Discussion of Class D Amps Application & Experiences

An air coil will have more resistance than ferrite unless it's huge. 3000 watt power supply is crazy,  600 watts is plenty for a purifi module, use a 1200 watt on dual. 

There is post filter feedback on these self oscillating amps do not touch the coil, others do not buy an amp where some nut has messed with the coils.

Some people have direct experience and others just have opinions. It is universal (to those that have listened and tested on their own system) that larger power supplies with lower impedance sound better.....even when using less than one watt.

Yes, there is tons of feedback around the coil.....so what. It sounds better with an air core coil. This I know because I listened to it. All theories are just that......opinions based on non experience. Only those that actually listen to what they talk about have any truth. Truth is experience.....not a bunch of made up stuff.

Who are the "others"?....There are lots of "others" who trust their ears and not someone’s opinion that is based on non experience.

There will be feedback soon about how the amp sounds and also there will be amps on tour so people can hear them in their own home and judge for themselves.


A quote by djones51:
"For example Take a stranded copper cable of 0awg and one of 12awg running 10 feet connected to any amp with a DF >300 and a nominal 8 Ohm speaker and there is no difference in sound. "

So, he thinks all cables sound the same? Every single piece of wire sounds different from any other brand.....even using the same construction.........Every piece of wire has directionality.....this I have heard. Every type of insulation has a sound. Damping a cable effects the sound. Whether it is stranded or solid core....the purity of the wire....whether it is cryoed or not.....everything changes the sound....AND....none of the above can be measured.......but you can hear it......if your mind is open.

Every coil I listened to on the output of the Purifi amp sounded different.....in serious...ways. Just like the type and gauge and purity of the wire in the coil....just like everything in audio.

DO NOT BELIEVE ANYTHING I or anyone says.....believe only your experience......and in audio.....that means what YOU hear in your system.

As long as it's what I hear not what I assume I hear while looking at it. 

It is all about trusting yourself. Back in the late 70s my friend knew the owner of Sumiko (who imported Supex cartridges, among other things)....so he borrowed 10 brand new Supex cartridges and we mounted each on on a universal head shell and put a number on each one with masking tape. We spent all day listening over and over again to each one.....and all three of us in the room agreed on which ones sounded best. A couple were not very good at all.....most were in the middle and three were at the top......and one was clearly the best. The frequency readout sheets that came with each cartridge showed practically the same response on each one......which had no correlation with the sound they gave. Once you do these kinds of listening tests with others in the room (all of whom are open minded) then you really start to trust what you hear.

I have been mind blown several times over the years.....I would think this "MU Metal" cable cannot sound good.....no way.....then it does sound good.....of course, there are way better cables now than those Lindsay-Geyer cables......

I sure hope that today’s cartridges are less variable than those made back then....BTW, we did the same test with 5 Fidelity Research cartridges and they all sounded different, as well.