Understanding the Schulte Compact Phasing 'A'

moosapotamus · September 20, 2006, 10:31:52 PM

Can anyone help me figure this out?
http://www.tasteundtechnik.de/bilder/compactphasing.jpg

What are those round things in the lower left area of the scheme... rotary switches? If so, which points are the poles and which are the throws? If not, then what? And, what's going on with the stereo input and output jacks?

I'm trying to re-draw the scheme so it's easier to understand, but I don't quite understand it, yet. Any help?

Thanks!
~ Charlie

Nasse · September 20, 2006, 11:51:13 PM

You mean that footswitch connector? I think I have seen such connectors somewhere, but one with a switch... Someone posted good link for DIN connector info but don´t remember what it was. DIN connectors were popular in Europe back then, and some not DIN but similar

Could very likely be that "the switch" is not inside connector but in the other side of footswitch cable there are two separate external spst switches on the footpedal case, controlling lfo fast/slow and on/off. 4,7 k connects to pin 5 and switch grounds it, but 22k goes to pin 6 but where does the switch go? Perhaps that is badly drawn and should go to ground

What is inside that footswitch or remote control box is not shown, there must be some circuitry maybe some controls doubled or external and voltage from zener goes there and other wires too... I just woke up good morning everybody

puretube · September 21, 2006, 02:14:17 AM

mhh - gotta find that old orange box that still awaits repair since 4 or 5 years...

DIN:
http://www.diystompboxes.com/smfforum/index.php?topic=33012.0

if link in above thread won`t work:
http://www.members.aol.com/rhjmayer/Elektronik/Stecker/_Stecker_main.htm

moosapotamus · September 21, 2006, 10:55:21 AM

Thanks for the replies, Nasse & puretube!

Oh... OK, so those are DIN connectors for remote footswitches?

Yes, the lower one near the LFO section is especially cryptic. Must have gone out to two different switches, one for fast/slow, the other for on/off (manual?). What pins would have had to connect/disconnect to implement those functions? :icon_scratching_head:

And, the upper one (directly below the input & output jacks) must be for effect bypass?

I think I'd like to figure out how all that switching was intended to work so I can show that in a schematic instead of the cryptic DIN symbols... a "complete" schematic, if you will. I might be able to get some of it on my own, eventually. But, I'm definately going to need some help to get it all. So, I'd certainly appreciate any additional thoughts... especially, in addition, regarding those stereo input & output jacks.

From the links puretube posted (thanks)...

Is this, sort of, what's going on with the upper DIN footswitch connector (effect bypass?)? The actual switching happens in the remote footswitch box, and would be wired directly between the DIN and the switches instead of those 3.5mm stereo jacks?

And, I still don't understand how/why the stereo input & output jacks are being used for the effect. Can anyone describe what's going on with the main input/output section?

Lots of questions about this one...

Thanks!
~ Charlie

puretube · September 21, 2006, 01:50:21 PM

the upper 2 jacks seem to be normal 1/4" stereojacks for instrumental input and output
levels (guitar-amp),
where the upper input when plugged in, turns IC1 into a differential (high sensitivity)
amplifier mode, by shorting the sleeve to ground.

when, however, a mixing console output or tape recorder output is connected to the upper DIN-jack,
(which is a more or less parallell second in-/out route),
left and right channel from the mixer/recorder (pin1&4) are being shorted
("mono-ized") and fed to IC1, which then works in a less-gain mode.

a buffered dry signal from IC1 appears on output-pin5 to go to one channel of a "PA",
while a wet signal (mixed between dry & phased by the "MODULATION"-pot),
appears on output-pin3, to got to the other channel of the PA.

the wet signal mix also appears at the instrumental 1/4" output-jack`s tip,
however attenuated by 22k:2k4,
while the buffered/attenuated (22k:2k4) dry signal appears at the sleeve.

so if you plug a mono-cable into the instrumental outputjack,
you get "phasing" (well, a balance between dry & delayed, depending on the
"modulation"-pot setting,
while if you plug in a stereo-cable,
you get one channel "dry"-only", and the other channel "wet".

now if the modulation-pot is set to all wet,
you have "vibrato" in one channel,
and "dry" in the other,
to obtain: "in-ear-phasing",
as opposed to the usual electrically mixed dry&delayed...

[just a rough thought...]

moosapotamus · September 21, 2006, 05:35:31 PM

Quote from: puretube on September 21, 2006, 01:50:21 PM
... [just a rough thought...]

Yeah, like... I sure would have had a rough time figuring that out all by myself. Thanks, puretube!

OK, now on to the DIN connected switching for the LOF section. Any more insights?

ITMT, I think I've got my head around enough of to start putting together a rough scheme. Will post when I get a chance.

Thanks!
~ Charlie

majormono · September 22, 2006, 01:30:55 AM

If it is of help, here's a shot of my Compact Phasing A which I got for free after long-time "storage" in a Cellar-Studio.
After replacing the supply-caps and VReg chip there's at least power but no phasing (or glowing lights) as of yet ;-).
If there's anything I can be of help, let me know.

http://i95.photobucket.com/albums/l155/fotofix/Geroedel/CompactPhasingA.jpg

puretube · September 22, 2006, 02:02:24 AM

yes, those LFO/remote DIN-sockets seem to have local switches built-in at their rear,
that act, as soon you plug s.th. in...
(obviously, that`s why they`re drawn so crypticly inside the circle).

one of them seems to be a very rare 6-pin socket.

as soon as I find the pedal I have "in repair" (since 5 years - it has an LFO lampdriver issue...),
I`ll dive in there with my cam, too.

moosapotamus · September 22, 2006, 09:10:33 AM

Cool, guys! I'm thinking this might be a nice one to build if we can figure out the switching stuff. I'm hoping to have some time to start re-drawing the scheme over the weekend.

