[sdiy] Fire bottle ladder filter

[Magnus Danielson]

From: Tim Ressel <madhun2001 at yahoo.com>
Subject: [sdiy] Fire bottle ladder filter
Date: Sat, 20 Apr 2002 16:38:09 -0700 (PDT)

> Yo,

<Jamacian style>
Yo man... 
</Jamacian style>

> Okay, I admit it is one of my more bizarre tangents.
> However, my glass-FET ladder seems to kinda work. I
> took five 12AU7 and stuck them into the Moog ladder
> circuit. I also changed the biasing a bit. It is
> acting like a VCF. A little distortion, but hey, its
> the first try. I'm using 100V at the top of the
> ladder, which is the highest I can go without playing
> games with filament supplies.

Yeah!

As I was dipping my nose into my RCA receiving tube manual I saw that
the 12AU7 (double triode) seems like a good starter for an experiment.

How did you wire things up? Cathode to lower stage, grid to bias
resistors and anode/plate to cap? Just plain drop-in?

The frequency responce (cutoff-frequency as result of input CV) might
need some work, but that is done in the CV path, so no worries.

> So next I need to complete the circuit and see how it
> all plays together.
> 
> Isn't this wierd?? It was a very strange feeling
> plugging in those tubes.

I can understand... ;O)

Cheers,
Magnus