I am trying to design a tube rectifier circuit for my upcoming tube project. I am doing lots of research and so on. I will be using a 6BY5G rectifier tube. I came across a 'hybrid bridge rectifier' - like th eone in the pic below:
Are there any benefit of using that type of a circuit ??
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Are there any benefit of using that type of a circuit ??
There are a few: you don't require a center tapped secondary, you get the full utilization of the secondary voltage, and it's fewer holes you need for the chassis, less heater power, and no problems with Vhk issues since you're substituting Si diodes for hollow state diodes.
Back in "the day", bridge power supplies would typically use something like a 5U4 for the positive rail, and two TV damper diodes for the negative. These being used with a center tapped secondary to implement "economy" power supplies, mainly for plate power and screen power for higher powered amps (audio or RF). A center tapped secondary also provides a ready source of both positive and negative rails.
If you use a center tapped transformer with a tube rectifier then you don't need the hybrid design/2 diodes. I think you would only use a hybrid if you happened to have a non-center tapped transformer on hand to use and wanted tube rectification, or if there was a non-center tapped transformer (possibly a toroid) you wanted to use, most likely because it is cheaper than a center tapped transformer. If you are on a real budget, Antek has some nice toroids with electrostatic screens and magnetic shields that are considerably cheaper than most center tapped transformers and could be used with a hybrid design.
The Antek transformers can be used with the regular tube rectifiers as well. They don't have center tapped windings, but they do have two separate windings. If you wire them correctly in series, you'll end up with the equivalent of a center tapped winding.
The only catch is that some of their transformers have bias taps at 70 V or so. Unfortunately, the windings are identical (not symmetric) so you'll end up with, say, 400-70-0-330-400 rather than 400-70-0-70-400 V. This is only an issue if you plan to use the 70 V tap, of course.
Note, however, that by the time you get the transformer and the cover bell, the solution cost is about as much as a typical Edcor transformer. The Edcors are a lot prettier... But E-I rather than toroid. Tradeoffs, tradeoffs.
~Tom
The only catch is that some of their transformers have bias taps at 70 V or so. Unfortunately, the windings are identical (not symmetric) so you'll end up with, say, 400-70-0-330-400 rather than 400-70-0-70-400 V. This is only an issue if you plan to use the 70 V tap, of course.
Note, however, that by the time you get the transformer and the cover bell, the solution cost is about as much as a typical Edcor transformer. The Edcors are a lot prettier... But E-I rather than toroid. Tradeoffs, tradeoffs.
~Tom
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