Shaka 5

[tca]

Heres what I wound up with. By paying attention to the ground wires on the breadboard, the hum was substantially reduced. I think it will be fine once its in an enclosure.

Suggestion: to get a little more compression and extra harmonics replace de 1k resistors at the sources of the minibooster by 1.8k resistors.

Cheers.

[tca]

Very nice! It's been a while since I fired up my Shaka 3 - still have it. I use a lot less distortion now so will be interesting what the next "shaka" will sound like.

The Shaka HV (the op-amp part) is great to overdrive anything. Simple and very effective.

[Cozybuilder]

TCA- They did just what you said, very worthwhile mod.

Rich- Good reading suggestions, thank you.

[aron]

Yes, I still use a variation of it all these years.

Very nice! It's been a while since I fired up my Shaka 3 - still have it. I use a lot less distortion now so will be interesting what the next "shaka" will sound like.

The Shaka HV (the op-amp part) is great to overdrive anything. Simple and very effective.

[Kipper4]

I'm still working on this currantly experimenting with post distortion eq.

On the breadboard right now
Link to schematic earlier on in the thread
the basic Shaka5 IC1 and clippers (mosfet) right up to and including the 100k trimmer
Whats new
A 1uf decoupling cap after the trimmer.
then an active 3 band EQ based on the TL082 application data sheet (redrawn by RDV with Bias).


see here
IIRC page 9

http://users.ece.gatech.edu/~lanterma/sdiy/datasheets/opamp/TL082.pdf
only differnace is that the oppy is biased with 100k to VB on the non inverting input

Option 2
after the decoupling 1uf
The active EQ from the ROG Thunderbird (might need some tweeking to my taste)


see here
http://runoffgroove.com/thunderbird.html
the final 2 op amps

A lot let noisy than my attempt with the mini booster
Wish me luck
Rich

[Kipper4]

Did some testing this morning with the tl082 tone control. It sounds awesome and has lost little to none of that greasy mosfet clipping even without the mini booster.
I'd like to change some of the caps/ resistor in the control. If anyone has any advice on how the work out the frequency cut off for the tl082 filter please feel free to advise me.
Thanks
Rich

[mac]

A 1uf decoupling cap after the trimmer.
then an active 3 band EQ based on the TL082 application data sheet (redrawn by RDV with Bias).


see here
IIRC page 9

http://users.ece.gatech.edu/~lanterma/sdiy/datasheets/opamp/TL082.pdf
only differnace is that the oppy is biased with 100k to VB on the non inverting input

mac

[Kipper4]

I think I've found the formulas I need at least to do the TBird filters here

http://www.diystompboxes.com/smfforum/index.php?topic=110210.msg1010097#msg1010097

[Cozybuilder]

Rich- Good call on the TL082 tone stack. I tried it in a few different ways, including removing the SRPP, a second chip (blah blah woof woof), and finally decided to simplify and just replace the tone-stack. It really came alive then, the stack as presented below sounds very good, yet I plan to tinker with C & R values a bit and hope to improve the top and mid responses (at least to my tin ear). The 60 cycle hum is reduced significantly compared to the SWTC-V3 that was in there before.

Here is what is on the breadboard now:

[Kipper4]

Russ.
I cut the SRPP from the design as the distortion circuit upto that 33k has enough u mph to drive the stack.
I left in the 100k trimmer from the original design (where you have the 33k)only difference is it is now a pot (level) and tagged on my tone stack after it with a decoupling cap 100f

[Kipper4]

Thus far
Errata.
R7 100k
R13 3k3
R14 1k8
and the second 1n34a diode on the second mosfet clipper should be above it not below(see Cozybuilders schematic)
Treble pot should be 500k

[graemestrat]

Hi Guys,

Love what you are doing with the tone stack but your diodes D4 and D4 are in backwards.
You might find it sounds quite a bit smoother if you reverse them. This is because all mosfets have a built in reverse polarity protection diode between the drain and source. This is what you are listening to at the moment.
Try it and see!

Cheers

[Kipper4]

sorry Q&D schematic you are correct D5 should be above the mosfet not as drawn.
thanks

edit :C10 is probably superflous too

[graemestrat]

Hi Rich,

What I am suggesting is to simply flip d4 (end for end) and put back in that way, and the same for D5. Try it, you'll like it!

Cheers
G

[Kipper4]

will do Thanks

[Kipper4]

sounds like silicone diodes. more gain/volume.

[graemestrat]

ok,

you have more volume because now you are hearing the mosfet distortion whereas before it was just the 2 diode pairs  in series.
At least now it is built as it was designed!

Cheers

[Kipper4]

how so sir?

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

[graemestrat]

Another thought,

The mosfets have this intrinsic diode in parallel with the drain and source, only backwards, so if your d4 and d5 are backwards they force the signal through the intrinsic mosfet diodes instead of the drain/source junction, which gives you the different sound. I think I need to draw you a picture but I"m new on here and am not sure how....... I have noticed a few places where I have seen this circuit that have these diodes around the wrong way...

You might like to try out the irf510 fets instead of the 2n7000's for a different sound.   

[graemestrat]

Pretty sure the muzique circuit is wrong too!