Any wiring guidelines re: wire height from chassis?

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Bob Simpson
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Any wiring guidelines re: wire height from chassis?

Post by Bob Simpson »

While wiring the 12ax7 sockets in, I'm trying to leave just enough wire to chopstick around, but is there a rule of thumb as far as which wires are airborne, and which should hug the chassis?

TIA

Bob Simpson
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Phil_S
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Re: Any wiring guidelines re: wire height from chassis?

Post by Phil_S »

The conventional wisdom is to raise heater wires into the air and keep the rest close to the chassis, though you could also do the reverse.

It is wise to leave a bit of slack in the wire, but that isn't related to whether it's on the chassis or i the air. One reason is for "service" and the other is to prevent stress.
Bob Simpson
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Re: Any wiring guidelines re: wire height from chassis?

Post by Bob Simpson »

Thanks, Phil_S.

I remember reading a post or two here ( I tried the search... )
where the builder was talking about wiring in several planes, but I don't
remember which ( grid, cathode, plate... ) wires were in which plane...

and whether that's really what the concept was anyway...

Bob
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Structo
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Re: Any wiring guidelines re: wire height from chassis?

Post by Structo »

I would put the grids flat against the chassis.
Then cathodes above those with plates higher yet.

But sometimes you can get some good overtones if you run the plates and cathodes together ala Dumble.
Tom

Don't let that smoke out!
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Cygnus X1
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Re: Any wiring guidelines re: wire height from chassis?

Post by Cygnus X1 »

When doing a total conversion or a scratch build I lay the filaments flat to the chassis then fly everything else over.
I criss-cross everything else to minimize high voltage to low voltage reactions.
Looks ugly, works fine for me.

The amps are really quiet when I do it this way.

But then I might learn something else to change my mind later!
Last edited by Cygnus X1 on Wed Aug 19, 2009 1:57 am, edited 1 time in total.
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briane
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Re: Any wiring guidelines re: wire height from chassis?

Post by briane »

Yes.

though I think everyone likely has different rules for it. I think for me its what I have done in the past that results in zero humm.

right angles, no touching wires of course.

I tend to think grounds should hug the chassy, as its near ground potential. that said the common practice on the cathodes I believe is to run them in the air, though of course best not to cross the grids at all.
it really is a journey, and you just cant farm out the battle wounds
Normster
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Re: Any wiring guidelines re: wire height from chassis?

Post by Normster »

Bob Simpson wrote:Thanks, Phil_S.

I remember reading a post or two here ( I tried the search... )
where the builder was talking about wiring in several planes, but I don't
remember which ( grid, cathode, plate... ) wires were in which plane...

and whether that's really what the concept was anyway...

Bob
That was probably me...several years ago. I tried several builds with the cathode wires against the chassis, grids about 1/4" above, and plate wires about board height. While it worked well and never created lead dress problems, I now elevate heaters and keep the rest of the wiring against the chassis. The exception is when I wire TW/Komet style amps. Then it's heater wiring against the chassis and elevated plate/cathode/grid wires.
briane wrote:... it really is a journey, and you just can't farm out the battle wounds.
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Structo
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Re: Any wiring guidelines re: wire height from chassis?

Post by Structo »

Yes, I suppose it all depends on how you wire your heaters.

The Fender way is to route the heaters high over the top of the sockets while the Marshall way is to put them on the floor near the back of the chassis.

On my D'Lite I chose the Marshall way because I installed an Ironsounds effects loop and the heater wiring would have been too close to that had they been over the top.
Tom

Don't let that smoke out!
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