A little tubbey

[Cantplay]

Gun blue it.

John

[Andy Le Blanc]

just hit it up with plastikote... bluing it is a great Idea

the kits look simple... just saw something on hot bluing

It be under foot you know how guitar players get, chewspit, bongwater, dog turds and beer.

[Andy Le Blanc]

not immediately happy with the spray finish either, a dip would simple, but its at tube amp and you need to preserve the ground points on the chassis

[Andy Le Blanc]

had to rig a fan in the shop window and put it under a heat light to flash off.
got an ice storm going on, surprised the power is still on.

[Andy Le Blanc]

Ice storm and power outages, still made some progress.

I also had the chance to noodle a bit with a bridge rectifier, it gave me nearly exactly 100v no load.

The real challenge is simply making sure the components all fit in the end.
Compact electronic designs in the pre-transistor era where simple out of pure necessity.
It's already just over 3Lbs... and it's just a 1 tube project.

[Andy Le Blanc]

Managed to get out yesterday and find some light bulbs at the hardware store,
Yes, you can still find radio light bulbs in New England at a hardware store.
Over to Aubuchon, and some of the TrueValues... and some of the old farmers unions...
Simple things, turn it on and it lights up, hit the stomp and the lights change.

[Andy Le Blanc]

Got around to finishing the circuit the evening, works good so far, I still have to finish the case and fiddle-n-tweak.
hum isn't bad, surprised actually, still gonna invest time and see I can't get it as quiet as possible.

So far its a fuzz/boost, you can adjust the clip and output gain... I'll probably tweak for more output volume.

The plate voltage ended up around 160V, I went with a bridge rectifier.
Puts things close enough around the 180v chart for the tube.
GE sheet says I can get a gain of 16 and 35v signal out, but so far it sounds
like its just adequate to hard clip and and still have a boost over the input signal.

I other words just enough for what you would need out of a fuzz box.

[Andy Le Blanc]

Works great as a boost, with .5v signal, the Vout is 2.5

[Andy Le Blanc]

With a .5v signal the measured output under full clip is 5.5v
1khz

apologizes for the shaky pict.

[dorrisant]

Looks so cool!!

Can we get a better schematic?

Tony

[Andy Le Blanc]

yep... digging out from this last snow, hopefully this evening

[Andy Le Blanc]

6c4 data sheet...

There's a little RC amp chart on page 2.
Take a look at the bottom of the chart where Rk is "0".

[Andy Le Blanc]

quick scheme... stupid simple

I'm intending to change the plate resistor to 470k, and the pot. at the output to 2m.
The best thing about such simple circuits is that you can easily fiddle with it and get it to taste.

The only critical values are the first to resistors, the 2.2m because of the bypass type.
You need a high impedance so the circuit won't bog down the rest of what ever signal path your using.
And you want it to keep the bypass switch from popping too badly.

And the 10m is the grid leak for the zero bias set up... I know you could vary the value but you really want a very high value there... 3m and up

beauty about grid leak, or zero bias, is that it can make point to point wiring very simple, right on the socket with very few lugs on a terminal strip or a few eyelets.

same deal as a fuzz... whatever diodes to preference

[Andy Le Blanc]

Power supply is just as simple, I ended up using a bridge... the other side of the dpdt bypass switch switches the lights, funny...

The back to back 12v transformers works well, done that for several little thing so far, drops the cost and is very easy.

[dorrisant]

Thanks for posting this, Andy... You know I've gotta try this!

Tony