Blend clean and effect signals

[Gabriel Simoes]

Hello..
I'm trying to mod some effect schematics for using them with bass guitar, but in my mind the best way for doing this without loosing low frequency response is to apply the effect to the signal after a high pass filter and then blending it with the clean signal from the bass ...
I don't know if I will face some phase problems, has anybody done this before ??/
Thanks for your attention and help, and sorry for my bad english,
Gabriel

[B Tremblay]

This should be marked as a FAQ at some point.

The Bass Paralooper was specifically developed for blending a clean bass signal with an effected signal.

http://moosapotamus.com/paraloop/paraloop.htm

The Splitter-Blend was developed for blending the contents of two effect loops.  It incorporates RG Keen's Polarity Reverser circuit for phase matching of the loops.

http://runoffgroove.com/splitter-blend.html

[Gabriel Simoes]

Correct if I'm wrong but both projects use a buffer so adjust the phase of the 2 signals ... so the output is always a low impedance signal , so a true bypass would not be allowed in this sistem ... right ?

What would be the problems of just running the dry and effect in paralel and then adding em together phase inversion the only way of adding 2 signals would be doing this ?
I know the question is like ... crap since this would be mad to add a low impedance and a high impedance signal , and since bass guitars sometimes have an internal pre amplifier ....
If the bass has an internal amplifier would the buffer be necessary ?
Thanks for you attention again and sorry for bothering with an old question and with my bad english,
Gabriel

[seanm]

Hello..
I'm trying to mod some effect schematics for using them with bass guitar, but in my mind the best way for doing this without loosing low frequency response is to apply the effect to the signal after a high pass filter and then blending it with the clean signal from the bass ...
I don't know if I will face some phase problems, has anybody done this before ??/
Thanks for your attention and help, and sorry for my bad english,
Gabriel

You might hit phase problems. If the phase is far enough off then it sounds like you have layered the wet and dry instead of summing them.

A complete phase inversion can be compensated for.

Usually the worst phase shift happens in the tone stack. If everything is clean from the tone stack on, you might be able to mix the wet and dry before the tone stack and let both signals be shifted.

[Gabriel Simoes]

what is that clean you call ?
In my mind I could just solder the 2 wires together after a volume control for each ... and the solder it to the output jack .... but I see I'm wrong ...

[Ben N]

Gabriel:

The Paralooper does not invert phase in either the loop or the LP filter.  It DOES assume that your effect(s) that are in the loop also do not invert phase.  However, especially if you are using the filter for the bypass, it may not matter that much.  The Splitter-blend (like the very similar Keeley looper-mixer box) allows you to invert the phase of one of the loops, which is handy if the effect(s) do(es) invert the phase.  In any event, you ought to be able to incorporate the phase reversing capability into the paralooper, butyou wont be able to use the existing layouts.

HTH,
Ben

[seanm]

what is that clean you call ?
In my mind I could just solder the 2 wires together after a volume control for each ... and the solder it to the output jack .... but I see I'm wrong ...

Sorry dry = clean, wet = effected.

You can't just solder the wires togeather or it will feedback on itself. You need at least one buffer to prevent feedback.

[Gabriel Simoes]

Do mixers use buffer stages to prevent feedback either ?

[seanm]

Do mixers use buffer stages to prevent feedback either ?

The simple answer is: yes.

[moosapotamus]

Correct if I'm wrong but both projects use a buffer so adjust the phase of the 2 signals ... so the output is always a low impedance signal , so a true bypass would not be allowed in this sistem ... right ?

My paralooper that I built has true bypass (total bypass) that grounds the input to the entire circuit when bypassed... no problems.

~ Charlie

[Gabriel Simoes]

So I think the problem is me and my ignorance ... because by what I saw you would always send a low impedance signal to mix with the effect signal , aand this would send a low impedance signal to the amp or line in .... and if you are using true bypass and have no pre amp in your bass, there would be a chance of impedance when you turn off the paralooper ... right ? how does this mismatch affect the overall sound ?

[seanm]

So I think the problem is me and my ignorance ... because by what I saw you would always send a low impedance signal to mix with the effect signal , aand this would send a low impedance signal to the amp or line in .... and if you are using true bypass and have no pre amp in your bass, there would be a chance of impedance when you turn off the paralooper ... right ? how does this mismatch affect the overall sound ?

You have it right. The impedance will be lower with the effect on. This does affect the sound unless you have a very very short cable. Generally, you will notice more treble.

This is one of the disadvantages of true bypass. All of my basses are passive. If I am using effects, I like to have one non-true bypass  pedal at the end of the effects chain to drive the cable. This is usually a SansAmp BDDI. However, if I am feeling paranoid, I will stick the SansAmp in a looper Some people actually build a buffer pedal to add to the end of the chain. For example, the AMZ Superbuffer.

I prefer true-bypass. I like to know that if something goes wrong, like a dead battery, I can hit the bypass and my signal will still work. While I like effects, they are just for colour. I can live without them.