Griffin Ricochet (Surfy Bear Clone) Issues

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Brandalones

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I just finished a build of the Griffin Effects Ricochet (https://griffineffects.com/byo-pcbs/modulation/ricochet-pcb) using the original mixer, and am getting power and signal in both bypassed and on positions, but when on, I don't get any reverb, only like a fuzz when dialed wet. No crash sound if I shake the springs either. I had the TP1 getting voltage at about 6.6 after adjusting R13. I also read on another post that someone tried removing Q3 - BC557B so I also did that. No real change.

Any ideas what else could be the issue? My only thought is maybe one of the MOSFETS are fried, but I am getting voltage readings on both of them. I don't know what they should be reading at each pin though.

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Locrian99 said:
You guys got any pics if your pedals? I got this one on the way and im debating the tank set up. Right now im leaning towards just mounting the tank to a piece if wood large enough to velcro the pedal to
Click to expand...
the surfy I built is in a tool box because I used the long two spring tank. the ricochet was in an ammo can with the shorter three spring tank. frame of reference, the toolbox will fit a full size amp head, the ammo can will fit the smaller "lunchbox" size like the OR15.
 
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Locrian99 said:
You guys got any pics if your pedals? I got this one on the way and im debating the tank set up. Right now im leaning towards just mounting the tank to a piece if wood large enough to velcro the pedal to
Click to expand...
I haven't housed mine yet, but I have another one going to a friend, and he already built an enclosure that's slightly smaller than a Fender 6g15 unit to mount his in. Mine will be closer to the SurfyBear form factor.
 
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For MOSFETs, it is necessary to install additional heatsinks so that they do not overheat. By changing R15 to 1.5 Ohm, the BIAS current becomes 400mA, which results in a power loss of 0.4Ax6V= 2.4W on each transistor at the set 6V center voltage. Therefore, it is necessary to conduct 4.8W of heat to the surroundings, for which the copper polygon on the printed circuit board is insufficient. I suggest an Aluminum L profile that is screwed to the metal housing. Of course, it is also necessary to take care of the electrical insulation between the transistors housings and the aluminum.
 
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Brilliant thread! Thanks mondxxi for solving this problem for so many here. I'm here doing a bit of research before taking the plunge on this myself.

I'm a little mystified as to what heatsinks for the fets would look like. Would anyone care to share a pic or two?
 
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Mickeyg said:
Brilliant thread! Thanks mondxxi for solving this problem for so many here. I'm here doing a bit of research before taking the plunge on this myself.

I'm a little mystified as to what heatsinks for the fets would look like. Would anyone care to share a pic or two?
Click to expand...
if you google image search surfybear diy you'll see what they used to use. here's an example that does not belong to me.

2nuuPzjoTm2bAjW6KMs2ow.jpg
 
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Mickeyg said:
Brilliant thread! Thanks mondxxi for solving this problem for so many here. I'm here doing a bit of research before taking the plunge on this myself.

I'm a little mystified as to what heatsinks for the fets would look like. Would anyone care to share a pic or two?
Click to expand...
Using the enclosure as a heatsink would have been wise but alas.
They're also kind of close together which limits your choice.
From tayda, these have the most mass
www.taydaelectronics.com

Heat Sink TO-220 14 Fins 25mm Aluminium Black

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www.taydaelectronics.com www.taydaelectronics.com
But not sure you'll get 2 to fit or if there's vertical room.
ICTRock said:
if you google image search surfybear diy you'll see what they used to use. here's an example that does not belong to me.

2nuuPzjoTm2bAjW6KMs2ow.jpg
Click to expand...
I think the PCB layout is too tight to allow those.
 
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I finally finished up my build and it sounds great. However, it was a rough build and I want to share my builds notes.

I would strongly suggest the following build changes:
Change the value for R15. Don't use 1.5k Ohms for R15. I chose 3.9 Ohms for my build, but 1.5 Ohms should also work.
As others have said, 1.5 K Ohms is way too high, and the Surfybear schematic shows 1.5 Ohms. Compared to 1.5 Ohms, 3.9 Ohms will make less current available to the tank, but it'll cause Q4 and Q5 to run cooler.
If you have enough heat sink 1.5 Ohms should be fine. The right value for your build will depend on the heat it can dissipate. With 3.9 Ohms I still get more than enough current at the tank, but you might consider buying a few values to experiment with. I wouldn't go lower than 1.5 Ohms. If you use 1.5 Ohms I would probably order a >1/4W resistor.
Add a heat sink to Q4 and Q5. I didn't try building this without a heatsink, but I don't think it would work without one. I used 3.9 Ohms and it still got way too hot for me to be comfortable using the PCB as a sink. I used a heatsink I had lying around, but on a do-over I'd have used something better. Make sure the heat sink is electrically isolated from the enclosure.
I would not recommend the improved mixer. I might be wrong, but I think the improved mixer circuit would cause more problems than it solves. I just used RV3 and it works great. I wrote an excessively long post about it here: https://forum.pedalpcb.com/threads/griffin-ricochet-surfybear-clone.18862/post-275911

I think these changes are a good idea:
Don't use a 1590BB enclosure. I used a 1590BB enclosure, but I should've used something bigger.
 
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...continued from before
I ended up adding some standoffs to raise up the lid. It works, but it's messy and I'll probably redo my enclosure at some point.
Pay attention to how the knobs connect to the circuit
I didn't think it through and I originally put the knobs on wrong. In my original mounting I had terminals 1 and 3 on the potentiometer swapped. Everything worked, but the operation was counterintuitive. I already cut holes for the knobs so I ended up cutting off the pot leads and fixing it with jumper wires.
Consider other JFETs
I used MMBF5457 (surface mount). Surfybear lists MMBF5457 as an alternate for their kit. I checked the signals with a scope and everything looks good.
Pick the right kind of cable to connect to the tank
A lot of cheap audio-visual RCA cables share a ground between the channels. This causes the drive signal to interfere with the received signal.
Other Random stuff
I added a 2.2 Meg resistor to ground at the output. It's not really necessary, but it'll keep the output from floating.
As others mentioned, the LED resistor could be a higher value.
I intentionally used an odd connector for power. I don't want to accidentally connect this to the wrong supply.

That's all I can think of. The thing sounds awesome, but it's easily the most challenging pedal I've ever built. Good luck.
 
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