Phase 45 just makes fuzz

[madboy]

I read some of the tips... if you strum hard, you just get a loud, sustaining fuzz. The jfets are 2N5952's, and I can't tell which pin is which. Also, here are the pin voltages.
IC1
1 1.5
2 3.48
3 3.48
4 0
5 2.28
6 3.48
7 3.48
8 8.63

IC2
1 3.6 - 5.2 ( I didn't think this was supposed to oscillate )
2 4.2 - 4.7
3 3.8 - 4.3
4 0
5 3.34
6 3.48
7 5.3
8 8.6

Q1
3.48
3.48
3.48

Q2
D 1.9
S 3.48
G 3.48

Zener diode cathode end
3.48

The main differences from a working example's voltages are IC1 pin 1 (about half the normal value), pin 5 2.28 on mine vs. 3.37 and IC2 pin 1 (mine is oscillating, theirs is not) and pin 7 (5.3 on mine vs. 3.53 on theirs.) So, what does all this mean? I've tried using the audio probe, but soon get lost as I start hitting the IC's. Please help!

http://www.tonepad.com/getFile.asp?id=12
Here's the layout.
Thanks in advance
Martin Bell

[jonathan perez]

heads up, the search button can be your best friend. i too have had the same problem...along with ALOT of other people. i wont tell you, because its time the search button get used more often. 

[Alex C]

I see this thread: http://www.diystompboxes.com/smfforum/index.php?topic=46082.msg338051#msg338051 .  Was this a double post that should have been abandoned? 


If you go here: http://tonepad.com/project.asp?id=13 and click "view build reports," you can see lots of posts where people mention that the pinout is displayed incorrectly.  You might try switching them around or looking up a datasheet for the pinout to double-check.

Here are some threads from this forum dealing with Phase 45 "fuzz" or "distortion:"
http://www.diystompboxes.com/smfforum/index.php?topic=40758.0
http://www.diystompboxes.com/smfforum/index.php?topic=28838.0  -this one has good info about types of JFETs to use; this could be your problem.
http://www.diystompboxes.com/smfforum/index.php?topic=31392.0  -this one says you need matched (or close) JFETs and describes ways to dubug and test.
http://www.diystompboxes.com/smfforum/index.php?topic=20038.0  -this one talks about the JFET pinout too.

This page (click) has great info as well.
Welcome to the forum, and good luck getting it working!! 

-Alex

[madboy]

Thanks for the quick replies, and the links.  I did use the search function (amazing amount of info you guys have here), and did turn up most of those links.  The problem is that just about all the ones that mention distortion say it should disappear when you remove the fets. Mine doesn't. I tried reversing them, a la the tonepad build reports, and no difference.  I didn't modify anything, and the closest thing I had to a substitution was a 5.1 V Zener diode instead of a 4.7.  I tried switching fets, IC's and the zener diode ( I socketed the IC's and fets ) but it doesn't seem to make a difference.  I actually got a list of voltages from the search function which highlighted the differences (as mentioned above) and was hoping that would be a clue for someone who understands this a lot better than myself.  Is there anything else I haven't mentioned that might help? Thanks again.
P.S. I will get this pedal working... oh, yes, I will.  Moo hoo haa haa (evil scientist laugh)

Martin Bell

[RDV]

Mine works but distorts. I've never been able to get it right either. It's worse with humbuckers.

RDV

[oldrocker]

I have a fuzz sound too but the difference is I'm getting 8 or 9 volts on just about all the pins on the IC's except pin 4's and pins 2 & 3 on IC#2.  I am seeing oscillation with voltages on pins 2 & 3 IC#2.  On the trannys all three pins have 8 to 9 volts and the cathode of the zener is 9 volts too.  It's a 5.1v zener too.  I ordered some 4.7v zeners from Mouser.  I'm determined to get mine going also.  I won't give up intil it's phasing DANG IT!!

[madboy]

The kicker is that under all the fuzz ( a thick, unusable fuzz, that is ) I can hear some phasing... is it too early to start a support group?  Also, did the people responding that were also having fuzz problems get their pcb's from tonepad? (Obviously not trying to blame anyone, it might just be something simple we've all done incorrectly). I read on the tonepad site that the fet pins were reversed. It didn't help mine, but it might help the other guys...

[R.G.]

IC1
1 1.5
2 3.48
3 3.48
4 0
5 2.28
6 3.48
7 3.48
8 8.63

IC1 is getting OK power supply voltage. Pin 4 is 0V and pin 8 is almost 9.
Pin 1 is way lot. Something is wrong there. That's the output pin, and it's at about as far negative as it can go, in spite of the + input and - inputs being held at 3.48V.

I would check to see if the 10K feedback resistor on that stage may be open. If it is, pin 2 is being pulled to 3.48V by the output of the preceeding stage, and the output is running open loop. That would also account for the fuzz signal.

IC2
1 3.6 - 5.2 ( I didn't think this was supposed to oscillate )
2 4.2 - 4.7
3 3.8 - 4.3
4 0
5 3.34
6 3.48
7 5.3
8 8.6

IC2 pins 1, 2. and 3 are the LFO. They're supposed to oscillate. That's OK.

But on the other side, pins 5, 6, and 7 are hosed. That could be an artifact of the problem with the stage on IC1, so fix IC1 first.

Q1
3.48
3.48
3.48

Good so far.

