Repurpose 5 vac rectifier filament winding?

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nuke
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Repurpose 5 vac rectifier filament winding?

Post by nuke »

Thinking out a next build, going through the stuff in the back corner of my garage that's been there way too long waiting for that spark of inspiration.

I can't see any reason not to re-purpose the rectifier filament winding of an existing transformer? I want to power some solid state circuits for switching relays LED and pedal, perhaps reverb too. Seems like plenty of current and with a voltage multiplier should handle everything I have in mind.

Unless there's something I don't know about. My understanding is that the rectifier filament winding just has plenty of insulation and isolation from the rest of the transformer since it connects to the high-voltage supply in circuit.
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martin manning
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Re: Repurpose 5 vac rectifier filament winding?

Post by martin manning »

It’s been done successfully many times. Tying the 5V heater winding to the high voltage winding is done to reduce the rectifier Vh-k.
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trobbins
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Re: Repurpose 5 vac rectifier filament winding?

Post by trobbins »

Also many cheap ebay style dc-dc converters around to achieve whatever dc voltage you want, including step ups like MT3608 and XL6009 based modules, and even for B+ rails with perhaps 20W level grunt from a Baxandall style (Royer-like) small module.

The step-ups can provide a regulated output level from what is an unregulated dc input, and can avoid using large filter capacitance on the rectified filament output or the need for a doubler or tripler with their diode losses or need to use schottky's. They can also be useful for dc powering preamp heaters.
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Re: Repurpose 5 vac rectifier filament winding?

Post by Stevem »

Maybe more important to your build depending on the gain level your looking for would be to rectify that 5 volts which would give you a nice 6.1 vdc to run the first preamp tubes filament from for a real low noise floor.

Or you could rectify that 6.3 vac, drop that dc down some and then power that first tubes filament.
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nuke
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Re: Repurpose 5 vac rectifier filament winding?

Post by nuke »

I had a look at some hybrid integrated DC/DC converters with +15/-15v outputs at Digikey, but most needed fairly tight input voltage.

I'm just looking for a nominal 30v (+15v and -15v) to operate some solid-state switching and perhaps a reverb, buffered loop IO, maybe. Don't need much current or anything special.
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trobbins
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Re: Repurpose 5 vac rectifier filament winding?

Post by trobbins »

Perhaps use a MT3608 to generate a regulated +12V or 15V, and then use a 12V to +/-15V converter.
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