[SOLVED] Very low / noisy HandClap

Hey guys,

I was lucky to face no real challenge during my build until now. I just finished the HandClap section and upon triggering it with the 5V pulse, I get a weird noisy / buzzy and low sound instead of the expected clap.

You can listen here : https://dl.dropboxusercontent.com/u/127 ... ndclap.wav

I'm 99% sure all my components are the right ones as I usually triple-check before placing them on the board. I checked to voltages on all ICs and they're correct. All my solder joints look nice and neat.

Could this be a faulty component? Or could it be that I overheated an IC pin? I'm not an electronics expert so I can't really tell what could cause that kind of output. I don't own an oscilloscope but I can use my soundcard (and I did, in the hope that tweaking TM1 would help, but it doesn't seem to do anything at this stage).

Any help would be appreciated! Thanks

Still scratching my head on this one. I finished the Nava tonight (HOORAY!) and everything works except this clap issue (pretty proud of myself this being my first electronics project -- aside from soldering a couple of LEDs onto my technics turntables).
I was able to kinda make the "bitcrusher" effect less bad by tweaking TM1 but the sound is still really low with a weird attack.

Another tiny detail is my Midtom is not as loud as the low and hi tom. Not a big issue but if someone has an idea for this problem, this would be appreciated too.

Often with DIY it's either bad soldering joint or wrong/falty components. I would look over the sections and check for error in your parts or the construction.

Check against the schematics and highlight what has been checked, work one direction toward the other. Don't jump arround if you can help.

You should also be able to get the scope images to verify that the waveforms looks correctly.
http://www.synthage.com/downloads/TR-909.pdf

Thanks for your reply. I'm sure the problem comes from the Handclap section since all other instruments sound fine (except that tiny volume problem on the mid-tom I mentioned).

I checked all resistors, capacitors, transistors, diodes and pots, one by one, and I have the correct ones in place, and in the correct orientation.

I checked all my solder joints and they are good. So now I suspect a faulty IC but how can I make sure? I don't own an oscilloscope but I can use my soundcard with Scope, although I think the max input would be +- 0.7V right?
I found this for the opamps http://www.suzushoweb.com/pdf_file/6300000000007.pdf maybe I can test them for circuit current or the likes? If yes, how exactly would I do that?

Could one find out what the problem is by listening to the output and matching against the circuit analysis here? http://hardware.freepage.de/cgi-bin/fee ... ndclap.htm

Another question: if I wanted to buy new M5218's to replace potential faulty ones, can I buy M5218 AL ? The ones we got says M5218L (not AL)

Did you do this?

http://www.e-licktronic.com/en/content/ ... e-finished

DIY Soundcard scope Probe's
http://www.ladyada.net/library/equipt/d ... probe.html
http://www.instructables.com/id/0-to-50 ... es-Cost-P/

Yes, I tried to do it, but I'm not nearly close to 2v p-p since the sound is so quiet.

Regarding this, I have a question: line input is often limited to +- 0.7V on conventional soundcards (i read somewhere). So how would I be able to measure 2V with a soundcard oscillo? There must be some kind of attenuation going on.. and I wouldn't know how to quantitatively determine the waveform p-p with my software oscillo...

beeb wrote:Another question: if I wanted to buy new M5218's to replace potential faulty ones, can I buy M5218 AL ? The ones we got says M5218L (not AL)

Should be same via NTE cross check. All data sheets I find are AL.

beeb wrote:Yes, I tried to do it, but I'm not nearly close to 2v p-p since the sound is so quiet.

Regarding this, I have a question: line input is often limited to +- 0.7V (i read somewhere). So how would I be able to measure 2V with a soundcard oscillo?

follow his instructions, you need a few parts that should be found almost anywhere to protect the input.
http://homediyelectronics.com/projects/ ... illoscope/

If it's not adjustable then your going to have to learn how to troubleshoot the circuit and find the " bad device"

One thing I recommend is to relax and enjoy the moment. Think of it more as a puzzle or education moment over a exercise in frustration.

Page 4 of the SM has the block layout of what is happening and the key components. Reference that to the SM schematics as you troubleshoot.

Alright thanks a lot!
How I see it, it's gonna be hard to get precise quantitative values with a software oscillo, no matter what the soundcard, because there is always gonna be some level of attenuation
that I can't precisely control unless I do some precise calibration etc.

I'll try to find someone with an oscilloscope that can lend it to me

Nevertheless, I think my sound is so quiet that I'm never gonna be able to reach 2v p-p.