Blend knob between two pedals?

Started by ISuckAtPedals, March 01, 2018, 04:40:43 PM

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ISuckAtPedals

I have an mxr distortion + and a fuzz pedal i built and i want to add a blend knob between them so i can choose to have more fuzz pedal or more distortion. I read about something called a buffered blend but not sure if that will give me what i need.

Also is there a circuit that will even outputs of pedals, my mxr is way louder than my fuzz and that may be a problem when blending. Thanks if anyone can help!

vigilante397

100k linear pot is a safe bet.

Put the pot between the two, Dist+ on lug 1 and fuzz on lug 3 (or vice versa, doesn't matter), and the wiper (lug 2) becomes your blended output. Obviously if the fuzz is quieter than the distortion you may have to crank the fuzz up or turn the distortion down in order to get 12 o'clock to be a balanced blend, but frankly that isn't even that important and you can still blend them anyway.

Hope this helps ;D
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ISuckAtPedals

That's exactly what i was thinking. Would a compressor circuit bring the two to even levels?

patrick398

Quote from: ISuckAtPedals on March 01, 2018, 04:53:15 PM
Would a compressor circuit bring the two to even levels?

Just use the volume knobs no? That's what they're there for.

If you want to use both pedal individually as well as a blended version of both i guess you wouldn't want to readjust the volume levels every time.
My first thought would just be adding a resistor after the mxr, before lug 1 on the pot. That way you could set both pedals where you like them volume wise individually, and then play around with resistor values to get them at the same volume going into the 100k pot, then you'd have an 50/50 blend...I'm thinking out loud here, beware of idiocy.

vigilante397

Quote from: ISuckAtPedals on March 01, 2018, 04:53:15 PM
Would a compressor circuit bring the two to even levels?

Depends, where are you planning on putting it? If you're counting on running the blend into the compressor, then no, it would be too late. If you put it after the MXR and before the blend, then yes you could compress the signal to a lower level if that's how you wanted to do it. If you put it after the fuzz before the blend you would basically be using it as a clean boost to bring it up to the MXR level.

Quote from: patrick398 on March 01, 2018, 05:04:35 PM
Just use the volume knobs no? That's what they're there for.

Definitely this. The MXR's volume knob is at the very end of the circuit, so turning it down is not going to affect the tone of the circuit. Putting a resistor between the MXR and the blend would achieve the exact same thing as turning the thing down, so just turn it down.

As a calibration, turn the fuzz up as loud as you want, then set the blend for 12 o'clock and turn the MXR's volume down until they are at the same level.
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ISuckAtPedals

I think ill try the resistor first, i built the mxr + from the schematic and its extremely loud so i wouldnt mind lowering it. My volume knob isnt working but its probably a bad pot. Thanks guys!

mth5044

Beware: your signals may be out of phase.

patrick398

Quote from: ISuckAtPedals on March 01, 2018, 07:47:19 PM
I think ill try the resistor first, i built the mxr + from the schematic and its extremely loud so i wouldnt mind lowering it. My volume knob isnt working but its probably a bad pot. Thanks guys!

That's really only necessary if you do want to use both pedals independently as well as blended version of both. I'd get the volume pot working first, if it's insanely loud you're going to want to be able to turn it down at some point anyway

antonis

I can't figure out how an MXR Dist + can sound louder than your custom-made Fuzz..
(unless your Fuzz has a pair of clipping diodes right before output of lower forward voltage drop, e.g. Ge diodes..)

What I'm saying is, for a signal (A) to sound louder than another signal (B), A's voltage must be higher than B's one..
(higher actually by an amount of 30% - due to humar ear "imperfection"..)

That given, your Fuzz should someway clip at about 500mV or your MXR doesn't clip (maybe due to open diode(s))
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

duck_arse

if both circuits have a volume pot on their output, why not just tie a resistor to each wiper, connect the free end - bosh, done. use the volume of each to set the - erm - volume - of - erm - each in the mix. you can even go mad with switch options between the pot wipers and mix resistors to kill one or the other effect from the output.

but as patrick says,
Quotebeware of idiocy.
You hold the small basket while I strain the gnat.

sixthfloor

If you don't mind building a pedal for blending your pedals, the Runoffgroove splitter-blend would do the job perfectly. It even takes phase inversion into account.

www.runoffgroove.com/splitter-blend.html

vigilante397

Quote from: ISuckAtPedals on March 01, 2018, 07:47:19 PM
its extremely loud so i wouldnt mind lowering it. My volume knob isnt working

You failed to mention that initially. Replace that pot. If you can't control the volume of the pedal that means it's probably on full-blast all the time.
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Elijah-Baley

Quote from: sixthfloor on March 02, 2018, 11:07:35 AM
If you don't mind building a pedal for blending your pedals, the Runoffgroove splitter-blend would do the job perfectly. It even takes phase inversion into account.

www.runoffgroove.com/splitter-blend.html

It's exactly what I'm gonna build, I got the component but I need the protoboard. :(
Do someone say something about the performance of that circuit?
Thanks! ;)
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sixthfloor

Quote from: Elijah-Baley on March 03, 2018, 04:44:41 AM
It's exactly what I'm gonna build, I got the component but I need the protoboard. :(
Do someone say something about the performance of that circuit?
Thanks! ;)

Well, I've built one some time ago and it works well, there is no noticeable noise  :icon_wink:

Elijah-Baley

«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

Danich_ivanov

A slightly more complex way to do this can be by building 2 jfet buffers, and connecting each output to the lugs 1 and 3 on the pot, pot can be anywhere from 100k to 1meg, and standard volume pot after lug 2. You could also adapt phase switch after each stage, by having equal resistors for emitter and collector, and switching between output from either one or the other.

antonis

#16
Quote from: Danich_ivanov on March 05, 2018, 11:19:52 AM
You could also adapt phase switch after each stage, by having equal resistors for emitter and collector, and switching between output from either one or the other.
It maybe have to be taken into account the significant difference of output impedances between Emitter/Source follower & Phase shifter modes for "equal" blend..  :icon_wink:
(first output impedance is roughly re (negleting Rbias & Rsource) or 1/gm where second is Collector/Drain resistor (negleting Rload..)
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..