phase 45 ticking

[Sir_Ian]

Ok folks. I built a phase 45. Its perfed, but I followed the layout off of tonepad. I used the same component placements and connections..etc.

It works but I get a ticking...and I'm 99.9% sure its the lfo. I did some reading and searching...and I can't find anyone else who built a phase 45 who has had this problem. I read some stuff on decoupling...but that was mostly for people designing their own phasers, and I looked at the phase 45 and it seems to have good decoupling. Maybe I'm wrong.

So basically...the thing is 100% perfect except for the ticking. Beautiful phasing...but its like I'm playing to a metronome. Is there a bad part that could be causing this? I'm just kinda curious if anyone else had the problem on the phase 45 because I can't find anyone else who had the problem. I read all the comments on tonepad...and none of them mentioned this problem....so I'm kinda just thrown for a loop. Any ideas or good articles on this would be appreciated. Thanks.

[oldschoolanalog]

What op amps did you use?

[plankspank]

Double check the  three 10uf electrlytics (Polarity correct, ect..).

[Sir_Ian]

I used TL072 for my opamps.

I'm sure my electros are orientated correctly...but I'll check for a cold solder joint..etc.

[Zben3129]

Does the ticking tempo change with the speed pot? If so then it is the LFO bleeding in.

You might try TL022 for the LFO opamp if possible. I am not sure if this will work for a phase45, but on chorus LFO's it is recommended over the tl072.

Zach

[Sir_Ian]

The ticking does increase with the speed pot. Thats what made me so sure it was the LFO bleeding in. I went and resoldered all my electro caps to make sure they aren't cold. They're fine....I think....I really should take some measurement with it running...but I'm being hurried at the moment. Its hard trying to fix a pedal with the whole family in town wanting you to do stuff and be "social." hehe.

I tried two other op amps in there. A jrcd4558d and and LMNsomething or another. Still had the ticking with the jrcd and had sound but no phasing and no ticking with the LMN. I'll try to go out and find a tlo62 tomorrow.

But if switchign the op amp doesn't work...anybody else know of any other fixes I can do? thanks.

LAST THING. I don't know if this matters...but I don't have the thing in an enclosure. Its on a pcb, but not in the enclosure. just thought it might be relevant. thx.

[Zben3129]

The 4558 has about the same specs with regards to gain as the 072. The point of using an 022 over an 072 is that the 022 has lower gain and will therefore produce less noise. When you tried the 4558, you got about the same results as the 072. When you tried the other thing, you got no ticking or phasing because the oscillator stopped oscillating. Probably was an incompatible op-amp. A tl062 may help, but it is not as good of a choice as a tl022, definitely worth trying if you don't mind the fact that it might still tick, however, as it could kill the tick. For me, I had a ticking problem in a phaser and going from tl072 to tl022 killed it.

Also make sure you put the new opamp in the LFO opamp spot, or else it won't change anything with the ticking 


And no, having it unenclosed shouldn't matter as the ticking is all internal to the circuit and is not produced from external RF or anything like that.


Zach

[oskar]

Allways link to a project you're refering to...

To start with, putting an oscilltor ( ic2a ) and an audio amp ( ic2b ) sounds like a risky thing. I saw some fix by zvex for LFO tick about a feedback cap something... search for this in the forum. Could be the 10n between pin 1 and two is doing just that. Check it up!
-Try holding different caps between pin 1 and 2 ( don't go soldering ) does the tick change?
-Did you make the PCB yourself? Try a wire direkt from V+ ,close to the battery, to pin 8... any change?
-Hold a big cap... 100u?... directly between pin 1 and 8. any change?      -else I don't know. Post readings and build descriptions properly.

You will find many references to LFO ticking and decoupling the LFO IC with an RC filter 100R/100u...
Since the LFO is hosted in an IC in the sound chain this is probably not a good idea in your case. ( fingers crossed )

[Sir_Ian]

First off, thanks for the ideas oskar. I tried them all with no effect. I still got the ticking but thanks. The one thing I did was get some voltages...so here it goes....

