PSA for all Cowpokers....(Those of you building the CowPoker board)

[MichaelW]

Many of you have been the recipient of the generosity of @fig with the CowPoker v2 boards that he sent out to you.
(@fig had this run of boards fabricated and sent all the necessary relay components at his own expense and out the bigness of his heart )

Just a heads up:

It looks like there is an issue with this version of the board. I think I may have built the first one out of this batch and would not have even known about the issue if @steviejr92 hadn't reached out to ask if he did something wrong with his build. (He didn't, his build looks AWESOME!!)

There is an oscillation issue at high gain in the form of squealing. This happens when one of a couple conditions happen.

- You have the volume and treble high and turn the gain up towards noon.
- You have the volume at unity and turn the gain towards 2-3 o'clock.

After Stevie alerted me to this behavior on his build, I checked mine again. The reason it wasn't happening for me is because I put my build in my pedal chain that has a buffer at the beginning of the chain. If I plug my guitar directly into the pedal, I get the same oscillation.

Been going back and forth a bit with @Chuck D. Bones last day or so trying to nail down what the issue is. Not completely sure what it is yet as it doesn't happen when the circuit is breadboarded, so it's something in the board layout. It does not seem to be related to how the I/O cables are routed as Stevies build and mine are inverted from each other and both builds exhibit the same behavior.

So you have a couple of options:

1) A buffered pedal in front of the CowPoker completely solves it. I've tried my TC Polytune 3, General Tso Compressor, and Cleaver boost, all of these solve the issue completely and I can dime the gain with no squeal. (Not that I suggest anyone run it with the gain dimed unless you have the spandex pants to go with it....)
So if you regularly run a buffer in your chain before your drives then this going to be a non-issue for you.

2) Wait to build the board for a more permanent solution as Chuck figures one out. I'll post an update as soon as we have something solid.

3) If you want to get fancy you can integrate a Simple JFet Buffer on the INPUT side of the board. I think @steviejr92 is going to try this. I have some of these boards and I think I'll test it today and see if it is also a fix.

I'm fairly certain any of the buffer projects @Robert has in stock would be a fix. But a certain EE I know would say this only a band aid and not a real solution

Me personally, I'm not doing anything with it. I love it the way it is and it's a non-issue for me since I always run a buffer in the front of my pedal chain (and so should you).

 

[Mentaltossflycoon]

Much appreciated!

 

[steviejr92]

Great write up dude! Im definitely going to be trying the jfet buffer board and see if that clears it up! I bought 10 (minus 1 im using) buffer boards if anyone here doesn't have one PM me and i will send one out to you asap!

 

[MichaelW]

Ok, I just tested the CowPoker with the Simple JFet Buffer and as expected it works in eliminating the squeal.

I used my Amentum Boost (EQD Arrows) build that has one of the Simple JFet Buffer boards on the output of the pedal. I used a J201 on that buffer board. (Although I'm pretty sure any JFet would work). I tested by hooking up the Cowpoker with only the output connected (nothing in the input jack). With volume at 9 o'clock, treble and bass controls at noon, I start getting the squeal as soon as I start cracking the gain (around 8 o'clock on my pedal). Plugging in the Amentum with the effect engaged it kills all the squeal.

Keep in mind that in my Amentum the way I have the buffer board installed it's only active if the pedal is engaged. It can be configured as an "always on" buffer either as in input buffer or an output buffer.

If I were going to use one in the CowPoke I'd connect the Buffer IN pad between the Input Jack tip side and the Buffer Out pad to the CowPoke Input pad. (IJ). Then connect VDC to by piggy backing off the DC in Jack. In fact the board is so small I'd probably just mount it directly to the input jack with some buss wire or solid core hookup wire. Should be plenty to hold the board in place. Or you could use a little double sided tape and mount on the back of the SPST footswitch. Lots of options.