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I tried the egghead with all sorts of diodes. Germanium with one silicon is nice but there's a little too much fizzies on the top end. What's a good passive rc low pass to keep all my mid range and get rid of those fizzies? Too lazy to do the math and I haven't found a tone control circuit I've liked more than cranking the mids up on my amp :-p

I read an informative article on hard and soft called "cooking your own distortion". Thanks for the help guys.

One more question, I have the egghead circuit on my breadboard right now and it sounds great. Could I substitute the clipping diodes for mosfets like in the zendrive, and make no other changes?

Also, I understand the zen has neg feed loop clip like screamer and the ocd has hard clip like dod250. But both use the bias voltage or faux ground. That's the thing that leaves me confused

Thank you for the response very informative! How come the mosfets need to be connected to a bias voltage or faux ground instead of actually ground?

I've been reading through schematics for the OCD and egodriver and zendrive. Instead of the clippers shunting to ground like in dod250 and other simple hard clipping arrangements. The ocd and the zendrive have 2n7000's in a clipping arrangement but the pair gets some filtered voltage. Why is this? Why is this important? How can I learn more about the need for filtered voltage to these mosfets as clippers?

In my mind a clean boost will not clip in and of itself. It simply amplifies the signal cleanly. Of course I know that an amplified signal fed into the front end of an amp will overdrive the preamp tubes, but clean infers that the boost does not clip on its own. Maybe I'm building it wrong but, my sho's at full gain produce thick distortion. Not something I would expect from a "clean boost"

Wow madbean. Honor. Thanks for the response. I just got my chunk chunk board from you.

Secondary question: the thunderpuss claims to be a clean boost but looks very similar to the sho and slam box. What makes this one cleaner than the other two?

I've come across a lot of mosfet booster schematics like the sho, and the slambox. They all start clipping the transistor about 1/4 way through the turn of the gain pot. Why then are these circuits not considered overdrives?

All three of these pedals use the same concept of the cascading bs170 gain stages, based on the sho boost by zvex. I've recently built the krankosaurus but was disappointed in the blatty fuzzy compressed sound at maximum gain. It seems like there's so much gain that the signal clips out. I do not have a Zener diode and was wondering if this diode on the first stage could contribute to the crappy sound at max gain. I've also omitted the tonal controls after the last gain stage. Anyone built these circuits and have words of wisdom for me?

I built the cave dweller but can't box it up with all that noise. People have good results from the sea urchin?

How can you filter out the noise but maintain fidelity?

How does the deep blue / sea urchin filter it out?

My cave dweller will not make it to an enclosure if the digital artifacts/noise on repeated delays is not eliminated. I was going to post a sound clip but haven't had time.

How does the sea urchin/ deep blue prevent this kind of noise? We sell the mad professor pedal at work an I've never heard that kind of noise come through.

Hi friends

I was surfing the web looking for some reports of jumper pin 3 and 4 of the PT2399 (my sea urchin sometimes stop the delay... and yes in my case it solved the issue..so far) and found a post on dsb that reports a supposed solution for the usual noise of the 2399

I would like to ask to you guys read it and make your comments..

"So, I was running through ideas on the Little Angel thread HERE and going through the new data  from Merlin and it dawned on me...

On the Datasheets, there are only 2 ends terminating to digital grounds. Merlin made note that the Pin 4 "Digital Ground" can be left unconnected, because it is already connected to analog ground through a 10 ohm resistor.

So, I have tried this on a Little Angel, and my noise pig Sewer Pipes Ringverb. I could not get the SP to shut up, no way, no how.

All we gotta start doing is connecting the delay resistor between Pins 6 and 4. That's it. No more "SSHhhhh" until the signal dies out. Awesome stuff!!!

Anyone else want to confirm this for me? I have quiet PT effects, finally! It's too sweet.

frequencycentral:
$h!t yeah!

Looking at the PT2399 datasheet, the delay resistor is actually connected to digital ground, not analogue ground. How have we all missed this crucial peice of information for so many years?

Genius David!

If this is as good as it sounds I'm amazed, excited and in awe!


WhenBoredomPeaks:
I am thinking about how to realise this on my Tonepad Rebote 2.5 pcb without too much destruction.

edit: it looks like that i should cut the connection right between the legs 3-4 and probably should ground that 47uf cap from leg 2 to an analog ground.

Earthscum:
yep, apparently the delay resistor just gets connected straight to pin 4 from 6. I'm still using LA Ver1 with 10n integrating caps and 1n filter caps, and it's still a bit hissy, but it's the regular hiss (may be getting most from the 5532, got an hour or 2 before I have to load stuff up for a show, so I'm gonna check it out now). I did no other mods to the circuits, and was about to start digging for tants, rewiring grounds, etc, bigger caps, and thought about this. So, I do believe this may be the final cure-all for the noise issue. I'm stoked to really start putting some pain to sound with these now... and I can realize my new project (noise was going to be the biggest issue, running harmonics only through delay).

I bet James' (anchovie)Noise Ensemble would even sound "GREAT" with this fix!

ETA: Yep... 100p across the 470k feedback took off the top hiss in the LA... now I think the last bit of digi noise I have is from the Vref. It's just slight clock noise I can hear now that the hiss is gone"

here is the link for that post
http://www.diystompboxes.com/smfforum/index.php?topic=92515.0;wap2

Can this mod be used on the cave dweller?

Will do. Sound clips coming tonight. stay tuned