Madbean tapanator - Phaser

[PMowdes]

Hi all, having a little trouble with the tapanator phaser.

All i am getting is a loud humming (similar to a synth VCO) even when the guitar input is not connected





Pin voltages as follows:

TL072
1:  4.22
2:  4.22
3:  4.19
4:  0.00
5:  2.08
6:  4.22
7:  4.22
8:  8.65

TL074
1:  4.74
2:  4.44
3:  4.30
4:  8.65
5:  4.30
6:  4.35
7:  4.08
8:  4.26
9:  4.84
10:  4.29
11:  0.00
12:  4.28
13:  4.53
14:  4.84

Thanks in advance

[PMowdes]

Turns out i had a bad cut between the input and +9v LED.  Seems to work ok although it's a little noisy and there is a dead  spot in the feedback control sweep.  I wonder if it's a bad pot?

[Alex]

Did you swap the capacitors you've mentioned in the Open Chat?
The 4u7 electr. cap goes to the Feedback.

[PMowdes]

Yeah,  I took a punt on that yesterday. I'm gonna give it a rest and finish off the trem and was before I do anything else with the phaser.

[PMowdes]

I have got tants in place of electros 'cause that's what I had,  shouldn't make a difference tho non?

[Alex]

Should be the same.

[PMowdes]

Alex,  I have a question about the wah,  there is a 100n cap on the right side of the layout which should run to ground as part of the power section.

On the layout it seems to run to ground through the 2k7 resistor off the emitter of Q2.

Is that OK? Or does it need a cut under the 470k resistor and a double link to gnd on the link directly left of the 100n?

Cheers
Phil

[Alex]

Oh God! And they've all been verified!
Just remove the 100n cap and increase the 47uF.

[PMowdes]

OK, so i've got past the horrible humming and it passes signal but there is something fubar with the feedback control and it really doesn't sound like a phaser to me.

The feedback pot seems to make the effect sound more like a tremolo before around mid sweep, at mid sweep it cuts out briefly and past mid sweep i get a no signal, just a clicking that mirrors the rate of the led.

Any ideas???