Power wire

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Originally Posted by Audio_by_Goodwill

Were you thinking of a UPS type box? If so, I don't think they necessarily produce a sine wave..... in fact I saw one the other day that specifically said it didn't.

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Cheap ones don't.

A/V On-Line, Pure Sine Wave UPS - 120V

Good quality UPS units are regularly surplussed when the batteries go bad. output is pure sine wave .

I paid 50 bucks each for two. The batteries are weak but work.

Colleges are a good place with surplus departments. Don't expect to find them every trip though, they are only there when they get rid of them.

Ohio State is nice, have a surplus sale one day a week and everything is posted online...

Worst thing is lining up in the cold when they have good stuff...

There are computer recyclers in most major cities, if you explain battery condition isn't important you might get them cheaper.

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Originally Posted by Altec Best

........phase I use this you just plug it into a receptacle ..........

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This is just a ground continuity and polarity checker, so from a phase POV it's only telling you whether it's inverted or not.

GM

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Originally Posted by bowtie427ss

........Tripp Lite was back in the late 70's........

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Ditto!

:rotfl: This is the brand/type of unit I was trying to 'remember' by doing a search. Of course I could have just looked under the desk to read it off my ISOBAR that's been protecting my PC/peripherals, phone system since '96 from the generally sorry local power and numerous annual direct lightning strikes, but I guess my 'old-timers' is more advanced than I thought. :(

GM

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Originally Posted by GM

Ditto!

Of course I could have just looked under the desk to read it off my ISOBAR that's been protecting my PC/peripherals, phone system since '96 from the generally sorry local power and numerous annual direct lightning strikes
GM

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Dunno who here is into SF, please don't say SciFi, but had a conversation about Tripplite with Jerry Pournelle..

His house ( Chaos Manor) took a direct lightning hit on its transformer. 4 PC's in the house. One on a Tripplite ISOBAR like GM has survived. Everything else, the other PC's, TV, microwave, etc all died.

I've got a couple of Isobars, too. One on the computer, one on the TV/Stereo, and one in sitting in reserve. The two that I have in use, I bought back in the mid 90's dirt cheap while working at Lowes. They were clearing them out, and then I got an employee discount on top of that. I think they were about $75 new, and I paid about $10 or $15.

I've got an old APC UPS that needs batteries. I bought it used. I checked on batteries and found they run about $100 for all 4. I planned on scrapping it. I wonder if it's output is a sinewave? Maybe I'll try emailing APC. It's certainly a heavy monster even without the batteries. If it's output is a sinewave, I might keep it after all.

Most true sine wave UPS units brag about from my experience...ie says right on it. Yer mileage may vary.

A quick Google for the model number may tell...

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Originally Posted by GM

OK, my power supply design knowledge is mostly limited to knowing that I've seen transformers between the AC cord and rectifier, so we have a coil affecting the PF that in theory needs some correcting and since rectifiers are non-linear, isn't it affecting it also? Or does the transformer sufficiently isolate it?

GM

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Well, I don't design power supplies, I just fix 'em, so my design knowledge is slim. Xfmrs won't improve PF, in some cases they may make it worse (lower PF). Still, once it's rectified, what does it matter (from a Q POV), since DC has no PF. I suppose no rectifier is perfectly linear (what is?), but non-linearities in a full wave bridge should cancel. The main concern with DC supplies is ripple, and proper filter caps smooth that into negligibility. Tube rectifiers can have regulation problems when the line peaks or sags (or when overloaded), but SS can cure that (within reason).

This all became clear to me in tech school when the teach had us monitor (with a scope) the DC out of our regulated bench supplies while he revved a crappy electric drill on the same AC circuit. The hash on the AC line was plum nasty, but the DC remained a motionless flat line.

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Originally Posted by Panomaniac

Well maybe not at line voltage. But stepped down it runs filaments in plenty of tube amps.
That's important.

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True, but filaments aren't an audio circuit. :p

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Originally Posted by Old Guy

Most true sine wave UPS units brag about from my experience...ie says right on it. Yer mileage may vary.

A quick Google for the model number may tell...

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I can try again, but I had a hard time finding much about it when I was looking for batteries...... it's that old.

ABG, the guys who rent half my old warehouse run a computer remarketing/recycle operation...if you PM me the model I will run it by them...they have LOTS of reference stuff....