Wiring Colors and how you use them

[Ed_Chambley]

I was wondering it any of you guys use and specific color of wire for different uses in amps.  Green is traditionally heaters in fenders.  I am going to rewire my first scratch build as it is pretty awful and I need to order some more wire so I thought I might ask if there is sort of a standard color for each portion of the circuit?

[stingray_65]

 There are no set standards.

You see green for heaters mostly, Red for B+, and black for grounds.

I like to use 2 different greens for my heaters or green and brown, because I keep the heaters in phase and it's easier for me with 2 colors.

I also use a couple different colors for where they land on the tube sockets, blue for screens, orange for plates, brown to cathodes.

The trick is to stay consistent in your build, it eases assembly and trouble-shooting.

[TIMBO]

Hi Ed, As stingray said there is no set standard, so to have your own standard makes it a lot easier to trace when there is a problem, etc.I actually use a multi core trailer wire that has five (some have seven)coloured wires that are .7mm which is perfect for tube hookups and i use a lighter .5mm for the pots and switches. I buy the trailer wire from the local auto shop and they sell in 5m and 10m lots and i can usually get two amps out of 5m.Thanks

[labb]

What is the voltage rating of the trailer wire you use?

[TIMBO]

12v DC and i know that i am running some with a higher voltage but they are only short runs of about no more than 3" that i did not think it would be a problem. I know that the insulation is a big factor but so far i have not had a problem with melting wires. Am i wrong in thinking this way. 

[labb]

I think the issue is with the insulation rating. Generally the insulation needs to be rated higher than the voltage the wire sees. If it works for you and you are not selling the amps then I would not worry about it.

[stingray_65]

You know, I've wondered that alot myself

most insulation is PVC

and as far as I ever saw is no thicker on 300 or 600V rating

it would be my guess they are the same and the only difference is the cost of manufacturers liability insurance

[TIMBO]

If one was wanting to build and sell amps i'm sure you would want make sure that all safety margins are greater than required.

[labb]

I generally use 20 ga. solid wire with the insulation rated for 600 volt. I have both 300 volt and 600 volt. The insulation on the 600 volt is thicker than the 300 volt.

[sluckey]

If you are concerned about the insulation voltage rating of wire, get a Biddle megger insulation tester. Cut 2 pieces of the wire to about 2 feet length. Tightly twist the two wires together (a portable drill is a big help). Connect the 2 wires to the megger and crank it up. A reading of infinity is highly desirable.

[RicharD]

Black ground
Red B+ & dc hots
White cathodes
Blue cold grids
Green filaments
This is my personal color scheme.  There is not a standard besides black ground and red hot.  I use this on my proto board fairly religiously so that poking around is safer.  Blue is a cool color so it is cool to touch.  My simpleton way of thinking.

[stingray_65]

If you are concerned about the insulation voltage rating of wire, get a Biddle megger insulation tester. Cut 2 pieces of the wire to about 2 feet length. Tightly twist the two wires together (a portable drill is a big help). Connect the 2 wires to the megger and crank it up. A reading of infinity is highly desirable.

I heard these were good for getting earthworms.

couple rods in a field and crank away

[EL34]

I like

Green for heaters and the power cord ground - AC earth grounds

Tubes and wires to and from the board:
Red for high voltage - plates - screens - the B+ rail - Filter cap plus leads - etc
Black for grounds - cathodes - ground wires leaving the board - filter cap minus - etc
White for AC signals - Wires to and from pots - wires leading to input grids

[LooseChange]

I'm with Doug on this one.
It's so much easier to know where you are with a consistent color scheme. If it's red, you know it's gonna hurt.

I do use a mix of colors for the connections to the pots because I twist them. BUT I add white to the mix because it's audio.

I've noticed consistency in a few amp manufactures. It makes things so much easier for diagnosis.

[Madison]

I like

Green for heaters and the power cord ground - AC earth grounds

Tubes and wires to and from the board:
Red for high voltage - plates - screens - the B+ rail - Filter cap plus leads - etc
Black for grounds - cathodes - ground wires leaving the board - filter cap minus - etc
White for AC signals - Wires to and from pots - wires leading to input grids

Been doing it Doug's way for years.
Works for me.
Simple is best.
I sometimes toss in an orange or purple for NFB or something.

[sluckey]

I heard these were good for getting earthworms.

