Availability 4 pole, and feedback about it for a beginner

I am pretty determined in giving the big step and build a Shruthi :slight_smile:
I would like to have many of them.
But for now I will be able to have only one.
The only other synth I have is a Blofeld.
Then the soft Synths in Ableton and the soft version of the Novation Bass Station. Still did not try any of those.
I would like to build the 4 pole, because (please correct me if I am wrong) it looks like that it offers more sonic possibilities than a smr4, without loosing anything of the smr4.
And because it´s enclosure is wonderful (specially with the blue eyes).
I wonder if the enclosure and the kit will be available again.
And if it would be a suicide to build this model without previous experience.


The 4pm is not available as a kit anymore… As a beginner you are much better of starting with a kit. For the 4PM you would have to source all the parts yourself wich is difficult if you are new to this (and will probably be more expensive with the risk of a lot of problems) The smr4 is available as a kit and will give you the shruthi sound. When you are more experienced you could even give it modifications that will give it a lot of the possibilities of the 4PM.
if you are new to soldering you could also better start on some simple kit to practice soldering.
you can ask fcd here one the forum for a special white case…

or a blue one… or a red…
Idoubt the 4PM will ever come back as a Kit. My advice would be starting with the standard SMR-4mk2 Kit. Its proven to be buildable by guys that never knew before that you have to melt metal to solder. It will give you the “Original” Shruthi Sound that can easily blow any recent non Mutable Instruments analog synth away (and your Blofeld). And you will build more Shruthis anyway. If you want some blinkenlights see the UFO Mod

As Shiftr already mentioned, if you have never soldered before, start by building something simple. Do some circuitbending, build a simple kit like these, buy Nick Collins’ Book Handmade Electronic Music and make some of the things he proposes. You’ll see it won’t take long and you will be ready to build a Shruthi.
I would also propose to start with the basic SMR-4 Kit. It’s a great sounding filter anyway! Then you can move on and build another one, and another one, and another one :slight_smile:
Also check out this page about soldering: http://www.midibox.org/dokuwiki/doku.php?id=soldering&s[]=soldering

Also…the other filters tend to use use polystyrene/styroflex caps. If you don’t solder them correctly they are easy to damage by overheating. The SMR4 doesn’t…

And if it would be a suicide to build this model without previous experience.
I think so.

Start with the SMR-4, it’s got a lot of horsepower already, and it’s simple enough to not get lost into countless possibilities, especially as a beginner.
If you have only the 4PM, most of the time you’ll end up playing with the 4 pole low-pass setting because it’s the adequate filter in most situations (hence the fair amount of legendary hardware synths that have adopted a 4P-LP filter as their first/only choice)

4PM has a high part count and lots and lots of different resistor values, which all need to be in the right place.

It’s simpler for people to help you here if you build the SMR4 kit. It is the board everyone tends to build first time.

I plan to start with a SMR-4 but I have enough parts on the way for two or three 4-Pole Mission filter boards. If anyone wants to build one without self-sourcing all the parts, feel free to send me a message.

one more advantage of doing the SMR4 first is that you can just purchase a whole kit and won’t have to hunt down all the control surface parts which are hard to get here. once you got a working unit and like to try another filter, you’ll only need to source parts that are easier to obtain. plus you already have some experience then.

I’d recommend going for the full Shruthi-1 SMR-filter kit, too, to start with. All the filters sound great, but there’s a lot more to the Shruthi sound than just the filters, and a lot of the really fun stuff (and the stuff that lifts the synth above all the competition) is common to all the Shruthi variations- the oscillator, modulation, sequencer and arpeggiator sections.


I agree with everyone else, and I have only built an SMR4 and a 4PM. Sourcing the parts is made easier by the BOMs (bill of materials) but building either of these synths takes patience and concentration. I would suggest you order your SMR4 kit, and a PreenFM kit (just Google it, they’re easy to find). Start with the PreenFM to get your feet wet (it’s much easier), but keep the SMR4 kit ready to go, because once you build the PreenFM, you will be really looking forward to building the Shruthi.

Hopefully you have tools ready (multimeter, small pliers, solder, flux maybe, etc.) and a good soldering iron, and know how to solder. There are threads on this forum that discuss tools and soldering irons, and lots of tutorials on YouTube showing how to solder. Being able to get a good solder joint is crucial. So is taking your time and reading the directions very carefully and making sure you have the right part in place before you solder. All of my screw-ups where because I did not follow the advice in that last sentence.

In fact, if i had to choose one Shruthi for the lonely island it would be a SMR-4

My vote as well, especially when you find out just how many features it’s possible to add to the SMR-4 later on for more sonic variety


Echo the above and IMHO the SMR4 is a better 4-pole filter than the 4PM (more of an edge)-it won’t be redundant if you build a 4PM later.

