I need some help designing a B+ supply for a 212 A Collins Broadcast Console. I am currently running it with three Heathkit HV regulated supplies because no single one will give me enough ma.
What I require is about 325 vDC @ 250 to 300 ma; 140 vDC @ 150 ma, and a filament 6.3 acv at 6 amps or so. I’ve looked at Hammond Transformers, but need specific suggestions on rectifier, chokes, and caps. The original supply used two 6H chokes in the 325 with 10 ufd and 20 ufd filters and two 15H chokes with two 90 ufd caps in the 140 supply. Parts list and schematic and I can build it, but I am not as confident about designing it. Any suggestions or general principals appreciated. I’ve read related posts. Angela Supply seems to have most of what I would need.
What I require is about 325 vDC @ 250 to 300 ma; 140 vDC @ 150 ma, and a filament 6.3 acv at 6 amps or so. I’ve looked at Hammond Transformers, but need specific suggestions on rectifier, chokes, and caps. The original supply used two 6H chokes in the 325 with 10 ufd and 20 ufd filters and two 15H chokes with two 90 ufd caps in the 140 supply. Parts list and schematic and I can build it, but I am not as confident about designing it. Any suggestions or general principals appreciated. I’ve read related posts. Angela Supply seems to have most of what I would need.
Here your link for the service manual on the 212A . That is an un regulated power supply . This a surprise in a broadcast board. Using separate Hv regulators gives better channel separation. so using 4 or more is far better than one large one. Which Heathkit regulators ?
http://www.ianbell.ukfsn.org/EzTubeMixer/docs/misc/Collins_212A-1.pdf
http://www.ianbell.ukfsn.org/EzTubeMixer/docs/misc/Collins_212A-1.pdf
Thanks for the reply. I am using 3 Heathkit PS-4s, regulated power supplies, any one of which will only delivery 100 ma.
I have the 212A power schematic. I don't want to duplicate it, but build something with modern components. The 212A dates from the late 1940s. I also have a 212E w/ the Collins supply, it's unregulated as well.
The B+140 is for the preamps; the B+325 for the monitor and line amps. So I guess I could build two supplies w/ separate transformers. My problem is knowing I have selected a rectifier, chokes, caps, with enough headroom. Any help appreciated very much.
Terry
I have the 212A power schematic. I don't want to duplicate it, but build something with modern components. The 212A dates from the late 1940s. I also have a 212E w/ the Collins supply, it's unregulated as well.
The B+140 is for the preamps; the B+325 for the monitor and line amps. So I guess I could build two supplies w/ separate transformers. My problem is knowing I have selected a rectifier, chokes, caps, with enough headroom. Any help appreciated very much.
Terry
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