Questions about wire

[d. spree]

Couple of questions -

What are the thoughts regarding the relative merits of solid core versus stranded wire? I find solid core wire easier to work with. What considerations should be given when choosing, and is there differential use of each type based on where it is used in a circuit?

Second question is to do with gauge and place in the circuit. For example, in a tweed deluxe what are the recommended gauges for each stage?

[soundguruman]

Couple of questions -

What are the thoughts regarding the relative merits of solid core versus stranded wire? I find solid core wire easier to work with. What considerations should be given when choosing, and is there differential use of each type based on where it is used in a circuit?

Second question is to do with gauge and place in the circuit. For example, in a tweed deluxe what are the recommended gauges for each stage?

The problem being that solid core wire BREAKS.
Musical equipment is subjected to great shock and vibration, this breaks the wires easily. That's why we use stranded wire.
In the older days the solid wire was made (in USA) to withstand more bending and stress. You can still get vintage type wire, which works good in many applications. So, use solid wire, if you like it.
Also the insulation was made so you could "push back" the jacket and solder it, instead of stripping it...that worked well in amp production factories. It's faster.

Personally, I use fine stranded copper, silver plated, teflon covered, 600 volt rated, military grade (aircraft grade) hook up wire.
This is manufactured by Belden, and others...and I think that for my builds, there is nothing better.

Now some people say that teflon covered wire is "brittle." But, of course it's not. It's actually stronger, and more flexible.
I believe it is superior to any other type available, also 75 cents a foot. I guess you get what you pay for.



You gotta learn how to dress it correctly to use it properly. Just like any other part in an amp, the wire is only as good as the technician who installs it!

I would never use PVC wire, because I think it's too cheaply made, and the temperature rating is too low for a tube amp.
PVC becomes "baked" hardens, and the insulation cracks off and peels.
With teflon, the temp rating is more than DOUBLE. 190C ! I can use wire half as large, with no problem at all. (the limiting factor with ANY wire is the temperature rating of the insulation, and the ambient temperature)

I use 20GA (teflon) for most of the connections, and 18GA for the heaters. No problems at all.
We built some Marshall heads that used 16GA teflon for the heaters, 18GA for all else, but I think that was overkill.

[Bruce / Mission Amps]

I prefer 22g solid core for almost everything except speaker leads... where I always use a min of 18g to 20g stranded wire.

For the most part, you can use that 22g almost everywhere... including preamp tube's filament strings that are normally short anyhow... like something between 8" - 16" long... etc.

Look up mil specs on those 20g through 24g wires and you'll stop worry about I^R losses of any preamp tube filament current in a 10" to 20" pieces of 22g wire.

I do use solid core 20g between the two power tubes though.
But they are like, what?, .... a max of 3" apart....and that is about it.

For leads off the rectifier tube and standby switch, I prefer to use the 600v 18g or 20g plastic stranded wire... just as the tranny manufacturer uses.
But I have never had a flash over from any 22g solid core cloth wire in any case.

I've worked on LOTS and LOTS of old vintage vacuum tube VOX amps that used a ton of inexpensive plastic insulated 22g wire and unfortunately, many of those amps did suffer from brittle, vinyl covered broken wires.

Every once in a while I'll find a vintage fender amp (with it's 20g-22g cloth wire) and and find a broken wire too, but mostly (95% of the time) they are the stripped off bare wire from ground points on the eyelet board over to the brass plate.
The most common one is the ground wire from the phase inverter section to the brass plate.
I'm sure others have stories to counter this but I also have been doing this since the late 60's ...... lots of wires soldered.

[Ken Moon]

Try this little experiment for yourself:

Take a piece of 20 gauge solid wire and bend it back and forth in the same spot.
Count how many times you can do this before it breaks.
Then try it with stranded wire of the same gauge.
As you will see, the stranded wire can take a lot more bending before it breaks.

However, if you use solid wire and only bend it once to wrap around a terminal or into an eyelet, and you aren't using the solder as a mechanical connection, it will last a very long time (probably longer than you'll live).
The same goes for vibration - if solid wire is properly installed, terminated and soldered, it will not be moved by amp vibration, and therefore won't break.

For me, I use 20 ga silver-plated teflon-coated stranded wire for everything but the heaters, where I use 18 ga. I like teflon because it doesn't melt while soldering. I also use liquid flux on all connections to get a good solder flow. I've bought a lot of wire on eBay and from Steve at ApexJr.com.