Posts Tagged ‘power supply’

Pastime Projects High Voltage Power Supplies

September 3, 2015

Pastime Projects ( manufactures amateur radio kits. Two of our most favorite are the “Remember When” slat board 6V6 kit which was featured in the 1948 (and elsewhere) ARRL Amateur Radio Handbook. This simple transmitter used a 6V6 (or 6L6) vacuum tube on a chassis made of orange crate wood. It was designed for the amateur radio operator to send CW (code) on 80 or 40 meters.
Our more recent kit uses a metal chassis and an improved oscillator kit introduced in the 1960’s Handbooks. It was more stable, easier on crystals, and oscillated on 80, 40 and other bands by switching plug-in coils. Ours uses a 50 ohm link coupled output which matches today’s antennas, antenna tuners, low pass filters, and dummy loads.
These circuits, as first published, were often accompanied by a power supply design which used a 5 volt rectifier vacuum tube. We chose to use modern solid state silicon rectifiers instead. This eliminated the need for a 5 volt winding on the transformer, and the added heat, light, current demand, vacuum tube, tube socket and so
on associated with the rectifier tube.
The result is a simpler less costly power supply for you to build and enjoy. Best regards, Glenn Brown W8JZI for

Summer at it’s best

July 26, 2013

Summer is in full swing here in mid ohio. We attended the radio hamfest in Van Wert Ohio and look forward to the Findlay hamfest later. Summer usually brings on lots of activities other than radio. We are working on stocking the new all metal chassis 6V6/6L6 little oscillator/transmitter kits. These have a bottom cover made of aluminum like the chassis itself, but with perforated holes for ventilation. We have measured power out at various plate voltages. The output ranges from about 2 watts at around 200 VDC to over 10 at 350 VDC through the link coupling which matches 50
ohms impedence. The link coupling keeps the kit simple and less expensive that a pi-network. Besides most modern radios use 50 ohms impedance output. My thinking is to supply the kit with a companion power supply that will provide the filament voltage of 6.3 VAC as well as 200 VDC for the plate.
This is plenty of power for some great CW contacts. Those more experienced would probably prefer to build their own power supplies anyhow. You can save a lot of money on used
transformers, chokes, and so on. Have your priced new transformers lately?
Enjoy your summer. Remember when
cooler weather brings back ham radio building projects to the old work shop.. 73 ES BCNU! Glenn