Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: warioblast on August 15, 2017, 11:34:49 am
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Can I put B+ parallel to ground ? Is there a safety distance ?
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Can I put B+ parallel to ground ? yes
Is there a safety distance ? It's so small you don't need to be concerned.
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Steve, once again thank you :thumbsup:
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> a safety distance
Seems to be much less than 0.01" for any likely guitar voltage, and no sharp points.
Obviously the mechanical shake allowance should be much larger.
It is usual to provide 3mm to 6mm (1/8"-1/4") "creepage distance" around line voltages, and this may be a good guide for small tube voltages. Double that for power tube plates.
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I think rather than a gap for electrical isloation you need to think about a safe distance such that a meter or scope probe that slips can't touch both.
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probe that slips can't touch both.
If there's no coupling problem, you might not have to probe :laugh:
probing is always an issue, pin gap on relay, tube socket, IC, Just like design, thinking ahead 2 steps keeps you outta the ditch.
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I've got another one Q.
I read the heater wiring should cross a signal wire at right angle. But can I have the heater wiring in parallel of a hot signal wire from 0.4 inches (1 cm) distance ? They would be parallel for 6 inches (15cm) FWIW.
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But can I have the heater wiring in parallel of a hot signal wire from 0.4 inches (1 cm) distance ? They would be parallel for 6 inches (15cm) FWIW.
Bad idea, especially if the signal wire is a low level preamp signal. But if you are talking about a speaker wire (that's a hot signal wire too) then you should be OK.
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They are wires going to the power tubes grids.
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What about the heater running along PT B+ ?
I've done it in my previous build but I'm not sure it is good practice.
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What about the heater running along PT B+ ?
I've done it in my previous build but I'm not sure it is good practice.
OK
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Many THX :worthy1: