Ludwig Phaser

[R.G.]

No, it's not done yet.

What I have been able to do is to slice and dice it into some more manageable pieces. There's a couple of input preamps in there, a couple of sheer gain stages perhaps that distort, two very oddly set up formant filters that I ... think... are voltage controlled from the stuff on the console board, and a UJT oscillation to run the "animation" stuff.

The thing runs on 35Vdc that it makes itself from a transformer that's presumably inside the box.


More as I uncover it, a bit at a time.

[toneless]

I hope i could help... :roll:
This thing looks a little complicated.
It's the biggest phaser out there,so i suppose it should have a big power transformer,too

[R.G.]

It's not a phaser, except in the sense that the random phase cancellations can cause notches to appear.

I had speculated about using filters to achieve vowel sounds out of wah like circuits, here and on GEO. Ludwig beat me to it by a couple of decades.

The P2 consists of a couple of gain amp stages, a distorting stage and a voltage or current controlled fuzz stage (more about that later), with two current controlled bandpass (I think) filter stages that are wobbled around by the stuff on the console board. All of the audio is on the fall plate board, near as I can tell.

The filters we can call formant 1 and 2, relating them to the vocal wah info you can see in the voice wah article at GEO. The formant trajectories are how the formants move: parallel (both up or both down in parallel) counter (one up, one down, then vice versa - I think) and vowel (one moves up monotonically, the other goes down, then up; see the voice wah stuff at GEO for why this is important).

The fuzz is "animated" somehow, I believe in intensity, by a UJT timing and one shot circuit on the console board.

There is a choice of voice fuzz or fuzz, meaning (I think) that the fuzz is routed through the voice filters or not.

I have to do some modelling to get more info about how it works.

I know some things already:
- it's a power pig. Without redesign, it will never get down to one 9V battery. Fortunately, a redesign from the block diagrams up with modern OTAs does look possible.
- the idea about fuzz animation kicked some old ideas I had back to the front. How about this - fuzz that is voltage controlled in intensity, so that as you turned up a control, the volume of signal does not change, but the amount of distortion does. Now make that controllable by an envelope or LFO. The distortion amount changes with the control

I have some holes in the analysis.
- what is "fuzz repeat"?
- the bypass circuitry and the bypass balance pot mentioned in the schematics is not shown; have to guess about that stuff in lieu of looking at a real one.

The redrawn schematics are much easier to deal with, but need more work before they're going to be useful to anyone but me.

More as I find it out.

[Tim Escobedo]

Where's the schem for this?

[Dan N]

Toneman uploaded Ry's schematics to a yahoo group:

http://groups.yahoo.com/group/schematic_trading/

in "files" in "ludwig"