For sale...New GI-46B 6 meter amplifier..
Posted: Mon Apr 22, 2013 9:20 pm
I have just completed a new GI-46B 6 meter amplifier..I have been interested in trying out a single GI-46B tube amplifier for some time and built this as a prototype..The finished result is a legal limit amplifier with some comfortable overhead..This would suit anyone who wants an amplifier that will run the VK legal power limit, easy to operate and reliable, definitely not a flogger ..
The amplifier has easy access to all circuits, with a fold down front panel...I have used the reliable W4ZT bias board and Plate idle current is adjustable from the front panel..
The amplifier tunes and loads smoothly..I use a Pi-L tank on the output side....The drive input is through a tunable T network which gives a flat 1-1 vswr..Plate and grid current are metered...The amplifier can be remote switched from an exciter as long as a sequencer is used...Hot switching an amplifier soon erodes relay contacts.. Amplifier cooling uses a 240 volt fan providing air into the sealed top RF deck, air exiting through the tube cooler and a Teflon chimney on the top cover..The cathode compartment is sealed with a 240 volt fan blowing air directly on the tube filament and cathode air exiting through vents on the bottom side of the amplifier....Using my infra red thermometer focused on the tube anode cooler when running long carriers the core heats up to around 85C..Air flow is sufficient to keep the tube well within a safe operating margin...Fan noise is quite low as the fan is buried in the HT supply compartment..
I have used an 850va Toroidal transformer into a voltage doubler rectifier stack and an HT step start relay/resistor circuit...The relays and bias cutoff switching operate from a simple 24 volt power supply..Amplifier function details are clearly lettered on the front panel..Amplifier dimensions are 18x17.5x 8 inches high with turned aluminum legs 2 inches..
I have run the amplifier in a long testing session into a Bird 500 watt dummy load and everything operates smoothly..I still have it set up on the test bench and regularly run it for 10 minutes or so from cold to make sure it is reliable...I will provide circuits and operating instructions for the amplifier....New tubes are readily available from RadioKomponent in Ukraine at reasonable cost as well as various other sources ..
As written above this amplifier is for those who want a reliable 6 meter amplifier that coasts at out legal limit..Anyone interested can phone me or email for full details..We can discuss price and shipping, this amplifier is under $1k and negotiable....73..Bob..VK3ZL..
The amplifier has easy access to all circuits, with a fold down front panel...I have used the reliable W4ZT bias board and Plate idle current is adjustable from the front panel..
The amplifier tunes and loads smoothly..I use a Pi-L tank on the output side....The drive input is through a tunable T network which gives a flat 1-1 vswr..Plate and grid current are metered...The amplifier can be remote switched from an exciter as long as a sequencer is used...Hot switching an amplifier soon erodes relay contacts.. Amplifier cooling uses a 240 volt fan providing air into the sealed top RF deck, air exiting through the tube cooler and a Teflon chimney on the top cover..The cathode compartment is sealed with a 240 volt fan blowing air directly on the tube filament and cathode air exiting through vents on the bottom side of the amplifier....Using my infra red thermometer focused on the tube anode cooler when running long carriers the core heats up to around 85C..Air flow is sufficient to keep the tube well within a safe operating margin...Fan noise is quite low as the fan is buried in the HT supply compartment..
I have used an 850va Toroidal transformer into a voltage doubler rectifier stack and an HT step start relay/resistor circuit...The relays and bias cutoff switching operate from a simple 24 volt power supply..Amplifier function details are clearly lettered on the front panel..Amplifier dimensions are 18x17.5x 8 inches high with turned aluminum legs 2 inches..
I have run the amplifier in a long testing session into a Bird 500 watt dummy load and everything operates smoothly..I still have it set up on the test bench and regularly run it for 10 minutes or so from cold to make sure it is reliable...I will provide circuits and operating instructions for the amplifier....New tubes are readily available from RadioKomponent in Ukraine at reasonable cost as well as various other sources ..
As written above this amplifier is for those who want a reliable 6 meter amplifier that coasts at out legal limit..Anyone interested can phone me or email for full details..We can discuss price and shipping, this amplifier is under $1k and negotiable....73..Bob..VK3ZL..
