cool reverb apart from switch spdt 'pop' issue

[deadastronaut]

@sam : not bothered either..


righto..

re breadboarded , node by node checked off on printout....all working yay!.

sw2 still pops though,  i'm getting 0.35v on right side on R22, which i  swapped  to 47k,

which now means the levels of TB and fully CCW Dry and also sw2 bypass are much better vol unity yay!......and stil have plenty of vol adjustment for reverb when fully wet too...yay again!

so were getting there, but sw2 still pops..


btw thanks merlin, its a much tidier and smaller footprint than i could have come up with..very cool. ...even smaller than my original,  sounds great

[deadastronaut]

Comments:

Try taking the feedback loop from the output of the IC2d (<edited for new schemo)  output cap (10u) rather than after the mix pot. This way, you will probably get more usable feedback/oscillation when the mix is relatively dry.

i'll try that, thanks sam..

could sw2 be swapped for the fet switch?.

[merlinb]

 i'm getting 0.35v on right side on R22, which i  swapped  to 47k,

Dinfinitely something not right. You sure you haven't got the inputs of one of the opamps accidentally swapped?

A leaky cap could also cause the DC on the switch, but I still suspect a wiring error.

[deadastronaut]

checked  all opamp connections fine..

from pin 1=4.57v  

into 10uf > negative side =0.07v

47k (R22) right side 0.00

1k (R21) right side 0.07v

right side of R12 =0.26v

right side of R19 =0.07

i'll swap my jumpers...they might be suspect.

it changes with sw2 position..

reverb on 0.07

middle 0.27

bypass 0.01

(haven't got a spdt at the mo , using half a  dpdt)

[Jdansti]

>@john:  switch is for tails and boss style...

[deadastronaut]

Comments:

Try taking the feedback loop from the output of the IC2d (<edited for new schemo)  output cap (10u) rather than after the mix pot. This way, you will probably get more usable feedback/oscillation when the mix is relatively dry.

sam, just messed with this...but not sure if i had it right, ...do you mean move the connection that goes from feedback pot 3 to the mix pot 2 , to the - 10uf?.. if so what happens to mix pot 2 ?.

the way i tried it was just wet with mass oscillation..

note: as per schemo i'm  getting oscillation when fully wet only...thats why i thought i'd try this.

:still getting pop.. ..tried a fet switch, but still lets verb through.

[samhay]

After the 10u output cap, split the signal so that it goes to both the mix pot and the feedback pot.
Mix pot 2 would now only go to the volume pot.

Realised last night that you can do an indicator LED with a Millenium bypass, so there should be no need for a FETswitch. Your pop is still a worry though.

[deadastronaut]

aha, thats better,

much better control over the feedback..

however were back to that old chestnut of tails dying off too quickly in sw2 bypass 

and dry is not fully dry now..when fully CCW

[samhay]

^much better control over the feedback..
That's what I was expecting

^however were back to that old chestnut of tails dying off too quickly in sw2 bypass
I can sort of see how that might happen

^and dry is not fully dry now..when fully CCW
That has me scoobied. Any chance you could post a latest schematic?

[deadastronaut]

yep, sure..

the sw2 definately pops whatever i do, breadboard this very carefully more than several times, but no joy...

[samhay]

^the sw2 definately pops whatever i do
have you tried large (e.g. 1M) pull-down resistors from SW2 lugs 2 and 3 to ground?

It's not obvious why you shouldn't get fully dry signal with the circuit as drawn, but then I'm probably missing something.

Other observations:
You probably don't need R11.
It looks like your dry signal in tails should be significantly below unity gain (22/57), but I'm guessign that is not the case?

[deadastronaut]

tried the 1M resistors to ground...no joy, still pops like a mutha..

if i remove R11 / 33k from vb, i lose all verb..

unity is pretty good,TB/SW2 bypass/dry (there is just a tad of verb when 'dry')  etc... fair bit of tonal difference , but that can be tweaked to taste later on..

think i may have to go with the 'reverb level' original pot from pin 13 after R8...vb etc...see if that helps with the pop issue as it wont be looping back to the sw2.
just thinking aloud....and go back to the wet/dry to pin12..hmmm...

as this had no pop issues a all..the sound clip was recorded in one hit while switching...so that loopback from mix to sw2 is the culprit ...i think.
http://www.diystompboxes.com/smfforum/index.php?topic=101126.msg941919#msg941919

[samhay]

^if i remove R11 / 33k from vb, i lose all verb..
That I don't understand either. At the moment, IC2d is just an inverting amp, just like IC2b and IC3b, so shouldn't need a bias restor to (+) input to function.

^unity is pretty good,TB/SW2 bypass/dry
As drawn, TB should be about twice as loud as SW2 bypass. Is R22 really 47k?

[deadastronaut]

unity: yeah sorry that is back to 10k... (didn't have my DI box plugged in to mixer.was messing around last night etc...) better now.

hmmm yep if i take that R11 out defo get no verb..


out of curiosity i went back to the original switching with the 2x1k's/2x47k's...and it is dead silent...no pop at all even with mixer maxed out...

[deadastronaut]

BINGO!!!!... DEAD SILENT SWITCHING..AT @#$%ING LAST!!!!!!!!...

the culprit was the 10uf after R12,  replaced that with 1uf np, and now its totally silent even with mixer full up..yay!!!

and as a bonus the feedback/decay is bang on too....

man, there was more than a few times that my breadboard was going out the window with this bugger.....but am glad i stuck with it.

as we cured one issue another rose its ugly head etc...phewwwwwwwwww....that was the longest headache ever...for a few of us too.

now to have a little tweak here n there and add the hi/lo switch back in.


that 33k (R11) definately has to be there btw.

tweak..tweak... ..going to try out a tone control instead of damp too.

man, i'm having a fireworks night beer or 2 tonight to celebrate...hic!

[Valoosj]

Great! I'm ordering parts ...

[alanp]

Kick-ass, once you post a final schematic I might work on a layout in eagle if that's OK...

[samhay]

nice one Rob.

[therealfindo]

Nice one!
Might have to build another DA reverb now...

[BuGG]

Excellent news!   Can't wait to build this one!