Build Your Own Clone Message Board

Okay, so originally I wanted to have a delay with two Delay Time pots and a switch to toggle between them...but I wanted the ramping speed between those two times to be both non-instantaneous and user controllable. I do plan to work on that as well, but my experiments led me down a different path that I feel is at least somewhat novel.

So what we have here today is a PT2399 delay, the base of which I lifted directly from madbean's Sea Urchin (with a few filtering value changes to shave off a bit more of the hiss in the delay line). I added an LDR in parallel with the Time pot and a resistor in series with both of those (to set the minimum time). The LED that modulates the LDR is activated by a momentary switch (normally open). The LED on/off speed (or rise/fall time) is controlled by some limiting resistance and a large cap. The rise speed is fixed to a greater degree, but the fall time is user-controllable through the Decay pot.

So how does it work / what does it do?

The LDR is in parallel with the Time pot. The LDR's dark resistance is about 5M, and in parallel with 25K, that gives ~24.9K, so the LDR is effectively not in the circuit when dark. Pressing the switch lights the LED, which causes the LDR's resistance to fall to about 500-ish ohms. This brings the Time pot value down to about 490 ohms (but there is a series resistor of 4K7 that keeps the value between pin 6 and ground from going that low). If this change happens really fast, there's not much interesting to hear. But if you slow down that change, you get some cool sounds. Especially as the LDR goes back dark and the Time pot value increases back up to 25K (plus that 4K7 in series).

It's like a cool detune that goes up in pitch and then slowly returns to the root note. And you can control how quickly (or slowly) that transition happens. You can do crazy tape wow-and-flutter sounds, and also more subtle bends. And you can do it all with your foot instead of bending over to fiddle with the Time knob. You can also quick tap the momentary to get multiple pitch bends in a row. I'm still figuring out stuff with this nutty thing.

Here's a demo. It's not the best because this is still on the breadboard and I couldn't use the switch hands-free. But you'll get an idea of what can be done with it.
http://soundcloud.com/effdub/neptune-proto-demo
(the clip has a lot of background hiss because I had to crank up the recorder's input as I was recording late at night)

Schematic is attached.

I'm working on a different version (more bells/whistles) for possible commercial development, but I just couldn't wait to share this version with my DIY homies.

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Function f(x)
TightCamera - Gear Reviews

Hey that's really cool!

That's pretty hot!

I'll get some of those pcb for sure!

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man, is it just me or is it raining cool delays these days? I will be keeping an eye out for this one!! Do you think it would be possible to have the detune go downwards? I thought I heard some on the demo, or is that just the detune returning to normal after going up? Anyway, I like the sound a lot.

The way it is set up now with the LED/LDR, I don't think you can make it detune down. At least now without revamping a few things and totally changing the sound of it. But I'll tinker and see what I can come up with.


The downward bending is pitch returning to normal. However, you could press and hold the momentary, then hit a chord or note, and then let go, and that would be just detuning down that you'd hear. The downside is that as long as you've got the momentary depressed, the delay time is really short (~80ms).

I can maybe work up a better demo once I get my test board built and have it boxed up good and proper.

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Function f(x)
TightCamera - Gear Reviews

Thought I should also add:

As I have it drawn up, minimum delay time is 80ms / max delay time is about 400ms. This is adjustable in a number of ways, but I settled on these values because it worked well with the detune sound, and also the max time repeats are still pretty clean for a 2399.

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Function f(x)
TightCamera - Gear Reviews

This is great......I figure this could get some cool Shoegaze/noise pop/MBV sounds. The detune on the shorter speeds sounds like some term bar warbling while strumming the strings ala MBV/Swervedriver/Slowdive.

CJ = Winning.

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Not gonna wait for you to ask........I'll take (at least) 3 or 4

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Let's wait and see how the prototype turns out. I want to make sure it sounds as good as what I've got on the breadboard before I get anything organized.

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Function f(x)
TightCamera - Gear Reviews

thats sooo cool how you came up with that and the way you did it. So essentially this is like adding a expression pedal to the time pot but instead of delay its just a momentary switch.