Another ?... Any idea what that little diagram below the 5-pin DIN symbol is about? Part of it looks kind of like a three-input mixer, but I'm not sure about the rest of it.

Thanks!
~ Charlie

puretube · September 22, 2006, 09:21:28 AM

I think it`s just a little demo-picture,
to show how to hook up a mixing-console/PA (like mentioned earlier)
to the 5-pin DIN jack,
in case that external equipment doesn`t have 5-pole DIN connectors,
but only 3-poled ones (mono).

of course you`d loose the buffered dry output.

in the 60`s/70`s, both versions (3 or 5) where wide spread in HiFi,
and studio equipment in Germany/Europe...

moosapotamus · September 22, 2006, 02:04:38 PM

OK. Thanks, I can see that now.

I just looked up the part number for IC13 and IC14 - 830CE. I wasn't familiar with that one. Looks like it's a +15V regulator, similar to 78L15 (in a TO5 package). I guess that makes sense, even though the scheme indicates +/- 16V.

But, I'm not sure what the dashed line going through the connection coming out of the junction of those two diodes means... optional?

And, there is another dashed line that looks like it goes from the freq trim, 500k -log with the note... fmin (50Hz), to pin 5 on the 5-pin DIN. Could that be an actual connection?

~ Charlie

puretube · September 22, 2006, 03:48:18 PM

dunno the 830...
but if it`s a 15V type, the dashed line makes sense as meaning "optional"
(depending on the individual voltage drop of the diodes used,
which are supposed to lift the regulated output to 16V).

the other (long) dashed line is a different kind of "dash" ;
usually, you would use this for ganged pots, or for indicating
ganged switch-poles.
dunno what is meant here...
(it`s a 500Ohm, though, - not kilo-Ohm!
strange to me, why they want a neg-log for an inside 2legged trimpot? ).

I also don`t quite understand why it`s called "fmin (50Hz)" ;
the "50Hz" reminds of the German mains-frequency
(would be "60Hz" in USA)...
is it a de-hummer? (minimize mains hum / hum-cancelling?) ?

actually, the bulbs get a mix of raw/ripply powersupply DC
via the 2N1613 for pre-heating,
plus a modulating voltage from the LFO via the BC237B & 2N1613.

maybe it means that the de-hummer is only neccessary to adjust,
if external equipment is used at the DIN-jack (think: ground-loop???) ?

that`s all for this weekend - more when I`ve found my pedal.

majormono · September 22, 2006, 04:09:44 PM

Interestingly in my Version (Rev. P/2a) VReg is done by a LM723 (µA723) IC.
Too bad I dind't find the time to trace this revision and revive this thing yet.

moosapotamus · September 22, 2006, 10:08:44 PM

Thanks again for the replies, puretube. Much appreciated. Oh, 500 Ohm... right. I saw that but my finger slipped.

majormondo - That's interesting... just one LM723 for a bipolar supply?

BTW, check this out...

compact clone

~ Charlie

majormono · September 23, 2006, 03:30:19 AM

Yes, Jürgen always puts my eletronics skils to shame

... and I don't even manage to take the time to repair mine. Anyway - taking good use of Germanys current weather conditions and a beautiful morning I took some more pics and uploaded them in full resolution: yes only one LM723, socketed (and replaced - now at least to power-light is on). Note the yellow tape on one of the bulbs....

http://s95.photobucket.com/albums/l155/fotofix/Elektrik/

puretube · September 23, 2006, 03:38:12 AM

aah: here you see the 6th pin in the centre of one of the DIN`s, and the switch on the back of the other,
that gets engaged, when plugged...

moosapotamus · September 23, 2006, 01:13:16 PM

Awesome pics, majormondo! Still absorbing them.

Yes, I see the 6-pin DIN, with the 22K going to the 2M2 Osc Period pot via the long green wire. Still wondering about the actual switching that would be happening on the other end, tho. So, I started redrawing the scheme so I can try to see it all more clearly.

But, what gets 'swtiched' when the 5-pin DIN gets plugged?
Based on puretube's explaination, I was kind of understanding that as just an alternative connector for stereo input/output from a console or recorder that just happened to also have a similar 5-pin DIN connector. Does that switching just disable the input/output from the 1/4" jacks, maybe?

I was actually thinking that the 5-pin DIN could just be removed because the 1/4" stereo jacks really do the same thing when you insert stereo plugs, don't they? And, of course, I want to get rid of the 6-pin DIN, too.

Thanks!
~ Charlie

majormono · September 23, 2006, 01:42:49 PM

Well maybe I could save 1000 words and give you this instead:

If anyone would magically fix it I'd even post an sound example

moosapotamus · September 23, 2006, 11:28:47 PM

!!!
Well, send it my way and I'll see what I can do.

Seroiusly, awesome pics! The graphics on that back panel do say a lot. Love that x-ray view, too.

Thanks, again!
~ Charlie

moosapotamus · September 24, 2006, 12:52:07 AM

These are just rough...

SCP'A' Power Supply

SCP'A' LFO Section

...still need to sketch out and edit these with the DIN switching stuff based on all the feedback from puretube and majormondo (thanks!).

...audio section scheme is working...

~ Charlie

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Understanding the Schulte Compact Phasing 'A'