Jawari Transformer Question

[Baktown]

I have a newbie question about transformers.

I'm going to build Tim Escobedo's Jawari (a simple sitar emulator) which uses a small 10K: 10K transformer (as seen below).

I assume that the positive side of the transformer goes towards the 9V+ input, is this correct?

Thanks in advance!

Rock on!

Axl

[railhead]

I don't think it matters with that tranny.

I have a jawari circuit built, but I just don't like it like I was hoping I would.

[Baktown]

What didn't you like about it? 

Axl

[zeppelinchld]

i seem to recall that layout having some errors

this is a good circuit to make your own layout

[Baktown]

That's exactly what I'm doing with it.  I found 3 different layouts, all different!

The sound clip on Escobedo's web page sounded pretty good, so I thought I would give it a shot.

Thanks,

Axl

[railhead]

I guess my main issue with it was that it wasn't convincing enough. Whenever I'm in one of my moods and want some crazy sounds, I can chord with it and get all kinds of coolness. As far sounding like a sitar, though, it's about as close as you can get -- but still not great. You really have to setup your guitar vol and tone just right, plus it helps to play with that bending stye, etc.

My plan is to tweak it some more, and maybe stage it with another effect just to get something totally nuts.

ALL THAT SAID, it's a fun build, so I didn't mean to seem like I was raining on your parade! Build the sucker and let us know what you think!

PS: I would like to have a more pronounced scoop, too, but I'm unsure how to go about doing so.

[Baktown]

I can't seem to get this thing to work at all.

Can someone with more knowledge than me take a look at my layout?  I'm wondering if there's a mistake on the schematic.  Shouldn't the GE diodes have opposite polarity?  Are they acting as clipping diodes?

Thanks in advance!

Axl

[Baktown]

OK!

I got it working, I had the J201 pinout backwards (oops), but it doesn't sound anything like the sound clip on Tim Escobedo's page, in fact it sounds like nothing at all.  The volume drops considerably when engaged, so I'm guessing something still isn't right.

Can someone smarter than me take a look at the GE diodes on the schematic and tell me if they're correct?

Thanks,

Axl

[PerroGrande]

The diodes look correct to me.  Your transformer is 1:1 (10K : 10K) correct?

[Baktown]

It is.  I bought 10 of them from Mouser and they're all correct.

I'm confused by the J201 pinout.  According to the datasheet, the pinout from top to bottom is DSG, while the schematic uses the standard DGS.  I haven't gotten around to switching the pins yet, but I'm sure this would make a difference.  FYI...  the voltage on the drain is only .07 volts, which I KNOW is too low.

Axl

[railhead]

As far as the layout goes, the difference between the schematic and the pin on the tran is rectified by how you hook everything up. The transformer should be going to the J201's drain, the 1M resistor should be going to the gate, and the source is going to the 10k pot.

Check out GGG's layout: http://www.generalguitargadgets.com/pdf/ggg_jawari.pdf

[MartyMart]

Your J201 should face the other way around ( from vero drawing ) and then swop input/vol 3 around for correct pinout.
so - flat side facing left top down is D-S-G , gate's your input.
Peace, Marty.

[Paul Marossy]

The Jawari is not supposed to be a convincing sitar substitute. For the effect to be msot noticeable, you need to use the bridge pickup or two out of phase pickups... 

[Baktown]

I'm building it as part of a multi effect package for a friend of mine who plays Rickenbackers, including 12 strings, through a vintage Vox AC30. 

I'm not sure how the Jawari will sound with this setup, but I'm sure it'll sound better than my Gibson SG running through my Marshall!  LOL

Axl

[Mark Hammer]

The Jawari is not supposed to be a convincing sitar substitute. For the effect to be most noticeable, you need to use the bridge pickup or two out of phase pickups.

...And like a lot of Tim Escobedo's projects, these are short and sweet conceptual circuits that come close enough for the time and money invested.  Tim's a very bright and innovative dude, but I don't think he makes any pretense of his various circuits being "finished" or sublimely optimized.

Paul is quite right about the Jawari having certain input needs.  I suspect something like a Tele bridge pickup is probably about right.

Certainly one of the potential shortcomings, or unfinished aspects of the circuit is that everything flows through those two Ge diodes.  My gut tells me that it might be more profitable to somehow split the signal up into highs and lows, run the mids and up through the transformer and diodes separately, and recombine the sitarified upper signal with a clean low end.  The weak link seems to be that when the whole signal gets crammed into those diodes, by virtue of the high-amplitude bass content they give you ugly distortion rather than sweet drone.  Separating the high and mids from the low end might also let people with humbuckers at the bridge use it too.

For now, the fairly obvious question is "What do you get when the .1uf cap on the output is replaced with a much smaller value, like .01uf, which will chop off the bass?".

[Baktown]

OK Mark, I'll bite.  What DO you get when you chop off the unruly bass?  A more realistic sounding sitar pedal?  I hope?

Thanks for the insight BTW.

Axl

[DougH]

Don't mean to pee in the soup, but I've gotten pretty convincing sitar sounds with different garden variety octave fuzzes, octavias, etc. Use bridge pup, turn down gain or guitar volume or both. If it's something that you  have to hold your left hand over your right eye and chant "there's no place like home" in order to get it to work, you may as well build something that can be used for other sounds too.

(Runs, ducks...)

[Baktown]

By all means point me in the right direction for a good octave/fuzz.  That's next on my list anyway!  I haven't had any luck with fuzzes, they all sound gated or too noisy or they just plain suck.

I need some good ideas....

Thanks,

Axl

[Paul Marossy]

I only chimed in because I built the Jawari a long time ago now, and read the text at the bottom of the schematic that explains that it works best with the bridge pickup, etc. Like Mark says, Tim doesn't make any false claims, he just gives us some circuit snippets to mess around with. 

Having said that, I think it sounds cool with a really high gain distortion, which makes it sound nothing at all like a sitar...

[Baktown]

Believe me, I greatly appreciate all the input from everyone.

I didn't wire the 3PDT switch like TE showed it, would that have an effect on the sound?  I wired it the usual way (or at least how I learned it).

Has anyone built the Psychtar, also by Tim Escobedo?  It looks to be a combination of a sitar pedal and an octave up.  I noticed on the schematic that it uses a Darlington instead of a Jfet.

Axl