Sound-Lab build. working but a bit Buggy

[mrmrshoes]

Hello All

This is my first post here, glad to meet you all. I've just finished the most basic sound lab build and its working first time, which is a buzz. but not a 100%.
All of the section's are doing their stuff but its seems a bit buggy like. I've been playing around with it and narrowed it down to the lfo and ar-gen units.
The problem is tied to the lfo. At first i though the lfo was not working at all, but i turned out it was.(it's taken me a while to figure out the interface) basically if the lfo amount is at 0% then the ar-gen won't trigger the VCA. and if it's at a 100% the lfo goes crazy. also if you Manuel trigger the VCA, with the ar-gen when the Osc lfo mod is enable it seems to also trigger the Osc AR-gen pitch mod. I hope that makes sense.
I was wondering if anyone has had theses kinds of problems. I'm thinking they may be a couple of culprit's. when populating the board i had to use some resistors which were close to the stated values. (I bought a resistor pack for this build). i defo's know i used 220k instead of 200k 3.3M instead of 3M and a couple of others. could this have knock on effects?
when testing the ics DC voltages i noticed that they was a drop in voltage from 8. odd to 7. odd volt's when i installed the PWM IC.

I'm in the middle of testing the thing and have checked all board components, the power rails for the ic sockets, and copper trace's for shorts and opens. I've also checked panel and board wiring with and without a DMM, 3 or 4 times.(very time consuming)
I going to find the resistor values i sub'ed on the panel and board make note of them, check the wiring one more time and start though ray's soundlab TS guide.
I hope someone can shead some light on this. I'll report back once i've got though some of this and post some pics of the build.

cheers for any help

mr shoes

[RF]

Hi mrmrshoes -
Glad to hear you got it mostly working

I would not suspect the subbing of those resistor values so much. Sounds more like wiring issue on the pots....

Good luck - I look forward to more info on your issues - and eventually some sound clips and pics of your build!

bruce

[mrmrshoes]

Cheers for the reply man. I've got the LFO working properly now. As you suggested it was a wiring fault. Not a major one, my panel & board wiring is fine. I think i was getting a short from a off board component. to be honest i'm not ever sure how i fixed it (so not much of a report on the trouble shooting front i'm afraid). I went though the troubleshoot guide and took meter reading and sound probes from the different modules and it seem's to be working fine. I am getting some bleed from the LFO and VCO2 is mixing with the white noise but by the looks of other posts this has got to do with the lengh of your wires and the use of cable ties. i'm using both.I'm quite happy with its performance so i'll get round to sorting that out in a bit. So the basic set up is up and running i need to add the fine tuners, S&H, and FM mods. You can see these empty sections on my front panel. I've also finished another WSG build with the Volume Mod. So i've added that to the pictures of my build.
One last question, Would you connect your front panel to ground in order to ground you pots and switches. I was thinking about doing this. I'm guessing that this is common practice.


By the way RF you have some impressive build's on your webpage. brilliant stuff. I love the ultimate and expander minimoog build. very slick.

Thanks for your help

mrmrshoes

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[mrmrshoes]

A couple more pics

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[Captain Biscuits]

Nice boxes - I'll be digging round in the attic later - I suspect there might be a tin lunch box or two up there which could replace the cardboard box my WSG has been in for the last year!