Octave Divider - only a distortion

[tuckster]

Hi everyone,

sometimes, well most of the time I do stuff where I hit a wall with my limited knowledge.
I used the schematic of the BYOC Divided Octave a Mu-Tron Octave Divider and created my own PCB for a 125B enclosure. Pretty dumb I know...

Original schematic
http://byocelectronics.com/dividedoctaveschematic.pdf

Mine (ditched the aux jack and added a 3pdt for switching




The signal becomes heavily distorted right after the first opamp IC1B Pin 7.
That's what I hear on the regular output. i can't hear anything on the bass only output.
I checked the parts and they are ok in terms of values (resistors/caps/ect).
No legs are touchings in this thight situation.
D12 is a 1N5817 not 1n4001
D1is a D9K not 1n60

Can you give me some advice on where to check first?

[tuckster]

Voltages

Code Select Expand


U1 RC4558
1OUT 1 O Output 1           7,65
1IN- 2 I Inverting Input    4,18
1IN+ 3 I Noninverting input 0
VCC- 4 — Negative Supply    0
2IN+ 5 I Noninverting input 0,45
2IN- 6 I Inverting Input    7,38
2OUT 7 O Output             7,67
VCC+ 8 — Positive Supply    8,35

U2 RC4558
1OUT 1 O Output 1           7,52
1IN- 2 I Inverting Input    7,52
1IN+ 3 I Noninverting input 0
VCC- 4 — Negative Supply    0
2IN+ 5 I Noninverting input 1,38
2IN- 6 I Inverting Input    5,35
2OUT 7 O Output             1,4
VCC+ 8 — Positive Supply    8,34

U3 RC4558
1OUT 1 O Output 1           1,47
1IN- 2 I Inverting Input    1,47
1IN+ 3 I Noninverting input 1,43
VCC- 4 — Negative Supply    0
2IN+ 5 I Noninverting input 1,03
2IN- 6 I Inverting Input    1,4
2OUT 7 O Output             1,4
VCC+ 8 — Positive Supply    8,34

U4 RC4558
1OUT 1 O Output 1           7,77
1IN- 2 I Inverting Input    0,21
1IN+ 3 I Noninverting input 7,51
VCC- 4 — Negative Supply    0
2IN+ 5 I Noninverting input 0
2IN- 6 I Inverting Input    7,51
2OUT 7 O Output             7,78
VCC+ 8 — Positive Supply    8,34

U5 RC4558
1OUT 1 O Output 1           7
1IN- 2 I Inverting Input    0,08
1IN+ 3 I Noninverting input 0,22
VCC- 4 — Negative Supply    0
2IN+ 5 I Noninverting input 0
2IN- 6 I Inverting Input    1,06
2OUT 7 O Output             7,78
VCC+ 8 — Positive Supply    8,35

U6 RC4558
1OUT 1 O Output 1           7,78
1IN- 2 I Inverting Input    0,06
1IN+ 3 I Noninverting input 4,67
VCC- 4 — Negative Supply    0
2IN+ 5 I Noninverting input 7,98
2IN- 6 I Inverting Input    7,41
2OUT 7 O Output             7,41
VCC+ 8 — Positive Supply    8,34

U7 4011
A1    1 I Inputs A of the four NAND gates        8,34
B2    2 I    Inputs B of the four NAND gates     8,34
Q1    3 O    Outputs from the four NAND gates    0
Q2    4 O    Outputs from the four NAND gates    8,34
A2    5 I    Inputs A of the four NAND gates     0
B2    6 I    Inputs B of the four NAND gates     7,62
GND    7 -    Ground (0V)                        0
A3    8 I    Inputs A of the four NAND gates     7,62
B3    9 I    Inputs B of the four NAND gates     7,62
Q3    10 O Outputs from the four NAND gates      0
Q4    11 O Outputs from the four NAND gates      8,34
A4    12 I Inputs A of the four NAND gates       0
B4    13 I Inputs B of the four NAND gates       7,62
VDD    14 - Supply Voltage (+3 to +15V)          8,34

