DC coupling

vetmed · 2230

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Offline vetmed

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on: March 21, 2012, 06:27:10 AM
I am having difficulty understanding how DC coupled circuits work in SETs. I can see that the plate voltage of the preceding stage has to appear on the grid of the following stage. After that I find it confusing. How is the value for the bias resistor calculated? Does it have any effect on heater to cathode values? etc... Thanks




Robert Lees

Robert Lees

Offline nullspace

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Reply #1 on: March 21, 2012, 06:57:54 AM
Hi Robert,

There was an excellent article in VALVE back in the day on just this topic. The issue is available for download here: Blues Master. Pretty much walks you through step-by-step on all the details. The output stage is a DHT, though, so no heater-to-cathode issues to speak of -- if you were looking at a IDHT, then yes, you would need to bias up the heater to be within the h-to-k ratings.

Regards,
John

John Bauman

Offline vetmed

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Reply #2 on: March 29, 2012, 04:09:47 PM
Hi
   Really appreciate your response, and the link was very useful. My concern regarding heater to cathode limits had to do with the more usual 100volt limit, but the tube I am working with has a 200 volt limit so of course is less of a concern. Thanks




Robert Lees

Robert Lees

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