OT Lead problem

[Drifting]

Last night I was wiring the OT leads to the impedance switch and screwed up. I must've misjudged, and ended up cutting the lead for the 8 ohm impedance too short. It is literally 2 cm too short to reach the terminal. It can make it if I tug at it, but I'd assume it's a bad idea to solder a wire with tension on it.

Is there anything I can do to remedy this...? I really don't want to buy another transformer. I also discovered I can't open up the tranny to re-attach the longer remaining wire at the transformer. Well maybe I can, I unbolted it, but didn't want to try and take it apart any further or damage it.


This is for a Metro 45 build by the way, thanks

[thousandshirts]

It's nothing to beat yourself up over. It happened, and sure, it shouldn't have happened, if you measured more carefully, but that being said, at least it probably won't happen again!

However, this happens. I've had to deal with a few amps (Traynors and Garnets) that were butchered by other people at some point in history, and had to make up a bit of distance. What you can do is splice some extra wire onto the end. Preferably use the same color and same interior diameter (so the actual core of the wire is the same diameter) type of wire. There are a number of different ways to splice two wires together, but whatever you do, don't use a marrette.

We really like a good mechanical connection in soldering. It's not always possible, but we try. So you could bend the end of each wire into a little hook, and join the two. You can get an idea of the 'hook' method here: http://www.teamnovak.com/tech_info/how_ ... index.html" onclick="window.open(this.href);return false;

Some OT's have solid core wire, and some have stranded. If it's stranded, you can kind of give each one a bit of a "DNA" helix, and then thread them together kind of tight, and then get them soldered up. Something like this: http://www.ehow.com/how_4487788_solder- ... n=yssp_art" onclick="window.open(this.href);return false;

Alternatively, you could rely on solder alone to hold the joint. If you do this, be sure to get at least 3/4" or 1" of a joint. Lay the wires out so each one has 1 1/4" bare wire or so, and pre-tin them; get them ready. Then be sure your joint runs nice and straight. Don't over-solder, but be sure you have a good connection along a good (3/4" or a bit more) length, connecting both wires side by side. Make sure you've done the job thoroughly. Use test wire and practice on your test wire by giving them some tug tests. NASA doesn't ask for a full 3/4", that's my own figure. Here's the NASA page: http://workmanship.nasa.gov/guidadv_rec ... splice.jsp" onclick="window.open(this.href);return false;

Finally, no matter which way you figure out to do this, you're going to want to get some shrink tubing. Be sure to put more than one layer of shrink tubing on. Cover any bare wire that you've spliced. When you're shrink tubing is where the hook method or joints that use wrapping or twisting become problematic, because parts can bulge or poke out of the shrink tubing. Just try to take it easy, though, practice up with some scrap wire, and you'll be fine.

And if you want to see a real involved way (requires stranded, non bonded wire):
http://jaguar.professional.org/electrics/splicing.php" onclick="window.open(this.href);return false;

Those Jaguar guys have to make LOTS of repairs.

There are also connectors made; 'solder sleeves.' http://www.skygeek.com/solder-sleeves.html" onclick="window.open(this.href);return false;

[Drifting]

It's nothing to beat yourself up over. It happened, and sure, it shouldn't have happened, if you measured more carefully, but that being said, at least it probably won't happen again!

Besides the actual technicalities of building the amp, managing my frustration has def. been the hardest part of the process, although this is my first real mishap, so far. Having Italian and Irish blood does not help this My actual reaction to cutting the lead was much less polite, I'll leave it to interpretation.

However, this happens. I've had to deal with a few amps (Traynors and Garnets) that were butchered by other people at some point in history, and had to make up a bit of distance. What you can do is splice some extra wire onto the end. Preferably use the same color and same interior diameter (so the actual core of the wire is the same diameter) type of wire. There are a number of different ways to splice two wires together, but whatever you do, don't use a marrette.

I've got tons of the same color lead left, having cut it too short, so that should work out. I've heard of splicing wires for more low-key stuff like pickup leads, but was unsure if trannies were a more serious matter. I noticed some other trannies, Marstran I think, had external terminals, is this what they're there for? To be honest, I have no idea what a marrette is Sounds like some girl I dated.

Some OT's have solid core wire, and some have stranded. If it's stranded, you can kind of give each one a bit of a "DNA" helix, and then thread them together kind of tight, and then get them soldered up. Something like this: http://www.ehow.com/how_4487788_solder-" onclick="window.open(this.href);return false; ... n=yssp_art

Alternatively, you could rely on solder alone to hold the joint. If you do this, be sure to get at least 3/4" or 1" of a joint. Lay the wires out so each one has 1 1/4" bare wire or so, and pre-tin them; get them ready. Then be sure your joint runs nice and straight. Don't over-solder, but be sure you have a good connection along a good (3/4" or a bit more) length, connecting both wires side by side. Make sure you've done the job thoroughly. Use test wire and practice on your test wire by giving them some tug tests. NASA doesn't ask for a full 3/4", that's my own figure. Here's the NASA page: http://workmanship.nasa.gov/guidadv_rec" onclick="window.open(this.href);return false; ... splice.jsp

My OT leads are stranded, I think I'm going to go with one of these two methods. Maybe the NASA one, it looks like the heat shrink would lay down more evenly on that surface.

Would 3 layers of wrap be enough to cover the leads? I'm assuming this is to lower the noise floor, or is it a safeguard from the joint ever seperating?

Those Jaguar guys have to make LOTS of repairs.

BMW's are like that too. Amazing vehicles, but the electronics were shit. At least they used to be.


Thanks again for all the help, I appreciate the time you guys put into helping me and other noobs out.

[thousandshirts]

I noticed some other trannies, Marstran I think, had external terminals

This is mainly for power transformers, and almost always with such PTs, the voltage taps are still hardwired. Still it's nice to have those solder lugs, and cut your own wires, in some ways. At least I like it anyways

To be honest, I have no idea what a marrette is Sounds like some girl I dated.

Ahh, my bad. Marrettes are those yellow, orange, or black plastic nubs that electricians use to make connections in house wiring. You can see them all over the place. They look like this:

My OT leads are stranded, I think I'm going to go with one of these two methods. Maybe the NASA one, it looks like the heat shrink would lay down more evenly on that surface.

Yeah. It definitely is a cleaner looking splice after being jacketed.

Would 3 layers of wrap be enough to cover the leads? I'm assuming this is to lower the noise floor, or is it a safeguard from the joint ever seperating?

Well, it's for electrical insulation, number one. You don't want bare wire making contact with the chassis. Preventing noise and hum is another thing. And helping to hold things together is another. Keeping moisture out... all of the same things that normal insulation jackets do.

Thanks again for all the help, I appreciate the time you guys put into helping me and other noobs out.

Glad to be of assistance.