http://www.themusic.net/eh16/

paul, I talked to the guy who made that page, & he told me he'd hook me up with some information to clone it for a couple hundred bucks... says he's working on getting more info & parts together


drew
www.toothpastefordinner.com

That Reticon elliptical filter could be replaced by a couple of those MF series switched cap filters, I'm sure. You can sweep those locked to the sampling clock, just like with the Reticon. Still a big job, though!

Discreet DRAM controllers..... yuck!

I'm impressed by it being 12 bits wide, but with only 64K, the sample rate is only 4K making the best case bandwidth only 2K. I assume the 7th order switched cap filter was used to squeeze every last drop from that 64K.

4164s have long gone the way of the dodo and so have 41256s, 44256s, 411000s, 441000s, and about a zillion other configurations.

I would suggest using something like a 44256 for anybody wanting to build a direct clone because it would only require 3 DRAMS for 12 bits. An even better solution using DRAM would be to use a 256K*16 bit chip to get all the memory in a single package (it's going to be a SMD BTW).

The best solution is to use an SRAM instead and forget all the pain of providing refresh. Big SRAM is now common and cheap.

The converters are another issue... There are so many good converters these days and the originals will be very hard to source.

In its day the EH 16 second delay was a breakthrough, but today I can't help but cringe looking at the schematic.

As anybody wanting to clone one would have to burn a 74LS288 (provided you can find them) and PROMs are not considered "space age" anymore, I would suggest investing in an Atmel AVR programmer and doing most of the memory circuit in software on the AVR. You could shrink the package and parts count by a LOT, decrease the price and circuit complexity, and get a better quality delay out of it with the ability to do MUCH more.

Thanks for posting the link Paul. I collect old machines and it makes me feel like I'm looking at the motherboard of an early 80s vintage computer.

Take care,
-Peter

I don't think anyone would want to clone it, just to make a delay. It's one of those things where the 'defects' have been associated with particular music.
So if a 'modern' version is designed, it would be as well to allow the sample bit length to be optionally reduced, for one thing.

Dynamic Ram??
why would anyone want 2 use DRAM??
StaticRam is Sooooooo cheap now.
Unless U just *like* gobs of refresh circuitry :shock:
U could make it 10bit instead of 8bit.
Now, 10bit A/Ds & D/As are sooooo cheap.
Keep the NE570 frontend.
Make clock voltage controlled.
2 in parallel, "InfiniteFlanger" possibliities :wink:
keepaclockin'
tone

I was surprised to see that it was a 12 bit device while most of the rest of the industry was content with 8 bits. Very cool.

At the time the EH 16 second delay was made, static ram was still small, power hungry, and quite expensive. If you wanted 64K * 12 bits you might have seen a 3rd circuit board in there with only SRAM chips in addition to SRAM on the 2nd board.

The 2114 was a fairly common chip from the previous memory generation. With a 2K * 4 bit configuration, it would have taken 96 of those things! The 6264 was common about the same time 4164s were and it would have taken 16 of them (all in DIP 28 packages) and you would end up wasting 1/4 of the array thanks to the *8 configuration. Too much real estate for a compact box for sure.

The DRAM solution allowed EH to pack a huge delay in a small space... even when you include the refresh circuits and the address muxes.

These days you can pack the refresh hardware into a few lines of code running on a microcontroller. Combine that with the companding and steep filtering of the vintage analog hardware and you would have a cool effect for sure.

I'm sure somebody has made a clone out there.

Take care,
-Peter

hey Paul.

do you know of Maneco? (manecolooper.tripod.com)
it's not a clone of the EHX 16sec., and sounds more like the digitech pds series as far as the delay as features it holds (i had one of his boxes).
but since you mentioned a "modern clone" i'd suggest you took a look at the great work Juan/maneco does.
he posts here regularely too.

- ced