Matt C

Searching For A Simple Delay Unit
« on: May 15, 2018, 05:13:34 PM »
I'm wondering if anyone has any recommendations for a piece of hardware that would fit the bill here.  I'm looking for a very simple line-level delay unit that allows for fine adjustment of the delay time. Maximum delay time would only need to be maybe 50ms.  I want it just for moving things around in time, not as a special effect box, so I don't need feedback or LFO modulation or any of the other crazy multi-FX box features.  Just simple delay that does not degrade the quality of the signal.  Is this a thing that exists? Is it realistic to build it myself (I've never built anything with digital circuitry)?


cyrano

Re: Searching For A Simple Delay Unit
« Reply #1 on: May 15, 2018, 06:48:11 PM »
Why is it people love to believe and hate to know?

squarewave

Re: Searching For A Simple Delay Unit
« Reply #2 on: May 15, 2018, 09:55:01 PM »
50ms ...  delay that does not degrade the quality of the signal.
It would definitely have to be digital. BBD would definitely affect signal quality and would be noisy.

Digital delay pedals are probably marginally worse than the fanciest rack mount Eventide sort of thing. It just comes down to how much precision of control is required.

Matt C

Re: Searching For A Simple Delay Unit
« Reply #3 on: May 15, 2018, 10:14:52 PM »
It just comes down to how much precision of control is required.

I don't need precision as in "I need to dial in exactly 24.57ms of delay", but I do want a knob for continuous fine adjustment of delay time. 

The way my effectron does this is nice - there's a bank of switches that set the nominal delay time (1ms, 4ms, 12ms, etc), and then a knob to fine tune it.  That  gives you finer control than if the whole range was available at once. Unfortunately that unit isn't the cleanest sounding thing in the world.

I searched around for digital chips and it seems like many have minimum delay times that are still too long for me.  I want a range of roughly 0.1ms - 50ms.

squarewave

Re: Searching For A Simple Delay Unit
« Reply #4 on: May 15, 2018, 10:28:52 PM »
Whatever "digital chip" you're looking at wouldn't be right anyway. A really good digital delay that would not degrade the signal and provide precise control would use a microcontroller or PIC with a DSP chip which may or may not have builtin ADC / DAC. And even if you made a board you would have to write some serious code to run it. A high fidelity digital delay is not ripe for DIY. Fortunately there are no shortage of digital delay devices out there. You just have to find one that has the right control.

tony hunt

Re: Searching For A Simple Delay Unit
« Reply #5 on: May 16, 2018, 02:39:29 AM »
Isn't such a unit called a Speaker Delay Line? Used for timing PA setups in large venues.

I have one here somewhere. It has very small delay increments and no other effects and several channels.
230V   50Hz

kooma

Re: Searching For A Simple Delay Unit
« Reply #6 on: May 17, 2018, 08:40:58 AM »
Isn't such a unit called a Speaker Delay Line? Used for timing PA setups in large venues.

I have one here somewhere. It has very small delay increments and no other effects and several channels.

Yeah, sometimes you can find these very cheap:
https://www.ebay.com/itm/ART-PD-3-3-Fach-Delayline-Prozessor-Professional-Delay-System-Top-Zustand/222976292364?hash=item33ea6c360c:g:1Y8AAOSwExlaVQQF
but I think those dip-switches are more common that trimmer/pot for delaytimes  :(

JohnRoberts

Re: Searching For A Simple Delay Unit
« Reply #7 on: May 17, 2018, 12:04:44 PM »
Delay used to be expensive but now with cheap digital conversions and cheap memory, delay is almost free if you are already operating in the digital domain, slightly more expensive if you have to perform the A/D-D/A conversion.

Yes there have been dedicated speaker delay alignment boxes (last century) but now it is pretty much built into DSP based speaker management (crossover) boxes.

For best bang for the buck, look at the used market for perhaps a sound reinforcement time alignment box... but you don't want the driver alignment function that is more like single digit mSec, but the longer delay alignment (tens of mSec). This wouldn't be a bad DIY project as some DSP micros have A/D and DAC built in, but the cheap built in A/D are not hifi. For simple pure digital delay, with no DSP filters or tricks, consider delta modulation, cheap and simple using modern technology.

JR
« Last Edit: May 18, 2018, 10:04:04 AM by JohnRoberts »
John Roberts
http://circularscience.com
Tune it, or don't play it...

abbey road d enfer

Re: Searching For A Simple Delay Unit
« Reply #8 on: May 17, 2018, 08:58:56 PM »
I searched around for digital chips and it seems like many have minimum delay times that are still too long for me.  I want a range of roughly 0.1ms - 50ms.
Typical A/D+D/A conversion time  is about 1-4 ms; that is with zero nominal delay.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
"The important thing is not to convince, but to give pause for thought." (B. Werber)
Star ground is for electricians.

JohnRoberts

Re: Searching For A Simple Delay Unit
« Reply #9 on: May 18, 2018, 10:06:15 AM »
Typical A/D+D/A conversion time  is about 1-4 ms; that is with zero nominal delay.
Delta Modulation wouldn't exhibit that much conversion latency but may be a bit much for a DIY project.

JR
John Roberts
http://circularscience.com
Tune it, or don't play it...


abbey road d enfer

Re: Searching For A Simple Delay Unit
« Reply #10 on: May 18, 2018, 11:11:47 AM »
Delta Modulation wouldn't exhibit that much conversion latency but may be a bit much for a DIY project.

JR
that's right; I should have writ PCM conversion. DSD is a likely low-latency candidate, but also very much for DIY.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
"The important thing is not to convince, but to give pause for thought." (B. Werber)
Star ground is for electricians.

iampoor1

Re: Searching For A Simple Delay Unit
« Reply #11 on: June 01, 2018, 04:29:46 AM »
Try building a freedsp board. Should be able to implement this fairly simply with SigmaStudio :-)

jstark

Re: Searching For A Simple Delay Unit
« Reply #12 on: June 20, 2018, 12:55:26 PM »
>  I'm looking for a very simple line-level delay
> I don't need feedback or LFO modulation
 
A Lexicon 1300s would fit your needs, as would most of the Deltalab units.
not here for a long time. here for a good time.

boji

Re: Searching For A Simple Delay Unit
« Reply #13 on: June 23, 2018, 03:14:40 PM »
Quote
"It would definitely have to be digital."

You're welcome to run a copper line to my house and get a return signal from me, so long as you're couple thousand miles away.




 

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