The Sentinel - PT2399 based pitch modulator, delay, reverb & drone verb

[spacefuzz74]

hey all.

I built the Sewer Pipes reverb last weekend (this here):
http://www.diystompboxes.com/smfforum/index.php?topic=88178.0

It's a nice little reverb/noise circuit that is fun to mess with.  it is a bit limited, however.  so, as i was looking for more info on the Sewer Pipes circuit, i found this (The Sentinel):
http://www.diystompboxes.com/smfforum/index.php?topic=102861.msg929070#msg929070

it is based on the Sewer Pipes & Noise ensemble circuits.  there is a schematic in the link above, and i have also attached it here.  

It is PT2399 based, which i know can be an instant headache sometimes.  but, i thought if anyone out there has the skills to draft a Vero layout, as well as a bit of free time, this Sentinel circuit would be a welcome addition to this community.

Check it out, and let me know what you think!

[Addy Bart]

I'm also curious about this one.

[Sergio]

Ciaran detected 3 ERRORS, SonusFluxa was able to see them, not me, what a shame these are now FIXED.





358 is downwards. I haven't verified or even tried this. If someone else wants to take a look at this, any help is welcome. Thank you!
 The bypass is not present in this layout, it could be connected through the IN and OUT without the optoelectronic bypass.

[Sergio]

[Addy Bart]

Thanks Sergio! Will try this when my next order arrives.

[Sergio]

Thank you, but thats nothing compared what with others here work at. Im a noob but I think that possibly the 33k resistor on the left side is what restricts the amount of modulation, maybe putting sockets there would be useful to try some other values. And the fx sounds really great, but lately I have seen and heard here a lot of good time and modulation effects and add-ons,so I wonder how go the delay part of that with the random lfo, http://tagboardeffects.blogspot.com.es/p/forum.html

Now I see that you are the one that was recording a video from that lfo! I liked it a lot by the way.  So you have it already built in case you are willing for some more testing. When I first heard your demo, I thought, what would happen if some of these 3 resistors where controlled from your playing via envelope detecting?  
And if you are interested in delays and their "noises" have you seen that post from freestompboxes?
http://freestompboxes.org/viewtopic.php?f=7&t=26945&p=259666&hilit=snazzy#p259666
thats another interesting take on the pt2399 modulation.

[Addy Bart]

I've been experimenting a bit lately with the pseudo random LFO on delays so I can try this out!
The LFO does crazy things when connected directly to a delay pot (example here on a Multiplex):

https://m.youtube.com/watch?v=7spG0nrUraA

It will likely create some interesting sounds on the Sentinel too

[Sergio]

When I heard your demo I thought what would sound to have various modulations at the same time, the snazzy wow and flutter and that pseudo random.. And  the king dubby delay came to my mind it uses 2 pt2399 controlled by a transistor some passive components and a single pot.
But what would happen if we used a double 50k pot instead, going to PT1 and PT2 and each of these delays would be feed with these modulations?  Snazzy to Delay1 and pseudo random to Delay2?
I have to try this, the problem is that lately i ve been building very little. Lots of thing to do at home!

[Addy Bart]

Yes I've built the Clarinot. One of my favourites (actually all of Doug's stuff is great).
I'll post a vid of the sentinel with the random LFO as soon as I can (might be a couple of weeks though due to some busy homelife). Thanks again for the layout!

[Addy Bart]

An envelope/random LFO combo sounds fun. Has the snazzy wow and flutter been traced or laid out for vero?

[Ciaran Haslett]

Great job Sergio!

