Ping Brian Gaff

[cpvh]

Hi Brian,

On my recent post on the cheap car head unit, you suggested using capacitors in series (or dearies / desires as my spill chucker had it).

How would these be used?

TIA

Chris

[Brian Gaff (Sofa 2)]

I was merely saying that you need to block any dc as it may be that such signals might be piggy backed onto the audio cables, so really all one would need was say a 0.1uf in series with the centre conductor just to be safe so there is no chance of damaging the input of an external amp. Brian

[Dave Plowman (News)]

Surely most domestic amps would already have such a cap on their input?

[mm0fmf]

You don't own any really high end HiFi do you?

[Dave Plowman (News)]

Have you got the schematic for yours? Including that of the ICs used? DC coupling from input to output is something I'm sure Russ Andrews thinks a good idea. Oddly, I can't hear DC.

[Theo]

I don't know about high end, but I'd expect any decent designer would employ a DC blocking cap. If you don't, the DC voltage may cause the amplifiers to go into saturation and start clipping - which would do horrible things to your audio.

Unless it's so high end that making your own blocking caps out of unicorn humps is going to make a difference?

Theo

[The Natural Philosopher]

A lot of 'seriously' hifi amps are in fact DC coupled throughout.

Provided they are fed from a true AC source like a pickup, this does no harm

[Dave Plowman (News)]

Can you name one?

Until you get a fault on something feeding that amp and burn out your speakers...

I have a very sophisticated moving coil pickup preamp. Designed by Steward Pinkerton. Balanced input. And even that isn't direct coupled throughout.