Choral Reef

chongmagic said:
Last non-PedalPCB I will post, but I have been wanting to build this for a year or so.

I love the bucket brigade chips.

photos.app.goo.gl

New item by Jonathan Freeman (Chongmagic)

photos.app.goo.gl photos.app.goo.gl

photos.app.goo.gl

New item by Jonathan Freeman (Chongmagic)

photos.app.goo.gl photos.app.goo.gl
Click to expand...
I’ve got a question that you’d be more knowledgeable in answering than I would. I built this same pedal months ago and it works great. My question is in reference to the 47uF electrolytic mounted to the left of the empty charge pump slot. I wasn’t sure which space it was supposed to go in. I’m not a pro at reading schematics, still learning. From what I thought I was seeing, I decided to mount it in the lower slot. I see that yours is in the top slot. Did I do it wrong or does it not matter which place you put it? The pedal works great but I’d rather have it mounted where it belongs. I’m hoping you could educate me
 

Attachments

  • F007A580-9130-479D-9936-6D89060E2DC0.jpeg
    F007A580-9130-479D-9936-6D89060E2DC0.jpeg
    492.6 KB · Views: 9
dlazzarini said:
I’ve got a question that you’d be more knowledgeable in answering than I would. I built this same pedal months ago and it works great. My question is in reference to the 47uF electrolytic mounted to the left of the empty charge pump slot. I wasn’t sure which space it was supposed to go in. I’m not a pro at reading schematics, still learning. From what I thought I was seeing, I decided to mount it in the lower slot. I see that yours is in the top slot. Did I do it wrong or does it not matter which place you put it? The pedal works great but I’d rather have it mounted where it belongs. I’m hoping you could educate me
Click to expand...
You have it installed correctly. Reference page 3 of the V2 VFE Switching document. Also, those spots are not interchangeable.
 
dlazzarini said:
I’ve got a question that you’d be more knowledgeable in answering than I would. I built this same pedal months ago and it works great. My question is in reference to the 47uF electrolytic mounted to the left of the empty charge pump slot. I wasn’t sure which space it was supposed to go in. I’m not a pro at reading schematics, still learning. From what I thought I was seeing, I decided to mount it in the lower slot. I see that yours is in the top slot. Did I do it wrong or does it not matter which place you put it? The pedal works great but I’d rather have it mounted where it belongs. I’m hoping you could educate me
Click to expand...

In the switching doc and the build guide for the Choral Reef, Brian indicates that C6 should be inverted to create a separate bias rail for the MN3008.

Your V- pad should measure 5v.

In the Choral Reef the following exceptions are applied. - - - - R5 (8k2) and R6 (10k) are only used in the Choral Reef. These resistors are left off in all other VFE projects. IC2 AND C5 are also left off in the Choral Reef. C6 is still used, but it should be installed backwards. IOW, the + side of the cap goes to the round pad on the PCB and the – side to the square pad on the PCB. The V- pad on the switching board is still wired to the V- pad on the Choral Reef audio board. But, in this case it carries approximately +5v to the Choral Reef audio board instead of -9v that we would have when using the charge pump. This is to give the CF board a separate bias rail it needs to operate properly.
 
chongmagic said:
In the switching doc and the build guide for the Choral Reef, Brian indicates that C6 should be inverted to create a separate bias rail for the MN3008.

Your V- pad should measure 5v.

In the Choral Reef the following exceptions are applied. - - - - R5 (8k2) and R6 (10k) are only used in the Choral Reef. These resistors are left off in all other VFE projects. IC2 AND C5 are also left off in the Choral Reef. C6 is still used, but it should be installed backwards. IOW, the + side of the cap goes to the round pad on the PCB and the – side to the square pad on the PCB. The V- pad on the switching board is still wired to the V- pad on the Choral Reef audio board. But, in this case it carries approximately +5v to the Choral Reef audio board instead of -9v that we would have when using the charge pump. This is to give the CF board a separate bias rail it needs to operate properly.
Click to expand...
Check the schematic. Your build has C5 populated instead of C6.
 
benny_profane said:
Check the schematic. Your build has C5 populated instead of C6.
Click to expand...
benny_profane said:
You have it installed correctly. Reference page 3 of the V2 VFE Switching document. Also, those spots are not interchangeable.
Click to expand...
Thanks for clearing that up for me. I was pretty baffled. I remember studying that build doc for a couple days straight before I dove in. I’m not real good reading the schems yet but from what I can tell C6 comes off of the #5 pin of the empty charge pump. I did reverse the polarity. C5 looks like it comes off or pins 2 and 4 and that is omitted. I guess I’m making some progress.
 
dlazzarini said:
Thanks for clearing that up for me. I was pretty baffled. I remember studying that build doc for a couple days straight before I dove in. I’m not real good reading the schems yet but from what I can tell C6 comes off of the #5 pin of the empty charge pump. I did reverse the polarity. C5 looks like it comes off or pins 2 and 4 and that is omitted. I guess I’m making some progress.
Click to expand...
Yeah, you’ve got it. Compare the schematic to the trace picture and you can see how it translates. Without traces, you have to use the continuity setting on your DMM. Definitely a worthwhile skill to develop.
 
benny_profane said:
Yeah, you’ve got it. Compare the schematic to the trace picture and you can see how it translates. Without traces, you have to use the continuity setting on your DMM. Definitely a worthwhile skill to develop.
Click to expand...
That’s exactly what I did. I just remember sitting on it for a couple days because I didn’t want to do it wrong. I hate desoldering, but it sounds like it works somehow either way.
 
I will have to ask Brian what the deal is, I checked all my voltages again today and they are matching up with the build guide.
 
chongmagic said:
I will have to ask Brian what the deal is, I checked all my voltages again today and they are matching up with the build guide.
Click to expand...
That capacitor doesn’t affect the voltage: it’s a decoupling capacitor meant to shunt noise from the power supply and isolate it from the circuit. The 8k2 resistor is there to provide the bias voltage (i.e., VB in the choral reef build doc). Both are important parts of the bias voltage circuit block, though.
 
benny_profane said:
That capacitor doesn’t affect the voltage: it’s a decoupling capacitor meant to shunt noise from the power supply and isolate it from the circuit. The 8k2 resistor is there to provide the bias voltage (i.e., VB in the choral reef build doc). Both are important parts of the bias voltage circuit block, though.
Click to expand...

Then I guess I should change it, it will make the circuit less noisy. With the jack soldered in it will be a pain.

I guess I could just put in C6 and leave in C5 since they dont seem to be connected without the charge pump.
 
Last edited:
You must log in or register to reply here.

Similar threads

Hirti
Schu-Tone DM-3 (Boss DM-3)
Replies
1
Views
190
Route14
R
Hirti
PedalPCB Mojito Deluxe Overdrive
Replies
0
Views
192
Hirti
Hirti
M
Cast Iron Overdrive (Lollar Overdrive)
Replies
10
Views
2K
joelorigo
joelorigo
owlexifry
DEMO ElectroVibe (w/ big muff for demo)
Replies
0
Views
179
owlexifry
owlexifry
M
Hard Rock Pinnacle Purebred Drive (Animals Diamond Peak CDB mod), new PCB revision
Replies
5
Views
238
jjjimi84
jjjimi84
Back
Top