WEM - Project V  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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Greenmachine
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Post by Greenmachine »

Uhm. By some strange twist of fate, I happen to know Paul Rudolph. I can call him and ask him some details about his gear if you want. Just tell me what you want me to ask him.
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Post by nightraven »

Greenmachine wrote:Uhm. By some strange twist of fate, I happen to know Paul Rudolph. I can call him and ask him some details about his gear if you want. Just tell me what you want me to ask him.
:lol: i have already hassled him about this pedal a while ago, he confirmed with me that it was his Project V that he loaned/gave to Brian Eno
whether or not he used the pedal with Pink Fairies is a different story and would be interesting to find out (if he remembers a detail like that)
there's a pretty strange shaped fuzzbox on the floor in this performance of his earlier band the Deviants :scratch:


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Post by grizzlytone »

nightraven wrote:hi guys, best Xmas present ever maybe? :lol: besides maybe the pedal itself

a guy in the States i have been talking to very generously took his pedal apart for me and the internet for that elusive trace side photo (THANKS!!)..... so without further ado

Image

the circuit of his pedal is exactly the same as Graham's pedal so now there are both piece of the puzzle... techie dudes: work your magic :)

merry Xmas!
Thanks man!

Here's my preliminary take on a PCB layout. I've studied every available picture on the internet to find out the component values but as you can see there's still a lot info missing -if someone has access to the missing values and the point-to-point solder lug mess Please fill in. I've drawn a schematic but I haven't got a scanner where I'm at right now.
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WEM Project V PCB layout version1 by Grizzlytone.pdf
(73.17 KiB) Downloaded 163 times

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Post by capricorn_1 »

nice work! could the component between q1 E and q2 B be a capacitor rather than a resistor?

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Post by nightraven »

fantastic! here's another photo in my little database (i hope the owner of it doesn't mind me posting)

Image

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Post by grizzlytone »

capricorn_1 wrote:nice work! could the component between q1 E and q2 B be a capacitor rather than a resistor?
Thanks capricorn_1, Yeah I know what you mean, it sure looks odd for a resistor but it can't be a capacitor because without DC bias Q2 wouldn't conduct at all, it could be (and looks like) an inductor though and it would make some sense as it would attenuate RF frequencies at the input -maybe a good thing since there's quite a bit of signal gain at the darlingston stage input that Q1 & 2 comprises...

Great pic nightraven! Do you have it in hi resolution as well?

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Post by grizzlytone »

nightraven wrote:fantastic! here's another photo in my little database (i hope the owner of it doesn't mind me posting)

Image
Thanks nightraven! Here's version2 thanks to your additional pic.
Attachments
WEM Project V PCB layout version2 by Grizzlytone.pdf
22k resistor value added. 1k resistor value changed to 1k5. resistor changed to sintered core inductor. capacitor voltage ratings added.
(73.5 KiB) Downloaded 115 times

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Post by nightraven »

sure thing!
http://dl.dropbox.com/u/44410908/P1010001.JPG
http://dl.dropbox.com/u/44410908/P1010003.JPG
you said you drew up the schematic -- does this fuzz resemble any other pedal designs? like Superfuzz/FY-6?

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Post by grizzlytone »

nightraven wrote:sure thing!
http://dl.dropbox.com/u/44410908/P1010001.JPG
http://dl.dropbox.com/u/44410908/P1010003.JPG
you said you drew up the schematic -- does this fuzz resemble any other pedal designs? like Superfuzz/FY-6?
Great! Thanks!!

Nope, the circuit is completly original, if anything the 6 transistor fuzz and output stage resembles something you'd expect to find at the speaker output of a small early seventies transistor radio minus o/p transformer (push-pull, lo-Z, DC -coupled). I'll post my preliminary schematic as soon as I get a hold of a scanner (visiting my parents over christmas. brought my laptop though) Thanks again.

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Post by capricorn_1 »

i agree, its not like anything i have seen before! i've done a rough schematic of just the board so far based on grizzlytones pdf and some other pics i have, need to check it and add the switches!

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Post by grizzlytone »

OK, here's version3
Attachments
WEM Project V PCB layout version3 by Grizzlytone.pdf
470R resistors changed to 4R7 (Gold bands -not Brown. yes, it really is a classic transistor radio o/p -stage). Cap value and voltage ratings added.
(74.1 KiB) Downloaded 124 times

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Post by nightraven »

amazing!!
well Mr Capricorn_1, are we going to see a Ghost Effects Project V soon to match your Pep-Box? :idea: wonder how long it will take for a pedal builder to start boxing up clones of this after all the hype and mystique!

