homemade power conditioner?

[Scott Dorsey]

Yes. the Furman did very little. The UPS eliminated essentially all
the noise I was getting. Some FX units that I just assumed had a high
noise floor became much quieter too.

I agree with the others that I think your UPS is really a standby unit.

But before doing anything else, you need to get a line analyzer or at least
a scope on your power line. See what is really on there and see if you can
figure out how it got there. It may be something the power company is
required to fix.
--scott

 

[Scott Dorsey]

I know it's not running off the batteries unless the power's down.

That is the definition of a standby UPS as opposed to an online one.

I said it has a sine wave output---is that not possible??

That's only important when it's running off inverter, and most of the
time it's not running off inverter. So the benefit you are getting has
nothing to do with the quality of the waveform from the inverter, it has
to do with the line filtering on the front end.

This pretty much guarantees that your problem is due to RF noise on the
power line. But what kind? And how did it get there? It isn't really
essential to know since you have a good workaround, but it would still
make me curious.
--scott

 

[Z]

I agree with the others that I think your UPS is really a standby unit.

But before doing anything else, you need to get a line analyzer or at least
a scope on your power line. See what is really on there and see if you can
figure out how it got there. It may be something the power company is
required to fix.
--scott

If consistent noise is an issue you may need to beef up your earthing.
Items with switch mode power supplies eg IT equipment, battery chargers
have high protective conductor currents. Fluorescent lighting also puts
gumph back on the mains.
/this current becomes evident as a voltage (i.e. noise floor) which
varies inversely as conductor resistance so low resistance earths help
reduce the noise.

For high quality audio such as studio gear one would generally be
thinking of a dedicated circuit from the consumer unit maybe even a
separate consumer unit.

I ran 10mm sq earths from the amp and t/table sockets to the main
earthing terminal for my hi-fi. Now clean as a whistle. I'm wiring a new
radial (branch cct in USA) circuit for hi-fi in Pirelli once the
harmonised colour cable is in stock at wholesalers.

Try these PQ links:
http://www.copper.org/applications/electrical/pq/homepage.html
http://www.marcspages.co.uk/pq/index.htm
http://www.lpqi.org/lwslib/ktwse?welcome need to register

 

[Frank C]

What about these? They seem pretty inexpensive.

http://www.equitech.com/products/seconds/seconds.html

 

[David Williams]

This is an old thread now, but I just read it. I didn't see anyone (though
they might
have) mention a motor-generator. Sure, it can be expensive and wasteful, but
you
can build one yourself, and with a massive flywheel, not much high frequency
or impulse noise will get through. You can drive it with a variety of
standby devices
when the normal feed is down.

Any inverter you could afford puts out an MFM (modified square wave) output.
This is an enormous source of noise, much more than on a power line.

Synthesized sine wave inverters have become much more affordable lately, not
that they will be "good enough," but they're definitely not "modified square
wave."
What's more, there's quite a bit of used equipment around now, as many home
power gurus end up buying larger inverters and selling the smaller ones.

David