help - no sound out whith minilab

[MindControl]

I finally finished mini-soundlab and I'm not getting any sound out of it all, so far? Its the basic minilab without any modifications.

I'm confident whith my soldering, but I may have misswired it somehow?

This is where I'm at, Iv got the SH101's CV out and Gate out connected to minilabs CV in and Gate in. Though, I am using 3.5 to 6.5 plug adaptors.
And the minilab's audio output is sent to my stereo amp.

I can't feel any heat on any of the IC's or transistors, I'm wondering whether if minilab is receiving any control voltage in the first place.

I guess I will have to spend a bit of time finding a better setup to test it.

Any suggestion's out there that could help in diagnosing the problem?

[MindControl]

I managed to get the circuit alive, something strange about the jacks?

There is sound there, but very faint. Some of the knobs appear to do things and some of the functions appear that they might work. Nothing from the main 2 oscillators. The CV and gate in sockets appear to work from the sh101 as well from trigger button. It sought of sounds a bit like very faint radio static so far.

I was wondering whether soundlab output is supposed to be standard line out or does it need to be connected to a preamp?

I think this project might turn out to need long term diagnosing so far? Only things I could see that I might get wrong might be a, resister, dry solder joint or a panel wire. Besides checking wiring and everything, I think I might have to realy study the circuit diagrams too.

[MindControl]

I'm finally getting something now Not sure if its working properly, it sounds radio frequency or circuitbent. I forgot to put the jumper leads in to bypass the 1 volt mod.

All oscillators work except for the noise I think. Filter works and most of the switches do something. Its hard to tell whith the modulation whith the sound being in the high frequency and treble region. I still think it needs preamplification so far?

At least something is happening now

[MindControl]

Still playing whith it now and not totaly sure if it is working properly, but I'm getting quite a few different sounds out of it. It might sound better through smaller speakers than my 15 in hifi boxes cause a lot of it is coming out of the tweeters I think. I'm using a small beringer tube preamp to bring it up to line level. The apegiator of sh101 is controlling the oscillator and I can adjust its speed on the sh101 too. Very scifi or detective movie indeed.

[RF]

Hi - You should not have to use a pre-amp for that. I think the outputs are pretty 'hot'.

Have you checked to make sure the output jacks are all wired correctly? It's easy to make a mistake there and run the ouput to the ground lug on the jack.

These are fun instruments - can't wait to hear some sounds and see some pics from yours.

bruce

[MindControl]

[Uncle Krunkus]

You should be getting at least 2-5V p-p output which is way louder than any line level, there's no way you would a pre-amp for it if it's working properly.

[MindControl]

[MindControl]

I checked all resistors on board and did have to replace R80 whith the correct value of 20k from 100k, and that did have an effect. All other resistors appear to be correct and all wiring appears to be O/K too.

I think my soldering was good in that all transistors should be working, and all diodes and capacitors in right orientation.

But, still very weak output from the VCA LM13700. Also, I'm not sure if the band pass? is working correctly on the VCF? And the noise generator is there but not really pronounced. You can sought of tell its there when you turn the filter resonance knob right up.

I'm checking it over, reading and thinking? I should be learning something atleast.

anyway?

[Uncle Krunkus]

A couple of things,
Have you got a scope?
A multimeter?
The next thing I'd check is that you have the right voltages on all the power pins of the ICs.
Then I'd be looking at signal levels before and after the mixer, VCF, and VCA stages.
That should shed some light on the problem area.

[MindControl]

Hi Uncle Krunkus

I don't have a scope, only the multimeter.

I'm getting full strength signal whith osc1, osc2, noise, LFO, mixer, before VCF and VCA, as one should expect now.

Filter appears to be working fine.

Still weak signal after VCA

Voltages on both LM13700 and rail were -7 and +7.10. Battery's were fresh, but I think the voltage is dropping a little.

This hex inverter is it powered, I don't know what pins if it is?

[Uncle Krunkus]

Yeah, the 40106 hex inverter will be ground on pin 7 and +V on pin 14.

[Uncle Krunkus]

It's the original SoundLab isn't it? Not the Plus or the Ultimate.

[MindControl]

[MindControl]

ahhhh figured it out, just a bad solder joint pin 16 of the IC.

So she is up and running now, and I can recommend this project.

This is like the sound of a modular in a little box, all that beautiful modulation.

[Uncle Krunkus]

Cool!

[Antimon]

Hehe - reading this thread (sorry I didn't read it until now) felt like Déjà vu. You pretty much mirrored my progress when I made the SoundLab - first no sound at all, tweak tweak, then a little faint weird sound, tweak check values against spec desolder solder x 10, more and more things start to fall in place, tweak worry tweak, it's there!

Krunkus tip about a scope and checking ICs is great, BTW (for anyone else having these problems). Ray has a great checklist for what signals should be on different pins and panel connections, and that helped me immensely after I got the scope.

/Stefan