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craggles wrote:it does pass a signal but it's very trebly (I already switched out c10 to pre-compensate but to no avail)

Remove R12 and see if any bass-signal passes! From there, continue to debug.

and I can hear odd glitches.

Hm that's weird. I suppose you don't have access to a scope and a tonegenerator?

The rate is all bunched up at one end (almost to a stutter speed)

Yep, mine has that too. All the usable speeds are in a small region of the pot. Be sure to use a 1M C pot! But it might need more experimenting with the usable range/steepness.

check for a dead FET. I noticed this can happen a lot from handling. I built it and it was fine but I did need to mess with a mod to get more depth.

Ok I think I got it sorted.

Found a tiny bridge in my etch. Cut it, and now all is good. Confirmed working!

The range sounds pretty good but as yet I haven't soldered the volume pot on so it's kinda hard to tell how transparent it's gonna be when at unity volume.

Cheers

FWIW, I purchased a xr2206 chip from a USA seller on eBay (for way too much money). It could very well be just coincidental, but this circuit sounds waaaaaaay better with the pricey xr2206 chip when compared with the three I purchased from tayda.

Sorry to revive an old thread, but I joined the forum specifically to troubleshoot a problem with my Catalinbread PHM.

Hopefully there might be a person or two reading this that still has their CPHM. I appear to have an output problem (a lack of output, to be exact).

I'm wondering if you can push the output volume into boost territory? If so, i'm wondering at what (roughly) potentiometer position are you achieving signal unity engaged vs bypassed?

The output volume should be well above unity gain if the pedal works correctly. Check the DC voltages on the JFETs first.

I remember that my pedal caused some distortion in the following pedal/amp, when the sweep was at the lower frequencies...

Hi,

I have a faulty v2 (from 2012) pareidolia and when trying to figure out the problem I realised that the output section is a bit different than the one on the schematic, do you think it could useful to you ?
I could check some values as well if you want to double check some parts.

yup!

Alright.

Here's a schem of the v2 "output section", it's different after the volume pot (from this schem https://www.sabrotone.com/?attachment_id=3758).



All the 5485 fets on the schem are 5484 in my pedal, fyi. I'll try and check the components values later.


By the way my pedal is really noisy even when just turning it on with no signal. I tried bypassing the "output section" (and turn it into the one on the sabrotone schem in case the noise was coming from there) but it was still noisy, and the volume was too low, lower than bypass even with the volume pot at maximum.
I'm probably going to check the Q1 and Q2 but if someone's got a idea I'm all ears !

Thanks !

if the jfet is damaged from electrostatic discharge then it will be somewhere between working and not working. everyone needs to use proper storage and handling procedures when working with jfets. you should only buy them from sellers that have stored and handled them properly. do you even know if they are working authentic jfets? have you tested them? do you know how to test them? do you have proper samples of known working jfets to compare to?

eatyourguitar wrote:if the jfet is damaged from electrostatic discharge then it will be somewhere between working and not working. everyone needs to use proper storage and handling procedures when working with jfets. you should only buy them from sellers that have stored and handled them properly. do you even know if they are working authentic jfets? have you tested them? do you know how to test them? do you have proper samples of known working jfets to compare to?

Hi. Thanks for your advice.

The answer to almost all your questions is no... Sorry.
To be honest I've fixed a few pedals by audio probing and then trying and change parts. I order them from musikding or radiospares, so I never had a problem with those and manage to fix all the pedals I tried to fix.
That being said, I should probably learn more and work more professionaly, you're right, but being a hobbyist trying to fix stuff while my kids nap it's a bit hard to do.

If I may ask, where do you think the problem might come from ? If not the JFETS I thought I could maybe disonnect the TL072 outputs (pins 1 and 7) or maybe the XR2206 and see if it's still noisy, but that's be applying my "let's try this" approach one again.

I still haven't taken the time to check for parts values differences between my pedal and the schematic on this topic, but if someone has some spesific parts they's want to check don't hesitate to ask.

Thanks again , M Eatyourguitar !

Here's another pic and link to the little schem I made, sorry it came out really small on the forum

https://i.postimg.cc/v41v0pwY/pareidolia-v2-output.png

After a few tries I found the first culprit to my noisy pareidolia : the (only in v2) Q7 2N5484 output fet.

It didn't solve the problem completely but it's a lot better. Now I only have a little background noise when the pedal is in the high frequencies part of the sweep, when the LED is yellow. If I'm not mistaken th high frequency sweep part is coming from the C3/Q1/Q2 part of the circuit.
(schematic : https://www.sabrotone.com/wp-content/up ... ia_1.1.png)

I'll post the end of my repair just in case someone has the same problem one day.

It turned out I didn't have any problem other than the Q7 fet.
I was hearing some noise because I was putting the volume at maximum and not switching the pedal on and off with a n actuel guitar signal passing through it, and therefore not realising that it's way past unity volume.
The Q7 fet actually boosts the signal too much when the volume is cranked up, so that's normal that I was hearing some noise. You don't hear anything below, at or above unity volume or even at 75% of the pot course which is way too loud for normal use anyway.

I did ask someone who has the same pedal to check and they have the same noise when the volume is at max, so nothing else than the output fet to worry about in the end.