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Post by grizzlytone »

Here's my preliminary schematic. Circled components are unknown values.
Attachments
WEM Project V Fuzz schematic version1 by grizzlytone 001.jpg

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Post by capricorn_1 »

nightraven wrote:amazing!!
well Mr Capricorn_1, are we going to see a Ghost Effects Project V soon to match your Pep-Box? :idea: wonder how long it will take for a pedal builder to start boxing up clones of this after all the hype and mystique!
haha I definitely want one, so maybe a one off to go with it? :thumbsup

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Post by nightraven »

thanks for the schem, Grizzlytone, if you could circle the missing components on one of the gutshots floating around i could forward that to one of the owners of the original units for additional info

by the way - Mictester - sorry to burst yer bubble :lol: your pedal is still very much welcome here (especially if it's a different three-transistor unit like you mentioned)
just had to get the trace side photo in this thread ASAP for obvious reasons :blackeye

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Post by grizzlytone »

nightraven wrote:thanks for the schem, Grizzlytone, if you could circle the missing components on one of the gutshots floating around i could forward that to one of the owners of the original units for additional info
Here you go: http://dl.dropbox.com/u/54740930/P10100 ... 0notes.jpg

Good Luck and Thanks for all

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Post by RnFR »

:applause: this thing looks fun! voltage measurements at key points would be great, too.
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Post by grizzlytone »

Thanks to Nightraven there's now only 4 unknowns left in this puzzle. A updated schematic is attached to this post.

These are my beliefs about the general circuit and the missing component values:
Like I've said before; the circuit looks like it came straight out of a late 60's / early 70's transistor radio that has been slightly modified by removing the negative feedback on the output stage thereby raising the gain drastically to allow for clipping at a low input level
*this is accomplished by adding the 2u5/25V cap to GND between the 27k and 10k resistors in the o/p stage feedback network, the cap shunts any ac signal above 2,4 Hz to GND so that any frequency above 2,4 Hz will not be attenuated by means of negative feedback. There is still DC feedback though that is adjusted by trimpot "A" witch will allow for adjustment of the DC voltage at midway point "4R7-4R7"
*the current limiting resistors 4R7 and 4R7, and the huge 320u cap at the output is compatible with power and frequency matching when hanging a 8 ohm speaker at the output.
*the huge 1000u cap on V+ is the current reservoar used with any power amp. The 47n cap in parallell with the 1000n cap is to compensate for the limitations of electrolytic caps at high frequencies.
*it makes perfect sense to protect the input of the AF amp in a transistor radio from RF signals that could otherwise modulate the AF signal. This is accomplished by means of the HF inductor in series at the i/p stage. The HF-inuctor is marked "R.C." for R.C. Components (still in business) and should not measure more than say 15 ohms DC resistance and the inductance is most likely in the uH range. It is not meant to have any impact on audible frequencies (try replacing with a straight piece of wire on a prototype)
*10k trimpots is a good starting point for both trimpots. Adjust "B" for 1/2 V+ at the 4R7 - 4R7 "midway point". Adjust "A" while looking at the output on an oscilloscope (1kHz sinewave at the input) or just use your ears and adjust to taste.
*this circuitry should dry out a 9V battery in no time at all -an external 9V inlet might be a good idea for a prototype
*the only missing cap value is for the cap standing in the corner of the PCB connected to the Edge switch, it should be very close to 10n.
*the person who adapted/discovered this circuit for use with rock'n'roll used his ears and taste and so can anyone.

OK. I think that's all I have to say. Much to my dismay I really need to take a break from this thread now when the holiday is over. Too many obligations in my life. Lots of skilled people on this forum.

Keep up the good work friends
And a special Thanks to Nightraven who brought life to this thread

Peace out
/MBqv
Attachments
WEM Project V Fuzz schematic revision2 -smaller.tif
WEM Project V Fuzz schematic revision2 -smaller.tif (775.53 KiB) Viewed 369 times
WEM Project V PCB layout version4 by Grizzlytone.pdf
(72.92 KiB) Downloaded 116 times

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Post by grizzlytone »

schematic in bmp format:
Attachments
WEM Project V Fuzz schematic revision2 -smaller.bmp
WEM Project V Fuzz schematic revision2 -smaller.bmp (764.45 KiB) Viewed 369 times

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Post by digi2t »

Well, I was intrigued enough to breadboard this baby. It's a very raunchy fuzz. It can go from really thin Maestro fuzz, to a more Muffish tone. Pretty good spread.

Just some things that i noticed though; Studying the schematic vis a vis the solder side shot, there maybe an error on the schem. Correct me if I'm wrong, but I believe that the 100K / 470pF / 22pF trio should be going from the base of tranny 7, to ground. That's what I see on the PCB pic, but I don't see it reflected that way on the schem. Can someone confirm this?

As for the trimmers, a 250K in position A seems to do the job, getting the voltage to 4.5v at the 4R7 junction. I'm still playing with trimmer B. This one is touchy, but the best results seem to be when it's right on the edge of oscillation. One thing I'm not happy with right now is that there is a bit of gating going on just as the note fades away. If I can figure out how to fix this, this one is a keeper. Anything that can range from buzz saw to muff, in one box, can go on my board, anyday.

For trannies, I'm playing with a mixture of 108's and 109's, with a 2N2907 in the PNP spot. I also tried 2N2904, 2N2905, and 2N5087, but all give similar results.
No matter how many times I cut it, it`s STILL too short!

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