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Homebrew Equipment A place to show, design and discuss the weird and wonderful electronic creations from the hands of individual members. |
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4th Oct 2008, 12:53 pm | #1 |
Hexode
Join Date: Sep 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 472
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Ever Ready Portable no. 24 Battery
In response to this thread https://www.vintage-radio.net/forum/...ad.php?t=32841, post #10, here are details of my power supply built into a replica box for my Pye model Q set.
The box is built from 6mm MDF, glued with small corner pieces for extra strength. The outside was then covered with glossy photo paper prints of scanned images of an original battery. The majority of the electronics are constructed on the base of the battery. It made sense to put the HT zener chain directly on the HT connector sockets on the top of the battery. As well as providing HT and GB, the original purpose of the battery, I have incorporated a regulated 2v supply to replace the original accumulator. LT supply uses an LM317T regulator. GB supply uses an LM337T negative regulator to give -3v. Further diodes provide a -1.5v tap. Using the resistor values shown, the 2v and 3v supplies are spot-on. The HT is zener regulated to give the highest battery voltage of 126v. I then used a string of series-connected 3v zeners to provide the other HT taps. All HT and GB battery connections are via wander sockets, the holes for which are counter-bored on the top surface to give a flush, neat appearance. The LT supply is an umbilical lead terminating with screw terminals to accomodate the original accumulator spade connections in the radio. The power supply was made largely with stuff I had in the junk box (I had to buy the zeners). I had to use 2 mains transformers with secondaries in series to boost the HT AC voltage high enough for the 126v HT supply. On the low voltage side, the 8-0-8v is actually a bit higher than required, hence the heatsink for the LM317T. I could have used a high power resistor to drop some voltage but I had the heatsink to hand. The power supply works well in the radio, plus it is a useful general purpose HT supply too. |
4th Oct 2008, 1:14 pm | #2 |
Heptode
Join Date: Aug 2006
Location: Sheffield, South Yorkshire, UK
Posts: 990
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Re: Ever Ready Portable no. 24 Battery
Hello Steve
Thanks for taking the time to respond to my earlier request. I must say that is an absolutely super piece of work! I can see a lot of thought and effort went into designing and building it. Just excellent! It would be ideal as a general bench psu, its got just about every HT value you might need. Only thing missing is a 1.4V LT output, which could easily be added of course. Many thanks and regards |
30th Nov 2008, 8:56 pm | #3 | |
Dekatron
Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
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Re: Ever Ready Portable no. 24 Battery
Quote:
Any ideas? It looks very handy. Cheers
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