It's alive!!!

[Afro88]

Woohoo! Just finished my Soundlab! It's still in the cardboard I used for wiring all the pots, but that'll do for now Be back in a few hours with some samples and pics

BTW - that noise source with high rez on the filter is evil!!!

edit: Ok, there are a few things that aren't working:

* The AR gen doesn't work with the manual trigger, but it does with repeat mode
* The LFO doesn't work at all. Assigning anything to the lfo results in a slight rise in pitch. Turning the Amount knob up makes the pitch rise, down and it falls.
* Turning up the AR gen's amount effects the oscillator pitch quite a bit even if the AR-Osc switches are off. Turning the amount up makes one of the osc's pitches rise then fall slightly at the end of the knob.
* Sync doesn't sound like sync at all, it just garbles the sound right up.

The question is - do I fix any of this? I kinda like the fact that it's really unpredicable...

I'd better go check every connection... Hello spaghetti city!

[Alex_D_Steak]

mind you, I'm tempted to leave the leg of the transistor long as it is now,
it's nice to catch some AM radio every now and then
Furthermore, I like to have some "improbability" in it

-- mind you again, I have the SAME exact problems you have.
For example, the LFO seems to be the source of sound instead of the
VCOs...
I'll make a testing session tonite, perhaps... if I discover something I'll
let you know.

[Afro88]

I think some of your post got deleted, but I get the gist anyhow

I kinda like the noise being very different from any other noise source I've ever heard before. I think I'm gonna leave that one alone . I've managed to fix the AR gen problems I was having, that all works now (and how!) so that's good. The sync is still weird - if I turn the tuning of osc 1 up slowly the sound out of osc 2 glitches but generally stays the same until I get really high up, then it garbles the sound. It sounds pretty cool to my ears, but I'd trade it for a good analogue sync if it's not supposed to sound this way.

My LFO still isn't working, but I'm pretty sure it's the capacitor I've got for C13 hanging off S17 that's the problem. I picked it up today, and it's not a ceramic but some other type. The guy at the store reckoned that ceramic capacitors don't come in 2uF so he gave me a different type. The odd thing is, if I turn the LFO on on one of the oscillators and set the second wave switch to ramp the amount knob will greatly affect the pitch. So ramp = amount knob increases osc pitch alot and rect = increases osc pitch a little. It doesn't matter what setting the wave is on (ramp, tri or saw). I think I was given the wrong switch for this anyway, because it's a 3 way switch, but it springs back to the middle (if that makes sense). Gonna have to get a proper 3 way switch.

So, the only problem I'm really having is the damn LFO . If I could get that fixed the range of sounds would multiply instantly!

But wow, this synth is amazing. It really is that crazy analogue Synthi style weird effects sound.

The filter is fantastic. Full rez backed off just a little bit gives a great analogue distorted filter sound (funny that!). Cranked all the way up and you get some really evil sounds, or if you find the right points, some nice slightly distorted harmonic-y sounds.

The oscillators sound great too. PWM on the rect is really good.

I couldn't be happier with the AR gen on repeat too. I'm glad the attack and release times go extremely short, you can get some nice audio rate modulation sounds from that.

This is a really interesting synth. It's exactly what I want an analogue synth to be. Unpredictable, warm, as evil or nice as you want it and it does really strange EMS Synthi style effects. Every now and then the filter reminds me of that "Chemical Brothers" sound which of course I love . The synth is full of character. And I'm not talking "heh, you turn the lfo amount and the pitch goes up but doesn't oscilate" character, I'm talking every sound that comes out of it has it's own unique sound and takes on a life of it's own. The best part is there is no way I (or anyone else I reckon) could emulate this on the G2. In fact, I challenge someone to build a filter that has resonance like this!!

The attached mp3 demonstrates the problems first. What the LFO does when I turn the amount up, first with ramp, then rect. Then what the sync sounds like, and what the noise sounds like. Then I go through the typical filter sweeps so you can hear the amazing quality I'm talking about, then onto the modulations etc. A word of warning - it's fairly long, I tend to get a bit carried away with new synths . The best part is, you can get these sounds without the LFO. I can't wait till I fix it up

[jksuperstar]

Nice...but where's the fault



Sounds good to me

[Afro88]

Oh, just the LFO not working. The start of the mp3 shows me turning the amount knob up then down again with the wave on ramp, then up and down with rect. It doesn't oscillate, it just adds voltage to the osc pitch. I'm going to get a new capacitor today and see if that fixes it.

I agree the rest of it does sound pretty nice I still can't believe an au$100 synth can sound this good

[Afro88]

Ok, I've got it all working now. It was just a case of checking all the solder joints and making sure no solder joined up 2 tracks and stuff like that, as well as connections to all the knobs and switches. I also realised I could use 2 1uF capacitors in parallel as a 2uF for the LFO, which worked out fine.

