Dry and wet knobs combined into one mix knob

[acehobojoe]

Does anyone have a schematic for this? I want to use it specifically for my pt2399 delay. I know I can just 100k them together, but how would I allow for a mix control: all the way down, completely dry, all the way up, completely wet. Thanks in advance.

[samhay]

The details matter. What's 'your' delay?

[merlinb]

You mean like the output blend pot in this schem? Assuming you have two low-impedance sources like opamp outputs, then this is the simplest way to do it.

[acehobojoe]

I'll give that one a try. Thanks.. here is my schematic if your interested. There is one error on R13, but you'll get the idea.

http://i.imgur.com/EOUSEzM.png

[samhay]

I assume the error is that you feed the output op-amp at the junction of R15 and R16?

Anyway, this is how I implemented a mix knob in something similar: www.diystompboxes.com/smfforum/index.php?topic=107226.msg973273

Essentially, you remove the wet mix and take the feed from this directly to lug 3 of your dry mix control, which no longer goes to ground.

[acehobojoe]

I'm going to PM you a pic of the final.

[GGBB]

As an alternative that is probably much simpler - use a dual 100k/100k pot and wire the dry side backwards.

[acehobojoe]

ok... explain what goes on what. I'm guessing you mean the dry one is completely reversed?

[acehobojoe]

I just connected it there to pin 1? will that work? seems too easy.

http://i.imgur.com/g65szvH.png?1

[samhay]

As long as the impedance of both the wet and dry signal feeding the mix pot are fairly low (relative to the pot) and of similar values then, yes that should work.

[acehobojoe]

ok, then how about this.. I want a tape sat sound, so I was thinking of just running the signal in to this thing. http://www.astersart.net/preamp/simulators/tapesat2.gif

theoretically, the signal will not go into it if the pot has a high enough resistance, right? then it will blend in at the end if I connect it back in. maybe separate them with a diode.

[GGBB]

I just connected it there to pin 1? will that work? seems too easy.

http://i.imgur.com/g65szvH.png?1

There is no change to the schematic.  Instead of using two separate 100k pots, you use one dual 100k pot or 100k blend pot.  For the dry side, swap pins 1 and 3.  Then you have one knob controlling both pots - counter-clockwise turns dry up and wet down, clockwise turns wet up and dry down.

[acehobojoe]

gotcha, then they just blend. makes sense.