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Conference napalm::commusic_v1

Title:	* * Computer Music, MIDI, and Related Topics * *
Notice:	Conference has been write-locked. Use new version.
Moderator:	DYPSS1::SCHAFER

Created:	Thu Feb 20 1986
Last Modified:	Mon Aug 29 1994
Last Successful Update:	Fri Jun 06 1997
Number of topics:	2852
Total number of notes:	33157

129.0. "Cry Baby Schematic" by CHEAPR::MCPHERSON () Tue Aug 06 1985 18:56

I've began keeping up with this notes file as soon as I found out it
existed.  The topics covered here are almost all deeply interesting to 
me, electronics/music being my hobby.  

Now I know something so grossly ANALOG and un-microprocessor-controlled
as a Wah-Wah pedal has precious little business being mentioned here, but
I kinda feel like the readers of this file might have the electronics back-
ground I need.

The bottom line is this:  I recently inherited a non-functioning Cry Baby 
Wah Wah Pedal from a guitarist friend of mine.  My pride became somewhat
wounded when I couldn't troubleshoot the problem without schematics.  I 
think some of the components literally have ROTTED internally (road use can
be hard on old pedals).

I need one of two things: 
        1. A genuine schematic to a Cry Baby Wah pedal so I can fix this one
   or
        2. A plain-vanilla schematic of generic wah wah pedal so I can rip
           the guts out of this one and build a new one.

Now I've done some looking for wah schematics and just general variable
filter-type circuits and the ones I could find all used some off-the-wall
voltage supplies. For ease of use and compatibility, I want a simple 9
volt dc power supply. I really don't have the time/inclination to try to 2nd 
guess & redesign someone else's ckt. to a single 9vdc power supply.

I can be reached at CHEAPR::MCPHERSON
My LOC/MS is        MRO3-2/R15
                    DTN 231-5281

Any help will be appreciated.
                                   

                                    Thanks,
                                    Doug

T.R	Title	User	Personal Name	Date	Lines
129.1		MILVAX::BUCKLEY		`Tue Aug 06 1985 23:46`	10
	My Cry Baby Crapped out a couple of years ago & I also have the intrest to fix the thing. I, however, Haven't been able to find the proper schematics either. I know they were discontinued as a product, but recently they were introduced back into the market. The schematics have got to be out there somewhere, but I haven't found them yet. If your come across them, please drop me a note, I'd really appreciate it. If I get 'em first I'll let you know. thanx, -William J.
129.2		AMBER::EIRIKUR		`Tue Aug 20 1985 20:12`	15
	I was going to point you at a Popular Electronics article, but it was vintage '72 or thereabouts. Even a good library might not help. Don Lancaster wrote a book on guitar amp repair. It had many schematics, chosen for general applicability. There were diagrams for some effect units, too, as I recall. Also, there's the good old signal tracing method. As I remember, there's only a one transistor amplifier in a crybaby. (Maybe two transistors? Maybe I was looking inside another wah-wah?) Judicious tracing, and lead lifting, etc. should let you test each component--and there just aren't very many. Consider yourself lucky. You don't have a brand X digital delay where X was a tradename of distributor Y and was made by one of three contractors, two of whom went bankrupt before distributor Y decided microwave ovens were more profitable. I had this sort of experience trying to get schematics for old combo organs... Eirikur Hallgrimsson
129.3	"everything is wah-wah"	DVINCI::CERTO		`Thu Jun 05 1986 19:14`	14
	I've got one too, in the same condition, I believe. I seem to remember that baby wah-wah's had some flaw and most of them burned out for the same reason. Good luck finding schematics, alot of those effects manufacturers used to be very secretive about their designs, which were easily pirated; for example, electro-harmonics is notorius for this, even going so far as to sand the numbers off the chips. I think these wah-wahs were made by Thomas Organ? It has an opto isolator that acts as a notch filter? also a transistor used in an odd way, like possibly avalanched? Anyway, if you come up with anything, I'd be interested also. Fredric
129.4	DDL -> WahWah	ERLANG::FEHSKENS		`Thu Jun 05 1986 21:38`	10
	Owners of digital delays with control voltage inputs (e.g., for modulation) can jury rig a wah wah by running a battery through a volume pedal into the CV input. I've never tried this, but I don't see why it wouldn't work passably well if you set the delay parameters up suitably (phasing/flanging effects). The CV changes controlled by the pedal shift the comb filter frequencies, just like a wah pedal. len.
129.5	DoDoDoDon't NeNeNeed A DDDDLL! ;^)	MAX::MCPHERSON	It's my life and it's my wife.	`Fri Jun 06 1986 16:10`	13
	Re -.1 Yeah... it _looks_ like it should work, but it's a little more involved than that. If it's a Cry Baby or similar make, then the "travel" on the pot in the pedal is pretty limited. I think it'd take a litle extra investigation as to changing to a diferent pot resistance or physically modifying the pedal to give it more travel. By the way, I'm still lookin' for some schematics.... /doug "beat me samson, 8 to the bar" mcpherson