Soul Sonic - Crackle NOT Okay!

soulsonic · Post by **soulsonic** » 27 Feb 2009, 10:45

Here is a Vero stripboard layout.

: Vero Layout for the SoulSonic's Crackle NOT Okay

allforone7 · Post by **allforone7** » 27 Feb 2009, 14:54

any recommendations for diode substitutes?

Barcode · Post by **Barcode** » 27 Feb 2009, 15:38

D2 appears to be for polarity protection, so any 1n400x diode would suffice as a replacement. The other diode looks like static protection for the mosfet, I would say any 9.1v zener would work. Soulsonic, please correct me if I'm wrong

briggs · Post by **briggs** » 27 Feb 2009, 15:47

yep barcode. You could also use a red led for static protection

soulsonic · Post by **soulsonic** » 28 Feb 2009, 03:07

Barcode wrote:D2 appears to be for polarity protection, so any 1n400x diode would suffice as a replacement. The other diode looks like static protection for the mosfet, I would say any 9.1v zener would work. Soulsonic, please correct me if I'm wrong

Yeah.... but if you just spend 50 cents and use the parts I spec, it will probably work better. This is all common stuff you can get from Mouser. Everyone should have lots of these diodes in their personal stock because they are perfect to use in just about any pedal. The 1N5242 is a 1/2watt 12v zener which is much easier to fit than those chunky 1watt ones, and the 1N5819 is a Schottky with an extremely low voltage drop, so you get a noticeably higher voltage than if you use a 1N400x.

You can substitute stuff if you want, that's perfectly fine, I'm just trying to raise awareness about these nice inexpensive parts because I feel they've improved the quality of my builds.

Barcode · Post by **Barcode** » 28 Feb 2009, 13:53

fair enough, but man 1n4001's are so cheap

I'll check these diodes out that you recommend and give em a shot.

Post by **audioguy** » 28 Feb 2009, 14:12

soulsonic wrote: The 1N5242 is a 1/2watt 12v zener which is much easier to fit than those chunky 1watt ones, and the 1N5819 is a Schottky with an extremely low voltage drop, so you get a noticeably higher voltage than if you use a 1N400x.

I've got a 1watt 12v Zenner and some 1n5817 Schottky, will these subs be closer than the others above?

soulsonic · Post by **soulsonic** » 01 Mar 2009, 08:49

audioguy wrote:I've got a 1watt 12v Zenner and some 1n5817 Schottky, will these subs be closer than the others above?

Yes, that would be fine.

cpm · Post by **cpm** » 01 Mar 2009, 09:55

soulsonic wrote:... and the 1N5819 is a Schottky with an extremely low voltage drop, so you get a noticeably higher voltage than if you use a 1N400x.

and they are nice for clipping too!

Post by **MarcoMike** » 03 Mar 2009, 21:23

About the think at the beginning... regarding the 2M2 resistors... what about a "clarity" control... substituting the Hi value resistors with, say, two 200K resistor plus a 2M+2M stereo pot... you know what I mean...

hopefully turning the pot would result in equal resistance on the two pots thus same res from "in to 9V" and "in to ground"

minimum res 200k (or lower) for low impedence, dark sound... and >2M at max for SHO clarity... maybe the low value should be even lower, as reading estragon's post at max gain the impedence is 140k, and I don't really hear a big difference in "clarity".. maybe because my ear drum is already quite stressed at that point...

soulsonic · Post by **soulsonic** » 09 Mar 2009, 09:18

Try turning the transistor around the opposite way. Most 2N7000 have an opposite pinout from the BS170.

Barcode · Post by **Barcode** » 09 Mar 2009, 17:39

ibodog2 wrote:Last night when searching through the forums I came on a thread for another booster that had links to the pinouts of several mosfets. I saw that the pinout for the 2N7000 is reversed from the BS170. I turned it around and tried a new one turned around, but still no audio at all from my board. Power is getting to the board. Are there some critical places where I could check voltages?

first thing would be transistor voltages.

also, looking at your build pics, make sure the two resistors in front of the 2n7000 are not touching.

Barcode · Post by **Barcode** » 10 Mar 2009, 04:41

those voltages look about dead on. probably a wiring problem.

soulsonic · Post by **soulsonic** » 10 Mar 2009, 07:25

Yes, those voltages are perfect. Somewhere, either the signal isn't getting in to the transistor, or it isn't getting out from it. The transistor itself is working exactly as it should.
Look for something possibly shunting to ground or maybe bad connections on the gain control.

briggs · Post by **briggs** » 11 Mar 2009, 10:27

The zener is not there to alter the tone - it is there to protect the mosfet from static discharge. If you don't install one your mosfet will end up blowing out. I use red LEDs and they work fine for the job.

The difference, as you mentioned, is in your "input impedance" resistor choices. With 10M resistors the max input impedance is 5M ohms (at min gain) this input impedance decreases as you increase the gain, at max gain the input impedance is much lower - only 140k. This has the side effect of rolling off some of the "cutting" treble at max gain, very useful. If you only used 2M resistors instead of 10M your input impedance is way lower than it should be (~1M at min gain and ~30k-40k at max gain), resulting in the looser, less defined tone you hear.

To understand how input impedance affects circuits check out this great article by Jack Orman - http://www.muzique.com/lab/imp.htm Everything you really need to know is there...

devastator · Post by **devastator** » 11 Mar 2009, 17:34

but maybe you remove the zener, i think BS170 has an internal diode.

RnFR · Post by **RnFR** » 11 Mar 2009, 17:51

devastator wrote:but maybe you remove the zener, i think BS170 has an internal diode.

those are the bs170KL[/color], mentioned earlier in this thread, which are apparently very hard to find.

briggs · Post by **briggs** » 11 Mar 2009, 18:19

All mosfets have an internal body diode, not all of them have internal static protection. Keep the protection diode there or it'll go PoP

soulsonic · Post by **soulsonic** » 12 Mar 2009, 05:57

ibodog2 wrote:Wow, I got in some BS170's and replaced the 2N7000 I was subbing in this circuit. Major difference! That 2N7000 was positively ratty by comparison with some dirt and grit even at low settings. The BS170 is much cleaner for further up the dial. Much better for my intended purpose in this pedal.

Oh yeah, that's why I've been using the BS170 in all the Four Bangers I've been building. I had originally used 2N7000 in a couple, but then I tried the BS170, and that's been my choice ever since. The 2N7000 sounds excessively noisy and grungy to me... it can sound cool in some effects, but as just a straight booster kinda thing, I think the BS170 is definitely superior.
I've tried comparing the cheaper Fairchild BS170 to the more expensive Zetex BS170P, but I didn't hear much difference... maybe just subtle differences, but not enough for me to justify 4 times the cost. Maybe I'd use the Zetex in something more expensive just because it's fancier.

How does your homemade one sound compared to the one in the Four Banger?

briggs · Post by **briggs** » 12 Mar 2009, 11:45

The BS250 is a P-Channel Mosfet, you need an N-Channel device for the SHO circuit. Think of the difference as the same as NPN and PNP Trannies.

Soul Sonic - Crackle NOT Okay! [documentation]