cool reverb apart from switch spdt 'pop' issue

[deadastronaut]

hi ian..

yes source towards the 22n..

i just tried various resistors (using my sub box ) from source to vb..no change.

i tried 100k from source,+  100k from drain to vb no change..

tried 2.2k's also...no change.

strange..


i stuck a 22k from source to vb..

now i have

D 4.55
G 0.68
S 4.55

[slacker]

Just to make sure we're not trying to fix a problem that doesn't exist, are you still using the same feedback set up as before? The Fet switch will not fix that you'll still get reverb when in bypass same as you did with my resistor solution. Any testing you're doing should be with feedback turned all the way down or with the feedback path broken some where.

[deadastronaut]

hi ian.. i'm still using this schematic,

http://www.diystompboxes.com/smfforum/index.php?topic=101126.msg938023#msg938023

but with he fet switch...

i just tried the fet switch with 'feedback'' turned fully down and the switch works...no reverb, and on there is reverb..

so were getting there i guess..

[slacker]

Cool.

[samhay]

OK, so if the FET switch works and tails works if feedback is off, then another FET switch shunting the feedback to ground/Vref aught to fix that...

[deadastronaut]

Erm ok....got a diagram ?..

[samhay]

Actually, I was think the wrong way round. It might be even easier - just put another switch (you don't need the LED) in series with the 33k resistor in the feedback loop. When off, the resistance will be large enough that the gain will be ~0.
The beauty of the FET switches is that you can tie the switch end of the 1k gate resistors together, so it only takes 1 pole on the footswitch.

I probably haven't quite painted 1000 words, but do you still need a schem?

[deadastronaut]

Yes please...cant quite see what you mean...cheers Sam .

[samhay]

I think this is worth a try:



You can then use the switching option I posted a few pages back - worth testing on the breadboard though.

[deadastronaut]

Brilliant, cheers Sam .

ill try it out, and ammend the schemo,

with fthe switching and wet/dry mod...nice one. 

[deadastronaut]

just about to try the other fet switch...

heres a clip of the wet/dry mod , fully wet, then half, then off, ....then fully wet again....love it. (10k pot)

https://dl.dropboxusercontent.com/u/7464107/reverbwet.mp3


using 33k( R13)  for feedback...i found oscillation will begin around 27K...22K can get a little bit much imo.

[deadastronaut]

ok, tried the other fet switch..

it works, and now i can turn up the feedback pot, then switch to dry...

however the feedback (decay)  is  considerably cut short....

[samhay]

The new clip sounds grand, and similar to what I am getting. I dig the chord progression too. Is your wet mod the pot that you had in an earlier design?

^however the feedback (decay)  is  considerably cut short....

Do you mean the tails are not as pronounced when you hit tails bypass?

[deadastronaut]

The new clip sounds grand, and similar to what I am getting. I dig the chord progression too. Is your wet mod the pot that you had in an earlier design?

^however the feedback (decay)  is  considerably cut short....

Do you mean the tails are not as pronounced when you hit tails bypass?

yeah the tails are not as lengthy when i hit tails...even fully up..

(i'll adjust my schemo in a bit, to show the wet/dry and fets....)the wet/dry was on R O tree's schemo a few pages back.

[deadastronaut]

heres the updated schematic...as i have it on breadboard now.

wet/dry is a 10k pot

[samhay]

Right - so at the moment, the 2nd FET switch is killing the feedback once you hit bypass. The feedback pot is out of the circuit at this stage, so shouldn't do anything in bypass and the only tails you hear is from whatever is rattling around in the brick.
If you want your tails to also include feedback, then you need to kill the dry signal in the feedback loop. As the feedback is taken from the output of the second op-amp, this will require some faily life-changing surgery.
If you are happy with having wet-only feedback when 'on', then it gets a little easier:



Edit - schematic updated to remove 2nd FET switch

[deadastronaut]

''life-changing surgery.'' 


lol, well to have tails at whatever setting i guess life changing is the only way to go...seeing as i have it on breadboard anyway....i'm up for it if it solves the issues..

i'll have to attach another breadboard though as i'm running out of space..

[samhay]

One other thing -  the 2nd FET switch becomes redundant at this stage and you don't want to switch it off in bypass.

[deadastronaut]

just a quick example of the 'tails' i have at the mo..

first clip...natural decay...1 2 3 4....decay................

second hit tails switch on ..1 2 3  (switched on 4)...

just to show how it cuts the decay.

https://dl.dropboxusercontent.com/u/7464107/TAILSTEST.mp3

[deadastronaut]

i was just having a nose about at ians echobase 'tails ' etc..

a guy here has a tails/feed/flashback mod without a 4066 etc...could this be applied to the reverb ...what do you think?..

http://www.diystompboxes.com/smfforum/index.php?topic=60662.msg791797#msg791797