Purifi Class D: Junk?

Ok here is the part I don't get. HOW anyone can charge 7500.00 for any Class D or 20-40,000.00 for any class a or A/B. That is the my problem.. NO BODY is that good...

I can see a Rolls-Royce costing 1/4 million, I understand that. The back right side door is a lot more complicated than ANY SOTA amp EVER made. But please explain, why THEY get 200.00 an hour for building an amp in 48 hours and expect ME or anyone to pay for it.. NUTTSO comes to mind..

Jesus help me.. I helped build and repair dams, bridges, aircraft, buildings, rescue people from other countries, on a job in Brazil pulling guys out of fresh bores 1000 feet underground. 50.00 an hour? MAYBE.

God give me strength.. something is wrong.. Where is the Roller I been waiting for to show up on my door step with a big ol thankyou and a RED ribbon.. AND Buffy the belly dancer as the chauffeur.

She gives wonderful hand massages. :-)

Now everyone's point it? Some people like apple, some people like oranges. Me I like mangos.

Regards

They charge it because someone will pay it. 

Most class D is junk, except the Rogue Sphinx and some class D Marantz, The Ruby comes to mind, as well as the pm10.

I will note one thing though- I've seen a number of SMPSs (Switch Mode Power Supplies) used in class D amps. I think its a bad practice. They work, sort of; the problem is that class D amps go from almost no current draw at idle to quite a lot at full power. SMPSs don't have a lot of capacitance at their output and so can be drained faster than they can replenish. A lot of them will shut down if you put a lot of capacitance at their output. So if you're not running an amp with a regular power transformer and a lot of capacitance available for the class D amp to feed on, you're probably not hearing what it can do.

I can't agree with this statement Atmasphere, it really depends on the power supply, how it was designed, and circuit limitations.

Most switch mode power supplies for power amps I see for audio are not power factor corrected. They tend to be single stage LLC, with a simple bulk capacitor arrangement on the front end. Poor design choice in my mind, but is what it Is.


They store most of their energy on the high voltage side, not the low voltage side. Let's say no PFC boost front end, so at 120V, say a bulk voltage with losses of 160. Pretty easy to put 1000uF, if not more on the front end. At 160V, that's 12.8 joules. That's the equivalent of 16,000uF at 40V. I would be more inclined to put a PFC boost front end with a link voltage of 400V. Now my 1000uF (450V capacitors) is like 100,000uF at 40V.


That 450V, 1000uF capacitor is lot smaller than the 100,000uF, 50V capacitor. All that is required is the LLC stage has high surge (added power capability), and suitable continuous capability.

JUNK? That’s kind harsh.. There are some good sounding class ds. NO they don’t float everyone's boat, but they get the job done for a lot of folks.. Is it my favorite amp? For some things, I think it is the absolute best.. I use 3 12k Behringer for SERIOUS bass duty.. I have 1300.00 invested. Come one come all, unless you have 4 of those things..:-) The best performance is 220 single phase. They can suck a PG&E pole dry, just like the rest of the welding machines can, too. Don't underestimate pro equipment EVER.. Couple of mods and some good cables. Can crumble a house...

It's how you got to hear it the first time. Live anyway..

NC500 I have a few, wonderful amp with buffer boards.. George has got them cooking along without, buffers. I didn’t like Ice or the Hypex 400 without buffers. Maybe he’s got something special there.

I use them in the hot summer months, with a tube front end. Valves in the cooler months..

Yea I don’t listen to junk. I never have. BUT then I like tone control, Mcintosh, Russco and VMPS speakers, too.

I like slower runnin' women too.. That's just me.. There is "too fast" ya know.. :-)

Regards