In the 3 elctrolytics.....(using the positive side..because negative is just ground and zero.
these are the cap numbers off the general guitar gadget schemtatic (the tonepad one doesn't number its caps...so I'm linking to the GGG one and using its numbers)
http://www.generalguitargadgets.com/pdf/ggg_p45_sc.pdf

C7: 3.46

C10: 5.8 to 3.3 v (fluctuates because it is part of the LFO, and I'm pretty sure its supposed to.)

C11: 9.02 v

All of those numbers seem right.

Now for the IC. Now I know i used the ggg gadget schematic before...but I think it would be best to use the tonepad layout and schematic for this one..because on the ggg schematic my 2 become 6's and stuff. So here is the link. http://www.tonepad.com/getFile.asp?id=70 These are the measurements for IC2.

1: 8.5-1.5v
2: 4-6v
3: 3.3-5.6v
4: 0v
5: 3.41-3.46v
6: 3.47v
7: 3.49v
8: 9.10-9.12v

Now pins 1,2, and 3 fluctuate. They go up and down with the LFO and this makes complete sense to me. Now Pin 5 fluctuates. At first I thought IT shouldn't...but then I measured pin 3 of the other opamp which has the same function...just on a different spot...and it fluctuates between the same voltages. So I think its ok. So basically...I don't think these voltages showed anything wrong...but they did help me better understand how everything works. I just got done saying how I'm kinda glad when things go wrong. Because it helps me learn and understand the circuit. Then again...I'm trying to finish this as a christmas present...we'll see if I make it in time....it actually doesn't have to be done till friday night...but the sooner i fix it the better.

I'm gonna run down to the electronics store and try and get some different opamps. the tl022 for example. If that doesn't work....I'm gonna try decoupling. (I'm not sure what that even means...I guess I got some reading ahead.)

Thanks for all the help and ideas. They are very much appreciated. I am kinda surprised that I haven't heard of anyone else having this problem with the phase 45. Makes me kinda feel stupid...oh well.

[German]

I think problem could be with fets.
Opamp cant tick..
Look for right voltage after zener diode, maybe try 5.1 zener.
That just sounds like bias problem, so 10uf cap need to be checked too.

[oskar]

I think C7 is supposed to hold the same voltage as D1's rating. ~4.7V
Either:
-Something is sucking down the voltage/ short ( anything getting hot? )
-Zener is wrong value/broken
-I'm wrong

http://www.datasheetcatalog.org/datasheet/SEME-LAB/1N5221B-LCC3.pdf


1. check for shorts ( measure current draw on unit )
2. get a new zener

[jfromel]

Did you match your FET's?

http://www.lynx.net/~jc/pedalsPhase45.html

[Sir_Ian]

All good guesses...but all wrong. The answer is...the op amp ticks. But my signal doesn't. I'll explain.

tonepad layou---> http://www.tonepad.com/getFile.asp?id=70

I kept going back and forth between working on the circuit board and searching the form for answers. I saw one guy who said he had a bad 10uf cap in the lfo section and he fixed it. I looked at mine and saw that it was fine. Red Herring. I think it was this same guy however who said he used his audio probe to listen to the ticking. GENIUS!!! So I listened. Pins, 1,2, and 3 all on the second opamp (the lfo) ticked like the devil. But once I got up by that 10 uf it was very subtle. In fact....once that ticking went through any resistors.....it got quite. So then I looked at all the my connections around the pins one and three. If you see in the tonepad layout....there is are two traces that go under the second opamp. One is from pin 1, and it ticks loud. The other (from pin 7) has no ticking at all. Amazing! But yet I still had ticking at the output.

