Gary Pimm's design looks really thorough. I will scan the 47 direct coupled article to you guys ASAP. I would like to say that these old radio craft and similar journals from the 50's and 60's are interesting reads. The explanations are somewhat simplified compared to Radiotron and The Radio Amatuers Handbook. I have a dream; that I can someday soon get started on the Transmitting tube amp. That is the power supply section I am trying to assimilate using some very good info from Eric on Damper diode full-wave rectifier circuits. Some of the DD's can be bridged to get 1200v on the plate but it requires seperate windings or a dedicated filament transformer. And which type to use? 6d22s may not have the juice. The other option is mercury rectifiers for some voltage regulation and high plate voltage, but they are difficult to work with. In answer to your question on the general forum Wayne(thanks for your kind offer to help) I have seen a full wave DD rectifier bridged for 1100 volts on a site that I can't seem to find again. This power supply is the one for the eventual SE 211 transmitting tube amp. Mercury is the most common circuit but I don't want to rule out the faster, cheaper better regulated DD's. Right now I am in the process of reading issue 17 of Vacuum Tube Valley; the article by Mr. Barbour called Rectifiers For Audio. I should have some questions for you all very soon. J.R. ( Both Colinhester and Thermionic have been a great help with transformer discussion also.)
Wayne Parham Messages: 18789 Registered: January 2001
Illuminati (33rd Degree)
Thanks, John. I might just do something with the 47's, just for fun. I'd like to do a transmitting tube amp too, but I doubt I'll get around to it for a while. I'm anxious to hear your progress on one if you are able to build one soon. Eric really knows his stuff on tube circuits, and I trust his judgement with the rectifiers. Seems to me the basic layout is pretty simple and that the hurdle to overcome is getting components rated to take the voltage.
Wayne
P.S. I'll send you the Stoetkit in a day or two. Gimme just one more day with it.
No Hurry, enjoy! I am building a new pre-amp now so the Transmitting tube amp is still on hold. I am thinking I may go with a schematic I have from this guy in New Zealand who has built one. It's a copy of a circuit that ran in AudioExpress a few yrs. ago. It uses regulated DC on the 211 filaments An IC regulator drives an NPN pass transistor. The tube requires 10.25v/3.25a DC on the Filaments. AC on the driver/input filaments. The High voltage side uses 900-0-900 200ma full wave cap input supply. Thats what I am chewing on now, well see. I should have the 47 tube info out this evening I just have to hook up the scanner. That looks like a nice little DC SE amp. Lots of fun.
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