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In Reply to: RE: Two-Wire Cord is Extremely Hazardous posted by Triode_Kingdom on July 09, 2021 at 21:05:54
If you were interested in a retrofit?
Punching the IEC hole in the 16ga Stainless Steel chassis could be a problem. I don't thnk a regular 'nibbler' would work. Chassis punch is $$$ for a one time use.
MIght be easier to take a drawing to a machine shop and let THEM do it? This prior to any assembly.
Before any of that? make certain you have enough clearance behind connector......
Too much is never enough
Follow Ups:
I don't think a machine shop can punch that after the chassis is formed. Buy a Heyco strain relief to fit a 3-wire cord (16 or 18 gauge) and file the hole to fit. Incidentally, contrary to popular belief, many stainless alloys are no harder than mild steel.
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Buy Chinese. Bury freedom.
I would suspect a 300 series stainless.....Austentitic / non-magnetic......Available in the 16ga thickness and not expensive.
Still and all, 18% to 20% Chromium.......and a smattering of 'other'.....Including Nickel?
But I DO suspect it's pretty tough.....
I DO have a strain relief fit for CL2 wire.....I can't find the dimensions now, but it does work.
I used one on my KENWOOD Integrated when I re-corded it, up from 18ga to 16ga
i wonder what OTHER stainless alloy qualifies? I think 400 series is magnetic, mostly, while stuff like Invar and Monel are much more $$$......
Bob Latino himself answered my post about nibbling or punching the chassis....and he was not optimistic about the prospects...
Too much is never enough
"Bob Latino himself answered my post about nibbling or punching the chassis....and he was not optimistic about the prospects..."
And he's right. A small taper file (triangular) and small rat-tail file will take care of this. It's a half-hour job at most to carefully make it exactly right for the Heyco. Be sure to use calipers to measure the strain relief before filing the chassis. They aren't always the exact size specified in the data sheet. If you make the hole too large, there's no going back.
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Buy Chinese. Bury freedom.
As you noted, not ALL stainless is 'created equal'....though by definition, must start at about 18% Chromium content. Without getting 'exotic', VTA probably commissioned a 300 series alloy. Some other VERY exotic alloys exist, like H1 which SPYDERCO uses to make knives for the marine enviroment which essentially WILL NOT CORRODE.......And they are $$$......
I'm looking at both the DRAWING and the PHOTO of the complete amp and I'm not certain of the clearance between an IEC connector and the transformer. I do NOT know how far 'below' the 'deck' the transformer protrudes nto the lower part of the amp.....The image doesn't have the 'depth' I'd like to confirm and no mechanical drawings are offered.
There IS space if the connecter were mounted on the TOP of the amp, 'prongs down'.......You would not need the 3rd wire unless you measured voltage from chassis to neutral.......You could check this easily using a GFI circuit in-house.
IF you could trace such voltage to the power transformer....IMO the only 'real' possibility, could a shielf of MuMetal fix the issue?
The Fix would take 2 minutes.....TOPS.......
Too much is never enough
IMO, the IEC hole is way too much trouble to cut. The Heyco is simpler and much faster, especially in stainless. Plus, you already have a "starter" hole at that location in the chassis. Even if you don't measure voltage to earth ground (highly unlikely), faults can occur at any time. There's no substitute for the three-wire cord in any piece of equipment installed within an audio system. Ix-Nay on the mu-metal.
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Buy Chinese. Bury freedom.
We were rewiring the utility and other switched outlets (all 110) on an ION IMPLANTER. The IDIOT that did the work managed a hot / neutral swap and the ENTIRE CHASSIS was HOT. Of course, he worked nites and was GONE for the next 2 weeks on vacation.
I've been around a LOT of high voltage. In E-Beam metals evaporation, the voltage is around `13kv.
I'm linking the manual. You'll see a FULL POWER Triode in the circuit. This was a WATER COOLED device and required a certain water purity since it was part of the circuit. A lot of current, too.
Ion implaneters have a 20kv Extraction PS which gets the ball rolling and the ions into the acceleration tube. Which is up to 200kv. The Glassman Power Supplies were mostly AIR as an insulator.
Wafer Fab, where I worked as a process and maintenance technician (2 differetn 'careers') was a dangerous place to work. All sorts of nasty chemistry.
So you don't have to convince TOO hard for me to go 3-wire to an amp.
I have MANY horror stories. How about a wrench dropped on the inputs of a trasnformer the size of a coffee table? Wrench simply vaporized with a VERY loud noise. Or the guy who was reaching Uder the base plate of an evaporator and got ZAPPED by the power supply? Or the METER we turned to charcoal whey measuring high voltage......I think it ARCED arounnd the HV probe shield and that was IT.
Lot smore funs stuff.
So In short? I REALLY appreciate your safety bias. Only thing? I have small bits for a DREMEL and may be able to get that hole right. I need to get a cord / relief 'set' so the cord workss with the relief.
Too much is never enough
Here's a 16-3 strain relief. 0.55 ROUND hole.
I could drill to 1/2" and GENTLY expand to correct size.......
I'd have to check out cordage, first, though.....
Too much is never enough
It's not round. The hole is either a D shape or an oval with two flat sides. That's what keeps the cord and relief from rotating in the hole. Check the data sheet for Heyco strain reliefs, you'll see what I mean. Also, there's a special tool to install these that prevents damaging the plastic. It compresses the relief into the cord while you push everything into the panel. I think you can find the tool on eBay, made by Philmore.
Coincidentally, I just ordered reliefs and 16-3 cords from Antique Electronic Supply. The part numbers are below, in case you want to look at the full descriptions. These are going into the amps I'm currently building.
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Buy Chinese. Bury freedom.
Other styles exist.......at least one for a round hole.
But I agree.. INSTALL is important and hole size critical. The one I just did on my ancient Kenwood is IN THERE for good....Well, I could get it out, but it is a real press-fit.
As the amp is issued? I'm not really in love with the simple Grommet used. That can be improved for minimal effort.
Too much is never enough
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