building etiquette

[dorrisant]

That seems to work. Thanks again Phil!

[pompeiisneaks]

Cool, yeah I had to dig around and found another spot where the actual permissions were set and figured it out.

[Rockwell666]

count me in for the PCBS!

[FourT6and2]

I'm pretty OCD when it comes to lead dress as well. I just bought a rather expensive amp. I took a peak inside the chassis and the build quality is... not what I expected.

[TUBEDUDE]

. Why....I would even return as a TAG participant rather than a judgemental bickering lurker asshole.
[/quote]

I'm tempted to make this my signature tag line. With a rep of "Judgemental Bickering Lurker Asshole", i'd set expectations low enough that my posts would appear brilliant and complementary by comparison.

[R.G.]

But meanwhile, back on hand-built vs PCB, I remembered during my comments on hookup wire that I really love the look of hand laced cabling. Hand lacing with waxed Nylon tape is just so vintage-cool and tidy that I got hooked on it and now have my very own lasts-a-lifetime spool of lacing tape and enough practice to make the stuff work right. I hand laced the wiring harnesses on the 3D printer kit. Looks great, to me at least.

I can come up with some links if there's any interest.

[pompeiisneaks]

Oh absolutely, I love that stuff! Links would be welcome from my end!

~Phil

[TUBEDUDE]

Waxed lacing was how we wired aircraft when i was in the Army. The wiring harmesses were compact, out of the way, and impervious to vibration. And pretty. Of course there was 400 Hz coupled to all the lines, no big deal, a little buzz in the headsets. I'm not sure how its implemented in audio amps. Seperate bundles for high current lines and low level/high impedance lines, sheilded wires?

[R.G.]

Oh absolutely, I love that stuff! Links would be welcome from my end!

These two are where I started:
http://www.dairiki.org/hammond/cable-lacing-howto/
http://archive.hnsa.org/doc/cabling/part5.htm

This is a derivative one that links those two:
https://makezine.com/2009/07/28/lost-kn ... le-lacing/

Wikipedia is good for the links to other stuff at the bottom:
https://en.wikipedia.org/wiki/Cable_lacing

More tidbits:
https://maritime.org/doc/cabling/part5.htm
https://tecratools.com/pages/tecalert/cable_lacing.html
http://www.aeroelectric.com/articles/ca ... _lace.html

But even more important - get some string, or better yet, waxed tape, and practice. Think of your wires as a guitar...

Amazon has spools of waxed tape for under $20. The wax helps the knots pull tight and "stick". I love the blue-handled "soldering aids" that I found at Frys and Harbor Freight, especially the hooked one, for a lacing tool.

[R.G.]

Waxed lacing was how we wired aircraft when i was in the Army. The wiring harnesses were compact, out of the way, and impervious to vibration. And pretty. Of course there was 400 Hz coupled to all the lines, no big deal, a little buzz in the headsets. I'm not sure how its implemented in audio amps. Separate bundles for high current lines and low level/high impedance lines, shielded wires?

Like all issues of noise coupled in cables, you have to know what signal is in each cable and what the driving and receiving impedance on each end of the wires is. You definitely don't want to cable un-shielded grid wires parallel with heater wires and/or output tube plate wires. But you either already know that, or will find it out quickly even if you don't lace cables. Anything other than knowing the signals in each wire and what it can and can't go with is going to be a noise and hum disaster no matter what cabling scheme you use. That idea starts out with layout on the chassis to keep input, output and power things as far away from one another as possible, and carries right through wire routing.

One nice side benefit of laced cables is that if you lace everything but the grids, you have more 3-space to run the sensitive wires around in. They don't all have to be laced in bundles. Like the song says, you gotta know when to hold 'em, know when to fold 'em.

[pompeiisneaks]

Outstanding stuff, thanks!

~Phil

[TUBEDUDE]

Waxed lacing was how we wired aircraft when i was in the Army. The wiring harnesses were compact, out of the way, and impervious to vibration. And pretty. Of course there was 400 Hz coupled to all the lines, no big deal, a little buzz in the headsets. I'm not sure how its implemented in audio amps. Separate bundles for high current lines and low level/high impedance lines, shielded wires?

Like all issues of noise coupled in cables, you have to know what signal is in each cable and what the driving and receiving impedance on each end of the wires is. You definitely don't want to cable un-shielded grid wires parallel with heater wires and/or output tube plate wires. But you either already know that, or will find it out quickly even if you don't lace cables. Anything other than knowing the signals in each wire and what it can and can't go with is going to be a noise and hum disaster no matter what cabling scheme you use. That idea starts out with layout on the chassis to keep input, output and power things as far away from one another as possible, and carries right through wire routing.

One nice side benefit of laced cables is that if you lace everything but the grids, you have more 3-space to run the sensitive wires around in. They don't all have to be laced in bundles. Like the song says, you gotta know when to hold 'em, know when to fold 'em.

I think about wiring and component placement long before any actual construction starts. First the transformer positions are determined using the headphone hum detect method. Then tube positions, considering where the input comes from, where the outputs go to. What is near by that signals will have to transit. It falls into place quickly from there. Just follow good guidelines, short grid wires, long plate leads, high and low current lines seperated as far as possible, if transiting is necessary, cross at 90° angle. Insure signal returns and grounds are local. Power supply grounds near the source they feed. Power tube cathodes and screen supply grounds connected together and seperated from the other filter cap grounds etc.
No bundling of wires, but dead quiet. Seldom do i even have to elevate the heaters. I'll bet no bundling will make my amps less quiet.

Of course if using a " common " chassis, where the cutouts for transformers are set, and all the tube socket holes are lined up in the back, optimization has it's limits.

[R.G.]

I think about wiring and component placement long before any actual construction starts. First the transformer positions are determined using the headphone hum detect method. Then tube positions, considering where the input comes from, where the outputs go to. What is near by that signals will have to transit. It falls into place quickly from there. Just follow good guidelines, short grid wires, long plate leads, high and low current lines seperated as far as possible, if transiting is necessary, cross at 90° angle. Insure signal returns and grounds are local. Power supply grounds near the source they feed. Power tube cathodes and screen supply grounds connected together and seperated from the other filter cap grounds etc.
No bundling of wires, but dead quiet. Seldom do i even have to elevate the heaters. I'll bet no bundling will make my amps less quiet.

Of course if using a " common " chassis, where the cutouts for transformers are set, and all the tube socket holes are lined up in the back, optimization has it's limits.

With that approach, you're well into the design considerations I mentioned before you look at where the wires go. It's a variation of minimizing wire length and minimizing even possible crosstalk. If your signal goes from an input jack to a tube grid 1" away, it doesn't need to go into a bundle for a ride to the other end of the chassis and back. Likewise, if the grid of one tube only goes to the plate of the tube 2" away, even if it runs parallel to a different signal wire, there's not much interwiring coupling because there's not much shared parallel length.
I'm fairly certain that if you're that careful, you don't have much trouble. You probably wouldn't even if you did lace all the cables you could.

I think that there are two prominent areas that get people into trouble with wiring - wiring to tone/volume controls, and reverb. On the controls, it's difficult to make the controls be in the right order if the people on the other side of the panel demand to see them as V - T - M - B no matter where the tube is that makes the signal for those wires. Happily, since there is no competing signal for a single channel's tone/volume setup, you can bundle all the wires to/from the tone/volume for one channel. Any cross leakage is merely some of the same signal. There might be some very tiny tonal shift of slightly more or less treble, but I suspect you'd need instruments to find it. Reverb is a way of putting a high level signal out of the amp then bringing a low level signal back to the amp over long distances away from the main circuits, then compounding the difficulty by "isolating" the reverb out and in with a high value and hiss prone resistor. The signal back from a reverb is as low or lower than a guitar signal for most tank setups. And the long runs may well imply cabling issues.

[TUBEDUDE]

Agreed, i gave up on reverb years ago. Heat, physical issues, space needed, current demand, etc. Instead, i use the tube for a good buffered effects loop. Much more versatile, and i'd rather hear my Afterneath, or my FV-1 based reverb than those sproingy crooked wires.