So I traced my ticking backwards from the output, and concluded it was getting in through the air on a connection lead wire thingy. If you look at the tonepad layout, there is a blue trace in the bottom right that goes from a 10k resistor over to the .05u output cap and then curves up and left to another 10k resitor. (kinda makes a U that is rotated 90 degrees counterclockwise.) I noticed in 2 places it came in close proximity to traces that were big tickers (off of pins 1 and 3). I resoldered those connections so the lead wire just stayed further away.

I also notice I had just solder blobbed the connection where the 3 150k resistors come together. I had also read somewhere to make sure the solder connections on the LFO don't connect to the board anywhere or else they might cause ticking. I desoldered that whole region and used a lead and very little solder to connect them. I also just removed excess solder on some of the other joints in the area. Stuff that normally wouldn't matter, but I just wanted to get as little metal in the air to pick up or send ticking.

When I tried it....it worked. NO TICKING. I'm pretty sure it was a combination of both things that helped. When I used the audioprobe, I still heard the really loud ticking on pins 1,2, and 3, but now, the ticking is not interfering with output signal....so all is well in the world.

WHAT I LEARNED: Even if you spend 5 hours putting a board together....it should have been 6. I just need to be a little bit more careful about keeping my distance.

Lastly....I would like to thank everyone who looked in or offered some advice. Even though nobody gave me a 100% solution...it was the little ideas that lead me to finding out what was wrong. Thanks for all the help. And like I said in my last post. I think I learned alot more about the circuit by having it not working. THANKS!!!!

[oskar]

Wow, thanks for the sum up!
Audioprobe LFO... but off course!


skar

[Paul Marossy]

I know that this is an ancient thread, but I ran across it the other day when I had a ticking problem after changing a few caps and thought I should add this.

I changed the (3) 10uF caps when I was having a problem because I thought it might be one of them causing or contributing to the problem (the originals were some pretty old caps). I didn't notice any ticking noise coming from the circuit until I experimented with the order of the pedals. It became very apparent when I put a high gain pedal after the Phase 45. The sound was definitely coming from the opamp, and it changed with the speed control. So after I read this thread, I suspected that it must have something with the caps I replaced. So I reflowed all those points of connection and the problem went away. One of the solder joints must have been bad although they all looked pretty good to my eye.

Anyway, I'm glad this thread was here or I would have been much more annoyed trying to find the source of the problem! 

[duck_arse]

I've just gone down the tikking osc route as well. after a number of different designs on the breadboard, it all came down to lead dress. careful wiring of the power supply to the osc opamp cured the problem.

[R.G.]

...So I reflowed all those points of connection and the problem went away. One of the solder joints must have been bad although they all looked pretty good to my eye.

I've just gone down the tikking osc route as well. after a number of different designs on the breadboard, it all came down to lead dress. careful wiring of the power supply to the osc opamp cured the problem.

Ticking from an LFO is a classic scenario for signal cross coupling between two mostly-unrelated parts of a circuit. The fast, vertical edges of the switching part of the LFO as it reverses direction are easy to couple capacitively and the sudden change in current in power supply and ground wires/traces to/from the LFO section cause sudden voltage changes in the leads, especially the ground wire.

If you have a high-resistance path to ground or in the ground, like a high-resistance solder joint, or a shared ground lead with a sensitive input, the tick from the current change flows right through to the signal circuit to be amplified.

If you have leads that are close to (that is, are capacitively coupled to) the fast edges of the LFO switching, the capacitance between those conductors lets the high frequency parts of the LFO signal jump into the other leads. Notice that it doesn't have to be lead-to-lead. You can get capacitive coupling by running a sensitive lead, like an input wire, close to the circuit board's surface over traces or wires carrying the fast edges.

The radio guys figured this stuff out long ago - use lead wires as short and straight as you can, and keep input wires away from output wires and power supply wires which carry high levels of current changes; also, use big enough wires (and good enough connections) to keep voltage drop across junctions to as near zero as it can be made.