cool reverb apart from switch spdt 'pop' issue

[deadastronaut]

vol ..is for overall volume..

level is the amount of reverb

decay=feedback.

hi/lo=  hi, a little brighter for my acoustic , / lo=normal.

yes i do care that its inverting.. , ian mentioned that earlier..

clip of TB and tails..
https://dl.dropboxusercontent.com/u/7464107/TB%20and%20tails.mp3

tb first, then tails/bypass..

[samhay]

Also, you can't have tails and true bypass, so I'm not sure what your intension is here...

IC2d needs a resistor from the non-inverting input to Vb. Actually it was better before, where the wet/dry pot was returned to Vb. Not sure why you changed that, because now it will make scratchy sounds..

I think the overal goal is to have a switchable tails option - stomp switch selects on/off and tails toggle switch selects true bypass or tails. This is quite do-able in the current schem with a 3PDT footswitch, but may make having an indicator LED a bit more challenging.

I think there is a case of too many cooks at the moment - The wet/dry pot is AC coupled and will be pulled to ground when the bypass switch is engaged. That's why I suggested it be tied to ground.

[merlinb]

vol ..is for overall volume..

level is the amount of reverb

If you did the mix control differently then you could get rid of the 'level' control. You would just turn the mix to 100% wet (if that's what you wanted) and then adjust the volume to suit.

yes i do care that its inverting.. , ian mentioned that earlier..

Ok, but the circuit you have now is inverting...

[merlinb]

I think the overal goal is to have a switchable tails option - stomp switch selects on/off and tails toggle switch selects true bypass or tails.

If you have a true bypass option, why would you want the tails to be switchable too?  Surely the only two options you need are:

1: True bypass
2: Not true bypass (i.e. tails).

What is the point of having the third option "not true bypass and no tails"?

I think there is a case of too many cooks at the moment - The wet/dry pot is AC coupled and will be pulled to ground when the bypass switch is engaged. That's why I suggested it be tied to ground.

Yes, the pot should go to ground as it is. Only R11 is needed.

Or get rid of R11, move C20 to between R24 and R19, and return the pot to Vb.

[samhay]

You want to have 1 of 3 options:
True bypass
Buffered bypass with tails
On

The toggle switch selects between true and tail bypass, the stomp between on and bypass.

[deadastronaut]

schemo above updated...

clip of TB, then tails/bypass..
https://dl.dropboxusercontent.com/u/7464107/TB%20and%20tails.mp3

[merlinb]

You want to have 1 of 3 options:
True bypass
Buffered bypass with tails
On
The toggle switch selects between true and tail bypass, the stomp between on and bypass.

OK I get that (I didn't consider "on" to be an option  ). But I don't see how the current schematic acheives it. The footswitch (which is part of another unit and not on this schematic, right?) is always true bypass, or on. What am I missing?

[samhay]

Something like this maybe: http://www.diystompboxes.com/smfforum/index.php?topic=101126.msg938146#msg938146
But with the middle lug of the 3rd row of the footswitch going to ground and the top and bottom lugs to the two resitor dividers in the bottom of Rob's schem.
Not much room for an LED left though.

Rob did you have other ideas?

[deadastronaut]

leds: i was pondering that i could use half a dpdt for the tails switching, and other half for leds. red on/green off.

and make that dpdt footswitch too.

and have a 3pdt with led as per normal tb. as i have it now.

like this:



?..how do we make this schemo non inverting then?...and what will be the advantage of doing so?

[BuGG]

I think you'll need to use the 2nd half of the tails switch to "bypass" the 3PDT when the pedal is off in tails mode, correct?

Since tails mode overrides the truebypass nature of the 3PDT, you'll want the Tails switch to maintain a connection between the output of the PCB -> output jack.

Otherwise true-bypass is going to kill your tails.

[BuGG]

..

[deadastronaut]

okey dokey..cheers bugg.

how do we make this schemo non inverting then?...

and what will be the advantage of doing so?

[scuzzphut]

Rob - you could also look at a bi-colour LED for your switch ,

http://spiratronics.com/optoelectronics/leds/multi-colour-leds/bi-colour-3mm-leds.html

[deadastronaut]

cheers mark, yeah i have some of those..

[deadastronaut]

well, seeing as its going to be a stormy day here..

i thought i'd get on this again...even though your all probably sick of it/me, and my dumbass ?'s...and i don't blame you

but when its eventually sorted, i reckon it'll be on your board for a very long time...i know mine will. thats why i'm persevering with it.

so...will just swapping the inputs to + like this make this a non inverting effect?..or is there more to it?..will this be ok?

[samhay]

You need to swap the inputs of IC3b. The overall volume now won't work, so you will need to move this to after the output cap.
R23 and R25 are obsolete. Not sure how well the switching will work - you may need to up R21, but this will then affect the gain of the dry signal into IC2c and also the wet/dry pot, so you may have to do quite a bit of tweaking.

[deadastronaut]

Cheers sam, so like this...and tweak R21.

[slacker]

so...will just swapping the inputs to + like this make this a non inverting effect?..or is there more to it?..will this be ok?

No that won't work, assuming you mean IC2c, the effected signal is fine it's the dry and bypass signals that get inverted. The bypass signal goes through IC3a non inverting then IC3b inverting do comes out inverted. The dry signal goes through IC3a and IC2d both non inverting then through IC3b inverting so comes out inverted.
The easiest way to fix it is to make IC3a into an inverting buffer, then the signals get inverted twice so come out non inverted, so + input to VB signal in through a cap and then a 1 Meg resistor into the - input and a 1Meg resistor from out to - input. Same as the input buffer here http://www.aronnelson.com/gallery/main.php/v/slackers-stuff/album170/echobase.png.html.
This can be noisy though due to the high resistor values needed to keep the impedance high so instead you could chuck a fet buffer in front of it, to provide a high input impedance and then use smaller resistor values in place of the 1 Megs.

EDIT: started writing this before the last two replies.

[samhay]

I was just going to chip in with slacker's idea of making the input buffer inverting. If this is not going to be at the front of your pedal chain, then you could get away with a moderate input impedance to keep the noise down.

As far as the current schem goes:
You need to make IC3b into a buffer like 1C3a (it's a comparator at the moment), so short the (-) input to the output, remove the Vb connection to the (-) input, and bias up the (+) input with e.g. a 1M to Vb.
Sorry, I meant to remove R24, not R25 (which I think will help, but may want to be the same value as R22).
If it works, then great, but if not, it might be a bit of a faff to get it to play nice.

Do you really care if the effect is inverting?

[deadastronaut]

''Do you really care if the effect is inverting?''

not particularly, but ian and merlin mentioned it earlier..so i presume this may be a bad thing.

what would be the benefit/possible pitfalls of it being inverting, compared to non-inverting then?.

is it a phase invert issue?..(recording etc)

anyway...does this look ok now?.