2 little errors just

Move the top leg of the input 10K down 1 row
Move Width 3 to the bottom of the 510r resistor
Width 1 and 2 to ground (pin 4 looks like a good spot)

[Sergio]

Thanks a lot Ciaran. Good spot. Your help is very appreciated!
And yes, Addy, it was traced, the freestompboxes link i posted is the one, i was about to lay it out, but i was wondering, hope someone can answer me, if with that 4007 ic it would be possible to make instead of one, likevsnazzy, 2 or even 3 envelope detector modulations.  I like very compact layouts and thinking that we could make more out of this ic, 14 pins are a lot of space, if this could do more things, this would be great, I took a look at the pinout and im almost sure a 2nd one would be possible. Thats where i thought of your 2nd youtube video from the pseudo random, if at least one of those 3 oscillators was enveloped, what could it sound?  
And another doubt i have, the snazzy mod i find it great while you are playing, the justnick video on youtube i find it awesome, but the moments you stop playing, something like addy 2nd video is very very interesting. So, is there a way, we could have another detector for playing or "you decided to give some space" that would send your signal to be envelope detected for:
Playing: signal to snazz wow flutter and maybe one fixed not enveloped modul from the random
Not playing: the other 2 random enveloped and the 3rd fixed, not enveloped random

For me, that would be the perfect modulation, at least from the videos i have seen.
Sorry for the mistake, and the maybe much too long explanation about my modulations thoughts.

[Sergio]

Just one more thing until monday i wont be able to modify this, im so sorry. I didnt send the file and i have it at another computer.

[Addy Bart]

Heaven knows what that would sound like!
Couple of thoughts:
On the Clarinot when you're not playing, the envelope doesn't change much. I made one with a crude feedback control added, sending the output back into the front of the circuit, and the repeats didn't alter the pitch much like I had hoped for. So it may not be that useful to 'envelope' the random LFO... If that's technically possible even?
Regarding your thoughts on switching between envelope and random LFO modulation: would some form of gating work, like in the DOD FX30B or zvex gate loop?
From looking at that fsp link, I realize that I'm not so familiar with the Wow and Flutter pedal. I don't know what the 4007 does. I need to watch some demos (perhaps I was wrong in thinking it's basically a Clarinot with repeats).

[spacefuzz74]

Great work Sergio!  Layout looks awesome, and your skills are top notch!  When i get a moment to build this thing (with noted corrections), i'll report back.  Thanks again!

[Sergio]

Thank you Nebula, Im just starting with this thing of layouts, so don't trust me too much, there are some schematics Im interested in, and I have attempted to do, but I always finish having some component angled or in strange positions, not the prettiest thing to look at....  You started the post, so then are you interested in different delay fxs, arent you, have you tried this one?
http://www.parasitstudio.se/stripboard-layouts/noise-ensemble

and theres one that I have been listening some demos and there was a post at freestompboxes, the judder fx, problem is that it seems to present some problems, from what I understood,
http://freestompboxes.org/viewtopic.php?f=7&t=22545
what a pity because demos were interesting, at least for me!

[SonusFluxa]

Been away from the forum for a while but I saw this and it looked interesting enough for me to build up tonight. Great layout! Just a few things to get it sounding like the demos.

- Like Ciaran mentioned, move width 3 to their other end of the 510r resistor.

- Move the bottom of the 33k resistor up to pin 6 on the pt2399.

- Remove the cut between the 2n2 cap and the 10k resistor (next to pin14 of the pt2399).

I did these, and it sounds like the video posted in the diysb link. Really digging this circuit, thanks again for posting!

Does anyone know how I could get an even slower speed from the speed pot? My guesses would be changing the pot's resistance or messing with the values of the caps surrounding the 358. Am I off base or are one of those a step in the right direction?

[Addy Bart]

How about the two 10k resistors around the 358? Increasing the resistance from the gates in the pseudo random LFO slowed things down considerably.

[spacefuzz74]

SonusFluxa,

Did you try different LEDs on the board of this thing?  Just kinda curious about what color LEDs you used.  I know that on the Clari(not), different color LEDs change the sound.

I'm going to experiment with some different LED, let me know what you ended up using.

thanks!

[SonusFluxa]

Nebula, used green LEDs since that's what was posted on the layout. I'd be excited to see what different colors sound like.

Addy, I could have sworn I saw a schematic for a 358 LFO somewhere, I'll try to find it and figure out what part controls the time, unless one of the LFO champs here knows off the top of their head, or someone wants to socket and see!