After more than a month of video-making abstinence I finally managed to make another one.
It’s about the classic Heathkit IG-102 signal generator. 2 Tubes, the 12AT7 and the 6AN8 make up 4 oscillators (3x RF, 1x internal modulation). Some little hack at the end…
if you need some manuals I probably can help you. I can’t put up any manuals ’cause Heathkit was a little cranky about that sort of thing – so until the situation is clear, just ask.
I just made up some working test setup for the homebrew oscilloscope project and the screen came to life for the first time:
Here is my setup:
By the way is the 3KP1 / DG 7-113 with the green p1 phosphor. If you ever come across the white phosphor (3kp4) you found some nice piece of rareness. The P4 version was used in the Pilot TV-37, one of the first portable TV-sets. Check out David and Marlene McClellans blog about restoring one! Also check out some video of it here.
In this video I quickly cover the electron tubes basics and show a little tube amp project, that uses the 1T4 (DF91). The 1T4 is a low voltage tube that can be operated from 45 (it actually works with 12V too) up to 90 VDC and a heater with only 1,5 V. It is also very cheap and can be as NOS for about 0,5 to 1€.
To make more bang I just put two tubes in parallel. In my configuration the whole set-up makes about 150 mW of sound power.
Okay I’ve been working on this for a year now but I can see the end and hope I get it done in a month or so.
Sorry Mighty Ohm The geiger shield had to take a step back before high voltage and vintage tube stuff.
Until I can make the vid you can enjoy these pics of the build:
This is a little vid about the classic Heathkit V-7A, predecessor of the Heathkit models IM-11 and IM-18. They all had an almost identical Circuit and were manufactured from the 50tier until the early 80ties. I am doing some little repairs on faults that came from a leaky batter and show how to measure with it.
So I’m working on this tube power supply and I found a way to get 300V~ by connecting a second transformer in reverse – the problem with this solution however is that I only got 2 power-terminals on it. So the road of doing it that way is closed.
Can I use 4 EY88 TV Rectifier Tubes (500 mA@5 kV) as a full-bridge-rectifier?