[Boatanchors] Diode replacements for 866 tubes, ratings needed ?

[Rick Poole WA1RKT]

From: "Rob Atkinson" <ranchorobbo at gmail.com>
Sent: Wednesday, November 12, 2014 10:19:56 PM
>>
>> You have to be careful making changes to a power supply
>> designed with a full wave rectifier and center tap
>> secondary... There are hams who not knowing any better
>> fried old power supply iron trying to double the secondary voltage.

Good evening, Rob.

Never had any thoughts about doing that.  At one time I did consider keeping the full wave center tapped transformer but replacing all of the filter components with a capacitor bank.  This would have resulted in a higher voltage than leaving things as is... theoretically as much as 2400 volts which would be well in excess of 811A ratings (most or all of the modern-day amps using 811A tubes already exceed the tube's maximum plate voltage rating) but comfortably within the 572B's rating.  But, regulation will suffer.  The whole idea behind a swinging-choke input is that the choke inductance goes down with a rise in current drain, so that at higher current drains the filter begins to look more like a capacitor-input filter, improving regulation.

Current plan is to leave things as they are except for replacing the 866A rectifiers with solid state.  We'll see how that works.  Hopefully the transformer, choke, and filter cap are all in good shape... we'll see about that, too.

Rick WA1RKT