Infact you can have as many Shruhtis as you like without redundancy. I know what I’m talking about…

one more thing: there’s step by step build documentation for the SMR4, although it’s easy to use that for the others too.

I’m not sure someone has told it already, but you better start with a SMR4 filter board…

Ok guys, thanks to you all for the precious tips, and, message received, I will build an SMR4 (no, Mic, I am sure that nobody had told it yet :D).

Now I have this concern: the reason why I wanted a 4 pole is that I always look for instruments which give me more sonic possibilities, because I like to create sounds which are captivating by themselves (= regardless the melody which I can play with them).
Considering this, and considering that I already own Blofeld+AbletonSuite+smr4+effectprocessors, and I have a limited budget, may I ask if you (as musicians, not as Shruthi lovers) would consider a “must” the purchase of an assembled 4pole?
I am simply not able to understand what it will offer which the smr4 cannot.

@ Shiftr: thanks, this info of the mods helps me to take it more easy and to be patient.

Same for Mic Mic, even if I have not clear why I would finish by using more the lp. I find quite interesting the clips of the hp, notch and phase…

@ Frank: that was unexpected. I would like to ear more about why the smr4 in the desert island :slight_smile:

Once again thanks!
If somebody who once wanted an assembled shruthi as cheap as possible, now is not buying an assembled mk1 at 160 euro (a friend of a friend, once in a lifetime occasion I guess) because he wants to make his own Shruthi even if he will end by spending more, well, I suppose you may be satisfied of the results of your suggestions and enthusiasm :slight_smile:
Specially considering that I do not even have the tools to solder. I hope I will find somebody here who can lend them to me, or it will be the most expensive self made Shruthi of the history.

@ Mic: yes, it helped.
I thought that the 4pole had not only more possibilities than a smr4 but also more charachter.
Now I understand more what did Olivier mean in the comparison table where he says the 4pole is clean while the smr4 is slightly distorted.
About the delay theme, I have never heard before the term self-oscillaton. A quick google search says that it is the result of the feedback knob at max. Correct?

@ P22: Piscione mentionned „multimeter, small pliers, solder, flux maybe, etc.“ so I thought I needed lot of things (particularly, a multimeter I suppose may be expensive. Anyway, I will very probably want to build other things in future so, nice to have one).

Ok, I will get the SMR4 and run it through other effect processors to get more sonic possibilities, and mod it when I will feel more self confident (or when Frank will allow me to visit him. Frank, I live near. Look, I am Italian, I cook wonderful pasta, and my mother just came here to reveal me her secret ingredient of her „secret ingredient Tiramisu“. What about trading Tiramisu and other italian food for a couple of hours of quick soldering - and later on modding - lessons? BTW, the blinkinglichten are super cool, exactly what I was thinking about, you read my mind. I wonder how would they look in a white case).


Same for Mic Mic, even if I have not clear why I would finish by using more the lp, I find quite interesting the clips of the hp, notch and phase…
Sure they’re interesting, but most of the time a lp4 filter is the best choice for your mix.
If You’re going to buy a shruthi already assembled, then yes, you might go for a 4PM rather than a SMR4 because it’s got more options (even though I like the flavour the smr adds to the sound). If You plan to build it and if You’re a beginner, then it’s a no brainer and go for the smr4 because of all the reasons previously written here.

If I was to get a SMR4 and then think about a second shruthi for more options, while only in a studio environment, it would depend on quite a lot of things :

  • if you’re all into weird drones and strange sounds and you like to spend quite a nice amount of time designing a sound, then the dual svf is probably a nice choice
  • if you like to process samples and want a real swiss army knife while preferring a “direct” approach, the 4PM is the way to go
  • if you’re more into rock and dirty distorted sounds, the polivoks is the right choice
  • if you don’t have an hardware delay capable of self-oscillation, and you like screaming filters, the lp2+delay is an excellent choice. Its delay is not as nice as a good tape or analog delay, but in my opinion, a self-oscillating delay that you can control with knobs is an absolute must-have in a studio setup.
    I don’t own a digital filter (but I might get one some day) but I bet it’s all glitch and chiptune-ish sounds, so if it’s your thing, just get this one.

So, quite logically (and fortunately), there’s no “right choice to go”. All the filters can get some use in most setups. You might think that given this description, the SMR4 is the less powerful, but it’s got a nice balance between character and transparency. The 4P and the Dual SVF have less character but compensate it with more options, the lp2+DLY, the digital filter and the polivoks have an strong character that may prevent you from using them in every situation.

Hope this helped.