Blue Steele pcb. No signal, voltages appear good, high frequency whine

[Locrian99]

Hello,

As the title says I built the blue steel board and I'm not getting any guitar signal.   

Voltages on all ic's and transistors appear to be in the neighborhood when compared with the listed voltages in the build doc.   My source is 9.28v vs the 9.5 that was used for the listed voltages so they are all 20-40 mV short.   

I attempted to audio probe the circuit.   I have signal at the input... and that is the only place I can find it.   I do not have it at the 10k resistor after the pull down resistor nor do I have it at the pull down resistor.    Probing q1 at the gate I have an very high pitched squeal.   And this kind of bleeds through at other points as well just far softer.   

I did so the suggested kid of eliminating d4 and using 1n4002's (I used 4001).   I am using some presoldered smd j201 adapter boards I picked up from aion.  Verified all polarized caps are correct on polarization etc.   

Kind of stumped with all the voltages correct that whine as to where to look since the signal doesn't get past the input it seems.   Just to double check my test box I tried another circuit on it and it worked fine.   Hoping another set of eyes sees the thing I am missing.   Also using a 5817 as the protection diode, need to set up a photo bucket acct to share pics. 

Thank you

[mauman]

Welcome!  Yes, pictures will be very helpful, thanks.  While you're getting those, does your wiring match the build doc page 9?  I'd suggest to verify your bypass wiring first.

• The input signal goes from the input jack tip, to the IN hole at the top of the PCB (shown as a green wire, although color doesn't matter!).
• Then a trace on the PCB carries it around the left edge to the J1 hole at the bottom of the PCB.
• Another wire (shown as orange) to lugs 4 and 9 of the foot switch.
• During bypass, lug 9 connects to lug 8, then a blue wire to J2 hole on PCB.
• A trace on the PCB takes it around the right edge this time, to the OUT hole on the top of the PCB.
• Blue wire to the tip of the output jack and you're done.

If you have a signal from IN jack tip to OUT jack tip during bypass, then check wiring continuity during the active state.  Click the foot switch. If you have power applied (not necessary for this) the LED should light.

• Same as steps 1-3 above.
• When active, foot switch lug 4 connects to lug 5.
• Green wire from lug 5 to IN hole at bottom of PCB.
• Trace takes signal to R1 and R2.

Visually check for any solder bridges between each of these wiring holes on the PCB and their neighbors (IN and GND at top of PCB, IN and LED+ at bottom of PCB, etc)

[Locrian99]

Hey thank you.   I always just connect the the i/o power and ground to test a pedal as soon as it's done.  It makes sense since this is a buffered bypass it needs to go through those pads at the bottom to go anywhere.    Doh.    I'll while up my switch tonight after work and report back if it's working now. 

[Locrian99]

Lol well I feel kind of dumb.   If I crank the volume and have the gain up it goes into that high pitch white but I wonder if thag is just from not being in an enclosure yet.   Thank you I just needed to wire the switch up, typically that's the last thing I do in an enclosure with the bypass stuff I guess it's necessary with this one. 

[mauman]

Congrats!  There's always something new to discover. 

[Locrian99]

This thing sounds great the only thing is though I still have that feedback I guess you'd call it if I max the volume tone and gain knobs.   It's only with all 3 knobs maxed, not that it's a setting I'd use just curious if this is normal for this build. 

[jwin615]

I haven't gotten around to my blue steel yet but...
Does the noise "ramp up" or just a on/off?
White noise or squela?
If it's a squeal that ramps up in tone or volume, even briefly,, could be parasitic oscillation. Check solder and orientation of your caps, especially filtering caps to ground.

[jimilee]

I'm guessing the oscillation is normal.  I would guess you wouldn't ever play it like that anyway. Over never even done that except when there's no sound coming out.


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[Locrian99]

K.   I'll check the cap orientation and see if it ramps up or down for s&g's though I'm pretty sure I already double checked all the caps once but who knows it wouldn't be the first time I missed something the first 3 times I double checked

[Locrian99]

I decided I'll never use it like that setting, it sounds really good, and it's in there too tight to want to take it back out so it's good as it sits.