CHASM REVERB

[bluebunny]

They need to be wired so that they're permanently connected to the input (and output) of the circuit on the PCB.  If they're the "other" side of the footswitch, then they have no effect.

[deadastronaut]

^ yep..

try adding the 1M's across your jacks.


note: the chasm was designed to have silent switching. i cant stand pops on trails/delays..

but you have managed to bring back the pop...

[wbgarman]

Just to make sure I understand correctly, I would place a 1M resistor into the 'G' and 'IN' and a second 1M resistor into the 'G' and 'OUT' holes of the PCB (with the pre-existing wires remaining in the 'IN' and 'OUT' holes)


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[bluebunny]

Yes.

[deadastronaut]

Yup. Worth a try...

[wbgarman]

The pull down resistors placed at the input and output of the PCB resolved the pedal pop. Thank you samhay, deadastronaut, and bluebunny for the help and guidance


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[samhay]

Excellent, and you are most welcome.

[PrettyVisitors99]

Hi, I'm looking foward to build this pedal but i can't acces to the PDF's of the pcb and layout on the first page
Am i the only one with this problem? i would be so grateful if someone could post those pdf's again. Thanks

[nepalnt21]

same on the no access... i get a 404 error page with those links.

with that said,

good info here

edit

o, and here u also go

[bluebunny]

The documentation is available on Rob's website - the link is in his .sig above.  The Chasm page is here.

[sargeras611]

Hi! I've just built Chasm reverb, it sounds great, everything is fine, every pot is doing what it is supposed to do. But problem is when i turn my effect off. It doesn't shut effect off, it keeps reverberating my signal even when i turn effect off. Could you help me with this please? I built it on etched PCB from page effectslayouts, before soldering i checked every trace, every pin, if everything's alright. Next i checked every component's value. I double checked wiring. I've used 3PDT switch, but just 6 out of 9 pins.

Here are some photos:





And there are readings when effect should be off (LED is off):

9,20 V power supply

Q1 (J112):
D. 3,40
S. 3,40
G. -1,70

Q2 (J112):
D. 3,40
S. 3,40
G. -1,15

Q3 (2N7000):
S. 1,90
G. 3,40
D. 6,80

REG (7805):
I. 6,80
G. 0,00
O. 4,98

IC1 (TL072):
1. 3,41
2. 3,41
3. 3,08
4. 0,00
5. 3,41
6. 3,41
7. 3,41
8. 6,82

IC2 (TL072):
1. 3,41
2. 3,41
3. 3,41
4. 0,00
5. 3,41
6. 3,41
7. 3,41
8. 6,82

Readings when effect is on (led is on):

9,20 V power supply

Q1 (J112):
D. 3,40
S. 3,40
G. -1,12

Q2 (J112):
D. 3,40
S. 3,40
G. -2,48

Q3 (2N7000):
S. 2,22
G. 3,64
D. 6,70

REG (7805):
I. 6,80
G. 0,00
O. 4,98

IC1 (TL072):
1. 3,60
2. 3,40
3. 3,06
4. 0,00
5. 3,40
6. 3,40
7. 3,40
8. 6,80

IC2 (TL072):
1. 3,40
2. 3,40
3. 3,40
4. 0,00
5. 3,40
6. 3,40
7. 3,40
8. 6,80

Thank you for any reply, I really appreciate that!

[niektb]

Hi sargeras611! Welcome to the forums!
I think your 'issue' might be a feature! What happens in the Chasm is that the input signal to the reverb circuitry is cut-off, not the output! In some pedals this is called the 'TAILS' option
Can you verify that new notes aren't reverberated when in bypass?

[sargeras611]

Thanks for kind welcome! And thanks for quick respond. I know about this feature of "Tails", for reverb it's great feature, but in my case, also new notes after switching to bypass mode are reverberated. Also all pots are reacting in bypass mode.

[deadastronaut]

Hi, 6.8v from a 9v supply... something wrong there...

Check over your values...trace through and see where the 9v is dropping if you cant see any obvious wrong value.

[sargeras611]

Hi deadastronaut, thanks for your respond! I checked it from power supply, after diode 1N5817 I'm reading 8,88 V, and after 33 Ohm resistor i'm reading just 6,8 V. Please do you have any idea what could be wrong? Or what should I check next??

[sargeras611]

Thanks to deadastronaut my problem is solved, it was bad mosfet transistor... I just replaced it and now it's working perfectly, thank you! It's great sounding reverb. Here is photo of my build

[deadastronaut]

Excellent, nice easy fix.....thought it was that.

Nice build man....   enjoy.