4-pole Mission build instructions seem a bit sparse

Compared to the standard(?) Filter board, the SMR-4 mkII, the 4pm doesn’t seem to have as much of a walk through for it. I’m a little worried because I just ordered mine, and I don’t want to make a mistake. :frowning:

Is it possible to compare certain parts of the build instructions for the SMR4 with the 4pm? For instance, if I wanted to build the power supply first to test the digital control board, would that be possible? Or should I begin building the digital controller first, in the order the 4pm page also follows? Has anyone else had any trouble building their 4-pole?

Sorry for all the questions, it looks like such a great synth, and I don’t want to ruin it!

The 4-Pole Mission is one of the most advanced filter boards (with the dual SVF) and as such, recommended for advanced builders who have cut their teeth on another filter board.

I personally don’t build the power supply section first because I think it gets a bit in the way of the rest of the build later. I build in the following order (shorter from taller):

  • all resistors
  • all ceramic capacitors
  • all IC sockets
  • everything else

The power supply is the same on most of the boards anyway. In the case of the SMR 4 and 4PM, they are the same, but with the parts in slightly different places. So you could still use the SMR 4 instructions to help get you started if you wanted. And naturally the digi board is the same for all.

I think the intention is that the all boards outside of the SMR 4 are for more experienced builders. Also, quite often people start with an SMR 4 kit, then try the other filter boards later, by which time they are generally experienced enough to cope with simpler build instructions.

So you still have pretty thorough instructions for around 60% of it. And for the other 40%, it still shows you what goes where… If you have built other things before, then you should get by ok. And you can always ask on here for advice too :slight_smile:

All right, looks like I let the allure of the pretty case and the price tag get in the way of what I’m comfortable building myself, even after ordering the extra parts from mouser, it was still a better buy compared to the standard kit. :smiley:
Hopefully I won’t have a problem building it, if I do you’ll be hearing back from me!

sure, you’ll get it made

Just take your time, read all of the instructions through once before you start, and then read each piece a couple of times before doing each step. Make sure your components are oriented properly and don’t pick the component based on what it looks like, look at the numbers on it.

Of course, I should start following my own advice.


I am exactly in same situation like you as I also ordered my 4-pole Mission kit the other day.

I did bit of soldering and ready to made kits years ago but I do have concerns due instruction for 4PM on website is really limited.

I do appreciate what ever help I could get from expert board members here.

Looking forward to hear from you all.

Thanks in advance

My kit arrived today and I’m a bit afraid to build this…is my first Shruti but I have already a little experience on DIY…I’ll go to learn the instructions :smiley:

just ask if you’re not sure. and if you feel more confident, please sprinkle some keywords in your posts, for easier derailment

Don’t be afraid ![](I It’s like a lego :wink:
My tips : Be careful, don’t reverse the two Voltage regulator 7805 and 7905)

Might want to start with the digital board? This is very well documented, and therefore great to get you “in the zone” :wink:

Yeah, I was thinking of doing exactly that! Only problem is how to power it, would connecting it straight to a USB power source be ideal?

you could start with the power supply section of the filter, amd build only that for the beginning. verify all voltages are correct, then the digital board.
the only disadvantage is you can’t work the whole board from small to big component that way, but if you just start the step by step approach would be advisable.

To power up the digital board for testing, you just need to connect the +5v and ground pins on the lower header.

Another problem with just building up the power supply section of the 4-Pole Mission filter is that, unlike with the standard SMR-4 mkII board, the instructions don’t call out which components are part of the power supply.

It’s the same subset of parts, just placed differently.

Big doubt: I need to connect the digital board with the filtrer board just only with the 8x1 connector or I need also to connect the 2 board with also the 6x1 connector (Output expansion) in the bottom left??? My shruti power on well and the display in going ok but what about that output Expansion???

You will need to connect this, too. Guess why its implemented on the Filter :wink:

Ok thanks :slight_smile:

Just a quick update since people are commenting on this thread again, the 4-pole filter board’s build instructions were actually quite easy to follow, putting components in the right place is deceptively simple!

And powering the control board via USB gave me some problems, the screen wasn’t powering up properly for whatever reason. After putting together the filter board and plugging in a proper power source the screen worked flawlessly.

2 Doubt about the LEDs:

  1. the SMD led should turn on simply when I power the Shruti?
  2. the various combination for connecting th