II changed the title of this post as I had a few more things I don't know what is so instead of making a post for each one I decided to ask all my enquirers to this old stuff in this one thread
I am keeping the stuff that pertains to tube testing as I sell tubes and other stuff on the ebay for a living and I am learning now that I regret selling some of the stuff I sold as I could have used them testing tubes and didn't know it at the time.
thanks for any info you may have on what the heck these things are

I found thing thing at an estate sale but I have no idea what it is
maybe some of you guys may know what the this thing is.


and one of the inside



the back of it

It has the look of a power supply.....but only tracing out the schematic can tell for sure.

--Chuck

Thanks Chuck
I see no name tag of number so I wonder if it may be a home made deal

Its home brew. A commercial unit would have some louvers to get rid of the heat from those two tubes.

--Chuck

can any one tell me what this if for and can it be used for testing tubes
thanks

Welcome Blaine,

Thats a RCL bridge, used for measuring resistors, capacitors, and inductors. Clean him up, and show a little respect, he's going to turn 80 next year, and if working properly, is an accurate, handy, piece of test equipment. When it came to RLC bridges, GR was king of the hill for several decades, and priced accordingly.



HERE'S THE MANUAL.

Today's direct descendent is closing in on $10K, a little pricey, but easier to use.

thanks mike
if it can be used for testing CAPs I guess I better keep the old device as I am starting soon to sell old CAPS on ebay so I will add the thing to my testing room,amassing what folks are paying for old sprague Caps that came in the old guitars and amps,
100 bucks a set sometimes
thank you for the help and thanks for the welcome

There's no particular reason to test the types of capacitors that guitar people want, since they will all be leaky anyway. They're looking for appearance and certain capacitance values.

interesting.
the whole guitar tube/caps thing is getting weirder all the time
I don't know how high they can go in price but they seem to be getting on up there
I all so think the old Caps leak as most of them where the oil type but now days most of what is being sold as original
ant as they are the paper kind,
looks like'em but no oil tube at the one end,the folk buying them have no idea,
here is a pic of both kink in this link
http://www.mylespaul.com/forums/tonefre ... r-oil.html

I just bought a fluke model 12 to test these caps as I was told it was easy to use
but I all so just came into this cool looking old sprague cap tester seen in the pic below,which one would y'all think be better or easier for a beginner such as I am I powered up the old sprague and the green eye lights up but have no idea how to use it yet,like most of the stuff I have, lol
it seems I have a lot to catch up on

The General Radio bridge is one of the few things in test gear that uses a hummer.

Despite, popular opinion some radio models do not use that part.

The GR 650-A that Blaine or Becky has doesn't have a hummer; it's got the optional 650-P1 tube oscillator/amplifier instead.

The Fluke is the way to go for measuring capacitance of new parts. Now whether its reading is affected by leakage, I don't know. You can find out by measuring some ordinary capacitor, say 0.1µF, and then shunting it with a 1 meg resistor and seeing if the readout changes.

You don't normally need to measure capacitance of an old leaky paper cap (they're marked on the case), but if you did, and if the Fluke gave erroneous readings, the old GR 650 could do it. The Sprague might do it; I don't know offhand. The Sprague will definitely measure the capacitance value of leaky electrolytics; that's what the "power factor" dial is for. That's equivalent to the "D" (dissipation) dial on the 650.

Just as an aside, the GR and Sprague may give different readings, as the Sprague measures at 60Hz and the GR measures at 1 kHz.

With electrolytics, leakage current at working voltage is a concern. The Fluke is of no use for this, nor is the GR 650, but the Sprague will apply a variable DC voltage, while reading the leakage current on the meter. It may indicate lower values of leakage on the magic eye; I don't recall. You can use the Sprague to reform old electrolytics (if you consider it worthwhile or safe; that's another whole discussion that has been covered here at great length).

Actually some of the ones without the oil-fill tube are paper, not mylar. They just don't have any oil.

But all the paper ones leak, oil-filled or not.

Uh Oh, now you've done it!!

WOW!!
very nice device
I did a search out of curiosity on ebay and say one similar for 8000 bucks
but then I all so saw this sold for parts for a 100 bucks,nice deal for a guy that could fix it,here is the link to ebay
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... true&rt=nc

Thanks, Alan, I didn't know that. Is there an easy way to distinguish the plain-paper types from the plastic film types?

Dave Wise

The stripers are always paper (as far as I know). For the ones with printed markings, yellow markings are paper and red markings are composite paper and mylar ("Difilm"). Someone can chime in if I have that backward.

I thought that was true, but I have encountered one or two color-coded ones that leaked as little as a modern film cap, and a few lettered ones that leaked more than a film cap should. Maybe they were just lucky and unlucky, respectively.

Dave Wise