14-12-2011, 04:48 PM
Forum members will know that forum member Tony Thompson ('Aerodine') is a noted author of several books and many vintage radio technical articles in magazines such as EPE, BVWS Bulletin and Radio Bygones. 'RB' subscribers will know that in RB 124, April/May 2010, an excellent 6-page article of Tony's appeared entitled 'Power for a Queen' - the 'Queen' in this case being an Ever Ready Sky Queen battery valve radio of the 1950s. The article describes the construction of a 90V HT/1.4V LT power supply built into a reproduction Every Ready B136 battery, but could be built into any enclosure desired by the constructor.
The power supply used a small mains transformer with two secondaries - one at 43-0-43V, the other 8-0-8V. The HT requires the addition of just four components - a bridge rectifier, resistor and two smoothing caps, the LT, two diodes two resistors, three caps, a pre-set resistor and an LM338 Voltage regulator, all quite simply built on a tagstrip, with a very clear layout shown in the article. All in all, a very neat ans useful project for battery valve radio enthusiasts.
My reason for writing this post is to say that the choice of transformer might seem a bit unusual and hard to come by, but was listed by Tony as having been from NR Bardwell, a long established Sheffield-based shop. I drove past Bardwells today on my way home from visiting Joe ('Pillenwerfer') and popped into 'Bardies' to see if they still have the transformers. They thought not, as coincidentally, someone went in yesterday and cleaned out their remaining stock of sixty! However, they were good enough to check in the attic and found another sixty or so. Only £2.00 each to callers, (£4.00 by post), so I bought a couple.
If anyone is contemplating building this excellent project, when these transformers are gone, they're gone, so get in quick! They've had them for years and they've never moved, and they couldn't understand why they'd been selling steadily for the last 18 months or so. I showed them my copy of RB and they were delighted to see their name mentioned as the supplier! NR Bardwell, 288 Abbeydale Road, Sheffiled S7 1FL. http://www.bardwells.co.uk/default.asp
Hope that helps any would-be constructors.
The power supply used a small mains transformer with two secondaries - one at 43-0-43V, the other 8-0-8V. The HT requires the addition of just four components - a bridge rectifier, resistor and two smoothing caps, the LT, two diodes two resistors, three caps, a pre-set resistor and an LM338 Voltage regulator, all quite simply built on a tagstrip, with a very clear layout shown in the article. All in all, a very neat ans useful project for battery valve radio enthusiasts.
My reason for writing this post is to say that the choice of transformer might seem a bit unusual and hard to come by, but was listed by Tony as having been from NR Bardwell, a long established Sheffield-based shop. I drove past Bardwells today on my way home from visiting Joe ('Pillenwerfer') and popped into 'Bardies' to see if they still have the transformers. They thought not, as coincidentally, someone went in yesterday and cleaned out their remaining stock of sixty! However, they were good enough to check in the attic and found another sixty or so. Only £2.00 each to callers, (£4.00 by post), so I bought a couple.
If anyone is contemplating building this excellent project, when these transformers are gone, they're gone, so get in quick! They've had them for years and they've never moved, and they couldn't understand why they'd been selling steadily for the last 18 months or so. I showed them my copy of RB and they were delighted to see their name mentioned as the supplier! NR Bardwell, 288 Abbeydale Road, Sheffiled S7 1FL. http://www.bardwells.co.uk/default.asp
Hope that helps any would-be constructors.
Regards, David.
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
