Soul Sonic - Crackle NOT Okay!

soulsonic · Post by **soulsonic** » 06 Jan 2009, 04:11

Okay, I measured it on the breadboard again, and estragon is right-on about the Drain voltage changing as the gain is adjusted in a standard SHO; and I got the same general voltages of 7-ish at minimum gain, and 4-ish at maximum.
BUT, I measured the Drain-Source voltage and found that it only changes by about a volt throughout the gain range. This must have been what got me thinking the bias doesn't change much as gain is adjusted. I asked Björn to give me some advice for the circuit, and he suggested seeing what how the D-S voltage behaves and work from there. He also recommended trying higher Drain loads, but I wasn't happy with how that sounded....
The way I came up with my final version was by working backwards from the end result I wanted. I wanted to keep the sound of the SHO circuit at max gain, so I started with that and figured out a new way to turn the gain down.

Thanks for your input, estragon! It's been very useful for helping me both understand how the original works and why mine sounds similar despite working differently. I appreciate it.

estragon · Post by **estragon** » 06 Jan 2009, 18:47

soulsonic wrote:Thanks for your input, estragon! It's been very useful for helping me both understand how the original works and why mine sounds similar despite working differently. I appreciate it.

One is glad to be of service!

guiltyspark · Post by **guiltyspark** » 18 Jan 2009, 17:54

RnFR wrote:first the Klon-buster, now the Krackle-killer? what's next?

On a more important note (just kidding), GREAT GIF in your sig! Is that Betty Page?

Guiltyspark

RnFR · Post by **RnFR** » 19 Jan 2009, 01:30

yeah, sure is.

when she passed on to the big burlesque hall is the sky a while back i changed up my avatar in reverence.

glad you like it!

dap9 · Post by **dap9** » 29 Jan 2009, 01:53

Awesome work and I can't wait to breadboard it. Got a question... Is D2 an "Avalance" diode? Why use that instead of a Zener? And how does one order that component? Sorry, it's new to me.

Thanks again!

Fuzzer · Post by **Fuzzer** » 29 Jan 2009, 02:43

A zener is an avalanche diode, it is also called that way because it operates under that effect.

soulsonic · Post by **soulsonic** » 29 Jan 2009, 02:48

dap9 wrote:Awesome work and I can't wait to breadboard it. Got a question... Is D2 an "Avalance" diode? Why use that instead of a Zener? And how does one order that component? Sorry, it's new to me.

Thanks again!

Oh, it's a zener... a 12v one. I use 1N5242 usually; it's 1/2watt size and easier to make fit than the 1N4742 1watt. Those 1watt zeners have big thick leads that are a real bear to get bent the way I want when doing perfboard stuff and they need bigger holes drilled than any of the other components when building on pcb, so I always prefer 1/2 zeners for antistatic protection; any bigger is a waste in this case.
If you don't have any 12v ones on hand, you could use probably anywhere between 7-15 volts and be fine... you could even use an LED (I think green would be better than red).

Oh, and if anyone builds this and finds it to be too hissy, you can put a small resistor in series with the Source to lower the maximum gain a little bit and cut down on some of the noise... try 330 to 560 ohm. If you really only need a little bit of boost, you could go even larger, like 1K, and there shouldn't be any bad hiss at all. Thanks to JHS for that recommendation.
But if you want the same max gain as the original SHO, the Source connected straight to ground is the only way to go!

dap9 · Post by **dap9** » 29 Jan 2009, 03:09

Thanks man! I have some 9vs around, but I'll prolly order the ones you mentioned - just to have them.

earthtonesaudio · Post by **earthtonesaudio** » 29 Jan 2009, 19:34

I'd rather use these:
http://www.vishay.com/docs/72705/2n70000k.pdf
...which are available from here (though the datasheet on mouser.com is outdated):
http://mouser.com/Search/ProductDetail. ... gbddq0I%3d

...Than have to put in an extra part for ESD protection.

RnFR · Post by **RnFR** » 29 Jan 2009, 20:35

earthtonesaudio wrote:I'd rather use these:
http://www.vishay.com/docs/72705/2n70000k.pdf
...which are available from here (though the datasheet on mouser.com is outdated):
http://mouser.com/Search/ProductDetail. ... gbddq0I%3d

...Than have to put in an extra part for ESD protection.

hmmm... a protected mosfet. fancy!

soulsonic · Post by **soulsonic** » 29 Jan 2009, 21:11

Thanks for the tip!

Mouser stocks the 2N7000KL, but not the BS170KL. Kinda annoying. After using 2N7000 for a long time, I found that I prefer the sound of BS170.

danielzink · Post by **danielzink** » 30 Jan 2009, 12:17

soulsonic wrote:Thanks for the tip!
Mouser stocks the 2N7000KL, but not the BS170KL. Kinda annoying. After using 2N7000 for a long time, I found that I prefer the sound of BS170.

http://www.mouser.com/Search/ProductDet ... jS45JSmrKs

?? not the correct BS170 ?

Please correct me if I'm wrong.

Says Fairchild - 10,000 of 'em in stock ?

Just trying to help.

Dan

earthtonesaudio · Post by **earthtonesaudio** » 30 Jan 2009, 13:10

If you check the datasheet of the 2N7000KL ( http://www.vishay.com/docs/72705/2n70000k.pdf ), you'll notice there is built-in ESD protection between gate and source. This is a hard-to-find feature on discrete, small signal MOSFETs, but Vishay/Siliconix also makes a BS170KL with the same sort of ESD protection. Unfortunately, Mouser doesn't stock that particular device.

So yeah, a different kind of BS170.

soulsonic · Post by **soulsonic** » 30 Jan 2009, 21:27

I checked Allied, Newark, Digikey, and Futurlec too... no one has 'em!

I'll get some of the 2N7000KL for Mouser just give 'em a try because I build these kinds of things alot so it will definitely be a great problem-solver... but the 7000's are so noisey... and gritty. I guess I can use the grittiness to an advantage; make it extra grungy.

danielzink · Post by **danielzink** » 30 Jan 2009, 23:47

Hate to say this but...........didja check eBay ?

Dan

soulsonic · Post by **soulsonic** » 31 Jan 2009, 00:41

danielzink wrote:Hate to say this but...........didja check eBay ?

https://shop.ebay.com/?_from=R40&_trksi ... Categories

devastator · Post by **devastator** » 03 Feb 2009, 18:00

Just one question :

With this mod we can have a real boost control all the pot. range is usefull ? not like the original SHO ?

earthtonesaudio · Post by **earthtonesaudio** » 03 Feb 2009, 18:05

The gain should go from about unity up to the same maximum boost available from a SHO.

Not sure on what taper should be used though... perhaps Martin (Soulsonic) can chime in on this.

GJonesy · Post by **GJonesy** » 13 Feb 2009, 13:20

Well Ive lurked on here for a while now trying to pick up as much as I can. So I thought I'd ask a (stupid?) question.
Could this be used as this first stage in a Box of Rock/Metal to remove the crackle from these effects too?
thanks in advance G

earthtonesaudio · Post by **earthtonesaudio** » 13 Feb 2009, 16:18

GJonesy wrote:Well Ive lurked on here for a while now trying to pick up as much as I can. So I thought I'd ask a (stupid?) question.
Could this be used as this first stage in a Box of Rock/Metal to remove the crackle from these effects too?
thanks in advance G

Absolutely. That's not a stupid question at all. Think of the "Crackle NOT Okay!" as a building block, general purpose gain stage (as Zach Vex did/does with the SHO).

Soul Sonic - Crackle NOT Okay! [documentation]