Bass Dist: Blending circuit help needed

[strungout]

Oi all!

I recently breadboarded a Rat (and a Tube Screamer) with a dry/wet blend knob so I can add some bottom. It works! My friend was happy with it when I had him try it, but after doing the TS9, I'm not sure I did it the right way. In fact I'm sure it can be done better.

I'm using this simple circuit: https://www.circuitlab.com/circuit/zpw254/minimal-op-amp-blender/

The problem is the balance between the two output. The Rat has a huge output but the dry circuit doesn't, so I have to mess with the volume on the pedal or even on the amp every time I mess with the blend knob. I did find some stuff like this here Split 'n' Blend: http://effectslayouts.blogspot.ca/2015/12/split-n-blend.html#comment-form
Haven't boarded it yet, out of 2.2M resistors.

Has anyone tried something like this and if so, which blend circuit did you go with?

Thanks.

[PBE6]

It sounds like you want something that can add clean signal while keeping the effected signal output constant. In that case, a panning scheme isn't going to fix the problem. An active mixer would though.

Here's an article on signal mixing and an example mixer schematic from Elliott Sound Products: http://sound.westhost.com/articles/audio-mixing.htm#s3

An internal circuit would probably be easiest, especially if you're building it from scratch, but an external circuit based on the same design would work too. Just be careful with the source signal polarities/phases so you don't end up cutting clean signal by mistake.






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[strungout]

Thanks PBE6, I'll go have a read!

I am building from scratch, so it'll be easier to fit the extra circuitry. And more fun!

[slacker]

Another approach would be to use a booster for the clean signal instead of a buffer,  then you can better balance the levels of the clean and effected signals.

[strungout]

Thanks slacker, problem solved!

I tried the simplest solution first: a booster (Shaka Boost http://diystompboxes.com/pedals/schems/shakaboost.jpg ) and it works like well with the Tube Screamer. Might lower the gain on the booster a little. Now, I just have to rebuild the Rat. Probably won't need to have lowered gain for that one. It'll be more balanced.

Thanks again both of you.

EDIT: Forgot to add that there is however a bit of a drop in volume overall... What might this be due to?

[antonis]

Forgot to add that there is however a bit of a drop in volume overall... What might this be due to?

Maybe because you have 2 shunt resistors in parallel on the output..
(100k of Shakaboost & 100k of TS9..)

[strungout]

Forgot to add that there is however a bit of a drop in volume overall... What might this be due to?

Maybe because you have 2 shunt resistors in parallel on the output..
(100k of Shakaboost & 100k of TS9..)

Hey, sorry, I was away on a fishing trip!

Just got back. I tried removing each 100k res but it didn't affect the output or not enough to make a difference to my ear.

[strungout]

Feel kinda dumb but I think the wolume drop came from the shaka side 'gain' not being turned all the way up. Sounds fine with the TS9 now. We'll see about the Rat...