Aquaboy needs a bath

[saxoftenest]

My Aquaboy is more than a little dirty and, being relatively new at this, I'm hoping for some help troubleshooting. It's built using the Cool Audio chips, using all the values supplied with Madbean's "V3205 Version" parts list. I've triple-checked all values, wiring, etc. and reflowed all the joints. It works, just dirtier and feedback-ier that it should be. Here are the voltages:

Pos lead @ jack: 9.5
9v in @ board: 9.5
Ground in @ board: 0

V3205D
1: 0
2: 2.15
3: .95
4: .96
5: 3.54
6: 2.16
7: .03
8: 2.22

LF353N
1: 4.74
2: .19
3: .30
4: 0
5: .80
6: .28
7: 4.75
8: 9.5

V571D
1: .21
2: .22
3: .22
4: 0
5: .92
6: .07
7: 2.96
8: 1.01
9: 1.01
10: 0
11: 0
12: .91
13: 9.5
14: 0
15: .23
16: 0

V3102D
1: 3.24
2: 2.16
3: 0
4: 2.15
5: 1.68
6: 1.88
7: .01
8: 2.22

Q1
C: 9.5
B: 0
E: 2.82


Q2
C: 9.5
B: .08
E: 2.27


Q3
C: 9.5
B: .09
E: 3.06


Q4
C: 9.5
B: .14
E: 2.56

[gtr2]

You need to adjust your voltage to pin 5 on the v3205.  It should be between 5-8v.  I'd aim for a little above 5v and see how that works.  To do this you need to adjust r19 to a lower value.  I'm assuming you have a 1k5 there.  I'd socket that spot and tweak as needed.  You'll need to recalibrate the delay after you get the correct voltage to the chip.  Take your time with the calibration because a very small adjustment with the bias trim makes a big difference in the delay dirt...  FWIW the v3205's don't clean up as well as some other bbd's but they can be acceptable in most cases.

For the feedback.  You can adjust r31 to change the feedback/oscillation point.  Don't fool with this until you get the voltage correct at pin 5 of the v3205 first.

Hope this helps out!

Josh

[saxoftenest]

Thanks! It's now been deemed clean enough to box up and put on the pedalboard, thanks to your tips (and Madbean's suggestions regarding the feedback control in the instructions).

For the record, I ended up with a 680ohm in R19 to bring power to pin 5 up to just under 6v and 47k in R31 to tame the oscillations. Super stoked! 

[gtr2]

Sweet.  Glad to help! 

Josh