CHASM REVERB

[deadastronaut]

@john:  looks great man, love the led under it too...white on white, classy, 

@mike: good man on helping brother jimi out ,

ive just been too busy to knock up more pcb's...

[Jdansti]

Thanks Marc and Rob!

[remmelt]

Would it be hard to add a BTDR3 instead of the 2? Adds another knob but I can do without the oscillator switch. Or would this not add any real value since the effect is good as is? If so, which BTDR2 is nice? Short, medium or long?

The data sheet for the BTDR3 is pretty similar to the 2
http://www.tubeampdoctor.com/images/File/BTDR-3%20DIGI-LOG%20REVERB%20MODULE.pdf

Or maybe I just need a more simple reverb after all...

[nick d]

         Only a fool or a knave would attempt to build this on perf .

           Clearly , I am both . I have just completed this , and to my complete amazement ,

                IT ACTUALLY WORKED FIRST TIME !!!!!!!!!!!!!!!!!!

            Sounds awesome , thanks Rob !  Well worth the effort - I would recommend it to anyone .
     
             BUT - be sensible - buy a PCB from Rob .

[loylo]

I mentionned on the other "cool reverb apart pop issue" topic that I'll have to test your design, and I did it. It was the right move! 
It sounds lovely.

I hadn't wired the "trail bypass" and the mosfet buffer, because I have other tests in mind (add a kind of slam/hold switch in the feedback loop).
And I don't know if it's because of those changes, but the feedback pot is inactive. Maybe I have to reduce the feedback resistor... As far as I remember, before you have added the fet switching, you had a 33K/22K feedback resistor, hadn't you?

[deadastronaut]

@loylo: yep i think so..i went through so many variations,combinations, its hard to remember now....my brain hurts..i'm still messing with 4 pt's..

@nick; no pics?.

[nick d]

         Here we go -
[/URL][/img]
[/URL]][/img]
[/URL]][/img]
[/URL]][/img]

   Just needs decorating now , but the main thing is it works and works very well ! I've only done a few perf builds ,
    and I've NEVER built anything without a schemo to work from , so I am feeling pretty chuffed with myself !
   
    All credit to you , Rob , a great job !

[deadastronaut]

^ cool, your a brave man doing perf..

[gtangas]

Hi Guys

Need some help. My chasm reverb is given me some troubles!

When the effect is on... UAU!!! Amazing reverb.... but when i disengage it and for a few seconds the chain signal becames distorted.... like overdriven sound... the effect it selfs works lovely and this think started a few days...

i tried to plug guitar>chasm>Amp (maybe another pedal was doing the mess) but same result

any hints?

[deadastronaut]

Hmmm...strange.

not sure what would cause that,

check over your board for values, and orientation etc...

[loylo]

It sounds to be something with the fets (distorting) in the switching. It may be too large value for the caps in the switching circuit (100 µF or higher instead of 10) or whatsoever.

For the dysfunction in the feedback loop of my circuit, it seems to be because of a break within a cable to the feedback pot. It's the first time I encounter this kind of problem, it was pretty hard to find! Now I'll have to try my kind of "slam/hold" swith with a DPDT momentary switch. 

[deadastronaut]

@loylo:  oh man, been there too...my jumper leads are getting tired now ( just bought a fresh set)  but a few in particular were preventing my delay from working,

it took ages to find the culprits..


: yeah makes sense with the switching i guess with ganstas issue..

[gtangas]

i was looking to the diagram and the pf caps that i have on the board are 100pf! but you point to change 10pf to 100pf!
can you point the caps to mess around?

this is my chasm reverb:

the faceplate didnt came out the way it should but i will install a new one (laser engrave)

[loylo]

I was speaking about the caps in the switching part of the circuit, with a value of 10 µF, not pF (the 100 pF are OK).
The switching is essentially the left part of the board on your pic. You should check the value of those components.

[gtangas]

ok i will check it, but i am 99% sure that those are the correct values.

the strange think is that i have the pedal working for a few weeks and this start to happen a few days ago...

[pinkjimiphoton]

next build on my bench. on perf. wish me luck!!!! lol

[loylo]

@loylo:  oh man, been there too...my jumper leads are getting tired now ( just bought a fresh set)  but a few in particular were preventing my delay from working,

it took ages to find the culprits..

Now it works like a chasm... heu like a charm!   
I have to do some fine tunings with the feedback resistor, because with 62K the reverb goes into oscillations with the feedback pot at only 50%.
I have another question about the mix control. With the pot at 0, my sound is not totaly dry (the reverbation is still audible). At the other end, the sound is perfectly dry. Does it act the same with yours, or should I question my pot?

I also wonder if there is a way to reduce the depth of the reverb below the nominal decay of the BTDR. With the feedback pot we can way over the nominal decay to infinite reverb, so It would be interesting to also be able to decrease the decay under 2 seconds...

[deadastronaut]

when mix is at zero fully left...no reverb at all, as it should be.

@1:50

http://www.youtube.com/user/100roberthenry?feature=mhum


as for time 'limiting' i think thats just down to the brick itself not allowing that. 2:85s..

[loylo]

Thanks Rob.
So the culprit may be the mix pot.

I still have to fine tune my "slam/hold" option, but it sounds promising. Hope to tell you more soon. 

[Maik]

Hi Rob,
building it now and I have one question. How can I change the predelay? I want the reverb closer to the signal. More like Holy Grail.
But anyway it sounds cool!