Shruthi Filter mode output level question

Hi Everyone,

Almost everything seems fine with my new synth after a couple of pointers from the forum. It’s my first bit of proper electronic hardware and I love it :slight_smile: I’m thinking there might be a bit of troubleshooting I need to do though. I have the 4 pole mission filter board. When lp4 or lp3 are active, the output level is much greater than any of the other filter modes. The output level is around what I would expect as well. The other filter modes however seem to have a consistent/expected level from what I can tell but much lower than LP4 and LP3. After looking at it through Ableton’s spectrum analyser while playing the same note at the same velocity, it appears that the level between lp3 and lp2 drops by ~20dB. I’m pretty sure that’s not what is meant to happen but readily admit I’m learning as I go and this may be my lack of knowledge that is making it appear to be an issue. Does it sound like there is a problem? And from the symptoms I describe, is there a specific area I should be probing to find out what needs fixing?


Post a photo of your board, you might have swapped some resistors.

thanks olivier, I’ll check against the reference photo first and post a pic if I don’t spot any dodgy resistors.

I checked my filter board against the photo and there’s a few discrepencies with the resistors. But then I checked a couple of the ones which looked incorrect using their codes and the schematic and they look alright…I think. I’ve attached a photo. if you can shed any light on the problem that would be great.

You’ve swapped 68k and 68. The blue, grey, black, red/gold ones.

Whoops! Cheers for your help, I’ll swap them over tonight and report back

Yep, that did the trick. Everything is a decent level now. Just flicked through some of the presets, it sounds really good! It was a fiddly job swapping those two over. Will be checking and double checking resistor values in future! Thanks for your help,