Shruthi Audio Problem SOLVED

Hello everybody!

I’ve just finished my Shruthi kit and i have some audio troubles…

here’s a little video…

the sound doesn’t start holding 2 secs the first button…
connecting the shruthi to a MIDI keyboard, a lot of presets don’t sound, but they make just a small thud and a rustle, while the ones that sound also have the rustle in the background…

i really don’t know what to do…

any suggestion?

Thanks everybody


Regarding the first button -> it’s normal, I changed this feature in the very recent firmware version (it’s now activated by holding the encoder).

As for the rest: please post pictures of your filter board (both sides).

Seems like something is wrong with the filter.
Do you have firmware > 1.0x … try pressing the encoder for 2sec.

There is a troubleshooting section in the end of the smr4 build page. Best is probably to try to trace your signal.

Could you also post pictures of the filter board both sides?

ok, it works with the encoder! thanks

here the pics of the filter board… i follow all the steps on the DIY resources page, i thought it was all right :-(… i know it could be solder better but it’s one of my first work! :slight_smile:

Thanks for the really fast answer

It’s a bit difficult to check the resistors with this pictures because of the colours and resolution aren’t that good.
Maybe you can check your board against this picture to see if all of your resistors are in the right place.

check all the solderjoints for shorts to their neighbors. On your picture it looks like there might be a connection on the pins of J4

hey everybody!
I check all the possible bridge and clean all the solders, everything in the back it’s ok, as well all the component in the front, all resistor, ceramic capacitor ecc are in the right place! BUT i think i put the male connector of 2-4 pole in the wrong way (short legs on the top, where there’s the cup), could be this?

here a video of a sequence played on shruthi, with different sound so you can see the difference.


> could be this?

Maybe. This would prevent the signal coming out of the filter to go through the VCA and continue to the audio output.

If you don’t care about 2/4 pole selection, add a solder blob between the middle pin and the “4-pole” pin.

Done, bridge For a permanente 4-poles, but always same problems!

And i Also noticed that the output level is really low… Am I without hope?? :frowning:

No - the two problems are related, not a big surprise. You’re not getting any audio on the output at all, and cranking the volume up just get you bleed/parasites.

Check the online build instructions of the filter board, the troubleshooting section at the end… and try tracing the audio signal…

Looks like one pin of the TL072P (IC 2) has a bad solder joint or is not soldered at all.

@cj55 pin soldered and the sound come out but the volume was really low… i started modifying some setting and here it is, SHRUTHI COMES ALIVE!

Thanks to everybody for the precious help!

I can now finally eat Victory Candy! :slight_smile: