different color in the manual

mete · 810

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Offline mete

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on: June 18, 2024, 09:02:38 PM
Are the white and red wire colors in the amplifier stages always supposed to indicate the channels ?

Because, in the manual (Crack_1-1_Manual_09-20-16), on Page 36, there is this step:

"( ) Cut a 2" (51 mm) piece of red solid core wire.
Strip both ends ¼" (7mm). Attach and solder one
end to A1 . Attach the other end to 5U.

However, this channel is normally wired white.

- on page 35:

"( ) Cut a 3½" (89mm) piece of white solid core wire.
Strip both ends ¼" (7mm). Attach and solder one
end to the center lug of the upper row of the volume
potentiometer. Attach and solder the other end to
A2."

- on page 37:

"( ) Cut a 5" (1 27mm) piece of white solid core wire.
Strip both ends ¼" (7mm). Attach and solder one
end to 5L. Attach and solder the other end to B4."

The input to 12AU7 grid (A2) is white.  From the terminal strip (5) (connected to 12AU7 plate A1) to 6080 grid (B4) is white, but from 12AU7 plate (A1) to the terminal strip (5) it is red. If this is not on purpose, I guess the first paragraph, has to be white wire. This is correct for the red channel, always red wire is mentioned.

Edit: The same can be said for the paragraph in page 44:

"( ) Cut a 1½" (38mm) piece of red solid core wire.
Strip both ends ¼" (7mm). Attach and solder one
end to B6. Attach the other end to 9U."

I was working on a diagram showing roughly both the schematic and wiring points, it is attached, not fully checked yet, there can be mistakes. The points I made above can be seen in the diagram on the blue channel. I used blue color instead of white for visibility.
« Last Edit: June 18, 2024, 09:38:07 PM by mete »



Offline Paul Birkeland

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Reply #1 on: June 19, 2024, 05:37:07 AM
"( ) Cut a 2" (51 mm) piece of red solid core wire.
Strip both ends ¼" (7mm). Attach and solder one
end to A1 . Attach the other end to 5U.
All connections to the tube plates in the Crack are made with red wire, denoting that these wires carry the highest voltages.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline mete

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Reply #2 on: June 19, 2024, 05:44:50 AM
All connections to the tube plates in the Crack are made with red wire, denoting that these wires carry the highest voltages.

OK, that makes sense, but B6 to terminal 9 is also red.



Offline Paul Birkeland

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Reply #3 on: June 19, 2024, 05:52:49 AM
OK, that makes sense, but B6 to terminal 9 is also red.
Yes, you are welcome to use a piece of white wire there if you prefer.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man