Linear vs. switching
Sep 14, 2011 at 8:48 PM Thread Starter Post #1 of 6

samsquanch

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So, I'm in a bit of a pickle...
 
I have a Hagerman Bugle phono pre that I run off of batteries, yesterday it seemed like I was losing one of the channels, I chalked it up to batteries going dead.  Today I get some new 9V's, pop them in, and nothing, as in absolutely no sound.  I fiddle around for a bit, then think to myself, "maybe I put the dead batteries back in?"  I go to swap both batteries, when I realize, that the negative terminal on one of the battery holders has broken off, con sarn it...
 
I'm flat broke at the moment, and can't afford the gas to go out of the way to a radio shack, let alone the mom and pop electronics shop, to go buy another battery holder, BUT!  I do have the parts at work to hobble together a ~+/-12V power supply.
 
After that long winded explanation, the problem is, the power supplys I have at work are 24V switching, I know that linear is the best method, but am I going to notice any noise or other issues?  Chances are that I'm just going to throw caution to the wind and build it, but I'm mostly worried about blowing something up.
 
Planned method would be power supply -> power cap -> opamp voltage divider -> ripple caps -> preamp
 
Any help would be pretty sweet, since I've got all these kick ass records but no way to listen to them, dag nab it!
 
Sep 14, 2011 at 10:07 PM Post #3 of 6
That's kind of what I was thinking, these are from the company Extron, which makes alot of pro audio/video gear.  I'll just throw a grip of ripple caps in, thanks!
 
Sep 15, 2011 at 2:36 AM Post #4 of 6
by filter, a C-L-C or C-R-C-L-C before the opa would be best, as its HF switching residue/noise that will likely be the problem more than ripple. the regulator you describe does not always enjoy driving a cap though, it will slow it down at the mimimum
 
Sep 15, 2011 at 10:13 AM Post #5 of 6
Do you have a few spare alligator jumpers? Just use them to hook up the batteries until you can get the right parts.
 
If you do go with the switcher just make sure that the switching supply has a "floating" output. If the switcher is grounded bad things will happen. With everything unplugged: measure ohms from the output connector to bits that go into he wall.
 
Sep 15, 2011 at 12:48 PM Post #6 of 6
good point, didn't even think about alligator clips.
 
That's what was sitting in the back of my brain about why switching supplies can be a problem, but just couldn't remember.
 
Thanks man.
 

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