Why waste it on bait. Take it straight to the pond! 

BTW, I hope none of you buy the one in the ebay link. The meter needle appears to be stuck!
 

[Fresh_Start]

Here's a sort of standard from the Radio Amateur's Handbook.  I started with that as a base and use:

HT: Red
Plates: Blue
Grids: Orange (or brown)
Cathodes: Yellow
Audio to controls:  white (mix in other colors as needed)
Heaters:  green or red/black 18 gauge
Ground:  black (or green when 18 gauge)
Bias supply: violet (or blue if no violet)

It really helps me both in initial wiring and debugging.

Cheers,

Chip

[XYZGnomon]

I like

Green for heaters and the power cord ground - AC earth grounds

Tubes and wires to and from the board:
Red for high voltage - plates - screens - the B+ rail - Filter cap plus leads - etc
Black for grounds - cathodes - ground wires leaving the board - filter cap minus - etc
White for AC signals - Wires to and from pots - wires leading to input grids

It's been 12 years. Have you changed your minds on wire colors? Is there new information to consider?

During the pandemic I built a Stew-Mac 5F1 Champ kit, which worked just fine, first try. I then proceeded to tinker more and more until I realized that some of my experiments, like a headphone jack, weren't practical. I just finished completely disassembling the amp, to have a rethink. I have already moved the fuse to a new hole next to the rectifier tube and put a switch where the fuse was, like the Fender '57 Champ they sell new. I think I'm probably also going to get a transformer with a filament center tap, now that I know what that is and what it does.

But my question is about wire colors. Tube Depot has every color under the rainbow and so I think I want to use this opportunity to wire it logically. Even a couple of feet of each color is still less than lunch, so it's not much of an investment even if I go back to only using the yellow stuff it came with.

I see some folks are even using blue for some things, and orange and some other colors. I am a novice, and I want to learn as much as I can. My violin teacher applied colored tape to my fingers when I was 4. Can this help me here too? Is this a good idea or a waste of time? This is a philosophical question.

If you know of a gallery of images of well-executed builds using intentionally colored wires, I would love to see it! Can you link to some examples here?

{EDIT: link-fix-- PRR}

[PRR]

Don't buy another hundred-buck transformer; two 100r resistors works fine.

If you are Philco or AT&T or Dell, use as many consistent color wires as your workers can deal with. Production and repair costs may get lower due to fewer build errors and faster diagnosis. If you work strictly alone and KNOW your amplifier, you can use all white wires (I have), but consistent colors does help when you come back to it years later.

RicharD (above) worked with in-wall power wiring and there we have MANDATORY rules about wire colors so when Tim came along later to repair/upgrade Rich's work, confusion is less.

[XYZGnomon]

Don't buy another hundred-buck transformer; two 100r resistors works fine.

If you are Philco or AT&T or Dell, use as many consistent color wires as your workers can deal with. Production and repair costs may get lower due to fewer build errors and faster diagnosis. If you work strictly alone and KNOW your amplifier, you can use all white wires (I have), but consistent colors does help when you come back to it years later.

RicharD (above) worked with in-wall power wiring and there we have MANDATORY rules about wire colors so when Tim came along later to repair/upgrade Rich's work, confusion is less.

Obviously a virtual center tap just works - I already knew that! I'm going to buy the other transformer anyway, mainly because I also don't like the fact that they spec'd a multi-voltage unit with a ton of extra wires in a tiny chassis with no place for a voltage selector switch. Since I want a different one anyway, the center tap is just a side bonus.

I am just me, and I am awful at guitar so I don't even need this amp. Just ask my neighbors!

I am looking for examples of good work with colored wires. My long post was just leading up to that, so you know why I was resurrecting a 12-yo post.

I now know more about what a cathode bypass capacitor is this afternoon than I did this morning, after I noticed that my Champ's circuit doesn't have one, unlike some very similar amps. Related, I don't like that there is a yellow wire from the tube socket to the cathode resistor and then a green wire from the other side of the resistor to the input jack, and then just kind of goes nowhere (obviously grounding to the chassis here). It seems like a violation of color continuity and simultaneously consistent with some other grounding points. This is the kind of question I want to answer with colored wires. I already understand that beyond a few basics, it's mostly personal preference.

The reason I'm asking is mainly because the folks I look up to and can reference (I also look up to a lot of folks who don't have huge websites) seem to also not be totally consistent about this.

In this instance, the signal from the input jack, through the grid stoppers to the preamp is pink.



But here it's yellow:



And I almost forgot, MERRY CHRISTMAS!!!

[acheld]

Check out Sluckey's collection:   https://sluckeyamps.com

Lots of good stuff there.

[Platefire]

I'm with Doug on colors except I like to use orange or yellow for cathodes.

[pullshocks]

Like a lot of others, I use red for B+ and Black for grounds.  I twist my heater wiring so I don't see the need to color them.


At some point I locked onto brown for wires going to a cathode, Yellow going to plates, and orange going to grids.


For everything else I try to use as many different colors as possible so I can easily check and recheck their origins and destinations.


The sockets in the picture below are 6dx8/ecl84m, not preamp tubes

[jjasilli]

Some time in the distant past, PRR posted the EIA Chassis Wiring Color Code published in an ancient issue of Popular Electronics.  I have it posted above my workbench.  I firmly believe in following established conventions (sex, drugs & rock-n-roll excluded).  It's got to be posted on this Forum somewhere.  Or let me know and I'll re-post it.

[PRR]

Tell me the file-name (I can't find mine), or simply re-post it (I have no ownership and PE probably can't care).

[jjasilli]

Here it is!  https://el34world.com/Forum/index.php?topic=25036.msg270864#msg270864

[XYZGnomon]

Tell me the file-name (I can't find mine), or simply re-post it (I have no ownership and PE probably can't care).

I was aware of the document, and I appreciate you bringing it up. I want to see a physical example of a build that follows this convention, so that I can learn from it. That's what I was getting at before.

For example, it says the yellow wires are for cathodes, as if I knew exactly what they were talking about. I kind of do, sort of, but I have only made one amp and it was paint-by-number. It wasn't meant for teaching me what each thing is, and consequently these terms are fleetingly familiar to me but not really in my fund of knowledge.

To reiterate, I'm looking for boilerplate builds that follow the convention in the doc. Better if they're tweed, but anything Fender is relevant to me personally for now. A 5F1, followed to the letter, would help me understand what I have right in front of me.

[PRR]

> it says the yellow wires are for cathodes, as if I knew exactly what they were talking about.

Then this is not a color problem. You want to go over electronic parts. There used to be books.

https://robrobinette.com/How_Tubes_Work.htm
https://www.rfcafe.com/references/short-wave-craft/radio-amateur-course-october-1935-short-wave-craft.htm

http://www.jollinger.com/radio/tubes/tube_schematic_symbols.html
https://www.ampbooks.com/mobile/tutorials/triode/
http://www.dogstar.dantimax.dk/tubestuf/mctheory.htm

[XYZGnomon]

Then this is not a color problem. You want to go over electronic parts. There used to be books.

Thank you for the references! As I said before, I made an amp once, color-by-number, and all it did was whet my appetite. I am 100% going to be reading more before I actually go through with building any amp again. That's why I'm here! I am starting a mechanical engineering degree in a couple of weeks at 46, after I was finally approved for VR&E through the VA. After I got out of the Army almost 11 years ago, I became a machinist and it kind of played itself out. I have had parts in space but it doesn't mean much when you can't pay the bills. I'm just trying to say that I am always learning and I value any and all relevant expertise.

I disagree... it is also about colors... to me. It is very clearly a convenient way to learn these components, when there are examples built using the convention described in the documentation. It's like looking at a subway map.

BUT it's also clear that few guitar amps actually follow the convention, so maybe it's a dead end. I just randomly found this video (start at the 10min mark) with a Gretsch amp with the following colors: orange, blue, brown, yellow, red, green, black, white, green/white & blue/white. The transformers add: red/yellow, green/yellow & brown/white.

The filament heater wires seem to use four different colors, if you start counting AFTER the transformer secondary. The rest of it seems like a dog's breakfast.

[PRR]

> I have had parts in space but it doesn't mean much when you can't pay the bills

Yeah, when I was young I thought drafting and machining would be steady work. Do they even make T-squares any more? Or only in China? AH! Mostly for drywall!

My uncle had a pump on Apollo 13. NASA would specify EVERY detail including a Munsell or Pantone color. AT&T/Western Electric lived by heavy color coding (ever drill-through an office's 50-pair telephone cable and have to patch it TONIGHT?).

