Gradual/fast switch

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norburybrook
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Gradual/fast switch

Post by norburybrook »

2: I'm putting the Komet fast/slow switch in, which is a plate voltage divider(I think) . Now.....looking at some pictures of the Komet 60 it looks like the switch is before the cap to the next stage, wouldn't that mean you've got B+ voltages going to a metal switch? shouldn't there be an extra capacitor and wired so the switch is after both caps, and then on to the next stage? and what's the deal with the wire coil around those cables, is it some sort of inductance shield, and how is it made and where is it attached?



Marcus
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martin manning
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Re: Gradual/fast switch

Post by martin manning »

You are right the high voltage on that switch is potentially dangerous (no pun intended). You could fix it as you describe, but I think you would need a large resistor across the switch-ends of the two coupling caps to keep it from popping. The coil is a grounded electrostatic shield. Just a coil of hookup wire, grounded at one end (tube socket mounting screw).
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M Fowler
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Re: Gradual/fast switch

Post by M Fowler »

What guys were doing back then was .1uf/600v cap with 1m to ground on each end of the fast/gradual switch.

The coil was just make your own wire coil with one end grounded to solder tab bolted to the tube socket and the other end of the coil the wire is pushed back inside the coil for neatness and also it helps keep the coil tight.

The Astroid layout notes how this is done.

Mark
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norburybrook
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Re: Gradual/fast switch

Post by norburybrook »

Thanks mark where is the asteroid layout?

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M Fowler
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Re: Gradual/fast switch

Post by M Fowler »

norburybrook wrote: Thu Sep 14, 2017 2:10 pm Thanks mark where is the asteroid layout?

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http://el34world.com/Forum/index.php?topic=22182.0

Way down on the bottom of the page reply post #33 beneath phoot of BNWitt's gut shot
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norburybrook
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Re: Gradual/fast switch

Post by norburybrook »

Thanks Mark, found it. Perfect [emoji16]. So,if I build it like that will it be OK? It still seems strange to have the direct B+ going to a switch.

Marcus

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M Fowler
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Re: Gradual/fast switch

Post by M Fowler »

Yes it has a loud pop on stock version when you switch, but the good news is I doubt most people operate on the low power side of the switch I know I don't.

Even Hogy from Komet talked about this here on TAG.
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norburybrook
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Re: Gradual/fast switch

Post by norburybrook »

I think I'm going to try this way.
phils Komet.gif

I'm sure it will still pop but there wont be as much voltage on the switch.

thanks for the input guys ;D

I'm on the road for the next 4 days but I recon i'll be able to finish this early next week ...


Marcus
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martin manning
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Re: Gradual/fast switch

Post by martin manning »

If you put a large resistor (4M7, say) across the switch ends of the caps as I suggested above you can probably kill any popping. Easy to try.
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norburybrook
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Re: Gradual/fast switch

Post by norburybrook »

so one 4M7 resistor connected between the outer poles of the switch?

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Re: Gradual/fast switch

Post by Roe »

norburybrook wrote: Thu Sep 14, 2017 11:09 pm I think I'm going to try this way.

phils Komet.gif


I'm sure it will still pop but there wont be as much voltage on the switch.

thanks for the input guys ;D

I'm on the road for the next 4 days but I recon i'll be able to finish this early next week ...


Marcus
I'm using this setup, except I use 15nf on slow and 2n2 on fast (with 33k and 68k resistors). Still, I rarely use the slow setting at all
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norburybrook
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Re: Gradual/fast switch

Post by norburybrook »

I've got the parts and the chassis is labled now so I'm forging ahead.

While this thread is still active, any thoughts on a PPIMV ? it's an easy addition, just wondered if it's necessary.

anyone?

M
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martin manning
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Re: Gradual/fast switch

Post by martin manning »

norburybrook wrote: Fri Sep 15, 2017 2:26 pm so one 4M7 resistor connected between the outer poles of the switch?
Yes, so that the caps are connected together by the 4M7 at all times.
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norburybrook
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Re: Gradual/fast switch

Post by norburybrook »

thanks Martin, is that something I can use in future on other builds when incorporating switches, or does it only work when you're dividing a voltage?



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Re: Gradual/fast switch

Post by Mark »

How did the fast/slow switch work out?

Do you use it much?

I imagine the amp sounds quite different between fast and slow.
Yours Sincerely

Mark Abbott
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