Ibanez - SD-9 Sonic Distortion  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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Dirk_Hendrik
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Post by Dirk_Hendrik »

mecmast wrote:I'm gonna try your schem whenever i get the layout. Cannot do anything without pcb/layout. So i'll be waiting for you or anyone to post it. That's all...
Uuh,
What is keeping you from giving it a go yourself instead of waiting for someone else to do the dirty work? Otherwise it might be a very long wait.

Other than that, AG posted a bunch of corrections above to the GGG design. Since you've got those boards already you might give those corrections a try.
Sorry. Plain out of planes.

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Post by jimmyjazz »

Bernardduur wrote:Trust Dirks!
Yes, you are right. Dirk, you are the man! Tried dirks, and its sounding like a distortion pedal! all the fuzz has gone! :applause:

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Crimson
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Post by Crimson »

Just a few question...
I checked Hendrik's schematic and another couple of schemes that i found online.

Hendrik:
Image
General Guitar Gadget
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Looking to the "drive" section: on Dirk's schemes the resistor is only 3K3 instead of 33K of the other shematic, the cap is 0.22 VS 22uF,the feedback cap is 1nF VS 220pF and one goes to GND the other to Vbias.What's the correct one?
I tried to connect the 470ohm res both to GND and Vbias...I found the same distortion amount, quite the same tone, but the drive control was acting better when connected to Vbias.
Also the op out cap is different...
So which schematic shold be the correct one? (i know that on GGG schematic there are some mods in tone control and the second Op amp stage).

Then: i've built a sample SD9 with some very small mods...I removed the out buffer, and i connect the out jack directly to central volume pot lug.So i removed the 10K res, the 0.1uF cap and the 2M2 res (the one that goes from signal to ground).Could it be a problem? The effect seems to work proprebly, with a good tone etc etc...

Here there's also a small verolayout (verified, i built it) for the SD9.
Image
The tone and the clipping stage are missing because i wired it externally to make some tests.I'm using a 1Meg Log pot for drive (but is not the best choice...i think the best way should be to use a 500K pot and to change R9 form 3K3 to 47K-100K).I also change C1 (from 47uF to 1uF) C3 (from 22uF to 0.22, as Hendrik schematics) and R6 from 510 to 570K.

Crim

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Dirk_Hendrik
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Post by Dirk_Hendrik »

I'll check your questions tomorrow for certainty but till that time, mine's the correct one.

The 3k3 and the .22uF (tantalum) are correct for sure. Checked that last week. The GND vs Vbias/Vbb thing needs to be checked but shoud not make a difference sonically. It's both "0" from an AC perspective (virtual ground).
Sorry. Plain out of planes.

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Post by Crimson »

Dirk_Hendrik wrote:I'll check your questions tomorrow for certainty but till that time, mine's the correct one.

The 3k3 and the .22uF (tantalum) are correct for sure. Checked that last week. The GND vs Vbias/Vbb thing needs to be checked but shoud not make a difference sonically. It's both "0" from an AC perspective (virtual ground).
Great, really thank you again ;)
I confirm that sonically seems to be no difference.Only the drive control works better...
Regards!

Crim

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Post by jimmyjazz »

My circuit is still at the breadboard stage. It sounds great, but i am having trouble getting hold of a 27nf cap here in the uk. At the moment it's a 22nf cap, and i know this is affecting the tone. I cannot wait to put it all together. It will sit nicely next to my new ts-9!

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Post by Crimson »

jimmyjazz wrote:My circuit is still at the breadboard stage. It sounds great, but i am having trouble getting hold of a 27nf cap here in the uk. At the moment it's a 22nf cap, and i know this is affecting the tone. I cannot wait to put it all together. It will sit nicely next to my new ts-9!
just use a 22nF and a 4.7nF in parallel ;)
Or try a 33nF...I would like to do some tests on it...Also on the "bass cap" in the tone section...