While there may be a universal dream of consistent colors, when it comes to dishwashers, radios, and g-amplifiers, it's just up to the maker and the maker's prime directive is "cheap". While _I_ may understand "yellow=cathodes", most of the $1.15/hour workers don't know or care. And if a big spool of pink/violet-stripe is hanging around the bench, use it up before you order more wire!

I'll attach a screen-grab of that video for folks following along at home. And yes, that is a mess. Not the worst ever seen.

[shooter]

ever drill-through an office's 50-pair telephone cable

had to have a new MRI system up by Dec31 (tax man).  last major part shows up Dec23 2,000lb tube with a pigtail hardwired at tube, 50-ish pin cannon plug on other end, MOLDED, can't push pins, was wired totally wrong.  EVERY wire was gray, or gray/blk.  Dec27th at midnight unplugged the solder pencil, went home, smoked a big'n.  calibrated n turned over on the 30th, was a hero for the day

[sluckey]

If Leo cared to follow that "standard" wire color chart, the champ might look like this...

[PRR]

had to have a new MRI system

Be glad you left that place....

Philips recalls 340 MRI machines because they may explode in an emergency
Rapid unscheduled disassembly not exactly a desirable quality for medical imaging equipment
https://www.theregister.com/2023/12/21/philips_exploding_mri/

[shooter]

 
we had one of those systems, PITA to work on.  a blockage from a quench, no matter the system, is a real danger.  I've been at the vent pipe twice when the system quenched, you move fast!!!
IIRC Philips moved from burst disks, BACK to their "flapper" valve.  burst disk was set at ~~~8lb, the flapper was a brass pressure relief.  If the flapper or spring gets froze before it fully opens things get critical. 
The gases through the vent under "normal" quench sounded like a jet turbo spoiling up, a stuck valve, the pipe would scream

[Jalmeida]

I was wondering it any of you guys use and specific color of wire for different uses in amps.  Green is traditionally heaters in fenders.  I am going to rewire my first scratch build as it is pretty awful and I need to order some more wire so I thought I might ask if there is sort of a standard color for each portion of the circuit?

There is an EIA chart shared here that breaks the colors down. I thought PRR or one of the other regulars shared it. I will see if I can find that chart.

For wire I built my first amp with some off the shelf 300v wire. It was not ideal because as I fixed mistakes every time I had to resolder it would further degrade the fragile low heat insulation.

My second amp build I used solid conductor Teflon insulation 600v wire. It looked pretty and held shape nicely. However any mistakes or rework meant disturbing/bending rigid wire that eventually cause other problems and breaks.

So finally I went with Tefzel stranded 600v aviation milspec wire and haven’t turned back.

I did build a Princeton with cloth wire which wasn’t too bad either. Some swear by that wire. I personally am
Paranoid about stray strands poking through the cloth on nearby wires. Admittedly an over exaggeration i’m sure. But the Tefzel just seems the best answer. Buy it from ebay or Aircraft Spruce in the colors you want.

[Jalmeida]

Here

[XYZGnomon]

If Leo cared to follow that "standard" wire color chart, the champ might look like this...

I was going to say something about how you inaccurately showed a connection from pin 2 on the 5Y3, but then I found this and it appears you have done this intentionally for vintage correctness. In my case, in the commercially available 5F1 chassis, the clocking of the socket makes pin 8 far more convenient. So that's what I did.

[sluckey]

If Leo cared to follow that "standard" wire color chart, the champ might look like this...

I was going to say something about how you inaccurately showed a connection from pin 2 on the 5Y3

Back when Leo was building a 5F1 the 5Y3 tube only had three electrodes... plate 1, plate 2, and a filament. There was no cathode. Instead, the filament had a special coating that would easily emit electrons when heated. This was called directly heated cathode. Since the entire heater was the cathode, it made no difference which end of the heater you took the B+ from. In fact, Leo took the B+ from pin 2 in the 5C1 Champ. Take a look.

The newer production 5Y3 does have a real cathode electrode. It's a sleeve that fits tightly (but isolated) around the filament. This sleeve cathode is internally connected to pin 8, so nowadays it's best to use pin 8 for B+.

This extract from RC-13 tube manual explains the differences between directly heated cathode and indirectly heated cathodes in more detail.