Solid Core Hookup Wire - Point to Point Wiring.

[Nanozeugma]

Hi.
Background:
Restoring a Heathkit MA12 power amplifier.
Chassis / Transformer Housings / Valvebase cosmetics seen better days.
Decided to strip out everything, refinish, replace valveholders.

Small problem:
The point to point wiring (red, orange, yellow, brown, green) appears to be (nearest modern equivalent) 20 AWG PVC insulated solid core tinned copper.
Conductor reads 0.8mm, with insulation 1.75mm (approx.)

For some reason, it appears you can get as much 1/0.6 solid core as you want (23 AWG) in a multitude of colours - try getting 1/0.8 (20 AWG equiv) - good luck!
It would probably DO except that 1/0.6 appears to be rated at 1.8A which is a bit low given that the GZ34 draws 1.9A and the rest of the valves combined draw 2.02A (2x EL84 1x ECC83, 1x EF86.)

I finally found (today) a supplier (Chinese) on Amazon that supplies reels of 20 AWG (six 8m spools) in six colours and have ordered some to try.

Why, one asks is it so difficult to source 20 AWG?

Att: A couple of images of a piece of the original wiring.

[wireman]

RS Components?

[G6ONEDave]

I am currently using a bobbin of TCW 20 wire copper tinned. It has the name H.C. Rowland & Co printed on the label, I think that this is the same as 30 Amp fuse wire. Sorry I can't remember where I got the bobbin from, possibly a radio rally or one of the electrical component suppliers such as CPC, Farnell, RS Components etc.

[GrimJosef]

CPC appear to have 67 products in stock meeting the 'PVC insulation' and '20awg' gauge criteria. 43 of them have an external diameter between 1.6mm and 1.8mm.

https://cpc.farnell.com/w/c/cable-le...e=inc-in-stock

Cheers,

GJ

[David G4EBT]

Tuofeng 20AWG (.08 mm/032") has been listed on Amazon for quite some time.

(20AWG the equivalent of 21SWG, which for hook-up wire, which would be a non-standard gauge in the UK):

https://www.amazon.co.uk/TUOFENG-Wir...085TPC8GZ?th=1

Lots of sellers on eBay too, but you may find that unlike enamelled wire for winding transformers or coils where listing the wire as AWG/SWG tends to be the norm, hook-up wire is often listed primarily not by diameter, but by cross sectional area, which - in terms of current carrying capacity - is perhaps more meaningful. 20AWG is 0.5 sq mm, so if you search for 20AWG you may not find it, but you will if you search for 0.5sq mm.

You'll notice that the offering at this link lists 20SWG as 0.5sqmm:

https://www.ebay.co.uk/itm/0-5mm-1-0....c101196.m2219

However, that's thin-wall insulation rated at 60V max, and I guess some of your wiring will be well in excess of that, so it wouldn't meet your requirements.

However, the solid core 0.5 sq mm/20AWG wire listed below is rated at 300V RMS, so that is reflected in the price:

https://www.ebay.co.uk/itm/1m-1-0-8m...-/233397557010

Some feedback on the wire you've bought would be of interest when you've had an opportunity to use it.
(Ease of stripping, melt-back when soldering etc).

Good luck with the restoration.

[Nanozeugma]

To all that offered their thoughts and comments, my thanks.

To David specifically:
Tuofeng is what I ended up ordering.

The thin wall offering (second suggestion) strangely though listed as single core, is illustrated as stranded and, as you say, appears to be low voltage rated.

I do actually HAVE some of the Alpha Wire, (third suggestion) bought some time ago as it looked useful, but on digging it out felt that the insulation looked very thin.

Regarding reporting back on the Tuofeng, I will if I remember. The lead time (probably conservative) goes into April and although facilitated by Amazon quite likely comes straight from China. We shall see...

[Gabe001]

I have some of this on order from china (AliExpress), in multiple colours. 20awg, rated 300v. It's taking a while to get here, but they always do in the end.

Gabriel

[G6ONEDave]

Sorry my mistake, thought you were referring to bare hook up wire. You might try looking for conduit cable. Standard single solid core copper types are 0.75mmsq, 1.0mmsq and 2.5mmsq and they come in a few colour varieties. I think there also used to be a 0.5mmsq but that might be harder to find now. 4mmsq and above become multi-stranded. The ref code was 6491x or /y, the stranded flexible version code was 2491x, sometimes referred to as instrument cable. Both types are insulated bare copper wire (not tinned) and are normally rated upto 1Kv, as they can be used for 3 phase wiring.
Dave

[Nanozeugma]

For David (if he's still interested) re:
"Some feedback on the wire you've bought would be of interest when you've had an opportunity to use it.
(Ease of stripping, melt-back when soldering etc)."

Took delivery of the TUOFENG wire this morning.
Chinese manufacturer, ordered via Amazon.
Package ordered 7/3 delivered by RM 16/3 (the estimate was 24/3 to 3/4.)
The product appears to be of decent quality.
Tinned copper conductor is 0.8mm (20 AWG) with insulation 1.8mm. PVC insulation therefore 0.5mm thick.
As supplied, the six individual spools are Cellophane wrapped to keep the wire close wound on the spools. The box is pierced to allow each colour to project through.
The Amazon illustration gives a false impression of size, attached images correct.
No trace of Ferrous metal in the mix detected (magnet,) just decent tinned copper.
PVC insulation cuts readily with a Swann Morton scalpel blade and slides easily off the conductor.
Conductor accepts solder readily at 420 deg C.
No excessive shrinkback of insulation beyond that anticipated (there is some, obvs.)

Given price / delivery time / quality, recommended.

[David G4EBT]

Thanks for the update.

As you say, the pics on Amazon are a bit misleading.

It looks good stuff from your pics.

Good to hear that it strips easily and doesn’t appreciably melt back.

Every success in restoring your Heathkit MA12 Power Amplifier.