The $5.00 USD mic pre

[mrc]

Exactly, that way you can use it with any mic pre, and still get the offline experience...it shold be free of any hash on the grid, and I can't see how there could be any loop. So with any decent ps, like Peter C's or maybe the one from JLM, probably many others as well, why wouldn't this work?
mrc

[Professor]

Oh, I see what you're saying MRC.
As long as you pull the AC cord completely, or modify it with a switch that should actually work. The trouble with typical UPS units though is that they use switch-mode supplies to charge the battery which makes them terribly noisy when they drive audio gear. When I installed AV systems we always told the consumers to not try those because they would probably hear the squeal in their system.
Also, even if it eliminates the line hash on standard AC power lines, it still runs through the device's AC-to-DC transformers, and if those are crappy wall warts, then the device may be slightly cleaner with the UPS but not much.
And either way, I wouldn't try to modify an existing preamp to run on batteries, but if I were building my on I might work it into the design.

-Jeremy

[mrc]

Sorry, I skip things. You're right, I wouldn't use a wall wart. I've had pretty good luck with APC and Conext units, but the Bel....somethings I tried did have problems with audio. The Conext units actually mention using them as isolators in the printed packaging. I'm sure Brian is sugesting top of the line ps units, I understand what your really get from a ps in terms of audio, but I thought the talk of deep cell batteries and all that, might be getting out there a bit. Good ups units and real decent powersupplies can be had for around a hundred bucks total, so maybe this is a better way to spend, with more possible bang. It's, of course, open for discussion... my only true expertise is as a proctologists' subject.
mrc

[mus1k_freak]

so has anyone actully ever built this?

[rob]

does anybody know where i can find the ina217?
my usual pedestrian sources are failing me.
thanks

[ulriggribbons]

http://www.digikey.com/scripts/DkSearch ... 61&Site=US

[Bill @ Irie Lab]

Rob,

Review: http://www.electronicstalk.com/news/tex/tex317.html

Purchase page (TI will send up to 4 free samples if you register): http://focus.ti.com/docs/prod/folders/print/ina217.html

Datasheet: http://focus.ti.com/lit/ds/symlink/ina217.pdf

Bill

[Bill @ Irie Lab]

BTW -

Here is the simplified schematic that started the thread rolling,

http://www.record-producer.com/learn.cfm?a=3080

Although a cheap IC-based pre will never have own forum, I think the DC power discussion we've had is a useful one.

I may try combining one of these with a discrete stage for some "fun with dick and gain"!

Bill