troubleshooting my shaka

tambek · December 02, 2003, 04:06:51 PM

ok, i finally got the shaka 5 laid out on my project board. The only problem is that it's not working. When i tested where i can still hear the signal, then i found that the volume and tone pots are working. So i guess half of the circuit is working (if you look at the schematic, then i mean the part from R1 to the volume pot - everything that is above the MOSFET and the TL072 part...).
So - that leaves me 2 choices... either the MOSFET's are wired wrong or the TL072. But the MOSFET's can't be, cause i checked them many times and they were wired up the right way. And besides, I checked where the signal is lost, then i could still hear the signal at the 5th lead of TL072 - that's where the signal enters the op-amp - but at the output lead it was lost. I could still hear click and pops and cracks and that sort of stuff, but no signal...

That leaves me the TL072 op-amp. I'd guess its wired up wrong, but i followed the schematic, checked the diagram at Stompbox FAQ and checked SHaka 5 PCB layout. Everythiung is wired up correctly. So - from my knowledge, i should have either a defected or fried op-amp, right? But i had the op-amp in a 8-pin socket. So, could it be that i fired it while soldering the wires to the socket? It didn't happen to me when i was soldering the wires to my MXR Dist+ socket withe the op-amp IN the socket...

Any ideas?

Thanks!

PS: could that show me something, that i still could hear pops and clicks at the output lead (the 7th one..?)

[edit] Now that i'm thinking, could it be that my battery is empty? Or that i've messed up the battery polarity... If I remember right - the red wire was + and the black one was - , right? Tell me if I'm wrong...

Zero the hero · December 02, 2003, 05:06:50 PM

Check for shorts around C3, C2, R2, R1, R3, R4.
Is the PCB correct? Use a DMM with continuity test to check if everything is wired (make this test when disconnected from 9V!!!).
Try changing the op-amp, maybe you've fried it. By the way, I've built it and it worked at once. I used TL082 instead of 72.

aron · December 02, 2003, 05:16:26 PM

QuoteStompbox FAQ and checked SHaka 5 PCB layout.

Did you make the PCB yourself? Did you get the orientation correct on the PCB? Sometimes people get it reversed.

Verify that the op amp is getting power and that the ground pin is grounded. Also that the input is biased via the two 10K resistors junction from power.

tambek · December 03, 2003, 12:18:38 AM

actually it'Ã¤s not on a pcb yet, it's till on my project board... or breadbpoard, whatever you call it...

OK, I'm a beginner, so... what is a DMM and why do I have to disconnect the battery when testing wiring?

Verify that the op amp is getting power and that the ground pin is grounded. Also that the input is biased via the two 10K resistors junction from power. - hmm, as far as I can see, there are no 10k resistors before the IC input, neither the inverted or non-inverted input. Or do you mean the Vcc+? Cause all I can see on the schematic is, that the vcc+ is connected to the+ of 9V battery, no resistors inbetween...

aron · December 03, 2003, 03:24:57 AM

When testing for shorts, you use your Digital MultiMeter (DMM) to test for continuity between pads that shouldn't touch (i.e. short) with the battery disconnected.

R3 and R4 are the 10K resistors. The junction of these two resistors should be half the batter voltage when testing for DC with your multimeter. Yes, the junction of R3 and R4 is Vcc.

http://www.muzique.com/schem/shaka5.gif

tambek · December 03, 2003, 07:18:18 AM

btw.. never mind my not-so-good english I'm not from an english-speaking country, but... let's get to the point...'

i built the shaka by following the pcb layout... yeah, it took some time to figure out how should i lay it out on my breadboard, but i managed to do it... and when i look at the PCB, i see that the V+ is directly connected to the Vcc+ of the op-amp, so... how come the junction of R3 and R4 is Vcc? One thing that i noticed when lookuing at the PCB layout, is that Jack used the Inverted Input2, Non-inverted Input2 and Output 2 instead of the first half (might be because it was easier to lay out the PCB that way?)... So i did the same...

http://www.muzique.com/schem/shaka5a.gif

sorry, removed the pic, now just the url...[/url]

amz-fx · December 03, 2003, 08:13:46 AM

Please post links to images and not the images themselves in forum messages... the reason is that if you put the image inline it requires that my site uploads that image everytime someone reads the message thread even if they are not interested in looking at the graphic. This consumes unnecessary bandwidth - my site ate up the entire 6G bandwidth last month even though I have been steadily adding more capacity since the beginning of the year... 3G -> 6G in 1G steps since April and my web host has said that I have reached the limit and will have to upgrade my hosting package instead of just adding more bandwidth.

Once my hosting contract expires, I have a T1 connection with unlimited bandwidth and disk space that should be available so the problem will ease up then. Using links is cool, and visit the site as much as you like, but please post links and not images. Thanks!

regards, Jack

tambek · December 03, 2003, 10:03:58 AM

sorry, i removed teh image and replaced it with a link... but still, can anyone help me out with this... I just bought a DMM.. and actually I have no idrea what should I do with it... :oops:

aron · December 03, 2003, 12:32:55 PM

Sorry about that Jack, your site must be about 20 or 30X more popular than mine.

I can't even touch your bandwidth.

Aron

amz-fx · December 03, 2003, 11:09:40 PM

Many thanks for the help! I had already moved all of my media files off to my T1 connection along with certain large graphics and then banned all site grabbers (sorry guys) but even with these changes I have not been able to hold down the bandwidth use which has been steadily increasing.

I checked my logs to make sure there was nothing odd going on and it is merely a jump in the number of hits, mostly from my direct links but also from search engine results.

Interesting stat? muzique.com had a total of 21,000 unique visitors in November and served up 1.02 million requests for images, pages, text and audio files! (obviously there are usually numerous images per page)

Thanks again, Jack

aron · December 04, 2003, 02:54:06 AM

I don't know how to check for unique visitors, but according to a "webalizer" program, I had:

20,000+ unique sites??? is that the same is unique visitors?

2.5 million hits? Can that even be correct?
1.1 million files served?

is that possible?

Even so, I don't even reach 1G of traffice per month.

Peter Snowberg · December 04, 2003, 04:21:05 AM

Quote from: aron20,000+ unique sites??? is that the same is unique visitors?

Keep in mind that dial-up users will show up at multiple addresses. One surfer can easily look like 25 or more.

The hits figure is funny because browser checks the remote file before downloading (to see if the data is already in cache) so each file will look like 2 hits minimum.

If you want php counter code, I have it.

mySQL also keeps stats, you might want to check those.

Those are some big numbers for sure. Congratulations.

-Peter

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troubleshooting my shaka