Long Echo/delay

[sirreg]

I'm looking for a schematic for a pedal with a long echo/delay.

[geertjacobs]

You're probably better off buying one.
For 150$ you have a delay pedal that does everything you can dream of and more. (Line 6 echo park, boss dd-5/6,...)

Most diy delay projects are analog or analog mimicing delays that have short delay times. Other projects are expensive.

edit: spelling

[Paul Marossy]

All of the DIY delays that I have seen have a delay time of 200-350mS. Not very long delay times.... 

[geertjacobs]

GeneralGuitarGadgets has the DH Echo for max 0.8S.
I believe the IC that was used is obsolete.

[Nasse]

You can buy spring reverb units, some of these have long reverb time

And lots of good music made with not soo much long delay time

[Mark Hammer]

Depends on what your definition of "long" is.  Compared to a slapback delay, individually audible repeats from a Memory Man type unit can seem long.  Compared to the couple-of-note repeats of a Memory Man, the entire phrases of an 800ms delay seems long.  Compared the complete phrase of an 800ms delay, the entire chorus of a 2-3sec delay seems long.  And then your have your phone message-length loopers.

The natural "breakpoints" in the technology seem to be around 50-60msec (slapback), 330-400msec (what you can do with 4096 stages of bucket brigade or with 20k of onboard DRAM in a digital chip), 800msec (what some inexpensivedigital chips can do with outboard memory), a couple of seconds (what the "digital delay" stompboxes like the DD3-through-6 and Echo Park can do), and loopers that extend into the double digits in terms of delay.  There ARE exceptions to this from time to time, but this roughly captures the spectrum of delays.

So, when you think "long", what exactly are you thinking of?

[Paul Marossy]

Which ones can youe get 800mS out of? 

[Mark Hammer]

The Holtek HT8955 and the Princeton PT2395 both get 800msec with the use of an off-board 256k DRAM chip.  Dean Hazelwanter's delay project over at GGG uses the Holtek.  Scott Swartz' PT-80 project uses the PT2399, with the built-in RAM to get Memory Man delay times.  I have yet to see any projects using a PT2395 and DRAM chip.

A delay time of 800msec allows you to cram in a few more notes in the phrase before the loop/repeat begins again, which could be critical OR meaningless, depending on your context.  From what I gather, the Princeton chip will deliver better quality tone than the Holtek one.  The Holtek one is still available through places like Small Bear, but is out of production.