How connecting a second filter to shruthi

Well well, here i am with a question that probably been asked several times before.
Its damn hard to find this info among all the other discussions in this forum :confused:
Im goin to connect the polivoksfilter to a shruthi with a smr-4 and a programmer.
Witch connections do i have to make?
Do i have to solder a wire from all the pads on J4 and J6?


Yes, you can do that.

Ok thanks.

You can’t use the Programmer + SMR-4 the Polivoks Filter Simultaneously for the following reasons:

  • SMR-4 and Polivoks have different Respose to F and Q CVs
  • The Programmer need the same Digital Lines from the Output Expansion Port as the Polivoks

But theres a Workaround:

  • Update to Firmware 0-96
  • Stack the Polivoks to the Digital Board without connecting the Output Expansion Port
  • Replace the 595 on the Polivoks Board with some Switches according to this schematics:
  • Wire the SMR-4 to +5V GNS OSC VCA on the Digital Boards stacking connector
  • Wire the SMR-4 F to the Digital Boards CV1out
  • Wire the SMR-4 Q to the Digital Board CV2out
  • Set Filter to Polivoks and CV to Programmer in the System Pages (and save these!)

Now the Programmer is Operated by the Output Expansion Port, The Polivoks Filter Modes are switched manually and the SMR-4 CVs are Fed by the 2 additional (most likely unused) CVs from the Digital Board.

Next time well try to make the Shruthi brew Espresso.

The 595?
Pichenettes was writing about the switches and removing the CD4053?

"If you want to use this filter board with manual control of the filter modes (for example from a Sidekick, or from a Shruthi=1 hooked to a programmer), just remove the CD4053, and look at the spot on the PCB with 3 pins marked ‘LP BP’. Connect a SPDT switch there, with the center pin connected to the first pad, and the 2 other pins connected to the pads marked BP / LP. You now have a manual BP / LP selector.

To activate the FM feedback, connect the two pads marked FM (a switch can be used to make this connection switchable)."

So if i understand this correctly:
I use the polivoks as the standard filter with the digital board,
(if i do not want the switches i just leave the filter as is?)
and after this i connects 6 wires to the smr4?

YOu can as well replace the 4053, i found recreating the Digital Signals that drive the 595 a bit more elegant as it doesn’t touch the original Audio Path and neither runs your precious Audible Signals thru Meters of additional Wire picking up noises et al nor adding nasty switching Transients from the ToggelSwitches… (as if this would matter once cranking up the Overdrive :wink: )

Its up to your taste, recreate the Signals that switch the 4053 (remove the 595) or Switch it all by yourself replacing the 4053 (and probably removing the then useless 595)

This might help also:

BTW, this is the recommended Way how its done in the Shruthi XT WASP Edition.
I shipped these to replace the 595.

fcd72’s wiring scheme is smart, please follow it!

Also, running audio signals through 4051 or 4053 definitely has an impact on sound. I’m going to sell a magic FX box in which the signal goes through a chain of 4051s for nailing that sound (with true-bypass relays of course).

Or make a 8x8 4051 switching matrix so you can rout the audio path in different combinations many times thru this Matrix…

I just printing pichenettes statement about my wiring scheme being smart and stick it to my workbench. Today is a positive day :wink:

This looks doable :slight_smile:
I will go for the removal of the 595.
The pic of the “polivoks Filter switch” is sadly, not undarstandable to me.
Could you explain this to me (like you talk to an idiot monkey)?

da da go go

Monkey Proof Version:

Monkeys aren’t as daft as you think.

Monkey waiters

Just need to teach them how to solder :slight_smile:

Oh man beautiful!
Its colours and bananas everywhere :slight_smile:

This is great!

It only works correctly when you use matching wires…its called a BananaLogic Diagrams.

How did you guys get so smart?! It’s really irritating to find such a large volume of smart people in one place.

I you want to feel like a retarded monkey, this is the place to be :smiley:


My Grandma tortured me with Sanostol and Rotbäckchen but i guess its a bit to late for both of you.

Honestly, i got most of my Knowledge about digital (hence i manipulated the 595) chips from a small TTL Logic Kit with a single 7400 in it my father gave to me when i was 8 or 9…

This place is definitely overflowing with brain matter. I’m hoping some lands on me and sticks.

Great design and wiring charts Frank. I actually understand the monkey one.

Now I know what to ask for from now on. Please send monkey charts. Perfect!

Just to be sure …all of the above is also true for the SMR-4 mkII, right?