Ok i built the Jawari Schematic finally.
But i have incountered problems.
I plugged it in and had to turn up my amp at full volume and i could hear a guitar signal struggling to come through, there was also alot of buzz,
I don;'t know what i did wrong.
If the buzz sounds like the same one when you touch the end of your cable to your finger, then it's probably a bad ground connection... or just a bad connection in general. Looking at the schematic, it looks like it'd be reasonably easy to forge to ground the 9v battery (I'm pretty sure you should always be doing this, I haven't built a schem where you don't have to... I'm still a novice though)
-Colin
You could try comparing your layout against the one I made when I made my Jawari, maybe it'll help.
http://home.att.net/~u2p0j0m4/jawari-pcb.gif
Check the pinout on the J201, I don't remember if I had a boo boo on my layout or not. Your problem sounds like it has something to do with your transistor installation to me.
Hope that helps.
i wanted to build one of these, and I realized today I have all the parts except the 1N34 Ge diodes - I figure I'll just use sockets and fool around with various diodes until I can get my hands on the right ones - I don't remember what other diodes I have, I know I have some Ge ones from small bear and some other misc. ones - any ideas what else would work well in the meantime?
Gonna hafta try messiin with mine. it sounds just like an octave [but gatey] and way below unity.
...Thought I had that Fet in there the 'right' way...as always with a probckt. ..could be anything.
Ok i fixed the buzz with your pcb diagram but, it didn't sound like a sitar at all, it just made a glorified tone control, i pluged on my battery and and it wasnt very loud so i turned on my amp dist to make it bigger then i noticed that all it was doing was filtering the distortion and making it more like overdrive and when i turned the pot the other way it got a bit quieter and bassy, i am confused.
SO i switched the trasformer around
1 6
2 5
3 4
to
6 1
5 2
4 3
i mean that i switched the connections cause i thought i had it right but thats no good cause it just wont let any signal through at all now.
I was wondering about the other way i had it, would it matter if the resistor ex: 100k, has a gold, silver strip on it, i know that that means the value is either higher or lower by a certain amount based on the extra strip but would that make much of a diff? If the 100k was in fact like a 105k or something liket that?
Cause i really don't know what this 'sitar' pedal is supposed to do now, it doesnt sound anything like the sound samples make it out to be.
It should sound like the soundclip does. Mine does anyhow. Are you sure that you have a 10K:10K audio transformer with a center tapped primary and secondary? I don't think it will work with any other transformer...
If your 100K resistor actually measured 105K, it shouldn't make that much difference. The silver and gold bands indicate the manufacturing tolerance.
ok this is what it says for info (transformer)
Hammond
Primary: 10k ohms CT
Secondary: 10k ohms CT
Unbalanced D.C. 1.5mA Max
Frequency @ 150 milliwatts
( +/- 1.5 db. 300Hz - 50KHZ)
Ok, it sounds like the transformer is OK. The only things that come to mind is that the JFET is in wrong, the diodes are damaged or installed wrong, or something is wrong with that transformer.
A thought just occured to me: Ge diodes can get fried if you apply too much heat to them when soldering them in. Maybe that is the problem. 8)
Sounds like there may be at least two things wrong. If it sounded wrong before you turned the transformer around, it should have sounded the same after it was turned around, too. That it sounded different (though still wrong) seems to indicate perhaps, in addition to the original problem(s), something else got mucked up after reorienting the transformer.
In case you don't know, the Jawari is intended to be used with the bridge pickup. If used with a neck pickup, it tends to sound like a weak octave up circuit. It normally decreases sustain, however, it shouldn't actually have a gating effect. It also isn't a very loud effect, but it should be at least unity gain.
If you don't have Ge diodes, Schottky diodes such as the 1N5817 can be subbed successfully.
I am just going to say the hell with this project and build something simple simple maybe.
I dunno it's too, complicated for my first project
That's cool. Sometimes I can't get something to work right, either. I have built quite a few circuits now, too. I get a problem child once in a while. :oops:
Try something different and revisit it at a later date.
I've got problems with mine - it's on breadboard and using an audio proble I get a sound after the transformer just before the Germainuim diodes (IN34) but nothing after the Ge diodes. The diodes are matched by hand to 330/331 from a bunch I had (I have tried other diodes but with the same result). I've tried removing the silicon diode but there was no diff - I tried bypassing the resistor after the silicon diode but the diode got very warm. The circuit I'm going after is he Tim Escobedo one and all the components are according to the schematic.
I tried to find alternative schematics just to try them but I have not been able to access them does anybody have an alternative layout or has anybody had the same problems as me?
/Taz
I've got problems with mine - it's on breadboard and using an audio proble I get a sound after the transformer just before the Germainuim diodes (IN34) but nothing after the Ge diodes. The diodes are matched by hand to 330/331 from a bunch I had (I have tried other diodes but with the same result). I've tried removing the silicon diode but there was no diff - I tried bypassing the resistor after the silicon diode but the diode got very warm. The circuit I'm going after is he Tim Escobedo one and all the components are according to the schematic.