But wow, now it's all working as it should, it's freakin amazing. The oscillator sync is really nice. I've never heard anything like it. It's not smooth like my evolver's sync, but much dirtier which rocks. Also the filter distorts more than it used to which is great, because if I can drive it hard or soft depending on how much I turn up the osc's in the mixer. Also the LFO works really nicely. The high rates are good fun, and combined with the AR gen on repeat you can get some really strange sounds.

I take back any negative connotations I might have given off in the last few posts - this synth is really really good. It's really nice for sound effects. I wouldn't want to use it for proper synth instruments, leads and basses (I'll stick with the G2 for that), but for effects it really can't be beaten. Everyone that has a spare few days should build this, it's that good!

Just to finish up from the last post, here's an mp3 with sync sounds in the beginning and modulation craziness at the end. And yes, those weird arpeggio's at the beginning are just the sync and lfo - no external sequencers or anything. Crazy, I've never heard anything like it.

[mosc]

Great, it sound very nice and I'm sure it is a lot of fun. Take your time and put it in a groovy case, then send us some snaps...

[Alex_D_Steak]

I just added the CV connector, connected it to the a100 midi/cv interface,
but nothing so far... then I started the signal route check, I've discovered
that by shorting pins 9 and 10 of IC5-C I get sound. And also CV controlled.
Now I have to check if the thing is valid also for VCO2...
Obviously, this is not a permanent solution....
anyhow it's very precise. I've matched it with a vco from the a100 and it
kept the tune for all the time it has been on (about 4 hours now).
And no, at the moment I'm not using tempco's now.

[Afro88]

Fantastic. I highly reccomend getting a magnifying glass, printing out a mirror image of the circuit board and making sure you haven't joined 2 tracks without meaning to, checking everything's soldered properly (no "grey" joints etc.) and checking that no wires are touching unnecesarily. You'd be suprised what you'll find if stuff isn't working. It's worth it, it only takes about 30 mins.

Thanks Mosc, I'm still looking around for the right kind of case to butcher... If I can't find a funky one, it'll be time to break out the wood! Either way, I'll have pics up here in a week or two

[jksuperstar]

Plexiglass/lexan can be worked with any wood tools (unlike steel), and is very affordable to boot. Plus, you can always see the circuitry that you sweated over. With the help of a heat gun, you can bend it, round/smooth cuts, and in general make it look very professional & clean. And still keep it personal (and you can paint the inside if you like for that Apple effect).

[Afro88]

That's a great idea! I didn't realise plexiglass was easy to mould and cut. I might have to use it for my next DIY project though, because I just finished fashioning a wooden case out of an old speaker ah well.

I'm pretty happy with this one though. Just finished painting it black, so now it's a matter of transfering all the pots and switches over. I'll put up a pic later on, and then a final one when I get all the knobs and stuff.

[Alex_D_Steak]

@Afrokid

I've put great care in soldering the PCB and the wires to the pots, I have
really triple checked everything... my suspects are going to some IC not
working properly... as soon as I can go to the electronics store I'll get
some new one.

Thanks for the advice anyway

Alex

[Afro88]

Hehe, sorry Alex. It's very easy for me to assume other people are as lazy and careless as I am

Hope your replacement IC's fix it all up!


Another update: I've drilled all the holes in the front panel, painted a few coats of black paint on it, and I tried to transplant the knobs and switches from my cardboard to the wood but it didn't work out. Everything was so tangled and messy, plus my layout is a bit different from the usual one so some wires didn't stretch far enough. I ended up desoldering most of the wires (leaving any components still attached to the switches/pots) and started the wiring process again. It's a hell of alot neater this time cause I know what I'm doing, but it's a pain having to do it again.... It'll be worth it though, the case looks cool

[Alex_D_Steak]

@Afrokid
it was the IC which was not working properly. And more, also the other IC
was partly broken

I've got now 10 ICs that I've tried, now it's working ok
I guess I have your same LFO problem, I'll check the parts...

Alex

[Afro88]

Well, I transfered everything to the new case which required resoldering all the knob connections and even though I've double checked all connections, the thing doesn't work as it should at all. In fact, it barely works

I think I may have overheated a few components when I was desoldering (solder sucking can get a bit difficult with the awkward joints). I'm gonna get a multimeter and test everything over the next few days.

Does anyone know if it's possible to damage resistors, potentiometers or capacitors through overheating? Or is it just IC's?

[Alex_D_Steak]

@Afrokid

not only IC get overheating... just think that potentiometers are usually
made of plastic, so even melting it can cause damage...

[Afro88]

Thanks Alex. I'm gonna get a multimeter and test all my pots, then start going through the components. If all else fails, I might have to buy a new set of IC's