Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: BrainDeadAmps on May 13, 2023, 02:26:03 am
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I've been pouring over schematics and stumbled upon a uncommon rectifier setup show here in the Gibson Ga-4RE.
Can anyone shed some light on this bizarre circuit?
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Your picture;
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That’s a voltage doubling rectifier, the unloaded V DC will be about 2.8 x the winding V AC, ie twice the V AC pk
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Start reading at Page 4-66 for an explanation of this type of
"half-wave voltage doubler" circuit (http://compatt.com/Tutorials/NEETS/New_PDF/14179A.pdf), and related configurations.
If you don't understand anything presented at that point, you can back up to an earlier point in the book.
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Start reading at Page 4-66 for an explanation of this type of "half-wave voltage doubler" circuit (http://compatt.com/Tutorials/NEETS/New_PDF/14179A.pdf), and related configurations.
This configuration, called the Delon circuit, is a Full Wave Voltage Doubler which is described at the bottom of 4-70.
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...this bizarre circuit?
Also used in a whole line of the last tube Bogen amps, up to the 300 Watt.
It gives low peak voltage on diodes relative to DC voltage output. In the year when high volt diodes were very much more expensive, this covered the cost of the added capacitor.
It can give high DC without a high volt transformer. I used just that plan and 234VAC (stock isolation xformer) with bigger caps to make 640V for a large "Champ".
It is just another way to do it.
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Thank you everyone, lots of great info to pour over now.
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A Conn 2 channel organ amp I rebuilt with the hope of using for a bench stereo uses the same PS rectifier arrangement.
It's called a Delon Doubler and is a full wave arrangement. As stated, many Bogen PA amps, Valco (Silvertone, Gresch, Airline) use it.
https://en.wikipedia.org/wiki/Voltage_doubler
--Pete
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A number of Univox amps use this doubler and additionally, most provide disparate HT voltages similar to the Bogen schematic PRR posted. Most are using 250V windings like the U-1236 and the U-1221. The U-320-A (Lafayette model) used 180V and did not provide disparate HT voltages.