Author Topic: Impedance of OPT  (Read 580 times)

Offline El Sid

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Impedance of OPT
« on: February 05, 2018, 08:34:51 PM »
The Partridge OPTs on the amp I recently acquired are marked 8000 Ω as shown below. I am assuming that this means that the anode of each PP valve is seeing 4000 Ω, which translates to turns ratios of 32 for the 3.75 Ω speaker tap and 16 for the 15 Ω. Please confirm that I'm not talking  :cr@p:

(If you don't trawl the DIY section, see my idea for the design: https://www.avforums.co.za/index.php/topic,69276.0.html )


Offline handsome

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Re: Impedance of OPT
« Reply #1 on: February 05, 2018, 09:23:39 PM »
The Partridge OPTs on the amp I recently acquired are marked 8000 Ω as shown below. I am assuming that this means that the anode of each PP valve is seeing 4000 Ω, which translates to turns ratios of 32 for the 3.75 Ω speaker tap and 16 for the 15 Ω. Please confirm that I'm not talking  :cr@p:

(If you don't trawl the DIY section, see my idea for the design: https://www.avforums.co.za/index.php/topic,69276.0.html )


each valve sees 4k in class A 2k in class B

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