proper installation of pots/jacks/switches

[john t]

Ok don't laugh, I have seen carling swithes installed in two configurations. Some with the round nut on top, and some with the six sided nut on top or the nrarest the toggle. Which is correct. Also the input jacks have a flat washer. In most photos I have seen of vintage tweed amps it appears the washer is directly under the nut. I have two sixty something amps and a reverb unit. No washer under the nut. I know it does not matter ,still what installation is correct.

John Thanks

[Tom Phillips]

proper installation of pots/jacks/switches

John,

I won't say one way is more "correct" but here are my comments:

Switches: For most installations I put the hex nut on top. This is for practical reasons because its easiest to tighten without damaging the front panel. (Using a hex driver not pliers is best) For cases where I want a more trimmed out look I put the kernelled nut on top. There are special tools available to tighten these or, if you have clearance in the back, you can snug up the hex nut on the rear.

Jacks: I like to use the flat washer under the nut and that seems to be the old traditional way. However, if the flat washer is missing I don’t go out of my way to replace it.

Regards,
Tom

[Bruce / Mission Amps]

I use the hex nut on the top of the chassis with an aux 1/2" star washer under the chassis and above the round finish nut.
I think this is backwards buts works the best and it's easy to toghten with the star washer under the chassis.

[jlatrace]

You have great tips. I have struggled trying to tighten those &^%$#@ finish nuts on carlin switches with pliers for years. I'm going to use the hex nut from now on. Thanks,
Les

[Enzo]

Just lose the idea of "correct" when it comes to appearance items. There is no "correct." The round knurled nut is intended as an attractive finish item - if you feel like it. I have one of those round wrenches for it around here somewhere, and I have not used it in at least 20 years. Put the hex nut out and be done with it.

If your flat washer is gone, no big. I am anal enough, and I have a large bag of them, so I do replace the flat washer if it is missing. But that is me.

[Rob Mercure]

I've recycled a lot of mil surplus items - which generally dispense with the knurled round nut - and the common mounting is a hex nut on the jack,etc, shaft then an internally toothed lock washer then the chassis then the common washer and then the final hex nut. Sometimes there are two internal hex nuts "locked" against each other to set the mounting distance. Or at least this was the common practice for mid 1950s to mid 1960s military tube equipment. I'm sure that there are contract mil-specs for the components but most variants I've seen have been for specialized pilot lights and fuse holders.

Rob

[Tom Phillips]

I have learned a lot of useful construction techniques as well as salvaged some really nice parts by stripping down old military as well as high grade commercial equipment. (Like 1950's & 60's Tek & HP stuff)

[Enzo]

I started learning electronics in the mid 1950s, and i would go in the alley behind the local TV repair place and take TV chassis they were throwing away. I would strip them down for parts. I am sure there are still some odd ancient resistors in my drawers from that era.

I discovered military surplus a few years later, like maybe 1962. In the Washington DC area we had some outlets for WW2 stuff. Lots of great old radars and other odd things sold by the pound? WOnderful high quality Ohmite and AB pots, and tube sockets and knobs and switches, transformers, tubes. I loved taking that stuff apart and trying to save parts. Learned a lot about how things were put together. Got a lot of screws and nuts too.

To this day, I still enjoy taking things apart and stripping them down. I cannot throw away a dead VCR without stripping it. If nothing else, it is a great way to build up your metric screw collection.

Something we have here, you might have in yuor areas. Michigan State University is here. 45,000 students, a very large facility. Lots of engineering and other science. Various labs and other things in the MSU campus become obsolete or not worth repairing - to them - so they get rid of them. MSU doesn't throw them out, they send them to the Salvage YArd at the edge of campus. The people ther sell things to try to recoup some of the expense of the item. Sometimes there ore just silly things there, but I have seen working scopes. I once bought an old HP 200 audio oscillator for $5. Didn't work. Took it home, straightened the bent plate on the variable cap, and all was well. FOund an old bench power supply for $5. Had 6VAC, and a variable B+ supply. My prize was a Grass Labs Polygraph. For $15 got a very nice 5' rack on top quality wheels, and all the sense amps in the rack - for the sensors they strap to you - were tube based. Of course sometimes you just want an old desk of file cabinet - got them too. Check with your local large institute of higher learning for some sort of salvage facility.

[Steve Conner]

OMG Enzo, you have a Grass Labs polygraph? I saw one of those at the university where my dad used to lecture, and drooled thinking of all the Telefunken 12AX7s that must have been inside. But they wouldn't let me have it One thing I always wondered: It seemed to have a regulated power supply in the bottom of the rack. Was it tube regulated and what series pass tubes did it use?

I have got some good salvage from universities, though, since I work for one. A couple of years back the engineering department threw out a pile of tube based equipment. I couldn't move the actual gear as it was too big and heavy, but I stripped all the tubes out. I got some Mullard EL34s (sadly the double getter kind) some GEC KT88s and best of all a pair of RCA blackplate 6L6s that had hardly been used. They mostly seemed to have a lot of life left, and my amps have been running on this stash of vintage power tubes ever since. I do keep some Russian tubes around for testing new builds though, and I'm a sucker for the look and tone of the new "Tung-Sol" 6550s.

I always put the hex nut on top too, and stick behind the panel whatever combination of nuts and washers is needed to get the right mounting position and stop the component from coming loose. I have managed to mar some front panels by trying to tighten the hex nut with an ordinary spanner instead of a socket.

[stokes]

"I started learning electronics in the mid 1950s, and i would go in the alley behind the local TV repair place and take TV chassis they were throwing away. I would strip them down for parts. I am sure there are still some odd ancient resistors in my drawers from that era."
I remember going into an old barn in upstate NY back in the '60's and finding what amounted to a TV and radio grave yard,spent half my summer stripping transformers and whatnot.Used the trannies in a few "clone" projects and they are still working today,as well as every other component you could think of.My tube matcher has a nasty old rusted PT that came out of that junk pile,still works fine.One mans garbage...

[Enzo]

I could have bought three polygraphs, but didn't feel like schlepping them in my truck. This model did not have a master power supply, each sense amp had an AC cord plugged into a two space power strip. On front a row of toggles for a row of outlets on the rear. On each amp chassis was a power transformer for that module alone. The module was a 3-space.

Hey, I have one of them sitting here - the power supply subsection anyway.

PT is one of those round hermetic jobs, about 10cm diameter and 12cm tall. 13 little solder lugs sticking out the center on bottom. It had a couple CT HV windings and a couple 12v windings. Also a 5v winding for the 5Y3 recto. Vreg done with 12AQ5s and 0A2s. A couple 12AU6 gain tubes for the reg tubes. Don't have the amp section here, but it was full of Telefunken 12AX7s, yep.