looks as though someone was making dummy loads for x-mitter testing...or if 10 of those "banks" where paralleled amp testing...?
How many ohms is it, effectively, when it’s all paralleled up? It would only be effective for transmitters to a few MHz at most (and probably still need an antenna tuner). But it would be in the ballpark of 50 ohms. For audio, 2 to 20. Maybe in banks of 8 ohms? Anything else might have been for load testing power supplies. Short of a simulation it’s the only way to determine the voltage under load. I load test my tube amp power supplies, especially to dial in custom power trafo winds. That requires higher R than a typical audio dummy load.
Those resistors are wire-wound and not suitable for RF unless right down in the long wave band I reckon - possibly a DC or audio dummy load, or motor dump load. A 750 ohm wire-wound has a lot of turns, for RF it would make more sense to wire resistors in series, not parallel, to get lowest inductance. It seems the RH series are still made, but owned by Vishay now, there are non-inductive winding versions, RH50NI. These resistors are about 55 years old from the datecodes (1968..1970).
Can't see any witness marks to show these were ever used on a heatsink... They look accurately spaced out and well soldered so perhaps these arrays were an actual product?
Can't see any witness marks to show these were ever used on a heatsink... They look accurately spaced out and well soldered so perhaps these arrays were an actual product?
Each rack of 10 measures 75 ohms on the dot.
Some are mounted to aluminum plates, but most are not. About half of them have a short clear insulated aluminum lead soldered at one corner about 4" long or so.
The one's on the aluminum plates have white dielectric compound under them and stainless steel screws, double flat washers and Nylock nuts.
There's too many of them to have been something he just made up and stored away. My guess is its something he bought and squirreled away for years. They all came from a load of plastic tubs that he had stored in a storage facility somewhere.
The caps that were in with them are impressive size wise but are likely too old to be much good. I'm not sure I've seen any this big before, at least not in anything I've worked on. I also found a few 3 farad caps, each about 4" in diameter and about 15" long rated at 36v branded Motorola.
There's also a bunch of ww2 aircraft dynamotors, radios, and misc transceiver components in the mix, but those were stored separate from all the resistors and capacitors.
Found some more of these, about 50 or so like these, made up of three 50w 30 ohm resistors for a total across the leads of 13 ohms.
What ever they were made up for they were never used, the screw holes in the plates have no witness marks at all.
The wire is only 18ga so they're not wired for any high amps or big power. Each resistor is set in a bed of white heat sink compound.
I suppose I'll never know what they were intended for, but who ever fabricated these took the time to make sure each one was identical, and every hole was precisely placed and spaced. In other words, they weren't likely just hand drilled and thrown together. Like many of the items from the same lot, they likely have nothing to do with audio but it just further makes me wonder what all he was thinking when he accumulated it all.
What ever they were made up for they were never used, the screw holes in the plates have no witness marks at all.
The wire is only 18ga so they're not wired for any high amps or big power. Each resistor is set in a bed of white heat sink compound.
I suppose I'll never know what they were intended for, but who ever fabricated these took the time to make sure each one was identical, and every hole was precisely placed and spaced. In other words, they weren't likely just hand drilled and thrown together. Like many of the items from the same lot, they likely have nothing to do with audio but it just further makes me wonder what all he was thinking when he accumulated it all.
At full power it’s 3.4 amps, well within the capability of 18 ga. wire. It would take short bursts of more. They’ve got faston connectors, so obviously he had something in mind. God only knows what.
What ever he had it mind I'll never know, he's been gone now for nearly two years and the guy who had these may just the same gotten them from some auction or some bulk lot he bought.
What ever they were for I have half a tub of them here. I stripped a few down to use the aluminum plates, but half of them have formed plates with the same diameter but with the edges folded over for attachment or to form a box.
A lot of the stuff that came from that same place didn't make much sense as to why he had it. He seemed to just be storing it.
I can't imagine how much he was paying in storage fees at all of the storage centers. His daughter said so far she's cleaned out 7 of them, all of which isn't counting what was stuffed into his house, garage, and a huge storage shed. Along with over 100 tubs that were in a camper he had in the driveway.
I suspect I'll be the better part of another year just sorting through it all. Having all the common parts sorted though makes things a lot easier when I have something I need parts for. I just wish he had more test equipment there, all we found was a couple of vintage analog multi meters, a few high voltage power supplies, a resistor substitute box, and an old BK tube tester and about 20 lbs of Weller soldering irons and another 10 lbs of new tips.
I was hoping for a decent scope but the only one we found there was from the 50's and missing pieces.
What ever they were for I have half a tub of them here. I stripped a few down to use the aluminum plates, but half of them have formed plates with the same diameter but with the edges folded over for attachment or to form a box.
A lot of the stuff that came from that same place didn't make much sense as to why he had it. He seemed to just be storing it.
I can't imagine how much he was paying in storage fees at all of the storage centers. His daughter said so far she's cleaned out 7 of them, all of which isn't counting what was stuffed into his house, garage, and a huge storage shed. Along with over 100 tubs that were in a camper he had in the driveway.
I suspect I'll be the better part of another year just sorting through it all. Having all the common parts sorted though makes things a lot easier when I have something I need parts for. I just wish he had more test equipment there, all we found was a couple of vintage analog multi meters, a few high voltage power supplies, a resistor substitute box, and an old BK tube tester and about 20 lbs of Weller soldering irons and another 10 lbs of new tips.
I was hoping for a decent scope but the only one we found there was from the 50's and missing pieces.