mxr phse 45 new build issues - full diagnostic included

Started by peterg, May 12, 2013, 10:19:27 PM

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peterg

Sound is present although weI've posted a few times about this project and I figuired I would give as much info as possible....

1. Sound is there although weeker than though bypass
2. Project is Pez 45 from Tonepad - an MXR phase 45 clone
3. http://www.tonepad.com/getFileInfo.asp?id=70
4. Mods to circuit: added a 4k7 res and an led - it works
Sockets for Q1, Q2, IC1 and IC2
Planning on out boarding the trimpot and narrowing it down to 10k. Have installed sockets for res at trim 3 and 2. Currently have a 250k pot wired and jumpers in sockets.
5. Part subs: .047uF caps for specified .05uF caps.
2N5951 ICs for spedified 2N5952 ICs
6. Not a pos to neg conversion
7. Used a Boss/Roland PSi120S converter
Did not breadbaord first
Created my own layout - 99% certain it is correct
Voltage readings:
IC1
p1 4.01
P2 4.01
P3 3.92
P4 0.0
P5 2.70
P6 4.01
P7 4.01
P8 9.41
IC2
P1 varies by speed setting and fluctuates
P2 as per P1
P3 as per P2
P3 as per P3
P4 0.0
P5 3.92
P6 4.00
P7 4.00
P8 9.41
Q1
G 4.00
S 4.00
D as per IC1 P3
Q2
G as per Q1 G
S 4.00
D as per IC1 P5
Power source: 9.41
All grounds: 0.0
Input:  0.0
Input cap/res: 2.68
Q1 res/res/cap at Q1 S: 3.96
Q2 res/res/cap at Q2 S: 3.96
Line below power line: 470 res/.05 cap/470 res/1M res/3M9 res:: varies ±3.92
3M9 res/speed 3/10uF/150K res: varies with speed setting and fluctuates
10k res/10k res/.05 cap between IC2 P7 and output: 3.98
Output: 0.0

Sound does not change when fets are removed or jumpers at trimpot are removed. Pots do not affect the sound.
Any help would be appreciated.

deadastronaut

hi peter

this is my modded version of the pez 45.

have you tried other fets?...j201's always work with my phase 45 builds..

and do you have them reversed..as the pdf fets are backwards..

heres mine..note the 10k+4.7k in series to lift the level for much better unity.

https://dl.dropboxusercontent.com/u/7464107/PHASEMODS.jpg
https://www.youtube.com/user/100roberthenry
https://deadastronaut.wixsite.com/effects

chasm reverb/tremshifter/faze filter/abductor II delay/timestream reverb/dreamtime delay/skinwalker hi gain dist/black triangle OD/ nano drums/space patrol fuzz//