cool reverb apart from switch spdt 'pop' issue

[deadastronaut]

yeah i think so, its not a patch on when it was inverted.. mad eh!..

[samhay]

(+) inputs are (very) high impedance.
(-) inputs are very low impedance.
It makes a difference.

[deadastronaut]

just a mad idea..

put it back to where it worked really well, with the loop etc.. (which it looks like i'll have to anyway)

and whack a phase invert switch on the out?..

[samhay]

Or just make the input op-amp inverting

[deadastronaut]

erm.....so would the out be non invert then..?

edit:

oh, sod it, think i'll just go with the inverted + loop as that was the most promising result with plenty of decay, and good levels and nicely tailed...with on/bypassed too, sounded lovely...

besides, if inverted is good enough for ian's excellent echo base its good enough for me too.

i'll re- breadboard it that way, and go from that standpoint......

[slacker]

erm.....so would the out be non invert then..?

No, input and output both inverted, so dry signal gets inverted then get re-invereted by the output so it come out the right way up, like maths a minus times a minus equals a plus.

Or like you said just sod it and let people who want to do fancy pants parallel effecting take care of any issues them selves  

[merlinb]

The schematic is fine- it has clearly been constructed incorrectly. Endless modification are a waste of time until you fix the wiring errors on your breadboard. Keep calm, and don't be hasty about it. You will be surprised how many you find.

[deadastronaut]

@ian, right, ok, so....now i'm really lost..

@merlin: hi, yep i know what you mean, i have had the odd face palmy moments with this , however,  believe me ive checked the last schemo/breadboard over and over...node by node with a pen and printout.

the various experiments and ideas we have tried other than the 'inverted+loop schemo' have had a  drastic effect on the brick reverb feedback/decay and behaves quite unusable, to me anyway...

(unusable meaning no point in tails at all really when the decay/feedback dies off to quick etc). ...it just becomes a very different, and too subtle effect compared ...

[slacker]

@ian, right, ok, so....now i'm really lost..

See my post number 537 from the other day.

[deadastronaut]

ok, cheers man, i must 've missed that..

so similar to this then?.

[merlinb]

believe me ive checked the last schemo/breadboard over and over...node by node with a pen and printout.

And yet, errors remain. It happens to all of us. Check again. And again.

so similar to this then?.

Yuk. Build that if you want a white noise machine.

Suggestion: (Bright switch could be implemented around IC2. Heck, since this version eliminates one pot, you could have a tone pot instead)

[deadastronaut]

well that looks different..  

cheers merlin, i'll give that a go on breadboard ( and i will make sure i  triple check ok.  

thanks man Rob.

edit:

ok, i have merlins  working on breadboard, and it works, yay!..but there are some issues , here are my findings.

: completely bypassed (breadboard 3pdt off ) =  true bypassed normal level . ( 3pdt pops like hell even with 2.2M pulldown added though) where it was absolutely silent before)

: breadboard 3pdt on, with circuit sw2 in bypass = vol halved, (vol pot will not adjust level)

:breadboard 3pdt on, sw2  reverb on = dry/wet acts as a reverb level , CCW is dry however, when dry that vol level is still half of TB. ( vol pot will not adjust level)
and when sw2 is switched to turn reverb on, but still dry, the level is higher than sw2 in bypass.

:when dry/wet is turned CW it is fully wet, but much quieter than dry ( vol control works on this but even at max its still quieter)

: feedback/decay is great...it even oscillates with just the 33k....but only when near or fully wet, it will not oscillate halfway etc..

:damp=fine..

[Jdansti]

How does it work without the 3PDT?

BTW, do you need a bypass switch for a reverb?  What happens if you omit the switch and just turn the mix or feedback pot CCW to eliminate the reverb?  I'm doing this on the Solstice and it works great.

[slacker]

: completely bypassed (breadboard 3pdt off ) =  true bypassed normal level . ( 3pdt pops like hell even with 2.2M pulldown added though) where it was absolutely silent before)

No reason it should pop any more than what you had before.

: breadboard 3pdt on, with circuit sw2 in bypass = vol halved, (vol pot will not adjust level)

The volume in bypass should be the same as true bypassed. If it's not you've either done something wrong or there's some flaw in Merlin's plan that I'm not seeing.
Volume pot will not adjust bypass level it only contols the effected signal.
The fact you say the volume doesn't affect the level of the effected signal in some cases sounds like a wiring error the volume pot should be able to turn the effected volume completely off in any setting of the other controls.

[merlinb]

( 3pdt pops like hell even with 2.2M pulldown added though) where it was absolutely silent before)

Have you included pull-down resistors at the input and output?

[samhay]

Merlin's suggestion is quite similar in topology to my design. Personally, I like the idea of a single mix pot rather than separate wet/dry and reverb pots too.

Comments:
Merlin's design is inverting too.
In bypass (sw 2 'down') the volume pot should not do anything. If you want it to, then move it back to the output.
Try taking the feedback loop from the output of the IC2c 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.

[deadastronaut]

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

@merlin, i have a 2.2M on in, 1M on out now, better, but still a little pop......however the sw2 pops like hell.

@ian:  i'll check it over,

@sam: so were still inverted then?.

the reason i want a ''reverb level'' pot is that on certain settings, e.g.  fully wet i want to be able to boost that a little to bring it up to bypass levels. (i do a lot of ambient music)

as certain settings can make it 'seem' a lot lower in vol...(as you'll hear in the clip)

here s a clip of what i have now..one take.

clip order:  true bypass/ then TB on sw2 off/ then sw2  on with wet fully CCW...Then turning wet/dry CW.../ then back to SW2 off / then true bypass again..
https://dl.dropboxusercontent.com/u/7464107/merlreverbtest1.mp3

i'll check this over in the cold light of day...make sure i have it right first, and redraw it so i can tweak.

[merlinb]

however the sw2 pops like hell.

Measure the voltage on all the poles of the switch- they should be zero. If not then you have a cap missing, or something miswired.

the reason i want a ''reverb level'' pot is that on certain settings, e.g.  fully wet i want to be able to boost that a little to bring it up to bypass levels.

You can acheive the same result by turning the mix control to 100% wet, then turning up the volume pot to give the desired boost (if it doesn't have enough boost then you just need to reduce the resistor connected to its wiper a bit, to increase the available gain).

[deadastronaut]

cheers merlin, yeah i have 0.28 on one of the poles..so something is up..

ive redrawn your schemo, so i can tinker...

i'll go over this node by node with printout paper n pen, oldschool style 

[samhay]

@sam: so were still inverted then?.
yes - IC3a in non-inverting and IC3b is inverting.

Does it bother me.
no