Purifi Class D: Junk?

Class D amps are only current limited by the designer. You can make a super high current class D amp (you just need higher voltage rails and larger fast power supplies and maybe a couple more output transistors.....and great output coil). Class D idles at practically zero current....because its output stage is switching at high speed......does not need to be "on" all the time. What you hear in any class D amp is the designers knowledge...nothing more, nothing less. Tons of high end speakers use class D amps for the bass. The big Von Schweikerts for example.....no loss of dynamics there. There are tons of things in any amp that effect the dynamics.....one bad part and dynamics are history......and this is true for high-current class AB types as well. This is why all class A/B amps sound different.....in the bass/dynamics and otherwise. I do various things in my mods to the VTV Purifi amp that allow for better bass and dynamics and speed. There is no end to tweaking.....no end to knowledge. The Purifi module does 400 watts into 4 ohm...and over 500 watts into 2 ohms (25 amps).......this is enough for most speakers but getting it all out of the module in the most tweaky, dynamic and great sounding way is an art.

02-21-2021 7:17pmWhat you are hearing is what class d amps do they produce high wattage with low current to save money on energy and expense of manufacture to make more money for the manufacturer and they will not have the required current to dive the proac speakers you have they like a good high current ab type amplifier i am glad you did not spend much money on the class d amp you dodged the bullet with that decision.

More making things up. I really don't consider 25 amps that limited. That's 1250 watts into 2 ohms. Class D amps primarily have thermal limits because real world music is not 1000W continuous, ever. That's a magazine test.

Class D amps are only current limited by the designer

Show us just one that’s not, and can almost double it’s rms measured wattage from 4ohm to 2ohm. The true indication of not current limiting, like many good A/B bjt amp.

The Purifi module does 400 watts into 4 ohm...and over 500 watts into 2 ohms (25amps)

This is pathetic to show off it’s current ability, some NAD’s can do that current, it’s actually limiting, should read closer to 800w into 2ohms if it were good at current into low impedances.

A 175w- 8ohm Gryphon will do
350w - 4ohm
700w - 2ohm
1600w - 1ohm
9000w - 1/4ohm
NOW this IS an amp that does current without limiting.

You only need the current you need. It does not matter if an amp doubles its current/power down to 2 ohms. All that matters is that it have enough current at 2 ohms to drive a 2 ohm speaker to the volume required. The IceEdge 1200 module puts out 700 watts into 8 ohms, 1200 into 4 ohms and I measured 1000 watts into 2 ohms......so what? Michael Fremer used this amp module on his 2 ohm Wilson Alexx speaker and said it was great in the bass. Of course, if he had a larger room and played way louder then maybe 1000 watts would not be enough......I mean, how many speakers are 2 ohm......not many. Let’s see......Alexx speaker is 91db sensitivity.....and say you are 10 feet back....so that would be around 82db with one watt......10 watts gives 92db and 100 watts gives 102db.....and 1000 watts gives 112db.......I doubt many listen this loud. This is why 500 watts into 2 ohms is plenty for most people and most speakers (most speakers don’t go near 2 ohms).

The Merrill class D amps all double their power down to 2 ohms.....all of them. Most class D amps don’t do this because it costs more money for larger supplies and it is generally not needed. Did you know that the big Parasound Jc1+ amp does not double all the way down to 2 ohms? Stereophile measured 500 watts into 8, 830 into 4 and 1200 into 2 ohms. I guess they should make an even bigger amp to satisfy those that need number doubling.......$16K and no power doubling.....too bad.  The 60 thousand dollar Gryphon amp doubles to 2 ohm....but it only does 700 watts at 2 ohms.....so my $2K IceEdge amp I sold last year will probably play louder than the $60K Gryphon.......doubling does not matter.....only the power you need matters.