively call "dry, sterile sound, and no life" can also be called "accurate". There is no debating personal, subjective preferences. If you prefer certain types of distortion, much like certain people like dollops of A-1 steak sauce on Wagyu beef, that's your prerogative.
Your ears and brain are a part of the equation, of course measurements aren't everything. But measurements are useful when a manufacturer says the amp puts out 300w but testing shows it can only manage 127 watts. Can't turn a blind eye to that.
