Aion Effects "Cerulean" (Bluesbreaker Clone) Won't Work

[GoodGuitarist]

UPDATE:

I used a battery instead of DC. I also played with the settings on my multimeter... there's a (good) chance I wasn't measuring properly, as I'm still fairly new to the troubleshooting side of things.

New voltages:

Battery: 9.02

IC1

• 1.49
• 1.416
• 1.619
• 0
• 1.472
• 1.409
• 1.408
• 8.82

Q1 - not sure about the orientation, but imagine top-down view, it looks like a capital D. Pin 1 would be the top (hope that's correct).

• 3.15
• 2.8
• 0

Hi,

I recently built a Cerulean by Aion Effects, from a kit. It kind of works but sounds like a wonky fuzz pedal (sputtery, as if the bias knob was turned all the way down on my Keeley Fuzzbender)

• The LED lights up
• The knobs all do something (volume is really quiet until the last 10%, tone definitely adjusts the tone, gain adds gain)
• The clipping switches don't really feel like they're affecting the sound much, but that might be because the whole thing is sounding pretty crazy

...but it definitely doesn't sound like a Bluesbreaker.

I've attached photos of the circuit board. Please excuse the flux, I didn't bother cleaning it yet since I might have to get back to work on it soon.

I measured the voltages on IC1 and Q1.

IC1

• 0.008
• 0.045
• 0.009
• 0.009
• 0.034
• 0.015
• 0.009
• cycles between 3 exact voltages: 0.00, 51.2, 5.74

Q1

• 0.006
• 0.009
• 0.011

I used a working PSU (one that came with a strymon pedal, that I've tested with my OD-3 to confirm).

Please see attached images, and thank you for any help... It's a real downer when a pedal doesn't work so I'm really looking forward to getting to the bottom of this. Thanks!

[idy]

Welcome to the forum!

What voltage is the power supply putting out? (measure it plugged into the wall, but not into the effect.) Sure its not AC?

I suspect a short close to the place the power enters the pcb. Or the power jack is messed up... sure you have the right terminal on the DC jack?  None of your readings are even 1v! (except that weird "51.2" which maybe millivolts or something?)

Check both sides of diode 1, and the + side of C10 and 11. C10 needs to have 9v on it, C11 around half that.

You need to  see 9v on the IC pin8, 0v on pin4, and around 4.5 on all the other IC pins.

[PRR]

Welcome!

Project link: https://aionfx.com/app/files/docs/cerulean_kit_documentation.pdf



> I measured the voltages on IC1 and Q1.

IC1
    0.008
    0.045
    0.009
    0.009
    0.034
    0.015
    0.009
    cycles between 3 exact voltages: 0.00, 51.2, 5.74
Q1
    0.006
    0.009
    0.011

{Hey!! You used Numbered List Code! Nobody does that!!}

Somehow (as idy is saying faster than me) you have 9V coming in(??) and essentially nothing at any pin except pin "8?". (You can pull 0.009V out of the air.) However 6V and 51V!! on that other pin is super odd?

[bluebunny]

My first thought given those IC voltages is that you have a short somewhere.  So your PSU is periodically switching off and on - which explains the variation on pin 8.

P.S. Welcome! 

[Carlinb17]

could you check double check the orientation of the clipping 3mm led's they look like they might be backwards, I know this doesn't address the powering issue it might cause some issue with the clipping features. Although sometimes if their both in backwards it will still work.

[garcho]

The JST connector next to the DC jack is missing 2 pins, the 2 pins that connect the PCB to the power supply.

[GoodGuitarist]

could you check double check the orientation of the clipping 3mm led's they look like they might be backwards, I know this doesn't address the powering issue it might cause some issue with the clipping features. Although sometimes if their both in backwards it will still work.

Thanks for responding!

I checked, and the flat side is in the circle hole, the long leg went through the square hole.

[garcho]

the flat side is in the circle hole, the long leg went through the square hole.

As long as they made the PCB correctly, you placed the LEDs correctly.

[GoodGuitarist]

Welcome!

Project link: https://aionfx.com/app/files/docs/cerulean_kit_documentation.pdf



> I measured the voltages on IC1 and Q1.

IC1
    0.008
    0.045
    0.009
    0.009
    0.034
    0.015
    0.009
    cycles between 3 exact voltages: 0.00, 51.2, 5.74
Q1
    0.006
    0.009
    0.011

{Hey!! You used Numbered List Code! Nobody does that!!}

Somehow (as idy is saying faster than me) you have 9V coming in(??) and essentially nothing at any pin except pin "8?". (You can pull 0.009V out of the air.) However 6V and 51V!! on that other pin is super odd?

Hi. Thanks for replying!

