Finals Screen Switch

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xk49w
Posts: 114
Joined: Mon Aug 25, 2008 12:14 am
Location: FL East Coast

Finals Screen Switch

Post by xk49w »

I'm researching a new project, sort of a Standel 25L15-ish design using 807 output tubes. This amp uses a UL tap for the screens. I would like this to be switchable, possibly for either pentode, triode, or ultra-linear operation.

A couple of questions:

1. What type of switch? I'm leaning toward a rotary wafer switch, single deck, two poles, three positions, like one of these. Specifically a D3G0205N or 3C0205N. I was wondering what switch others have used for a screen source switching application.

2. I was going to go with a non-shorting contact. It is reasonable to require the user to put the amp in standby before selecting a new screen topology but you never know how the thing will be used. Is there a risk if the screen is momentarily open while switching, even under a signal condition?

TIA, -- bradley
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