Troubles with Tonepad's Phase 90

Started by Pedal Junkie, December 30, 2010, 05:43:37 AM

Previous topic - Next topic

Pedal Junkie

Hello,
Great forum you got going on here. Lots of usefull information. I recently made the Phase 90 from tonepad and all I'm getting is a clean signal, no phasing. I measured the voltages and there is definitely something wrong. On pin 5 of ic1 and on the gates of the fets there is a variation in the voltages.
For the fets I've used J201's which I rotated appropriately. For the fifth transistor I used 2N3906.
Anyway's here are my measurements:
ic1:
1 - 3.89
2 - 3.89
3 - 3.72
4 - 0
5 - 3.33 - 5.16
6 - 3.33 - 5.16
7 - 3.33 - 5.16
8 - 11.66

ic2:
1 - 3.89
2 - 3.89
3 - 3.72
4 - 0
5 - 3.86
6 - 3.87
7 - 3.87
8 - 11.66

ic3:
1 - 3.89
2 - 3.89
3 - 3.72
4 - 0
5 - 3.86
6 - 3.87
7 - 3.87
8 - 11.66

q1:
g - 1.3 var
s - 3.88
d - 3.87

q2:
g - 1.3 var
s - 3.88
d - 3.87

q3:
g - 1.3 var
s - 3.88
d - 3.87

q4:
g - 1.3 var
s - 3.87
d - 3.87

q5:
e - 3.87
b - 3.3
c - 2.14

If you need any more info just let me know. Any help would be greatly appreciated.
Thanks.

Greenmachine

I can't really offer much help, but I've built that circuit before.  Did you use four matched fets?

Skullnick

Yes, I did. Regardless of that I think that all the voltages should be stable.

elshiftos

Could be something is shorting or blocking the phased signal path, ie a dead IC2/3.
Also, you appear to be running it from a 12V psu, in which case the 'biased' points in the circuit (IC2/3 pins 1/7) may be reading lower than normal. That could be due to a dead zener.

Dunno - just guessing/clutching here  :)

frequencycentral

J201 are not the best choice for this circuit. Try 2n5952 or 2n5485.
http://www.frequencycentral.co.uk/

Questo è il fiore del partigiano morto per la libertà!

new

The flat side of J201 should be turn left and
You have to adjust trim POT slowly untill meet  the phasing point.

Govmnt_Lacky

Quote from: frequencycentral on December 31, 2010, 07:47:43 AM
J201 are not the best choice for this circuit. Try 2n5952 or 2n5485.

+1  ;D

I would ditch the 201s and go with the 5952s. I have built three of these and they are the best choice!
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of 'up to and including my life.'