ROG splitter-blend with tone control?

[BJM]

Hello everyone,

I've some time ago build a simple version of the ROG splitter-blend (without the JFET and phase inverter).

It's working OK and mixing parallel effects is fun. The only thing is, I have a very simple delay in one of the loops and would like to have some tone control over the repeats. I've looked at the negative feedback Baxandall tone control, build one as a stand-alone box and that works also. The next step would be to combine the two circuits. I suppose putting one after the other would work but then it looks like I'm using more parts and space then necessary? The Baxandall tone control also uses the first opamp to boost the signal, I'll probably can do without that.

I'm hopefully correct thinking I can use IC1A and B both as tone contol for each loop?  I'm a bit puzzled because the signals in the ROG go in the IN+ and in the Baxandall in the IN-. The Baxandall with the boost inverts twice, without the boost only once? Would that cause problems? To my (limited) knowledge it shouldn't if both loops are symetrical but I'm not quite sure about that..... Also, if it's possible to skip the first half of the Baxandall do I still need the 1 M resistor (pulldown??) and the 1uF capacitor?

Any ideas/help would be great .

[ElectricDruid]

You could replace one of the buffers in the blend circuit with your boost+baxandall circuit. I know you said you don't need the boost, but you've already spotted that the circuit will invert the signal if it doesn't have that inverting amplifier stage in front of it, so it's best to leave it in. If you really don't want the boost, just drop the trimpot and only use R3/100K.

I'd take U2B and the associated parts out of the ROG blend circuit, and then bolt the boost+baxandall in instead. The final C6/1u replaces the 10u that the ROG buffer uses, and you might find the ROG value is better than 1u.

It should be pretty simple to do. The only annoying thing is that we finish up with an odd number of op-amps!

[BJM]

Thanks!

[antonis]

What is the purpose of a booster in front of an active Baxandall tone control..??

[ElectricDruid]

They don't like being fed from a high impedance, Antonis. So it's not there to boost so much as to provide a reliable low impedance drive and correct the inversion. Turning that stage into a boost is an "added extra" in my view.

[antonis]

A simple buffer should be more than adequate, Tom.. 

Not necessary inverting due to ROG Splitter - Blend U2A phase switch option..

[ElectricDruid]

OP said they left out the JFET and phase switch.

I agree otherwise, a simple buffer would be enough.

[antonis]

OP said they left out the JFET and phase switch.

I presume I have to read more thoroughly some posts..

[BJM]

I presume I have to read more thoroughly some posts..

No problem, thanks for the input  .

I left out the phase switch because it looks like I don't have any pedals that inverse the phase.