Small Stone from Tonepad. Help please

Started by jkokura, April 09, 2010, 09:21:18 PM

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jkokura

1.What does it do, not do, and sound like?

It bypasses signal, and when engaged, there is negligible change from bypass. There is no phase happening. Wiring is correct, triple checked it. sound is going through the board, and coming out the output of the board with no phasing happening.

2.Name of the circuit = Small Stone

3.Source of the circuit (URL of schematic or project) = http://www.tonepad.com/project.asp?id=11

4.Any modifications to the circuit? Y or N

Yes. I added a stomp switch for the colour switch. It does change the sound, but it's more like a loss of lows than anything else.

5.Any parts substitutions? If yes, list them.

None

6.Positive ground to negative ground conversion? No

7.Turn your meter on, set it to the 10V or 20V scale. Remove the battery from the battery clip. Probe the battery terminals with the meter leads before putting it in the clip. What is the out of circuit battery voltage? => 8.33

Now insert the battery into the clip. If your effect is wired so that a plug must be in the input or output jack to turn the battery power on, insert one end of a cord into that jack. Connect the negative/black meter lead to signal ground by clipping the negative/black lead to the outer sleeve of the input or output jack, whichever does not have a plug in it. With the negative lead on signal ground, measure the following:
Voltage at the circuit board end of the red battery lead = 8.31
Voltage at the circuit board end of the black battery lead = 0

Now, using the original schematic as a reference for which part is which (that is, which transistor is Q1, Q2, etc. and which IC is IC1, IC2, C1, and so on) measure and list the voltage on each pin of every transistor and IC. Just keep the black lead on ground, and touch the pointed end of the red probe to each one in turn. Report the voltages as follows:

Q1 = 5088
C = 6.37
B = 2.643
E = 2.2

Q2 5087
C= 4.09
B= 7.02
E= 6.98

Q3 = 5088
C = 6.94
B = 3.857
E = 3.393

Q4 = 5088
C = 6.97
B = 3.39
E = 2.803

Q5 = 5088
C = 6.94
B = 3.845
E = 3.389

Q6 = 5088
C = 6.96
B = 3.387
E = 2.8

Q7 = 5088
C = 6.93
B = 3.796
E = 3.386

Q8 = 5088
C = 6.95
B = 3.382
E = 2.795

Q9 = 5088
C = 6.92
B = 3.78
E = 3.4

Q10 = 5088
C = 6.95
B = 3.402
E = 2.795

Q11 = 5087
C = 5.22
B = 5.85
E = 5.89

Q12 = 5087
C = 5.88
B = 5.22
E = 5.88

Q13 = 5088
C = 6.91
B = 5.87
E = 5.37

Q14 = 5088
C = 5.84
B = 5.36
E = 4.83

IC1 (or U1) All IC's are CA3080E
P1 0
P2 2.791
P3 2.79
P4 0
P5 0.604
P6 3.838
P7 6.93
P8 0

IC2 (or U1) All IC's are CA3080E
P1 0
P2 2.791
P3 2.79
P4 0
P5 0.604
P6 3.838
P7 6.93
P8 0

IC3 (or U1) All IC's are CA3080E
P1 0
P2 2.791
P3 2.79
P4 0
P5 0.604
P6 3.838
P7 6.93
P8 0

IC4 (or U1) All IC's are CA3080E
P1 0
P2 2.791
P3 2.79
P4 0
P5 0.604
P6 3.838
P7 6.93
P8 0

IC5 (or U1) All IC's are CA3080E
P1 0
P2 5.2
P3 5.83
P4 0
P5 0.557
P6 5.86
P7 6.92
P8 0

Any help is much appreciated. I've been working on this one on and off since last thanksgiving!

Jacob

Ummagumma

Before you dive in into sea of changes and modes, make sure to swap 470R resistor with 100R one.
that will get you phasing ;)

Cheers

frequencycentral

#2
That's some great debugging information you provided - the best I've seen. Much better than the average single liners we see.  :icon_wink:

Ummagumma may well have spotted the issue. All the 3080's have 6.93v at pin 7, from a 8.31v battery (try a fresh battery too). Something is dragging down your +ve, so unless you have a microscopic solder bridge, the other thing would be R2, the 470 ohm resistor. If it were me, I'd remove it altogether, but replacing it with 100 ohm sounds like a plan.

BTW, that resistor doesn't appear in the original EH schematic (which of course uses 3094s not 3080s): http://www.kyletompkins.com/wp/wp-content/uploads/2007/10/eh_smallstonephaser.jpg
http://www.frequencycentral.co.uk/

Questo è il fiore del partigiano morto per la libertà!

jkokura

The note about the 100 ohm resistor got me thinking. I had ordered a bunch of tonepad boards a while back (this one included) and when I ordered the parts, I thought that when it was written "100" in the BOM, it was an error and the K had been forgotten. So in a tube screamer I had an error because where there should have been a 100 ohm resistor I had put in a 100k resistor.

Sure enough, I had done the same thing here with R24 - I had put in a 100k resistor instead of a 100 ohm. I switched it out and, oh happy day, it worked!

I didn't change out the 470ohm resistor, I left it as it was.

I'm using a 1M Rev Log pot in this, and it gives me a HUGE range of various sounds in this. It can go from super wacky space man sounds, right to really dark slow phase. It's cool cause I can replicate an old Our Lady Peace song I can think of, or any time you have that "sounds like a radio that's been recorded" kind of guitar sounds when the colour switch is on and the rate is right down. Cool sound.

I'm not posting pics of this thing, cause it's soooo ugly (by my standards). Maybe it'll show up in a future Pedal board pic!

Jacob