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September 29, 2023, 01:14:00 AM

Author Topic: Question regarding Magnequest transformers  (Read 155 times)

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Offline JohnEss

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Question regarding Magnequest transformers
« on: September 12, 2023, 12:37:12 AM »
A friend gifted me a pair of the Magnequest transformers from an older SEX kit and I was wondering if anyone here has the specs and correct wiring diagram for these. Writing on the outside says "CUSTOM PART NO 05009"...Thanks in advance.

Offline Paul Joppa

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Re: Question regarding Magnequest transformers
« Reply #1 on: September 12, 2023, 04:35:38 AM »
I'll dig out my notes - and get back to you shortly.
Paul Joppa

Offline Paul Joppa

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Re: Question regarding Magnequest transformers
« Reply #2 on: September 12, 2023, 06:09:57 AM »
OK, found my notes. The transformer is the BH-1, our first custom/proprietary Magnequest product. Spec is 8000:8 ohms. The core is M4, a higher grade of grain-oriented silicon steel than the usual M6. A few were made with nickel pinstripes. This is a parallel-feed (parafeed) output, so no DC current - it was used with the PC-2 plate choke which is a Magnequest BCP-15 modified with a smaller air gap for more inductance (50 henries at 40mADC).

I can't find any documentation of the lead colors, but my personal SEX amp has the upgrade installed. So I took  down to the lab and found the standard colors were used - primary winding blue to plate, red to AC ground; secondary orange is positive to speaker, black is ground.
Paul Joppa

Offline JohnEss

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Re: Question regarding Magnequest transformers
« Reply #3 on: September 19, 2023, 07:00:33 AM »
Thanks for looking that up.