View Full Version : DIY 120VAC Power Conditioning

12-01-2005, 02:59 PM

Thinking of building one of those...but frankly, seems almost too easy for the benefits touted :)

Anyone with experiences with something similar?

12-01-2005, 04:38 PM
The last two DIY amp projects I worked on I installed one EMI/RFI filter
on the AC input like the one shown in the link. Reason? Because they cost me $5 at the
surplus store so why not ? I wouldn't spend $100+ on power conditioning
though. These are just capacitor and coil filters, perhaps cascaded to give
more filtering. There is no magic inside.

On the other hand, a common amplifier power supply designs may have
some capacitors already installed [but not the coils] in various locations in the
power supply or power input which is pretty good. Usually, the higher powered
amplifiers will have the capacitors and coils already designed in.

These filters are also used to keep equipment noise from leaking into your
house AC power, ie if you have a SMPS power supply inside your amp
that switching noise would not be cool to exit into your AC mains so one of
these could be used to keep the noise from leaking out. It also should keep
noise from coming in if it's designed accordingly.

Look here;

That filter design could filter out noise in and noise out.

Here is what these EMI/RFI filters look like;

Notice the schematics for each type are similar. They have line and load side
because they were designed as 'one way' devices but they could be used
both ways, perhaps with reduced performance.