Correct heater wiring ?

[copperheadroads]

I noticed this Video about heater wiring & about humcanceling ,please discuss ?
if there is a proper way to do heaters ,One thing i guess it to use 2 color heaters like Marshall uses .
I tried to test this on my 5E3 with my All green heater wires but there is continuity on all my heater wires even the pilot light so this may or may not be correct .
https://www.youtube.com/watch?v=E84YebuhfFc

[Gingertube]

All you need to know about heater supplies and wiring is here:
The Valve Wizard

Cheers,
Ian

[The Dude]

As you noted, there will be continuity on all heater wires because of the light bulb, the filament wires, and the filament transformer. Notice he never checks pin 2 to 7 for continuity. If he did, he would see the error in his "instructional" video.

[Randall]

Yeah, the only way that technique will show any meaningful results is if you pull all the tubes, the lamp, and lift one side of the filament wiring coming from the transformer. Otherwise, it's useless.

[mikepukmel]

Hi All, Im new to tube amp build stuff, have about the same question, re how best to do heater wiring. After way too much reading, I found two main "you MUST do it THIS way" camps: The fender style, running the twisted pair in mid air above the tube sockets, and marshall style, running the twisted pair tucked down in the corner of the chassis. Has anyone had any better luck with either style?

[Justin Thomas]

Has anyone had any better luck with either style?

Not to be a smartypants, but you kinda answered your own question...
Seriously, though, how many Marshalls. AAND Fenders don't have hum & noise problems from heater wiring? Lots. Like, bazillions. More important than the actual technique you choose is the underlying principle of WHY you do it. First, the AC heater lines are always twisted so that the induced currents within the wires will cancel each other out. So, always neatly & tightly twisted pairs.

The second "always" is to keep high current AC wiring as far from the low current signal bearing wiring as possible. So you will notice in the Fenders, the signal wires are kept as closely packed to the chassis as possible and the heater wires are as far from the chassis as possible. In the Marshall it's the exact opposite (and the same in vintage 60s Ampegs). But the PRINCIPLE is the same - as much space as possible between low & high current AC & signal wiring.

FWIW I've done a mix of both in the same amp; when I was rebuilding a preamplifier section I had to rewire the heaters fir the pres tubes. No heater hum despite using both right next to each other in the same amp, because the principle of WHY overruled the "Law of How." Other opinions may and probably will vary...

Justin

[mikepukmel]

Not to be a smartypants, but you kinda answered your own question...
Seriously, though, how many Marshalls. AAND Fenders don't have hum & noise problems from heater wiring? Lots. Like, bazillions. More important than the actual technique you choose is the underlying principle of WHY you do it. First, the AC heater lines are always twisted so that the induced currents within the wires will cancel each other out. So, always neatly & tightly twisted pairs.

The second "always" is to keep high current AC wiring as far from the low current signal bearing wiring as possible. So you will notice in the Fenders, the signal wires are kept as closely packed to the chassis as possible and the heater wires are as far from the chassis as possible. In the Marshall it's the exact opposite (and the same in vintage 60s Ampegs). But the PRINCIPLE is the same - as much space as possible between low & high current AC & signal wiring.

FWIW I've done a mix of both in the same amp; when I was rebuilding a preamplifier section I had to rewire the heaters fir the pres tubes. No heater hum despite using both right next to each other in the same amp, because the principle of WHY overruled the "Law of How." Other opinions may and probably will vary...

Justin

Thanks Justin!

[Tom Phillips]

Welcome to the forum Mike.
In addition to what Justin said be sure to read the article that Gingertube linked in post #2 of this thread. Particularly the section regarding lead dress.
Cheers,
Tom

[big_teee]

I too like the valve wizard way!
Colors doesn't matter, I use red and black.
T

[mikepukmel]

Welcome to the forum Mike.
In addition to what Justin said be sure to read the article that Gingertube linked in post #2 of this thread. Particularly the section regarding lead dress.
Cheers,
Tom

Thanks, will do!

[Enzo]

One element of lead dress: try as much as possible to have heater wires and signal wires cross at 90 degrees. If they are parallel, they can couple, if they cross at a right angle, they couple a lot less.

[mikepukmel]

Not so far off topic, but what gauge and should the heater wiring be solid or stranded? Is 20 ga solid ok? Im thinking solid so that the heater wiring can stay put when bent into position. (working on my first amp build)