Q2
D 1.9
S 3.48
G 3.48

That's bizarre. The drain is supposed to be connected to pin 5 of IC2, which you show at 3.34 V. Either they're not really connected by a wire (and that's a real problem) or there is a measurement error.

Zener diode cathode end
3.48

S'OK.

[madboy]

Thanks! I'll check that out when I get home.  As for the last fet readout, I may have it backwards. I will let you know. ( I guess I know I have a problem when in the time I have spent stressing and fretting over this thing, I could have spent at work and been able to buy about three of the d@mn pedals at the local music mart.  Such is... )

[oldrocker]

I think I got mine working to some degree.  Since all the voltages were too high for an unknown reason I decided to swap out the 10k resister coming from + volts to the zener diode cathode and replaced it with a 470k.  It brought all the voltages down to where the sound is coming out nice and clear and I am able to adjust the trim for a nice phase.  I don't know for sure if this is how it's supposed to sound especially since I didn't match my FETs yet but I like how it sounds now.  It mimicks a great sounding chorus.
Hey MADBOY good luck on getting your Phase 45 up and running.  Don't give up.  I know it's a pain sometimes getting these things going sometimes but when you finally do get it working you'll feel good about yourself.  That's something a store bought stomp box will never give you.

[madboy]

Thanks. I was wondering if that would work, I'll have to try it tonight. Last night's planned debugging marathon was shelved when I blew a tire getting on the highway... fortunately, I know that my jack and spare tire are in good working condition seeing as how I also had a flat five days ago. D'oh! Enough frustration for one night.   I'm just glad I decided to go with the phase 45 instead of the 90 or 100. I will win, oh, yes, I will.  So anyone have any ideas as to why the voltages are so high? Mine seemed to eat batteries rather quickly just while testing and debugging... are the two related?
Thanks
madboy

[oldrocker]

MADBOY I'm not sure if the problem with your P45 is the same as what I have.  All my voltages were way high like 7,8 and 9 plus volts on all the IC pins and trannys too.  So I when I swapped out the 10k I kept trying different values until I brought the voltages down to get the fets working.  Your voltages look like a lot lower than what I had.  Even with my 470k resistor my voltages are still larger then what your testing.

[madboy]

Hmm... okay, that does sound different. Just out of curiosity, did you make your own pcb, buy it or make it on vero, etc?

[oldrocker]

I built mine with Radio Shack perf board.  I used the perf that has some holes connected in 3's with 2 strips of holes connected for I think grounds and + volts.  This made it a real pain checking out the circuit.  After going over the circuit using highlighters and checking my perf over and over again (I swear 20 times)I came to the conclusion that my circuit was right.  But the voltage coming in on the zener cathode was still 9.10 volts.  So there's still has to be something wrong but since it's working great right now I'll just leave it as it is unless some problems develope later.  I'm worried about excessive battery drain or something heating up and frying.  You never know what can happen when you operate a circuit that's not to the specs outlined on the schematic.  So I may not be out of the woods yet.

[R.G.]

 

But the voltage coming in on the zener cathode was still 9.10 volts.

What's the voltage on the zener anode?

Zeners are used with anode negative, cathode positive. The anode of that thing is supposed to be 0V - ground. What you describe seems very much like a floating anode zener connection. With nothing to pull it down, the cathode floats up. If you connect the anode to ground and the cathode is still 9.10V, then you do not have a low voltage zener. It's either open or the wrong kind.

[oldrocker]

Yes R.G. I think you're right because I bought the Zener from RS and they only had this 1N4733A 5.1v zener in their stock.  Since it's all I could find I decided to try it.  Problem is I'm not sure at all if this is the right one or if it will even work.  (By the way anode is grounded.)  I ordered the right one from Mouser which I should receive in a few days.  I will install this and try putting the 10k back into the circuit since I don't know what effect this large 470k res will have on the P-45's operation in the long run.  Thanks.

[oldrocker]

I received my correct zener diodes from Mouser today and installed it.  I also replaced the 470k resistor with the correct value 10k and (IT WORKS!!)   So thanks again R.G.  I wasn't sure if I was going to mess with it since it was working fine but after reading what you wrote I knew I'd better make it right.  I hate it when I have to go against the schematic trying to get an effect to work unless it's a mod I'm experimenting with.  I still have to match my fets yet so I'm going to look into that.  I only had 4 to try and I have the best 2 in there so it phases strong.  It sounds good now but I read so much about how important it is to match the fets so I'm off to find some more to test.  I'm using MPF102's and I hope these will be OK.  I know there are some who say not to use these.  I'm considering ordering trannys listed in the schematic.

[oldrocker]

Hey Madboy,  How's that P-45 coming along?  Are you getting anywhere with it?  Just curious.

[madboy]

This week has been kind of a pain in the @ss... I've ended up working 13 - 14 hours a day ( and that's before the 45 minute commute ) so I get to choose between sleeping, eating, or fooling with pedal.  Sleep deprivation is apparently not good for soldering... ( Why is this handle so hot?... oww!! ).  I will get it sorted this weekend, I hope, because I've already got my eyes on a few other pedals.  Any recommendations for other usable pedals? Thanks.

[oldrocker]

I don't know if this is usable for you but did you ever try building the Shocktave?  It's an effect that Quackzed had brought to my attention.  Cool sound and great octive down with a little distortion in the low end but it can be tweaked nicely via the knobs.  Not hard to build but it sounds like it is.
http://www.diystompboxes.com/analogalchemy/pedals/shocktave.gif