36W PT Question

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Holmes
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36W PT Question

Post by Holmes »

I am building a variant of the 36W EF86 and have a set of spare Weber transformers that I would like to use. The OT I have no worries about and should work OK.

The PT is rated for 40W and supplies higher voltage than standard (I think) for the typical 36W designs. The lower voltage secondary taps are shown as 660 VAC @ 200 mA.

A couple of questions:
1). Can EL84s survive if run using the stock power supply circuit (Richie, et-al) or are plate & screen voltages likely to be too high?
2). Any suggestions on modified power supply designs to drop voltages to acceptable levels?

Am trying to decide whether to drop money on a more appropriate PT or live with what I have available.

Thanks for any and all help,

Holmes
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BBQLS1
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Post by BBQLS1 »

You will have to drop the power by one of the below.

Using a different rect tube with a greater drop. You'll have to search to see which gives what drop, I don't know off the top of my head.

Using Zeners to drop the B+

Using resistors to drop the B+

Save yourself the hassle and get a transformer more suited to what you need. I did what you are talking about and I never was happy with it.
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Holmes
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Post by Holmes »

BBQLS1 - Thanks for the response.

I am giving the zener approach a try. It that fails I will order up a Heyboer.

H...
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