No sound from synth but drums is ok?

Hi

Have strange problem with my Anushri. Have just finished building and testing all voltages without problems. However, only hear the drums when I start it. Synth does not provide any sounds at all. Have checked all the solder joints and it looks ok. The gate led flash when I press a key on the midi-keyboard so I guess it´s receiving midi.
Have run out of ideas now and start to lose heart. Any suggestions on any checks that should be done or something?

Obvious possible answer: Is your cutoff knob for the synth fully open? Also check VCO range, volume, etc…

@kyle Tested your tips with no results … :frowning:
Would have been nice if it were that easy!
I will continue to explore solutions in this forum.

klingan

It was worth a shot. I only suggested it because that was my problem too lol.

Have you tried pressing the ‘hold’ key for 10 seconds ? This should start a ‘drone’ tone, independent of the MIDI interface (although this seems to be working) or channel settings.

@eelco Tested it but still silent…

Then MIDI is fine, and you’ll have to get yourself a nice big coffee, and check everything again:

  • correct ICs in the right place, and oriented correctly ?

  • all pins actually soldered (I forgot a few pins once !) ?

Which socket did you use for audio out ? The one in the back, without using the top panel ones ?

Scroll at the end of the build instructions there are dozens of points to check!

@eelco I used the audio out in the back.

@pichenettes I have measured all the voltages and they are ok but I do not have access to an oscilloscope.

What about checking the audio signal at the test points?

@pichenettes

Good idea! How can I do that? Read something about it but didnt really get it…

Use an audio input signal lead (rca, jack lead, whatever) connected at one end to your high impedance amp (most amps are just fine). At the other end, connect the outer sleeve to the synth ground (alligator clips are very handy) and the tip to your test points. Follow the signal chain as per the “Signal Path” section of troubleshooting at the end of the build instructions http://mutable-instruments.net/anushri/build and see what is making noise! Some signals might be LOUD, so turn your volume down first.

You can also do this with a pair of cheap earbuds, by the way.

I don’t recommend this for two reasons:

  • earbuds are very low impedance so they will load the circuit and might cause it to behave differently. When it comes to probing/monitoring, the higher the impedance, the better.
  • you don’t want a 5V pp signal piped straight to your ears.

Cheap ones are often still high impedance, but yeah, I should have added that you don’t actually want to put ’em in your ear.

@pichenettes

Now I’ve finally checked the audiosignals at the test points. Get sweet sounds from most of the points but not from points R, S, T, F and U. Does it lead anywhere?
Maybe I’ll photograph my circuit board so maybe some sharper eyes than mine find any mistakes!?

This is strange, because if you have nothing at point U and F there’s absolutely nothing to feed the rest of the signal chain and you shouldn’t get anything anywhere else.

Can you confirm that there is nothing at point F and U? If this is the case, then what do you get exactly at point M, N, O, P etc…

@pichenettes
With nothing I mean no sound, silent. On the other points I hear different sounds. Strange. Maybe I had some knob or switch in a wrong position or something?

Pic of main board

Pic of other side…