U8 4013
Q1 1 O Outputs from the two D Flip-Flops                      8,34
-Q1 2 O Inverted outputs from the two D Flip-Flops            0
CLK1 3 I Clock input for the two D Flip-Flops (Rising Edge)   0
C1 4 I Reset the Flip-Flop output to 0                        0
D1 5 I D (data) input for the two D Flip-Flops                0
S1 6 I Preset the Flip-Flop output to 1                       0
GND 7 - Ground (0V)                                           0
S2 8 I Preset the Flip-Flop output to 1                       0
D2 9 I D (data) input for the two D Flip-Flops                0
C2 10 I Reset the Flip-Flop output to 0                       0
CLK2 11 I Clock input for the two D Flip-Flops (Rising Edge)  0
-Q2 12 O Inverted outputs from the two D Flip-Flops           0
Q2 13 O Outputs from the two D Flip-Flops                     8,24
VDD 14 - Supply Voltage (+3 to +15V)                          8,34

No U9....

U10 1044
Boost 1   8,34
CAP+ 1    4,98
GND 3     0
CAP- 4    -3,35
VOut 5    -8,32
LV    6   3,70
OSC    7  5,19
V+    8   8,35


Q1 2N3904
1,58
2,17
5,26

Q2 2N3904
2,52
3,12
6,84

Q3 2N3906
0,69
0
0,68

Q4 2N5457
0,06
0
0,23

Q5 2N3904
0
0,69
0

Q6 2N3904
0
0,60
0,06

Q7 2N3904
0
0
7,98

I swapped in a NE5532 for U1 which made the distortion less extreme but unfortunately I have only one. Lm358 is the same result as RC4558.
But it can't be the Opamps, right?

[ElectricDruid]

I think there's some serious confusion going on.

You've got a LTC1044 creating a negative supply, so that the op-amps can be powered with bipolar power, +/-9V. And all the op-amps and biasing is done to ground, as it would be for bipolar power.

The only thing is, you've powered all the op-amps from Ground and +V, and ignored the -V supply.

No wonder it's distorted. Everything is pinned to the rails.

That PCB is probably a write-off, sorry. It happens. I binned a "Mk1" only last week because of a dumb error.

[tuckster]

Thanks for the hint. I did something like this before. But I also remember using the replace all function. It ,,might" be that I replaced all of the negative supply. I will try to cut some traces and use wires. Edit: no there is still one pin going to the negative supply. But then it still was a mistake by not paying attention :-(

[duck_arse]

I agree with Tom, I think you are better off just turning your back on that built board because of the number of trace cuts you would need to make to get V- where it is supposed to be. and one single missed trace cut will latch-up one of the oppies, and you'll be tearing our hairs out trying to find it.

a minor point about your shown build - if you insist on using IC sockets, you really need to seat the IC properly in them. push them in till they go clunk, don't just sit them in mid air.


----- or - lift all the opamp pin 4's out of the sockets, bent sideways. solder daisy-chained fly-wires to each of the Vcc- pins, and take them back to the invertor chip. that way you can [probably, possibly, hopefully] keep the rest of the traces intact. I think.

[tuckster]

When you think it's bad it gets even worse. I desoldered four sockets, cut the traces, rewired gnd and v- then read about the lifting of pin 4 and now I want to quit pedal building. On the positive side I learned how to desolder sockets perfectly. They don't always survive but the pcb is a very good condition. Lots of flux and solder wick. Fortunately I didn't use a ground plane but unfortunately the gnd traces are most of the time directly under the sockets. Dumb dumb dumb. Lift pin 4.. so easy. Will do that to the last two.

[tuckster]

I finished it today and it works. Thank you for your help!

[duck_arse]

we would be needing proof-of-life photos ......

[tuckster]

Sorry I noticed the last comment yesterday...




Of course does this "Mutron Divider"  divide Mutrons into one Mu and one Tron.
I already ordered a fixed pcb let's see how that turns out.

[duck_arse]

that's an impressive looking board, flying links or not.

[ElectricDruid]

that's an impressive looking board, flying links or not.

Yeah, I agree. It should almost be in the "your best rescues" thread. Back at the beginning looking at the schematic, it looked like a no-hoper to me, so I'm impressed that tuckster's managed it without any "frankencircuit" modifications. A few flying wires is nothing!

Nice work.

[amptramp]

The flying wires are like grid caps on 1930's tubes.  No extra functionality but a lot of extra mojo.

[tuckster]

Thanks for your kind words. Although I'm not good at electronics I think I'm not so shabby with tools :-)