Crim

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Post by Dirk_Hendrik »

Crap!
It is a 33k :oops:

And the 470E resistor does go to ground.

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Post by Crimson »

Dirk_Hendrik wrote:Crap!
It is a 33k :oops:

And the 470E resistor does go to ground.
Thank you man for the answer ;)
And the filter cap from pin 1 to pint 2? is it 1nF or 220 pF ?

Crim

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Post by Dirk_Hendrik »

1nF confirmed.
The 0.47uF (so not 47uF) confirmed too ;)
Sorry. Plain out of planes.

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Post by jimmyjazz »

[quote="Dirk_Hendrik"]1nF confirmed.
I removed the 1nf completley and it sounds BETTER. More gain. Could this spell trouble though?? :scratch:

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Post by Dirk_Hendrik »

jimmyjazz wrote:
Dirk_Hendrik wrote:1nF confirmed.
I removed the 1nf completley and it sounds BETTER. More gain. Could this spell trouble though?? :scratch:
Jep.
Oscillation at high gain and level settings.
Sorry. Plain out of planes.

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Post by Crimson »

Dirk_Hendrik wrote:1nF confirmed.
The 0.47uF (so not 47uF) confirmed too ;)
Perfect :)
Thank you again for your help Dirk ;)

Crim

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Post by jimmyjazz »

Hello to all. It is worth trying higher value resistors in the feedback network, as more gain can be made by doing this. Ok, so I like high gain pedals, but i also like to roll the gain right back and have a slightly overdriven sound. The quest to have both with this one continues.....I may add a mini toggle switch to "add" more resistors.

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Post by Crimson »

jimmyjazz wrote:Hello to all. It is worth trying higher value resistors in the feedback network, as more gain can be made by doing this. Ok, so I like high gain pedals, but i also like to roll the gain right back and have a slightly overdriven sound. The quest to have both with this one continues.....I may add a mini toggle switch to "add" more resistors.
Try a 5K or 10K fixed resistor and a 500k or 1meg (log) pot...
You could have much more gain and a better gain regoulation without adding any switch.

Crim

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Post by jimmyjazz »

Crimson wrote:
jimmyjazz wrote:Hello to all. It is worth trying higher value resistors in the feedback network, as more gain can be made by doing this. Ok, so I like high gain pedals, but i also like to roll the gain right back and have a slightly overdriven sound. The quest to have both with this one continues.....I may add a mini toggle switch to "add" more resistors.
Try a 5K or 10K fixed resistor and a 500k or 1meg (log) pot...
You could have much more gain and a better gain regoulation without adding any switch.

Cheers, will try that. :)

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Post by Crimson »

Now i'm using it with 3K3 + 1meg, but at lower drive setting i think the pedal loose a little bit of sense...
It's not distorted, and a so low drive affect really a lot the output of the effect...
Maybe 10K would be enough to have "not much distorted" sounds at low drive,and a decent output...Try let me know :)

Crim

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Post by jimmyjazz »

Thanks, i will try it later. It has to be said that it is sounding amazing, and i ran it alongside a ds-1 and a digitech hothead and the sd-9 circuit sounds so much better. It sounds more organic. I am trying different caps in the filters and will soon decide on the two i like the most. As i have mentioned earlier in the post, i am using a TL072. I want to try the 4558 but have not got hold of any yet. I have my box etc, and will soon put it all together.

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Post by basuramail »

Dirk_Hendrik wrote:Crap!
It is a 33k :oops:

And the 470E resistor does go to ground.
Hi Dirk, could you please update your schematic with the new corrections

thanks you very much

B.

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Post by Dirk_Hendrik »

basuramail wrote:
Dirk_Hendrik wrote:Crap!
It is a 33k :oops:

And the 470E resistor does go to ground.
Hi Dirk, could you please update your schematic with the new corrections

thanks you very much

B.
'd love to...

But I cannot find the source file. :oops: :oops:
Sorry. Plain out of planes.

http://www.dirk-hendrik.com

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