GGG Sample and Hold Pedal

[newperson]

FINALLY WORKING,

I replaced the 2 CA3080e chips and now it works.  And now for a couple more questions:  What transistors are you using for the non Jfets?  Should I change any to make it sound better?  The filter works and the sample works.  It likes the noise trimmer to be turned all the way up and the 100k to be about at 2 o'clock if 3 o'clock is centered at 0 volts. 

I would like to try a charge pump to run it off a 9 volt wall wart.  I have found that it really likes batteries as I was probing it.  Can you point me to a "how to" for installing a pump for this unit?  I do not hear any clock ticking noise, but it is not in a box yet. 

I think that my problems were: dead CA3080e chips and wrongly placed Jfets.  I looked up the data sheet for the BF245a and found that it is backwards from the J201.   This is why things started to look better after I put the J201 in.     I guess I could have killed the 3080 s from this?

Thank you so much for walking along with me on this project.  I have been waiting to build this for a long time.  Your help was great.  It is nice that a stranger will help out another person like you have done.  And I would also like to thank R.G. again for all of his help with getting the NeoVibe up and running. 

Paul.

I made a working readout of the audio probe and volts to pass along for other's testings.  Again, the "y" and "n" tell you if sound is passing.

Finally Working effect readings:

Battery  B2: 8.96
B1: -8.92


Q1-2N5088
E y  -.7
B y -.0.69
C n   8.44


Q2-J201_DZ4Z
D n  8.43
S y   -.01
G y  -.04

Q3-3906
E y  .56
B n  0
C y  click -6.89 to -7.59

Q4-2N3904
E n -1.61
B n -8.34
C n -8.91

Q5-J210
G y -3.4 loud static and click
S y -.06 to .46 click
D y  .06 loud static

Q6-J201
G y   -.04 to +.15  click
S y   -.06 to +1.05click
D n  8.95

Ic1-Ca3080e              Data Sheet for CA3080
1 n 0                  NC
2 y 0 very very quiet       Inv. Input
3 y 0                    Non-Inv Input       
4 n -8.37 moving         V-
5 n -7.76 moving              Amplifier Bias Input
6 y -.04                          Output
7 n 8.43                        V+
8 n 0                   NC

1c2-CA3080e
1 n 0
2 y 0
3 n -0
4 n -8.34
5 n -7.7 moving
6 y -0
7 n 8.41 moving
8 n 0

IC3-KA741               Data Sheet Info for LM741      KA741
1 y -8.88 very quiet click/sound bleed     1 Offset Null                  Offset Null
2 y -0                               2 Inverting Input                IN (-)
3 n -0                           3 Non-Inverting Input       IN (+)
4 n -8.9                                4 V-                                 Vee
5 y -8.88 quiet click w/ sound source      5 Offset Null                   Offset Null
6 y -.22 loud                          6 Output                     Output
7 n 8.94                                 7 V+                        Vcc
8 y 0 quiet sound bleeding            8 NC                          NC

IC4-KA741
1 n -8.88
2 y -0 static
3 n -0
4 n -8.89
5 n -8.88
6 y .06
7 n 8.93
8 y 0 low bleed noise

IC5-KA741
1 y -8.88 click
2 y -2.69  click
3 y higher thump -4.58
4 n -8.89
5 y -8.87 quiet click
6 y -6.7 moving click
7 n 8.93
8 y 0 click bleed

[Roobin]

Hurrah!
Well done - it must have been very hard work. Hope it's all been worth it. 

[Ry]

GREAT!  Way to stick with it and not give up! 

It was my pleasure to help out, this is one of my favorite pedals.  Now that you have it working, I would try different transistors for Q4, I really like a 2n2222, get a bag of 10 or so and audition them to find one you like, combined with playing with the 10k  trimmer, R27.  The other ones don't matter so much, the types that you have are exactly what I have in the other positions.

I don't know how your 3080's got fried, but they do tend to be pretty sensitive to static.

I have both of mine running from a charge pump and a 9V DC converter.  They eat batteries too quickly otherwise.  For the power supply, I really, really like this one because it's dead quiet:

http://www.generalguitargadgets.com/index.php?option=content&task=view&id=77&Itemid=106

From that supply, you can hook up a charge pump for a bipolar supply (make sure you use a MAX1044 chip and not a 7660 - the 7660 is really noisy, the 1044 is not.)  A diagram of how to hook it up is at:

http://www.geofex.com/circuits/+9_to_-9.htm

Again, congratulation on getting it working!

Ry