EH 16 second dly

[harrybissell at prodigy.net]

Delta Modulation needs only one bit, the bit is the ourput of a comparator fed by the audio signal and the integrated output of the comparator... The "error" signal is what is passed in the shift register.

If the audio signal is less than the integrator, the polarity sets the integrator to "ramp up" as long as the 
integrator remains low. when it exceeds the integrator, it ramps down... sort of "servo" tracking.

Adaptive delta modulation changes the integrator gain with increasing numbers of "error" in the same direction. So a "1" would equal an integrator gain of one, "111" a gain if two, "111" a gain of four... etc.
This allows the system to track high slew rate inputs with just a little distortion...

IMHO The adaptive delta modulation (like Delta Lab Effectron... ADM****) is a great sounding delay and outperforms most 12 bit systems... OTOH is is not so good for reverb type effects... there is very little "math" you can do with a 1 bit system.

:^) Harry

 ---- On Dec 14 ">>>marjan<<<" <urekar.m at EUnet.yu> wrote: 
> > Do you mean with "delay process in software" that the delay time is set
> > with the offset between read and write addresses rather than with the
> > clock rate? This can be done with discrete logic too.
> > 
> 
> So I run my audio thru Windoze and I get superb delay(s :)
> 
> > When the delay time is controlled by the clock rate only, the range
> > can't be very high. For short delay times high  clock rates are needed
> > and the ADC becomes very expensive. Is it really done this way in old
> > digital delays? What is the delay time range?
> 
> Some DDLs used Delta Modulation, based on assumption you have high
> sampling
> rate and "slow" signal (audio) so next sample can be the same as
> previous one
> or one "step" up or down, so you need only 1.5 bit resolution. Used
> DRAMs
> to store data, which used to be expensive so you got short delays up
> to 1 or 2 sec (I guess some has more). I have Ibanez dly with 900ms. It
> uses
> 8 4116 16kx1 DRAMs.
> EH 16 otoh uses standard ad conversion, 12bit but that's the part of the
> schematic I can't read :) but DAC is 6012 ? Someone help me here...
> 
> 
> 
> marjan