"Eeyore" wrote in message
...
:
:
: "Bob H." wrote:
:
: Bob H. wrote:
: Eeyore wrote:
:
: 2000uf polypropylene btw ?
:
: Graham
:
: MY Harmon Kardon uses a 100uf cap, and it's the only one in the signal
: chain. Since it's my only SS amp, it's what I'm familiar with. And I
: will be replacing them with at least Silmacs, and probably foil caps
: when I get around to it.
:
: Actually, I think it's 1000uf, and yes it's the coupling cap to the
: speakers. I remember a factor of 10. I'll check the schematic again
: when I get home. But how about 1 or 2kuf silmac or similar, bypassed
: by a 100 or 50uf film?
:
: Is this a 'single supply' amplifier design ?
:
: The idea of bypassing is yet more unfounded nonsense btw.
:
: I'm not sure what the great idea's supposed to be with silk included in the
: dielectric. I'd use a modern low-ESR design. It'll help to use a larger value
: too like the 2000 uF I mentioned.
:
:
: Does anyone build low voltage foil caps? (lower than speaker caps).
: They could be wound with thinner film, for smaller size, and for SS,
: much lower voltages are needed.
:
: The lowest voltage film caps I've normally seen are 50V. There's a limit to how
: thin the film can be made reliably.
:
: Graham
a modern stacked polyprop can easily have some 2500 layers.
as the thickness of the metallic layer can be neglected, a 10 mm
tall stack makes for a 4 um dielectric thickness. the odd and even
layers are end connected by what is called the Schoops process.
quite advanced manufacturing at work :-)
50V across 4 um is like 12 KV/mm, so limits are imposed by the
dielectric's punch through capability
Rudy