Low Rider - Clean signal good, no upper octave

[keysandguitars]

I assembled the Low Rider and went to test. I turned down clean and DOCT1 and DOCT 2 and cranked UOCT1 to set the trim pot. I can faintly hear signal, but it doesn't appear to be oct up, just a raspy signal of the original source. The trim pot doesn't seem to have any effect. Turning the Doct2 all the way up produces the desired effect, but not really strong, and doct1 just sounds like same note or frequency as the clean signal.

I did the C10 and C12 mod. I'm assuming I don't need a jumper on c12, i just left it out. I purchased my IC's from Smallbear and bought the only CD4013's that he had listed. The chip itselt says GS 9534 then below that it reads CD4013B. The C kind of looks like a G though. My small bear orders have always been spot on, so at this point I'm assuming he sent the right IC.

I'm using 2n5457's. I'm trying to determine if the GSD is different than the stock 2sk30. Whether or not that even affects the problem, idk. I'm trying to figure that out as well. Is my thought process correct in thinking that this is amplifying the signal, and perhaps could be an issue? I've been trying to read what I can on the octave circuit and how it works, but damn I'm a noob.

I'm in the process of checking all the other components, but i was very careful measuring and putting them in. I'm assuming that because I have clean signal, my error lies with the IC's or the trannies.

Does anyone have any thoughts? TIA, Brandon

[LaceSensor]

The only difference I saw in the transistors was the 2n5457 tracked much better than the 2sk's

If you dont get any good ideas post up your voltages and I can cross refereence them with mine over the weekend. I built two of these that perform flawlessly.
You dont have to jumper the caps c10 and c12 for the mods to work.

[keysandguitars]

Thanks for the offer LaceSensor. I took the readings this morning and some pics with my iPhone, I hope they are of some help. I'm going to find the data sheets for the ICs and try and make sense of the readings.


   IC1       TL072CP
1   5.16   5   9.43
2   5.16   6   5.16
3   4.52   7   5.16
4   0   8   4.69


   IC2      LM324
8   2.1mv   7   5.34
9   5.16   6   5.16
10   5.14   5   5.11
11   0   4   9.43
12   5.15   3   5.11
13   5.14   2   5.16
14   8.16   1   5.09


   IC3      GD4013B
8   0   7   0
9   9.43   6   0
10   0   5   0
11   9.43   4   8.12
12   9.43   3   0
13   0   2   9.43
14   9.43   1   0

   IC4      GD4013B
8   0   7   5.34
9   0   6   5.16
10   0   5   5.11
11   0   4   9.43
12   0   3   5.11
13   9.43   2   5.16
14   9.43   1   5.09

   IC5      TL074CN
8   5.14   7   5.15
9   5.15   6   5.15
10   5.14   5   4.67
11   0   4   9.43
12   4.67   3   5.1
13   5.15   2   5.15
14   5.15   1   5.15

   IC6      TL074CN
8   5.15   7   5.15
9   5.14   6   5.15
10   5.15   5   5.15
11   0   4   9.43
12   5.15   3   5.15
13   5.14   2   5.15
14   5.06   1   5.15

[keysandguitars]

Update: checking resistors...i ordered a bag of 200, 330k resistors from mammoth...turns out they are 360k. Face palm! I can't be too mad because I should have checked that. I'm just thinking, how can they send me a whole bag of the wrong value? Shaking my head...

[keysandguitars]

 I found an error I made with a cap, I used 220n when it should have been 220pf.  I swapped out the 360k resistors for the correct 330k value. To my delight, it's working and sounds awesome. I've never owned an octave pedal. The upper octave is much more pronounced when playing higher on the neck. I assume that's normal.

I'm pretty sure the ICs I have are GD4013B's. I'm going to try and track down the one Brian rcommended and see if there's a difference in the quality of the tracking.

[LaceSensor]

I found an error I made with a cap, I used 220n when it should have been 220pf.  I swapped out the 360k resistors for the correct 330k value. To my delight, it's working and sounds awesome. I've never owned an octave pedal. The upper octave is much more pronounced when playing higher on the neck. I assume that's normal.

I'm pretty sure the ICs I have are GD4013B's. I'm going to try and track down the one Brian rcommended and see if there's a difference in the quality of the tracking.

Glad you got it sorted. It's a really nice project and a wide range of usable sounds.

The upper oct is much more pronounced from the 12th feet, yes, this is typical and expected. Try using your neck pickup and roll of your guitar tone control.

Cheers