Just clicks and pops [solved]

well here we go, my first synth build, and I’m having a bit-o-trouble.

The build went pretty smooth, I’m pretty confident everything is right, I took my time, and really checked every resistor before I soldered anything in.

I tested the power when building the SMR4 board as suggested, all points are -5, 0, and 5.03 V respectively, menus work perfectly on the controller board as well.

I have shruthi hooked up to my pc, using lmms, and an oxygen keyboard.

When I hit E4, or any key, all I hear are pops and clicks. I have adjusted the reso pot all over the place… I never see a change, just pops and clicks… just to verify it was not my pc, I plugged it in to my guitar amp… I get a pop when the key is on, and a lighter pop when I come off the key…

I’m stumped, what to I check now?

well… I put it under a microscope looking for shorts, and found one lead that wasnt soldered… fixed it and I have NOISE!.. I’m back to tuning… thanks

Noise as in white noise or noise as in funky bass ?

neither really… I boxed it up and it is working…but I may have really messed up the pot settings… when I plug it in, using the default settings I seem to get a lot of distortion in the lower notes.

I’ll keep tweaking, its definitely working though… add another successful build to the list.

ok, I’m a bit more familiar with the menus now… and I’m definitely getting a lot of distortion. anything low or bassy distorts.

to the point that a good 30% of the samples sound a lot like each other.

doe this sound like something I can fix with the pots… I think its pretty possible I tuned it all wacky, or would going back to setup be a waste of time?

Check the input gain at your soundcard.

Also: Sync24 had a similar problem and he had mixed some of the resistors (swapped 220 and 10k near the filter section).

Yeah put your soundcard input gain lower. Wich soundcard do u use?

totally crappy integrated laptop soundcard, on a dell laptop… I need to get an external one.

turning the gain down really helped alot, I pretty much turn it all the way down, and most patches sound good. One question though, should I need different gain settings for different patches? with the gain all the way down, some of them actually go silent.

for example, with my new gain setting, very low gain:
as I roll through the samples, #22 e-piano, is very quiet.
#30 is pretty quiet
#31 planar is pretty much silent at all gain settings.
#33 sleepy is silent unless I jack the gain way up… then it is quiet, but I can hear it.
#68 imodium, sound pretty quiet… kind of like my gurgling stomach… so I think that one is just aptly named :smiley:

I just want to know if this seems correct before I open up the case and start looking for problems that may not be there.

If its not distorted everything is OK. Seems more a problem of you Soundcard. What about getting a small outboard mixer like this as things will start piling up anyway once you get in the ShrutiVersum™…

well I think its all working how does it sound to you?

Ops - sounded ok via the iPhones Speaker…

#22 is very deep if your filter is badly tuned, or if you play the notes softly (try hitting the keyboard).

#30, #31, #33 are pad, the amplitude gradually raise up if you keep the note held long enough.

#68 uses filter self oscillation, it will be very quiet, or very loud if resonance is badly tuned

I had a look at the video and it sounds awfully distorted. Check Eaty’s video to hear how the preset sounds should sound like

I’d really advise you to check:

  • the gain setting on your soundcard
  • if you haven’t swapped resistor values in the filter section
  • in last resort, replace the 68k resistor above IC3 by a 10k

ok thanks for the feedback, the gain is WAY down on my sound card so I’m going to pop the case back open… maybe tonight.

Honestly I think I fubar’d the tuning, but I’m going to re-check the resistors as well.

thanks again for the feedback.

getting much closer… in fact I may be done… not sure.

My gain is 0 on the sound card… all the way down.

I checked the resistors, they are all correct, however I found C29 in backwards… it puffed a little on the top, but it looks ok. I removed it, and put it back in in the correct orientation. I then re-tuned it… is it possible I fried a chip?

I think it sounds much better, similar to eatys video… not the same but close.

what do you think?

thanks again for all the support guys, it really helps.

The way the sound is recorded in this video makes everything sound THIN and bleepy, but it looks like the correct sounds sent through thin recording equipment, not distorted sounds sent through thin recording equipment.

Mounting C29 backwards is bad, check that you have not damaged it (electrolytic capacitors mounted backward bulge and swell, and may even pop).

yeah played it on a crappy laptop, and recorded with my iphone… but the distortion seems better(gone) I’m not sure if I should keep tinkering to get it tuned better…

It did bulge a little… I was going to replace it but the closest thing I have is a bunch of 100uf 25v caps

is it ok to use the cap if it bulges?.. I’m sure it has not popped, or vented, it just looks a bit “proud” when compared to the one next to it. If the bulge means its bad, I’ll order a few replacements from digikey.

ok, I think I figured out the “quiet” samples as well… I have to re-tune the cutoff.

When I load #30. #31. #33 etc. they are silent, until I adjust the cutoff. I think these samples have a low cutoff already, and I trimmed the cutoff pot too far.

I’m saving this for another day… spending too much time with my totally addicting shruthi!

And please replace the bulgy cap. It’s likely that it already has no filtering effect on the power supply.

will do… thanks for all the help !