[Trevor Wilson[_2_]]

"Arny Krueger" wrote in message
. ..


**It seems your memory is faulty. I will explain why so many caps are
used.

* ME amps use no Global NFB.

As I said, some people do crazy things. Not using loop NFB in a power amp
is a genuinely crazy thing. Almost no modern power amps lack loop NFB.

**Wrong. A number of other manufacturers are now emulating what ME did 30
years ago (and still do today). I will readily acknowledge that few mass
market manufacturers choose to do so, however. Additionally, most listeners
prefer the sound of an ME amp which eschews the use to Global NFB. And yes,
ME did some blind tests to establish this. Listener preference for Zero
Global NFB was overwhelming.




Why is a dc block needed in an active crossover?

No, these are decoupling caps, for the power supply. A large number of
electrolytic decoupling caps are not needed - the decoupling caps that
show up in any volume at all are ceramics or film caps, and those
typically have much longer lives than electrolytics.

**Nope. Most domestic products use electros as decoupling elements.

Nonsense. Check the schematics at the Rane site - they are typical.

**I don't need to. Rane are not represented in the domestic market. I
suggest you look to Sony, Panasonic, Sanyo, Marantz, NAD, Rotel, Denon, et
al. These are what most people would regard as domestic equipment
manufacturers. Rane would be what I would refer to as pro and semi pro
equipment manufacturers. Additionally, I suggest you keep in mind that
Stephen's crossover is 20 years old.


Sometimes, these will be bypassed with small value film caps as well.

The bypass caps are often needed. Power supply decoupling for most op amps
is silly and rarely done in audio gear outside of the wasteful high end.

**Wrong. It is VERY common in domestic audio. And trust me when I tell you
this: I KNOW what I am talking about. In fact, I just checked the schematic
of my newly acquired Harman Kardon HD970 CD player. Yep. It uses 47uF
decoupling caps, bypassed with 100nF film caps. It is hardly high end
(though it sure sounds like a high end player). I could go through my filing
cabinet to locate more, but I really cannot be bothered. You'll need to take
my word for it.

Trevor Wilson