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'Beast Champ Layout'
Author:Evilchippy (guest: search)
Date: Mon, Nov 26th, 2007 @ 17:02 ( . )

I'm going to build the "Beast" Champ, and I was wondering if someone could give the layout I'm copying a quick look. As far as I can tell, I think it's good, except maybe the power tube's cathode bypass cap and resistor that are located by the diodes. I'm not sure if that's a big deal or not?

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'Beast Champ Layout'
Author:Dave Z (guest: search)
Date: Mon, Nov 26th, 2007 @ 17:07 ( . )

Well typically you don't want your A/C anywhere near your signal. But I've seen designs where the diodes were alongside (though on the OTHER) side of the cathode cap. But more typical is the cathode caps on the other side of the filtercaps. You could easily do that here, that reduces the lead for the cathode by a long shot, which I prefer. I think it was Aiken which I read long ago which suggested keeping cathode leads short.

But, hey, if that design is up & running with no problems, you are good. Or are you modifying this design, with more gain? In that case I'd be more careful with the cathode.

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'Beast Champ Layout'
Author:Evilchippy (guest: search)
Date: Mon, Nov 26th, 2007 @ 17:53 ( . )

I'm not planning on increasing the gain, but I think it might be worth moving the cap and resistor to the opposite side of the PS caps just in case.

Is there any issue that can arise from having those components close to the pre-amp (coupling cap, specifically)?

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'Beast Champ Layout'
Author:Russ S (registered user: 41 posts )
Date: Mon, Nov 26th, 2007 @ 20:43 ( . )

On 11/26/2007 @ 17:53, Evilchippy wrote :
I'm not planning on increasing the gain, but I think it might be worth moving the cap and resistor to the opposite side of the PS caps just in case.
:
: Is there any issue that can arise from having those components close to the pre-amp (coupling cap, specifically)?
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Shouldn't be since that's mostly DC. Why the double diodes? Are they the UF series?

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'Beast Champ Layout'
Author:Evilchippy (guest: search)
Date: Tue, Nov 27th, 2007 @ 02:12 ( . )

UF5408

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'Beast Champ Layout'
Author:stevem (guest: search)
Date: Tue, Nov 27th, 2007 @ 06:24 ( . )

I would not change the layout as it should be fine, but I would add a .001 ceraimic cap across each diode and if the B+ is close to,or over 350 volts I would go up to 1 watt plate load resistors.
Oh, and maybe add a switch to lift the ground on tone stack so you can bypass it for about 5 db more gain.

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'Beast Champ Layout'
Author:Evilchippy (guest: search)
Date: Tue, Nov 27th, 2007 @ 11:54 ( . )

I have a question about bypassing the tone stack. Someone at sewatt suggested the use of a coupling cap when bypassing. I don't understand how a ground lift would require a coupling cap?

Thanks for your help!

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'Beast Champ Layout'
Author:stevem (guest: search)
Date: Tue, Nov 27th, 2007 @ 12:07 ( . )

The ground lift will not, but with a bypass you still must block the dc plate voltage from the grid of the next down stream tube.
This cap will also let you shape how much bass frequency gets sent to the next tube.

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'Beast Champ Layout'
Author:Zoe N Iain (registered user: 8137 posts )
Date: Tue, Nov 27th, 2007 @ 12:17 ( . )

On 11/27/2007 @ 12:07, stevem wrote :

: This cap will also let you shape how much bass frequency gets sent to the next tube.
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(Iain) Very important in some Marshall and Orange style amps, as there's a whole boatload of bass getting through once the stack is lifted. A coupling cap after the TS will let you dump some of that and keep a balanced tone. It's sometimes a bit fiddly finding the right size cap to get what you want, though.

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