I tried to find alternative schematics just to try them but I have not been able to access them does anybody have an alternative layout or has anybody had the same problems as me?
/Taz
When moosapotamus.com comes back up, you can access Charlie's layout.
Check the forum archives, there was a recent discussion (December?) about the Jawari, specifically on its shortcomings. It can be a frustrationg little circuit, but sounds VERY cool when everything falls into place.
Travis,
Aha so the moosapotamus site is not gone for good? I read the threads about the Jawari including the one u mentioned and then I tried to find the moosaputamus site and it wasn't there - freaked me out a bit 'cos I was there only a couple of weeks ago.
Do you know when it will be back?
It should be back up pretty soon. Charlie seemed somewhat surprised that it was down.
I have a working PCB layout that I designed if you're interested. Drop me an email at psalmist@att.net if you're interested.
I built mine, using the first schematic Tim offered (the one with the MPSA13, *not* the one with the variable-gain JFET) in less than an hour and it worked great first time.
It *does* require you to use the bridge pickup, and *pick* near the bridge. I haven't tried it out with bridge-position humbucker, but I imagine it works better with a single-coil pickup than an HB, given all the other things one needs to do to keep the lows to a minimum and the "bark-ey" mids to a max.
Tim, what are the pros and cons of the two versions you've posted? (Darlington vs JFET)
Hmm... I didn't know there was two versions of that circuit.
My PCB layout at http://www.diyguitarist.com/PDF_Files/JawariPCB.pdf is based on the JFET version.
As shown, the Darlington version has more gain, the idea that it could be capable of octave-up effects. But it's more complicated. BTW, a regular BJT would probably work in there as well.
I win......the prize for biggest moron.
I decided to biuld my Jawari on breadboard because I'd read about some of the problems that people have been having. So I borrowed one that has holes in groups of 5 both vertically and horizontally.
I checked the board for continuity with a voltmeter and all was fine until I got the Jawari on there and of course it did not work - I knew there was something fundamentally wrong but as I am new to building pedals I knew not what.
I got a PCB layout from Paul Marossy (Mega thanks) so I could compare with the schematic and mine was laid out similarly (according to Tims E schematic on snippets- what is going on?!?!?! Removed the 1K resistor and the silicon diode got really hot - this is so very wrong most people gat hardly a signal yet I can't hear anything but the diode is burning up? Turned out that the horizontal holes of 5 are not just connected to each other but to the next group of 5 as well across the whole breadboard - and I had my 9v battery coming in on these further along the board - oh no. Fixed that -
I now have a working JAWARI!!!!!!!!!! and it is seriously cool (Thanks Tim E)- using an SG it works on all pickups selections but better or worse on different parts of the fretboard but always plucking near to the bridge. I have a lot more than unity gain.
Experimenting with changing components and stuff - now it works.
I have it plugged into my Adrenalinn II on the Hiwatt Amp setting "talking bout my chicken masala"
So is there a prize for temporarily having a lower IQ than a plank of wood?
/Taz
I win......the prize for biggest moron.
I decided to biuld my Jawari on breadboard because I'd read about some of the problems that people have been having. So I borrowed one that has holes in groups of 5 both vertically and horizontally.
I checked the board for continuity with a voltmeter and all was fine until I got the Jawari on there and of course it did not work - I knew there was something fundamentally wrong but as I am new to building pedals I knew not what.
I got a PCB layout from Paul Marossy (Mega thanks) so I could compare with the schematic and mine was laid out similarly (according to Tims E schematic on snippets- what is going on?!?!?! Removed the 1K resistor and the silicon diode got really hot - this is so very wrong most people gat hardly a signal yet I can't hear anything but the diode is burning up? Turned out that the horizontal holes of 5 are not just connected to each other but to the next group of 5 as well across the whole breadboard - and I had my 9v battery coming in on these further along the board - oh no. Fixed that -
I now have a working JAWARI!!!!!!!!!! and it is seriously cool (Thanks Tim E)- using an SG it works on all pickups selections but better or worse on different parts of the fretboard but always plucking near to the bridge. I have a lot more than unity gain.
Experimenting with changing components and stuff - now it works.
I have it plugged into my Adrenalinn II on the Hiwatt Amp setting "talking bout my chicken masala"
So is there a prize for temporarily having a lower IQ than a plank of wood?
/Taz
"So is there a prize for temporarily having a lower IQ than a plank of wood?"
Well, I don't know what a good prize is for that, but don't feel too bad. I tried using a dual timer chip (556) for something not long ago, but I didn't realize that there were certain rows connected together. So, I had stuff connected wrong, and the chip got so hot that it started to melt my breadboard. :oops:
Anyhow, congratulations! Great feeling, isn't it?
Paul - it's a luvvvley feeling absooooluuuuutley.
Thanks for your help!
/Taz
Glad to be of service, Taz. 8)