Author Topic: ROG Splitter Blend with possible boost in series rookie help needed?  (Read 748 times)

200hz

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Hey all!

I'm building a variation on the ROG Splitter Blend and I was thinking about putting (or not putting)
this version of the LPB-1 in series after the Splitter for some volume or boost fun. I was hoping
some of you could clear up a few rookie roadblocks I'm having trouble with.
Here is the original ROG schematic and the LPB-1...







a) Is it possible to wire a pot instead of the 1M on the output of the ROG just to squeeze a little bit
of extra volume without making the impedance much higher into the next pedal? The said unity
gain and 1M output value kinda throw me here on exactly how to accomplish that  ??? Seems I could
use a resistor and the pot to set the min/max, but I'm lost on the values and don't know if there is
much volume to be had anyhow.

b1) If not, and I wanted to add the boost, would I have to connect anything in series other than the
ROG output to the boost input?

b2) There looks to be two 10uf filter caps in each signal leg before the blend pot in the ROG and the
100nf on the boost input. Would it be "better" to remove the 10uf's or the 100nf with the two circuits
in series? Or is it  okay to just leave all 3 as is? I'll probably put the boost on a switch so it's bypassable,
so the 10uf's might need to stay.

c) I've read about decoupling the two +9V feeds when combined like this, but the ROG schematic looks to
have some form of decoupling on the +9V already (?), and the LPB-1 doesn't. If that's actually correct,
would it work as is in the schematics? Or better to also add decoupling to the LPB-1?

Learning a little about that last part made me think of my Snark 9V adapter, and the daisy chain I've never used.
Probably a stupid question, but is it possible to build simple, little 1 resistor 1 cap to ground type decoupling boxes
to go between the daisy chains and the pedals (much like a 9v starve looks there)? 

Any knowledge or pointers would be greatly appreciated. Thanks!

WormBoy

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Re: ROG Splitter Blend with possible boost in series rookie help needed?
« Reply #1 on: April 29, 2017, 10:50:25 AM »
Changing the 1M at the output for a pot will not give you more output. If you like to boost something before the send, you can modify one of the input buffers (or both) to a simple booster, something like an MXR Micro Amp. Or modify one of the buffers after the return, depending on what you'd like to accomplish exactly.

200hz

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Re: ROG Splitter Blend with possible boost in series rookie help needed?
« Reply #2 on: April 29, 2017, 11:18:43 AM »
Thanks Worm! That's what I figured. While it's probably more economical to reconfigure the opamps to get more gain,
I'd really rather add a boost like the LPB-1 at the end.

WormBoy

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Re: ROG Splitter Blend with possible boost in series rookie help needed?
« Reply #3 on: April 30, 2017, 07:49:21 AM »
b2) There looks to be two 10uf filter caps in each signal leg before the blend pot in the ROG and the
100nf on the boost input. Would it be "better" to remove the 10uf's or the 100nf with the two circuits
in series? Or is it  okay to just leave all 3 as is? I'll probably put the boost on a switch so it's bypassable,
so the 10uf's might need to stay."

I would keep all three, and get rid of one of the 1M resistors. My guess is that the two 10uF caps are there to prevent the bias voltage of the two op-amp halves from interfering. And, you need the 100nF to keep a stable bias for the LPB1. In any case, that should work. It probably can be done more efficiently or beautifully, but I will leave that for someone more knowledgable than me ;D.

200hz

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Re: ROG Splitter Blend with possible boost in series rookie help needed?
« Reply #4 on: April 30, 2017, 05:34:49 PM »
Good catch on the 1M. I hadn't even noticed that  :o