cool reverb apart from switch spdt 'pop' issue

[deadastronaut]

Hi guys:  like it says, everything is fine with this reverb..in fact its great....but.....

i added a bright / warm-normal switch, (using middle and outer lugs of an spdt) , and i just can't get the bugger to not 'pop' when switched. (used a 47n/22n as i didn't have 68n )

ive tried all sorts of remedies to no avail....any solutions,  i have it on breadboard so i can try any suggestions!!!.. .  cheers guys.

schematic:



edit:  R.O.tree (mike)  suggested a 1M from VB to the right of the switch caps, ...much much better.!!!!... thanks mike

[PRR]

For one less part, return the bottom of R15 to Vbias.

However a large resistor across the switch is a good general plan when a cap runs from mid-voltage to ground.

[J0K3RX]

Rob,

Looks nice! I always love your schematics... easy to follow! Wouldn't mind doing a reverb...

~ Jim

[midwayfair]

Is this based on the Tenebrion?

[deadastronaut]

@paul:  cheers, i'll give that a go.

@jim : cheers man, yeah its a pretty cool verb...with the feedback control it stretches the time out further than the spec 2.8secs., and the damp is nice too. for more subtlety.

@jon: never heard of that, this was originally the 'box of hall schematic' , but it was way too bright  compared to bypass signal imo, so i tweaked the 'tone' of it,

armndry(larry)  suggested the feedback idea...which is really cool, (R13 sets the max feedback) lower values with self oscillate, but i have it just on the edge of that.

i added the bright/warm  . warm being 'normal tonal unity' , and bright which just lifts it, which is really sweet with my electro acoustic , and nice n plucky on my ibanez rg470. a cool option.

i also added the volume so i can tweak volume of bright/warm, plus i'm pretty much a control freak...well worth a build. sounds great with delays/chorus etc...and nice to have it under foot rather than on an amp.



original 'hijacked' thread..

http://www.diystompboxes.com/smfforum/index.php?topic=93421.msg891944#msg891944

[deadastronaut]

aha...mike (R.O Tree) suggested this, and it works great, totally silent switching.  excellent. cheers mike.

i shall try some other fets too just to try...

revised schematic.



sorted.

[midwayfair]

@jon: never heard of that, this was originally the 'box of hall schematic' , but it was way too bright  compared to bypass signal imo, so i tweaked the 'tone' of it,

Ah, yeah, same thing. "Tenebrion" is CultureJam's improved version (with the feedback loop) that he did with Grindcustoms very recently, basically trying to get higher headroom. Anyway, I had a board for it on the way, and I was looking at extra things to do with it. Your bright/dark switch for the reverb seems like a cool idea.

[deadastronaut]

@jon: gotcha, yeah its pretty cool. when the reverb is dialed all the way off, there is proper 'tonal' unity now.


ive just made a layout with the new schematic , a little messier than i'd like but i'm aiming to get it to fit a 1590b.

[R.G.]

ive just made a layout with the new schematic , a little messier than i'd like but i'm aiming to get it to fit a 1590b.

If you're short on PCB space, Paul's observation that the cap needed to be "pulled down" is one part instead of several.

Your pop was for the same reason that input and output caps without pulldowns pop on effects. The cap gradually leaks down. If you're switching a cap carrying audio signal, you always need to pull both ends to a DC voltage that is not changed by the switch operation. Otherwise, the cap will have to charge, and will then discharge depending on the switch state, and you'll get a pop.

In your case, pulling the switched end of the cap to Vb with a large resistance, maybe a meg or more, would do the trick. So would Paul's trick of pulling the "ground" side to Vb if you also pulled the switched side to Vb.

It lets you use fewer parts. But the JFET switch works too, by making the transition very slow.

[deadastronaut]

cheers R.G.

nice explanation, thanks.

ive managed to squeeze the fet circuit on there, i did try pauls suggestion but there was still a little pop, not as bad but still noticable.

ive been trying this fet switch all day and its fine.

i just need to brush up on my layout skills a little more i think. its like doing 12 crosswords at the same time, but i masochistically enjoy it , strange but true...

[R.G.]

ive managed to squeeze the fet circuit on there, i did try pauls suggestion but there was still a little pop, not as bad but still noticable.

ive been trying this fet switch all day and its fine.

Well, if it ain't broke, don't fix it!   

Great!

[deadastronaut]

 

[deadastronaut]

ok heres a test vid, with normal/bright, electro-acoustic.  (simon&patrick)

reverb full , damp off, just adjusting the length...(feedback)...as per schematic above ok.

[bluebunny]

Very nice, Rob.  Have one of these:

   

So nice, I'm just gonna have to build one.  BTW, which flavour of BTDR-2H did you use - L, M or S?  Or does it even make a difference?

[alparent]

Nice one ....... I need to get me one of those reverbe BTDR-2H and try this.

Now this is funny!

Just yesterday I got an hour lecture on poping in Mark Hammer's office. I just went to get 2 switches and come back with a ton a new knoledge. (and the switches!)

Having Mark as a friend as put my effect building/knoledge on warp speed!

[deadastronaut]

@marc:  i used the ' L'... thanks for the rare sausage pic... i have 2 now. 

@alain:  very cool, my friends just talk bollox mostly...

[slacker]

Sounds great Rob, nice demo.

[deadastronaut]

cheers ian, highly recommend building this one...very useful..

[alparent]

Very nice, Rob.  Have one of these:

   

So nice, I'm just gonna have to build one.  BTW, which flavour of BTDR-2H did you use - L, M or S?  Or does it even make a difference?

I know we already voted against a karma system for this forum.......but what about a sausage system?

[Ark Angel HFB]

ok I want to make this... mind if I give my hand at a Vero of it... or can one of you do that... I'm such a hack. XD