"Splitter-blend" question! HELP NEEDED! =)

[SpufuZ]

hello!
In this project
http://www.runoffgroove.com/splitter-blend.html
there is a small transistor circuit right after "green return".
My question is what is it there for? Is it needed?
can i just skip that part and lead the return signal right in to the "U2A" IC, same as red Return?


//david

[Skreddy]

Green return is set up with a polarity-reversing switch (assuming two amps are being used and that some amps are out of phase with others).  The buffer is needed for that application. 

[SpufuZ]

Green return is set up with a polarity-reversing switch (assuming two amps are being used and that some amps are out of phase with others).  The buffer is needed for that application. 

yes i know that there needs to be a buffer, but do i need the j-fet circuit before the ic-circuit!?
Theres none at red loop...

[Skreddy]

If you want to do the polarity switching, you need the buffer in front of THAT.  If you don't need the polarity switching, just make both channels like the red side.

[SpufuZ]

If you want to do the polarity switching, you need the buffer in front of THAT.  If you don't need the polarity switching, just make both channels like the red side.

ok! good to know! thanks.
But do i NEED the phase-inverter?  Im just going to use one of the loops for effect and the other one as a "dry" channel to be able to blend in the effect to the dry signal!
This is possible right!? And do i simply connect red send to red return and its fine?!
Would i need the phase inverter if im only to use green as Wet and Red as dry?

heres a scheme i did!



would it work?

[Skreddy]

In that case, you wouldn't need a return section for the straight signal.

But the phase-selector switch is still a good idea, because you really have no idea what phase the effects in the loop are going to leave your signal in or whether you might even like it better out of phase.  I'd use the RunOffGroove version anyway, just because it's so much more versatile and not really that much harder to do.

[SpufuZ]

so the phasing could be a good idea after all i think, but could i use some other transistor than the 2N5457? They cost so much?
Does it have to be FET? could i use a NPN like the BC547 or so?

[Skreddy]

2N5457's are $0.19 each at Mouser.com.     A FET makes an ideal buffer because of the high input impedance.  Since you're planning to build a straight-signal/effects blender, though; you have another half of an opamp you could use as the buffer in front of the phase selector.  So you could use IC1A and IC1B for the two inputs, and IC2A as the effects-output buffer (instead of the FET) and IC2B as the phase selector.

so the phasing could be a good idea after all i think, but could i use some other transistor than the 2N5457? They cost so much?
Does it have to be FET? could i use a NPN like the BC547 or so?

[SpufuZ]

2N5457's are $0.19 each at Mouser.com.     A FET makes an ideal buffer because of the high input impedance.  Since you're planning to build a straight-signal/effects blender, though; you have another half of an opamp you could use as the buffer in front of the phase selector.  So you could use IC1A and IC1B for the two inputs, and IC2A as the effects-output buffer (instead of the FET) and IC2B as the phase selector.

hmm i dont relly understand exactly how you mean...
sorry if im a bit slow, im quite new to this!
can you explain it a little mor exact?

thanks
//david

[SpufuZ]

oh! i think the coin fell down. hehe.

so is this how it could be done?

[Skreddy]

Actually I was thinking something more like this...

[SpufuZ]

ok! i see! thanks!
But are the 220K resistors needed, and what are they there for? Stupid question maybe! =)
Btw, would 100k pots work fine?

[Skreddy]

Those are what make the phase-selector switch reverse the phase of the signal and maintain a 1:1 gain of the signal at the same time.

A 100k Blend pot would work, but might possibly be quieter in the middle and louder at either end.

ok! i see! thanks!
But are the 220K resistors needed, and what are they there for? Stupid question maybe! =)
Btw, would 100k pots work fine?

[SpufuZ]

ok i see! thanks for all help this far!

[SpufuZ]

OK i think i need some help here.
Ive soldered the IC1A&B now and tried it to see if it worked. And what i get is a "bluddery" small distorted and quick fainting sound.
I kinda have to strike the strings hard to get any sound at all. Get it?
I wired lug 1 on the IC to output as on the schematic above, and lug 7 nowhere since i just wanted to check if this worked.
No can this be done really? Or must the whole circuit be soldered for it to work?

I really cant find out whats wrong?
Anyone who can help me out with this?
Any ideas!

[SpufuZ]

up up!

[Skreddy]

Did you use the 10uf cap on the output?

[SpufuZ]

yes i did!
strangely i got it to work yesterday but the tone was a bit harsh and a little distorted!
So maybe something is soldered bad? though ive been very careful when soldering!!

[SpufuZ]

to give a little more feedback, i discovered that i get almoast no sound, you know the "bluddery" tone i explained with a 9V Battery.
BUT, with the DC walltransformer (not regulatet so maybe a few more Volts than 9) i get more sound, and distorded tone!
What can this be!??!?!

[SpufuZ]

no idea?