Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: Colonl_Charisma on March 26, 2021, 10:37:51 AM
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I've been considering swapping my PEC pot with a Goldpoint attenuator, and I would purchase a "blank" 100K version because I would like the experience of populating it with resistors. I have seen that I can use 1/4 W resistors, and I saw in a past post that Doc recommended populating with Dale resistors.
What other specs on the resistors should I pay attention to (e.g. Resistance, Voltage Rating, etc.)?
As always, I appreciate the help!
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For An attenuator you can use 1/8w resistors. Smaller and less cramped.
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Dale RN55 is listed at 1/10w and some times 1/8w.
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Dale RN55 are fine. The RN series are all de rated being mil spec vs the Industrial CMF range. A RN55 is 1/8w vs a CMF55 which is 1/2w, yet both are physically identical in size.
They are also rated by tolerance, 1% being the norm, but .5% and .1% are also available at a higher cost. Personally i would buy a bunch of 1% for the same cost and measure them myself, but 1% tolerance is perfectly fine for a volume control, you will never hear the difference. Finally there is a temperature coefficient, 25ppm, 50ppm, 100ppm, the lower the better, but again irrelevant for a volume control so just stick to the basic 100 or 50.
Finally, what resistance values to use. Goldpoint have charts on their website which are a good starting point https://www.goldpt.com/r_series.html (https://www.goldpt.com/r_series.html) ..don't forget to double up when ordering as you have a left and right channel to build.
I have built a few vintage Goldpoint stepped ladder attenuators that have 96 resistors on them, the novelty wore off fairly quickly ;)
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Thanks mcandmar and Thermioniclife! You all gave me the information I needed.