Soundlab Next, Checking parts

Fenris

Hi All

I recently finished my WSG MKII. It works fine and is only waiting to be cased. Now my next project is a Soundlab (Basic). To this end I have been checking my usual suppliers and I can get all the IC's no problem.

Second to that is the capacitors but this is more to do with finding ones of the correct ratings BUT with the correct physical lead pitch. So to this end I have compiled a list of the capacitors I need by value and pitch. Now the pitch has driven the selection of the type of capacitor IE. Ceramic, polyestor, etc.

Ceramics have a bit of leeway as the leads can be bent slightly to fit the PCB if needed (so long as the lead length isn't excessive) Polyestors have been selected where the the leads would be excessive if a ceramic was used.

I know the different type/materials they are made from have qualities that are better at audio, or high frequency, filtering etc etc etc. But does it matter what type I use in the Soundlab?

Other than that everything is clear so far. I have started an online order for everything else so just need a yay or nay please. Smile

I probably know the answer as my voice mod is built using polyestor caps but people have built it with ceramics caps instead with no problems.

regards

Fenris

valis

Fenris · Posted: Wed Jun 10, 2009 5:17 am Post subject:

Thanks for that. I knew about the voltage ratings. It's the getting caps that will fit the PCB pitch. Some caps of course have legs that can be bent to fit. Others however do not and getting them in the right pitch can be problematic. So, So long as I maintain the quality of the component I can use what physically fits I guess.

regards

Fenris

Uncle Krunkus · Posted: Wed Jun 10, 2009 6:00 am Post subject:

I think the only caps on the original SoundLab which are even close to critical would be the integrator caps in the oscillators. The other typical one is a low leakage type for a sample and hold, but the original SoundLab doesn't have one.
I'm fairly sure the integrators on the old schem are C6 and C7. Have a look at this page,
http://www.musicfromouterspace.com/analogsynth/OLD_SOUNDLABMINISYNTH/soundlab.html
AFAIK the best integrator caps are polystyrene. 100pF styrene should be fairly easy to get, but not from your average RadioShack, Dick Smith type store. You'll need to take a step up to Mouser, Farnell, Digikey, that kind of supplier.

Fenris · Posted: Wed Jun 10, 2009 8:40 am Post subject:

Hi Uncle

Well if only I practiced a bit of RTFM......... I must be going blind. It's all so obvious now Very Happy

Cheers all

regards

Fenris

Uncle Krunkus · Posted: Wed Jun 10, 2009 3:49 pm Post subject:

RTFM?

Fenris · Posted: Wed Jun 10, 2009 4:00 pm Post subject:

Read The Flaming Manual............. At least thats the clean version Very Happy

regards

Fenris

Uncle Krunkus · Posted: Wed Jun 10, 2009 9:49 pm Post subject:

Uncle Krunkus · Posted: Wed Jun 10, 2009 9:58 pm Post subject:

BTW I messed up. The integrating caps are C8 and C9. These are shown as 1nF, but Ray mentions that you could go as low as 300pF, (as long as you increase the resistors) so there's a fair bit of scope there to find styrene.

Fenris · Posted: Thu Jun 11, 2009 2:28 am Post subject:

Thanks for the heads up Uncle. Much appreciated.

regards

Fenris