pt 2399 echo chip equivalent

[Frances Rhodes]

hi everyone

i'm looking for a delay chip (digital or analog) that would allow a time delay of less than 5 ms, maybe even less than 1 ms.
i read the pt 2399 datasheet, it looks really easy to use but it seems that le smaller time delay possible is about 30 ms with an external resistance of 0.5 ohms.
would anybody know of a chip that may allow really short time delays and not be a pain to use... and not be a micro controller either?

thanks

[WilliamK]

Check this out, those guys managed to go under 1ms on the PT 2399 chip.    (unless I read wrong)

http://www.sabrodesign.com/wp-content/uploads/2010/10/Little-Angel.gif

http://www.freestompboxes.org/viewtopic.php?f=13&t=10276
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Best Regards, WilliamK

[Frances Rhodes]

Check this out, those guys managed to go under 1ms on the PT 2399 chip.    (unless I read wrong)

http://www.sabrodesign.com/wp-content/uploads/2010/10/Little-Angel.gif

http://www.....org/viewtopic.php?f=13&t=10276
(requires login)

Best Regards, WilliamK

thanks a lot! i was actually looking for that schematics!
unfortunately, the second link doesn't work, where is it supposed to lead?

[Taylor]

Check this out, those guys managed to go under 1ms on the PT 2399 chip.    (unless I read wrong)

http://www.sabrodesign.com/wp-content/uploads/2010/10/Little-Angel.gif

http://www.....org/viewtopic.php?f=13&t=10276
(requires login)

Best Regards, WilliamK

thanks a lot! i was actually looking for that schematics!
unfortunately, the second link doesn't work, where is it supposed to lead?

It leads to a forum to which we can't link here. But, there's no need to go there, as this circuit has its own very long thread right here on DIYSB. Try searching "angel".

[Frances Rhodes]

It leads to a forum to which we can't link here. But, there's no need to go there, as this circuit has its own very long thread right here on DIYSB. Try searching "angel".

ok, thanks!
i'm currently going through this topic right now http://www.diystompboxes.com/smfforum/index.php?topic=86297.0
it's 37 pages long, so i think it must be the one you're referring to!
this was not my goal to make a chorus in the first place, but this circuit doesn't look hard at all, it would be nice to modify it in several ways... maybe i'll try to discuss about it there and see where it goes

[Taylor]

I actually am skeptical about the assertion that anyone was ever able to get the delay down that short - I thought the limit was more like 10ms. If you're trying to do a flanger, 2 pt2399s might be necessary - delay the "clean signal" and modulate the other one around it.

[Frances Rhodes]

what i want to build is a unit with variable but extremely short delay, feedback and no modulation.
i posted this topic twice in 2 different sections because i didn't know where to post it in the first place.
in the other topic someone pointed that very short delays and long feedback would give a very special effect, i believe they were talking about a reverb, but that's not what i'm looking to build.
i don't know if you've ever heard of Jean-Claude Risset, but he was the first composer to play recorded music on stage, without any performer. just someone to turn the tape recorder on, and off at the end. to create his piece called "Sud" he used a computer to generate notes from the sound of the sea that he recorded by delaying it. i have a Boss DD-20, which is supposed to go down to 1ms, but i doubt the clock is really precise, not only in that range, but at all. the thing is that when i run my guitar or white noise through it at the shortest delay possible, it works. but the delay variation is not continuous, and i'd also like to get shorter delays.
Mark Hammer suggested that i used an overclocked MN3207 BBD to generate 1 to 5ms delay, i found some 3206 chips on ebay so i may be able to go shorter, but since BBD chips induce losses in the delayed signal, i fear that this may not work as fine as a digital processing. that's why i was looking for that kind of chip. and since i no nothing about how to program a PIC or AVR chip (if ever it is possible, which i'm not even sure), i think i don't have any other choice. but of course, i'm open to any idea!!

and since you're talking about this, what would be the difference between chorus and flanger? i know they are both created by delaying the dry signal, modulating the delay time a little and then mixing the 2 signals together, but where is the difference?

[slacker]

Chorus is a short delay that wobbles about a bit, so you might have a delay that varies from 25ms to 30ms, Flanging uses shorter delays but wobbles more so it might go from 1ms or less to 15ms, flangers also use feedback to make the effect more intense chorus generally doesn't.
What you're wanting to build is a comb filter, which is essentially a flanger with no modulation. Some flangers include this, you can turn off the modulation and control the delay time directly with a knob.
For very short times the signal degradation you get with BBDs isn't a problem, so you could go down that route.

You could do this very easily with a Spin FV-1 chip, you can get delay times down to less than 1ms, you'd have to program it, but it would be a very simple program.

Just remembered this this http://www.diystompboxes.com/smfforum/index.php?topic=85946.msg794468#msg794468 which sounds like it does similar to what you want, but probably with longer delay times.

[Frances Rhodes]

Chorus is a short delay that wobbles about a bit, so you might have a delay that varies from 25ms to 30ms, Flanging uses shorter delays but wobbles more so it might go from 1ms or less to 15ms, flangers also use feedback to make the effect more intense chorus generally doesn't.
What you're wanting to build is a comb filter, which is essentially a flanger with no modulation. Some flangers include this, you can turn off the modulation and control the delay time directly with a knob.
For very short times the signal degradation you get with BBDs isn't a problem, so you could go down that route.

You could do this very easily with a Spin FV-1 chip, you can get delay times down to less than 1ms, you'd have to program it, but it would be a very simple program.

Just remembered this this http://www.diystompboxes.com/smfforum/index.php?topic=85946.msg794468#msg794468 which sounds like it does similar to what you want, but probably with longer delay times.

this is precious information, thank you very much Ian!!
i will look into the FV-1 datasheet to see if i can do this myself, and i'll go read that topic as soon as i have time.

[Frances Rhodes]

i guess i may have found something interesting here http://www.polaraeng.com/delay-lines.htm
the delay times available go down to 1ns, and up to over 100µs, i'll have to have a look at the datasheets to see how they work

has anybody ever heard of those chips?

[anchovie]

This module is built for audio, can do delay times well below 1ms, and has all the A/D and D/A stuff included on the PCB:

http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=RA-FX1D

[Frances Rhodes]

This module is built for audio, can do delay times well below 1ms, and has all the A/D and D/A stuff included on the PCB:

http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=RA-FX1D

thanks a lot! i'll have a look at this

[armstrom]

This module is built for audio, can do delay times well below 1ms, and has all the A/D and D/A stuff included on the PCB:

http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=RA-FX1D

According to the product page the delay range is 0-250ms in 1ms increments. So it seems the shortest delay time is 1ms (I don't count 0ms as "delay" time )
-Matt

[Ronan]

The data sheet gives zero to 11mS in 0.042mS increments as one option. Or half that in stereo mode. Looks like just what you need!?