I have updated the original post with new voltages, as I believe I may have not measured them properly:

Battery: 9.02

IC1

• 1.49
• 1.416
• 1.619
• 0
• 1.472
• 1.409
• 1.408
• 8.82

Q1 - not sure about the orientation, but imagine top-down view, it looks like a capital D. Pin 1 would be the top (hope that's correct).

• 3.15
• 2.8
• 0

THank you!

[idy]

So you're getting 9v to the IC, but the inputs and outputs are not "biased" to mid voltage, 'VR'.
This mid voltage is created by R9 and R10. They should both be 47k. If you try to measure them (disconnect power first) they will probably start near 0 and then climb up as the capacitors charge. They should be 47k, but if one was for example 4.7k you wold only get .9v. A bad solder joint (you can't always see!) at R9 or10 would be enough to cause this.

With the power on you want around 4.5v at junction of R9/10. Short? You will also need to look at the places this mid voltage goes to see if there is a short somewhere.
Get to know your schematic. All the places that say VR.  IC pins 3 and 5.
The diodes go there as do the tone and presence and "RX1."

[GoodGuitarist]

So you're getting 9v to the IC, but the inputs and outputs are not "biased" to mid voltage, 'VR'.
This mid voltage is created by R9 and R10. They should both be 47k. If you try to measure them (disconnect power first) they will probably start near 0 and then climb up as the capacitors charge. They should be 47k, but if one was for example 4.7k you wold only get .9v. A bad solder joint (you can't always see!) at R9 or10 would be enough to cause this.

With the power on you want around 4.5v at junction of R9/10. Short? You will also need to look at the places this mid voltage goes to see if there is a short somewhere.
Get to know your schematic. All the places that say VR.  IC pins 3 and 5.
The diodes go there as do the tone and presence and "RX1."

Thank you for the advice. Let the learning process begin!

[GoodGuitarist]

Okay, so I finally had some time to try out these troubleshooting tips.

First, I checked all the resistors. R9 and R10 were going up to 27k, so I desoldered them, checked them, and they both register spot on at 47k.

The 2.2m resistor was reading 1.4m. Removed it, tested, it's 2.2m.

I removed the DC jack and resoldered it, and then decided it would be a good idea to reheat every connection and make sure there weren't any cold solders. I also used a multimeter and checked for any continuity along the diodes and capacitors (incase some solder slipped under them and bridged? I dunno...)

I am now getting 4.5v to the junction between R9 and R10.

And when I measure the voltages from Pin 1 to 8 on the IC, here's what I get:

• 4.5 v
• 4.5 v
• 4.5 v
• 9.4 v
• 4.5 v
• 4.5 v
• 4.5 v
• 223 mV

According to the documentation, Pin 4 should be zero, and Pin 8 should be 9.4 v, but they seem to be reversed! Not sure what's going on. I'm trying my best to read through the schematic, and follow the traces on the PCB, but I don't know what the voltages should be, and where, and the Ohm's law thing... I'm trying my best to do the math, but I just don't know enough about this stuff.

As far as how it sounds, it's almost decent, but still a farty, sputtering mess.

Any leads on where to go next? Any idea on what certain voltages should be, etc?

[idy]

Are you sure you are numbering the pins on the IC correctly? Putting the "notch" "upward" and counting down the left side and up the right, counter clockwise?

Memory tip: when you orient the dual OPAMP like this, with pin 1 on "top", the ground (-v) is "down" and the V+ is "up" on diagonal corners.

If you are reading things backwards your numbers look good. If you are reading correctly I would have to think you are writing from a parallel universe... by that I mean the Opamp seems to be functioning, accepting a bias voltage on its inputs and bringing its outputs all up to that number. If the voltage were really backwards that would not be the case.

Not sure what "farty sputtering mess" is caused by. Could be the name of a boutique pedal FSM....You're come this far, you can probably figure it out.

Signal probe: take an instrument cable and cut off one plug. Attach "any" film type cap to the conductor, and an alligator clip on some wire to the shield. Alligator clip goes to a ground on your pedal, maybe on one of the jacks. Plug the other end into a small, not precious amp. Use a looper or an iPod for anything to inject some sound into your pedal's input. Now probe...is the sound still Ok when it hits the Opamp the first time (pin5)? How about the second stage, pin2?

The only other active item is the output stage, the JFET transistor. Not all of those on the market are legit, much variation from specs. If I had to bet, I would guess the you would hear smooth distortion going in the gate and "FSM" coming out the drain.

[GoodGuitarist]

Thanks for the reply. Yes, I'm certainly measuring it in a circle, counter-clockwise, and those are the readings. The little circle is in the top-left corner. One of my friends had a few extra TL072's lying around so I swapped it out and got the same readings.

I'll try the ipod thing next... gotta make it happen!