hello,
i'm currently modding my lite2 preamp cathodes to a on/on dpst switch so i can switch between different values,at the moment the leads are around 2 inch long but i will be lengthening them to 7 inch to the switch so can anyone forsee any problems i might have? i.e. are they prone to picking up interference and is it worthwhile to use shielded cable?
appreciate any help/advice
cathode leads
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signal.glow
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Re: cathode leads
Cathodes have medium to low impedances, so even longer runs aren't a problem normally. Haven't tried 7 inch, about 4-5 inch from high gain input tubes didn't cause problems. Same with anodes which are higher impedance so are more suspectible to interferences.
A lot depends from trafo, some wire's EMI, material of chasis and some more. Pro audio scene takes a lot of precation against it (mu-metal, copper, steel shields, etc.), i haven't seen much of this in guitar amps...
Grids are a lot more problematic regarding this, it is worth shielding them at least on input tubes. Doing it on volume and some other controls lowers noise too, of course if all grounds are done properly.
You could put 5V relays on a piece of veroboard and switch vathodes where they are now, if 7 inch gives problems. 6,3V for this relays works just fine.
A lot depends from trafo, some wire's EMI, material of chasis and some more. Pro audio scene takes a lot of precation against it (mu-metal, copper, steel shields, etc.), i haven't seen much of this in guitar amps...
Grids are a lot more problematic regarding this, it is worth shielding them at least on input tubes. Doing it on volume and some other controls lowers noise too, of course if all grounds are done properly.
You could put 5V relays on a piece of veroboard and switch vathodes where they are now, if 7 inch gives problems. 6,3V for this relays works just fine.
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