From: Steve Ahola   (steve_ahola@yahoo.com)
Date: 5/31/2000 5:15 AM
Subject: Color Codes for DIY amp wiring?

    Since we may end up working on each other's amps someday (or at least
looking at the pix) it seems like a good idea if we were to (optionally, of
course) follow some sort of color scheme. I guess green has been used for
the filament windings for 40+ years, but what about the other wires? Seems
like black has been used for ground wires since prehistoric days so that
leaves the wires going to the plates, the grids, and the cathodes. Any
suggestions on this?

    Here is one color scheme I've seen in a recent book:

filaments: yellow (actually not specified)
cathodes: green
grounds: black
grids: blue
plates: white

... although I like red for the wires going to the plates because it seems
"hotter" than white (which always seems "neutral" to me). Also for colored
layout drawings, white tends to blend into the background... :D

--Thanks!

Steve Ahola

P.S. Here are the traditional color codes as posted a few years back:

Black: Grounds, grounded elements, and returns 
Brown: Heaters, or filaments, off ground
Red: Power supply B+ 
Orange: Screen grids 
Yellow: Cathodes 
Green: Control grids, diode plates 
Blue: Plates 
Violet: Power supply minus leads 
Gray: AC power line leads 
White: Bias supply 

    I hate to break with tradition unless there is a really good reason to do so.
I don't a problem with the filament/heater windings sharing a color with
another function since they are usually twisted together (although it might be a
good idea to assign a secondary color for when a dc filament supply is being
used— and maybe the positive lead should be a "hotter" color than the
negative...)

    Another idea might be to standardize the colors going to the tone stack...
like Red from the Treble cap, Black from the Bass cap and White from the
Mid cap. (I often use 4 conductor shielded cable for BF-style tone stacks so
that gives me Black, White, Red and Green to choose from...)

    And how about the various B+ leads from the power supply? Seems like
Red would be best on the node right after the rectifier. Maybe use Orange
for the second node (since that would be the "traditional" color for the screen
grids). Following the color wheel, the third node should be Yellow. As for
continuing around the color wheel, I think that I would skip green and maybe
even blue which would leave Violet for the fourth node. After that, I would
just repeat the colors (Red, Orange, Yellow, Violet). Or omit Violet since
many of us may not have that color.

    Any suggestions would be appreciated! (I hate cracking open a 1972 SF
amp and finding all of the wires going to the tube sockets the same color-
like a sickly yellow!) 

From: Stuart   (castledine@btinternet.com)
Date: 5/31/2000 6:18 PM
Subject: Re: Color Codes for DIY amp wiring?

No attempt to be original - I copied the colours in my Marshall:

fil: red & black
cathodes: yellow
grounds: black
grids: green
plates: blue
dc+: red

also, from standard ac wiring practice - 
live: brown
neutral: blue
ac ground: green/yellow 
 
From: Steve Ahola   (steve_ahola@yahoo.com)
Date: 6/1/2000 5:00 AM
Subject: Re: Color Codes for DIY amp wiring?

Stuart:

    So other than the filaments, Marshall pretty much follows the traditional
color codes. (I like red and black for those in case you run DC to your
preamp tubes... no need to guess which is which- eh? ;) ) Although those
colors aren't as intuitive as I'd like (i.e., hot colors for the higher voltages) if
Marshall is using them that is a good reason to stick with the tried'n'true...

--Thanks!

Steve Ahola

P.S. So do you live in the UK? In the US, black is hot, white is neutral and
green is ground (although we are starting to see electronic air cleaners wired
up with the EIC colors). First time I ran into those colors was when a
customer asked me to rewire a lamp that they had brought from England...
"Blue? Brown? What do those colors mean???")