Need help deciding best way to route power transformer wires.

[Mike_J]

The PT for my amp has a stand-up style.  One side of the transformer has the 120 V primaries and the B+ wires and the other side of the transformer has the 6.3 V and the bias supply wires.  My question is if I twist the pairs together can I run the heater wires and the B+ wires  by each other on the outside of the chassis?

Thanks
Mike

[sluckey]

Sure you can. You don't even need to twist them.

But why? Putting the PT wires on the outside of a chassis exposes them to possible abuse. I would rethink my layout if I was considering putting those wires outside the chassis.

[hesamadman]

How big is the chassis and what's the amp model. Like Sluckey said, best to not run outside of chassis but I've had situations where I had to. I've used various things to protect the wire and hot glue to hold it.

[Mike_J]

Sure you can. You don't even need to twist them.

But why? Putting the PT wires on the outside of a chassis exposes them to possible abuse. I would rethink my layout if I was considering putting those wires outside the chassis.

Sluckey

I just wanted to make sure I can run these wires in close proximity to each other.  There is no reason that I can not run them inside the chassis.  Is it the fact that they are AC wires the reason they can be run close together?

Thanks
Mike

[Mike_J]

How big is the chassis and what's the amp model. Like Sluckey said, best to not run outside of chassis but I've had situations where I had to. I've used various things to protect the wire and hot glue to hold it.

Hesamadman

Good name, wish I thought of it.  The chassis is 25-1/2" X 8-1/2" X 3".  It is based on Sluckey's Plexi/800 layout and schematic with OD and an active effects unit thrown in.  It also has a separate tone stack for both preamps.

Thanks
Mike

[terminalgs]

Depends a lot on the chassis/cab design.  I did this with excellent results:





but, i put a cover plate over the top of the chassis:







made for a tidy under-carriage.  you can see the MAINS wires are on top of the chassis, and exit at the rear near the fuse, and enter near the front on a grommeted hole near the power switch.





Not really practical, and not really necessary.  It was a build that I thought "what if I...".,  and it worked.  But I think it would have worked fine with everything inside the chassis as well.

[Mike_J]

Depends a lot on the chassis/cab design.  I did this with excellent results:





but, i put a cover plate over the top of the chassis:







made for a tidy under-carriage.  you can see the MAINS wires are on top of the chassis, and exit at the rear near the fuse, and enter near the front on a grommeted hole near the power switch.





Not really practical, and not really necessary.  It was a build that I thought "what if I...".,  and it worked.  But I think it would have worked fine with everything inside the chassis as well.

Terminalgs

Very nice looking build.

Thanks
Mike

[PRR]

> make sure I can run these wires in close proximity to each other.

Yes.

Close, not wedged-in so tight that the insulation will saw-through over the years of bad roads.

I'd also like to keep an air-gap between the 120V wall-wires and everything else. Laying 1/8" apart is plenty. Just so there is NO chance you or your grandkid will have wall-power on the guitar or amp-knobs.

[Mike_J]

> make sure I can run these wires in close proximity to each other.

Yes.

Close, not wedged-in so tight that the insulation will saw-through over the years of bad roads.

I'd also like to keep an air-gap between the 120V wall-wires and everything else. Laying 1/8" apart is plenty. Just so there is NO chance you or your grandkid will have wall-power on the guitar or amp-knobs.

PRR

Thanks for the reply.  What is your opinion concerning twisting the AC wires?  I know you have to twist the heater wires but are there any others that you would twist.  I looked at the Dumble 124 pictures and he twisted the heater wires and ran the other wires with wire wraps on them to keep them together.  Like you said the 120V wall wires were separated from the secondary wires.

Thanks
Mike

[sluckey]

There is no technical reason to twist the PT wires. I do it because it puts wires in easily identifiable groups and just looks neater to me. Here's a pic of a '64 Deluxe Reverb PT. See how easy it is to identify the PT wires? That amp would work just as well without a single twist in any of those PT wires.

You still want to keep all those PT wires away from sensitive signal circuits.

[PRR]

Heater wires HAVE to go near sensitive audio points.

Wall-power and HT rectifier wires usually DON'T (and shouldn't) go near audio.

If you have a poor layout, like power switch in the middle of a bunch of audio controls, twisting and shielding might help, but in my experience never enough. My preference is to keep all that power stuff in a separate box, but this is awkward. Keeping power junk right-rear and early audio stages left-front (or verse-visa) usually does OK for guitar work.

[Mike_J]

There is no technical reason to twist the PT wires. I do it because it puts wires in easily identifiable groups and just looks neater to me. Here's a pic of a '64 Deluxe Reverb PT. See how easy it is to identify the PT wires? That amp would work just as well without a single twist in any of those PT wires.

You still want to keep all those PT wires away from sensitive signal circuits.

Sluckey

Thank you for the response.  Had another question.  Can I run the choke wire going to the HT B+ together with the OT CT wire?

Thanks
Mike

[sluckey]

yes