extending transformer leads

[zimm]

Im working on a new build, using transformers from another amp. Problem is the tranny leads are too short. Any advice as to the best way to extend the leads? I was thinking of using comparable rated wire, and soldering and heat shrinking the the connections, or soldering a barrel connector between the old and new lead and heat shrinking. Any help is appreciated. Thanks!

[Phil_S]

I've done this a few different ways.

I don't care for the barrel because it is a big inflexible hunk of metal.

I've done the Western Union splice, soldered and covered with heat shrink. When you are done with that, you end up with something a bit more manageable than the barrel, but not that much better.

The last couple of times I did it, I make a hook on each wire, hooked together, soldered, and covered with heat shrink. If you do this right, there is a small lump inside the heat shrink, but it leaves you with the most flexible wire arrangement.

If you are adventurous and your transformer has a "friendly" configuration, you might be able to pull the end bells, find the actual connection to the winding and replace the whole lead. This is not for the faint of heart. It demands meticulous work, and be aware that the high voltage winding is done with very, very thin wire that is hard to work with.

In the end, if you've got the space and leads are long enough, the easiest execution is to put a terminal strip near the transformer. Bring the leads to the terminal strip, and use that as the junction point for the additional wire. Frankly, I like this one best.

Use whatever wire is appropriate for your circuit. On the high voltage secondary, I'd go for 600V rated 20 ga. For the filaments, 300V 18 ga is probably what's recommended.

Disclaimer: I am an amateur and this advice is worth what you paid for it. Confirm what's appropriate at your own risk.

--Phil

[Structo]

Another thing I have seen others do if you have the room, is to use a terminal strip near the OT wires and solder the OT wires to the strip then run wires from that to your power tubes and speaker jack.

[zimm]

Thanks, I like the hook idea, and considered the terminal strip but Im not sure that will work on this one. Its a d-style non hrm and my OT leads come out under the board. Im not sure they are long enough to have a strip off to the side. I thought the barrel was a bit heavy too. Ill look it over tonight.

[David Root]

Refresh my memory on the Western Union splice would you please, Phil. I can't remember what it looks like.

I have to extend most of the leads on my old Bassman iron in my current build, especially the PT. The terminal strip sounds good IF I have the space, which is dubious as I am cramming a 50W #13 ODS into a BFPR chassis.

[Structo]

[img:350:402]http://www.claytonengineering.com/Train ... g12-15.gif[/img]

I've kind of gotten away from that at least with stranded wires.

It works good with small solid core though.

For stranded wire I twist then tin the end and make the hooks like mentioned above.
Then I take my small needle nose pliers and smash each hook down tight.
Making a good mechanical bond before soldering it. Then heat shrink.

[Phil_S]

Refresh my memory on the Western Union splice would you please, Phil. I can't remember what it looks like.

Tom got this one in spades (thanks.) Didn't you learn this in 7th grade shop class? Opps, my age is showing. I was in the 7th grade in 1965-66. I suppose they did away with shop class sometime in the last 30 years or so.

Anyway, it is a cumbersome splice and works best where it was intended, in a telephone/telegraph line that was strung on a pole or wiring frame, not curled up in a guitar amp chassis.

[David Root]

No my shop class didn't do any electronics, unfortunately!