Below is a schematic for a blender. It is used to blend the dry signal
from an instrument with the wet signal from an effect (or an
effect chain). It has lots of uses:
- to mix in some bass so that guitar oriented pedals
- as a buffer for true-bypass effects
- for developing effects
- with the gain mod it can be a clean boost
- Almost any opamp will work.
- If too much signal is pushed through the opamps they will
start to distort. For added headroom the blender can be run off
12V or 18V. Just make sure that caps are rated high enough.
- The 1M resistors basically set the input
impedance. Depending on the opamp, you can use almost anything
from 470k to 10M.
- All the .1uf caps can be replaced with a cap from .01uf up
with no loss of bass.
- The 10uf caps are probably overkill also. But I buy them in
bulk and they are very cheap.
- If the send and return jacks have a no connection terminal,
they can be connected togeather.
- The only opamp that is absolutely required is OPa to prevent
- Here is a minimal FET blender.
There are about 867 mods that can be done to this pedal to make it
more versatile. Here are some I have tested.
- Gain mod adds a gain
to the dry signal. As shown you get a gain of about 5. Replace
the 2.2k resistor with 1k to get a gain of 10. This is a boost
only, you cannot attenuate the signal.
- Volume mod adds an
attenuator to allow the output volume to be reduced.
- An untested mod would be to add a filter ala the Bass
Paralooper (see links below).
gaussmarkov at the diystompboxes forum did a
perfboard layout. Information is at his
page. Here is a link to the thread
that also has a picture of the final perfboard. Very nice job!
Jari Oinonen sent me a nice email with
a compact PCB layout as a PDF file and BOM.
- Paralooper at Moosapotamus. Another bass blender.
at Runoffgroove. This is for blending two effects chains, but
would be easy to mod as a dry/wet blend. Just use jacks with a
NC for one or both of the chains.
- You can google Buff 'N Blend by Joel Purkiss. Very cool
single transistor circuit. Unfortunately his site is gone and he
specifically disallowed posting on other sites.
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