[FullRangeMan]

The Guillotine:  http://www.thermionic.org/projects.html

[Niteshade]

That is indeed a spiffy project!

[JohnR]

The trick must surely be to get a pair... assuming you can get OPTs for them

[FullRangeMan]

The trick must surely be to get a pair... assuming you can get OPTs for them

I must understand RF Transmitters also need OPTs??

[JohnR]

Hi - no, I was just joking about using them for audio

[Niteshade]

An "easy" big bottle tube to work with: 572B



The issues with most RF tubes is an oddball filament voltage plus high B+ voltage. They're not for beginners.

The 572B's filament requirements are modest: 6.3volts @ 4 amps each. Large tube amp transformers can easily provide it. That same large transformer could also provide something like 750 volts with a center tap. You will get about 1050 volts with a bridge rectifier. Add to that a couple of single-ended transformers with a 10K primary and you've got the parts for a nice amp.

[FullRangeMan]

Hi Niteshade,
When you place this post I see this 572B tube in Tubedepot advert for about $140 each, but today the Tubedepot page are gone, looks the stock finish even at this hi price.
Really amazing, Gustavo