Ludwig Phase 2 Schematic at GEO

[R.G.]

For those of you who are not GEO-watchers, I put the completest possible schematic (given the current information level) up at GEO.

There are some missing things, but it should be enough for repair of an existing one, if not cloning.

I'll have filters done in a bit for a more buildable version similar to.

[toneman]

Awesome! effort R.G.!!

U use "British" resistors I C :lol:

The "format" filters are wayyyout there!
i'd go 4 an OTA or even 2 twinT's in series.
MayB i'll do a simulation of the "formats"(?)

So, Q5 & Q6 are the "fuzz" trannys?
Driven by 2nd preamp, Q3.

Oh, what R those 3 "kickingman" symbols 4?

again, great effort!!!
:-)
tone

[travissk]

They're formant (with an 'n' in there) filters; I know there are better pages out there explaining formants, but here's a starter link:
http://www2.sfu.ca/sonic-studio/handbook/Formant.html
For anything beyond that you might want to search Google some more; I haven't ever had the chance to play with a Ludwig II and would be interested to hear what the formant sliders can do

[Marcos - Munky]

COOOLLLL!!!!! Thanks a lot, RG.

[R.G.]

i'd go 4 an OTA or even 2 twinT's in series.
MayB i'll do a simulation of the "formats"(?)

I haven't done a sim of the filters as they sit. When I saw the complexity, I decided that any real world pedals would not use them verbatim. I have designed a voltage controlled filter using a single LM13700 dual OTA per formant. The OTA would probably do the same job, much simpler. I did a state variable that sweeps from about 50 Hz to over 10k. Lotsa room there for a voice filter. Two LM13700's do the two formant filters.

Oh, what R those 3 "kickingman" symbols 4?

Don't know. They were on the original schemos. I took them to be part of the setup for the filters. I believe that the voltage on those points is set by a trimmer cap, and that at setup you'd tweak the trimmer to... some voltage, now lost.

[Mark Hammer]

What the hell does it DO?  I've looked all over the net and I still have no idea.

[Ry]

It looks pretty and smells even better!  The formant sliders change the scent from lilac to cinnamon and every shade in between.  This is a rarely used effect for today's working band, as I think is pretty evident if you've ever stepped into a tour van.

Okay, it's actually a kind of wah/fuzz sounding thing with a very interesting sounding wah effect that does the formant vocal thing with the two filters.  It can go oy-oy-oy wah-wah-wah, that sort of thing.  I think it does more than that, but this is all I've heard from it.

Thanks for re-drawing the schematic, R.G.!

Ry

[Bill Bergman]

I was wondering the same thing, Mark.

[Ry]

Reference Sonic Youths 'The Diamond Sea' from their Washing Machine album.

[Tim Escobedo]

A very simple circuit to try this formant idea can be found on Jack's site, the Anderton wah-antiwah.

For more extensive info on this in a musical context, check out:

http://www.oldcrows.net/~patchell/voicesynth/voicesynth.html
http://www.oldcrows.net/~patchell/vocalfilter/vocalfilter.html
http://www.oldcrows.net/~patchell/synthmodules/vocalfilter.html

The samples on the last page are amusing. However, those circuits are very complex.

[Ry]

Oh my.  That is very cool!  Thanks for the links!

Ry

[Tim Escobedo]

Here's a sample of a simple Anderton-like circuit doing the best vowels it can. If you use your imagination, you can kinda hear a "A-E-I-O-U". The circuit uses a modest gain/clipping stage into two parallel multiple feedback filters. The gain/clipping stage adds some harmonics, which seems to enhance the "vocalness". The two parallel multiple feedback filters are tuned differently than Anderton's version. But it's otherwise the same. Using some BP state variable filters would probably get much nicer results.

[puretube]

R.G. : my compliments!

(but for the rest, I got reasons to stay out of the discussions on this...)

[R.G.]

(but for the rest, I got reasons to stay out of the discussions on this...)

Got a vocal filter in the works, eh? 8-)

[puretube]

...lots of various OTA-stuff...

[R.G.]

Yeah, me too.
- OTA state variable single filter that can do
 -- wah
 -- voicing filter
 -- parametric EQ
 -- random sweeps
 -- LFO controlled sweep

- OTA vocal filters with stepping from vowel to vowel instead of just a rocker sweep
- trying to do a dipthong generator; that's a lot tricker than just an "ooooooo" generator, as you know.
- OTA amplitude effects based on the OTA current controlled amplifiers that I've already posted on GEO. Includes attack delay, envelope shaping, voltage controlled distortion, morphing, etc. as well as normal tremolo
- PIC microcontroller operated versions of combinations of the above.

I have the advantage of you somewhat - I don't market the things I design, so I don't have to keep them secret.

[Bill Bergman]

I don't market the things I design, so I don't have to keep them secret.

That why we like you so much :lol:

[puretube]

...so that people who can`t read schems and solder, can plug`n`play...

[Bill Bergman]

Hey is that a crack at me? :shock:

[puretube]

hey B.B.: that one was referring to R.G.`s remark before.
I have to keep `em secret because marketing them, in order that those who can`t read schems and solder....