Adding large caps?

[Rino odorico]

Anyone ever make a "cap bank" to add to the AC line before your gear? What I meen is add this "bank" in-line of the AC...wall outlet--"bank"-- audio gear.

Just wondering if this could/would help anything...and how much is enough?


Rino Odorico

[Peter Daniel]

Check this thread: Anybody tried that?

[tiroth]

You don't want to bypass your AC line to neutral with large capacitors. It sounds to me like you are thinking of applying the bypassing used in a DC supply to the AC mains--totally different things.

Sometimes one bypasses line-neutral, line-ground, neutral-ground but only with capacitors chosen for higher frequencies. That is, we might want to remove noise at 100kHz-5MHz and leave the fundemental (50/60/400Hz) relatively untouched.

Another thing that is possible is AC coupling the mains line. This is usually done for a specific purpose, e.g. eliminate DC on mains from causing transformer problems. It needs to be done very carefully.

[Rino odorico]

Peter, thanks for the reply!

Sounds like a good idea, cheap to try at least. But what I was thinking is adding this "cap bank" in line or series, just like in car audio.

Rino Odorico

[sam9]

I looked at some of the photos on the thread that was cited. Scary stuff. I think I'd rather play patty-cake with "Ole Spaky".

(For those of you not in the US, "Ole Spaky" is the nickname for Mississipi's electric chair.)

[tiroth]

Car audio is a DC supply, unlike mains AC. Please make sure you completely understand what you are doing!

A good idea might be to test any device using an isolation transformer unless you are absolutely certain it is safe.

[haldor]

Originally posted by Rino odorico
Anyone ever make a "cap bank" to add to the AC line before your gear? What I meen is add this "bank" in-line of the AC...wall outlet--"bank"-- audio gear.

Just wondering if this could/would help anything...and how much is enough?


Rino Odorico

Be aware that any cap that is wired across the AC mains has to be non-polarized and should also be rated for such use. If you put a computer grade electrolytic on your AC power it will self destruct quite violently.

There is little reason to do this anyway. An effective RFI filter on the input to your power supply is what you need. Unless you are building a monster class A amp, your not going to be loading down the AC lines anyways.

Remember power = Volts time Amps. At 12V you've got to push a lot of amps to get power. At 120V you only have to push 1/10 the amps, so voltage drops in the cable are greatly reduced.

Phil