Finally - power and light!
The nearly finished pentode preamp/soft clipper/beam modulator was
fired up and tested last night. The beam modulator works very well.
With two audio freq CV inputs and an audio grid input, it produces
two very nice sideband outputs.
The clipper does indeed require a preamp, but it sounds great!
Unfortunately, the screen voltage pot fried after a few minutes!
Apparently, a 1/2 watt, 1M is too puny for the 200 VDC being tapped
from the plate supply. My grandson was very impressed with my calm
reaction to fire, too! In my little world, it's not fun until
something smokes. Obviously, a limiting resistor is necessary to
keep the current low enough through the screen voltage pot. That'll
be installed and tested tonight.
Most of the part for this project were straight from the junk box.
The enclosure and chassis started life as a RCA tube sine
oscillator. I made a new front panel for it and added a couple of
holes. This device also provided the transformer and pilot light
assembly. I bought some 6AU6 and 6BN6 tubes from Antique Electronic
Supply and scrounged everything else from my parts bins. Total
investment - under $10 (it would have been less but I bought two of
each tube, just in case). Total fun factor - way high!
I'll post a photo or two in the near future. Thanks to Eric Barbour,
Ken Stone, and Dave Wright for your input!
Chub- fun is my business and I've got the scar tissue to prove it!
The nearly finished pentode preamp/soft clipper/beam modulator was
fired up and tested last night. The beam modulator works very well.
With two audio freq CV inputs and an audio grid input, it produces
two very nice sideband outputs.
The clipper does indeed require a preamp, but it sounds great!
Unfortunately, the screen voltage pot fried after a few minutes!
Apparently, a 1/2 watt, 1M is too puny for the 200 VDC being tapped
from the plate supply. My grandson was very impressed with my calm
reaction to fire, too! In my little world, it's not fun until
something smokes. Obviously, a limiting resistor is necessary to
keep the current low enough through the screen voltage pot. That'll
be installed and tested tonight.
Most of the part for this project were straight from the junk box.
The enclosure and chassis started life as a RCA tube sine
oscillator. I made a new front panel for it and added a couple of
holes. This device also provided the transformer and pilot light
assembly. I bought some 6AU6 and 6BN6 tubes from Antique Electronic
Supply and scrounged everything else from my parts bins. Total
investment - under $10 (it would have been less but I bought two of
each tube, just in case). Total fun factor - way high!
I'll post a photo or two in the near future. Thanks to Eric Barbour,
Ken Stone, and Dave Wright for your input!
Chub- fun is my business and I've got the scar tissue to prove it!