High end Class D amps?

I made a general statement, and I am not prepared to discuss at length. I have made a general observation, and that observation will be shown true or false over time as I build systems, but usually my first instincts have been correct.

Regarding comparison to the XA200.8, I have not done direct comparison yet, but I will. One of the XA200.8 has been back to Pass Labs for repair following my bone headed blowup wherein a metal plug of an IC was touching the output. Amazingly, the amp survived another four weeks before giving up the ghost. It's not back yet, so no chance to compare.
I attest to the sensational service of Pass Labs; no arguing, no bickering, no guilt trips, no plea for me to cover return shipping, which would have been expected, given I hurt the amp; just, "We'll arrange pick up, get it done and back to you." That is a big part of why they are world class!

For any kind of meaningful conclusions, several systems have to be made. This amp is very different from the XA-200.8, but so far to my ears, as legitimate. I think this may settle out like the two motorcycles I own; Yamaha Stryker and Yamaha FJ-09; two very different rides, but I love them equally. I am not of the school where there is only one form of excellence in amps and systems.  (If you are, great! So be it.) I have built too many rigs and used too many speakers, such that I do not wish to limit myself to one expression of fine audio.  :)  However, I do try to maintain a high standard for excellence across a variety of systems.

Especially since audiophiles love to jump to contusions, I usually withhold names of equipment before the time is right (publication). Sorry; sometimes you just have to wait.  

The answer is simple: Gain knowledge instead of made up stories.

These are words of someone either in denial or in product protection mode.

I currently don’t make, sell, or market any amplifiers and have no skin in the game either way. I do understand quite well amplifier topology though.

georgehifi, given your obviously thin educational knowledge w.r.t. amplifier topologies and again obviously without the practical experience to compensate for that knowledge gap, perhaps you should be giving pause to the fact that people with far more knowledge of amplifiers theoretically and practically are all telling you you are wrong. Not just one, but everyone.

The answer is simple: Gain knowledge instead of made up stories.

These are words of someone either in denial or in product protection mode.

George, as a simple tip: the ability to admit that you were wrong is a strength, not a weakness.


In my quote above I was simply stating a fact. My advice is to study how class D amps work (the theory is simple) and keep in mind that with any current output device (MOSFET or GaNFET; the difference between them these days is slight) the output impedance is going to be lower than any traditional solid state amp, often by a couple of orders of magnitude. As I mentioned earlier, the PuriFi modules (not made by me, so clearly not in 'product protection mode') have output impedances that are tricky to measure as they are about the same as a few inches of 12Ga wire.


So this is not about denial, its physics. When you have an amplifier with an output impedance that low, it pretty well makes no difference what phase angles the speaker has nor its impedance, since both are several **hundred** times more than the output impedance of the amp. This simply means that the amp will be able to make constant voltage into that load.

I currently don’t make, sell, or market any amplifiers and have no skin in the game either way.

You are delusional, I didn’t say you. Go back and read.

But then you are a 50’s kind of guy and you don’t hear too well anymore

George, as a simple tip: the ability to admit that you were wrong is a strength, not a weakness.

Ralph lay off protecting, you do the same with preamps.