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BH4RJ

Thanks for another scheme Forrest!
And DC, imagine the mascis tremolosolos we can play with this thing

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Nice. And I can testify that this breed of swoops and dives can be fun. I used the sledgehammer approach (as usual):

http://circuitworkshop.com/forum/index.php?topic=709.0

...which became this:

viewtopic.php?f=8&t=29623

Mine can also be set to allow LFO modulation to fade in and out (just another LDR). And the momentary switch has some logic attached, so it can also be latched.

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http://www.frequencycentral.co.uk/

The prototype works!

It needs a bit of adjustment, but likely only to some values in the filtering. I had some issues with the regulator I was using, which I think may have damaged the 2399 a bit. I gave it both too much and not enough voltage.

Interestingly, the 2399 will run at 2v. But the repeats are wicked-dirty (like fuzz). I'm tempted to use a schottky diode to force the 5v regulator to put out 5.4v and see what happens.


Something I had not noticed before is that with the delay time set on the low end (short slap-back range), you can get a sort of "swell flanger" kind of sound happening. It's pretty sweet.

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Function f(x)
TightCamera - Gear Reviews

Damn your layouts are good Forrest!

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I want one of those boards.....!!!!

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http://srceffects.com/

Custom knob sets and effects. Free shipping in USA.

I'm no madbean, but I try. Thanks!

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Function f(x)
TightCamera - Gear Reviews

Alright, I've got it sounding the way I want it to with just some parts value changes. I'm going to do my best to shoot the demo Friday. I need a day to get it boxed up.

Details:

• I know a lot of people say this, but I really think this circuit has a genuinely "analog" sound. And by that, I mean BBDs.

• I did some appallingly heavy-handed low-pass filtering on the delay line. This ain't no crystal-clear-repeats type of delay. It's dark and gritty... but NOT hissy. I really HATE hiss in repeats, so I worked extra hard to filter that shit out. I did so good that I was even able to up the max delay time and still have it almost totally his free. It may be too dark for some amps that are naturally also not that bright. This can be adjusted easily with a couple cap values swaps.

• You can hit it hard with neck humbucker output (clean), and it won't distort noticeably (it just gets a *little* grittier, but in a good way).

• The new "stock" circuit has a minimum delay time of about 150ms and a max of about 500ms. Those are approximations, and will vary somewhat from circuit to circuit. And of course you can make some value changes to adjust this.

• With Feedback set more than about 75%, there is runaway oscillation. You can also set it so that it almost repeats forever (or like 45 seconds, which is pretty close to forever).

• With Mix set to max, the repeats are louder than the dry signal. I think this is cool, but it could be adjusted so that max mix is unity with dry.

• The "up" swing on the modulation footswitch is now slower than it was before, which sounds better. I'm going to keep screwing around with this to see if I can get it even smoother. But it sounds pretty good now.

• A couple of the pots are backward on the schematic. Imma fix that.

• I'm not terribly sure how usable most people will find the LED/LDR footswitch modulation thing. I did mainly because I'd never seen it done, not because I thought it would sweep the nation. To that end, I will also almost certainly do a separate circuit that has a more traditional LFO for modulation. It's also possible that this layout could be used with an external LFO (just leave off the parts for the in-built modulation and manually hook up the LFO to the Delay pot).


That's enough blathering for now. More deets as the sitch develops. (<< I'm so hipster!)

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Function f(x)
TightCamera - Gear Reviews

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Imma need you to stop making all these awesome circuits.


Suh-weet.

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Got a build finished and demo video up:
viewtopic.php?f=8&t=37113

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Function f(x)
TightCamera - Gear Reviews

This is pretty much finalized. These are the exactly values I have in my build right now. I just tried increasing R17 from 10K to 18K, and it still sounds pretty clean...but now the delay time max is about 550ms or maybe a little more (and minimum is now about 200ms). But, 10K - 22K will work for R17.

I shot the demo with 10K in there, FYI.

Here's what I'd recommend using:

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Function f(x)
TightCamera - Gear Reviews

really nice work on this dude. cheers! now have a beer, you've earned it

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Damn nice work of ya effw!

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Are there any changes on the blue version of the boards?

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http://srceffects.com/

Custom knob sets and effects. Free shipping in USA.

I can't recall. There might have been one or two value changes, but the layout is exactly the same. I think maybe I incorporated some value swaps I liked in that last version. I'll look when I get home.

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Function f(x)
TightCamera - Gear Reviews