White Pink Noise Generator?

[R.G.]

Looks like a 23 stage gives 2+/- minutes repeat time at 71kHz output speed. Again, probably good enough for rock-n-roll. Maybe good enough for classical. Two minutes is an awfully long time to remember hiss.

[R.G.]

10F200 and 0805 SMD parts make a pink output on a board 1" by 0.5". Where to put the pads for wires  and the 78L05 regulator is a big part of the PCB design. They're about half the PCB area.

[PRR]

> The designers of the National noise chip sweated a chip floorplan and layout for getting those 17 flipflops and control logic into a silicon mask. Lot of work.

At the time, IIRC, full-adders and parity generators and even the rate multiplier were standard items. I don't recall thinking a 17-stage on a die was an amazing thing. However for the limited and cost-adverse market, it WAS work.

> sound like a repeating hiss-hiss-hiss...

To listen steady, it was strong-flavor.

But as a percussive chuff or tizz on an "organ" or "percussion" voice, a few milliSeconds, beat-rate never in-sync with the chip repeat rate, it probably was not a real flaw. Yes the VU meter bobbled a few dB but a real hiss in music will vary quasi-randomly with drummer's coordination or organ's notes-load.

> 89 years. .... 5million years. I'd hate to play a show where that would matter.

There's a 'Dark Star' mash-up, "Grayfolded", on 2 CDs running 103+ minutes. I recall Phil Corner hosting concerts that ran for days with rotating musicians. Somewhere on the Web I ran into a composition which has been playing continuously for 12 or 13 years, I don't remember if it is meant to play forever or if an end is expected at some time. _My_ attention span is more Buddy Holly to JS Bach.... 2 to 20 minutes.

I think that if the hiss is not the star, but only spice on the music, the MM5837 is nearly there and anything "better" is for the mathematician, not the musician. (Didja see the newly proposed proof of prime gaps? Wanna get tickets and go to the show?)

[ulysses]

oh wow- ive never done any audio dsp coding

i found a copy of the schem for the noise generator in the original minimoog. what is interesting is that it has white pink and red(brown) where the minimoog only had white and pink available on the board.

unfortunately its got +10/-10 voltage. ill have to work something out for that but looks like i'll be able to make myself a minimoog noise generator

ill post the schem up to my layouts section

cheers

[ulysses]

here it is
http://www.aronnelson.com/gallery/main.php/v/ulysses/misc/Screen+Shot+2013-05-28+at+7_12_45+PM.jpg.html

cheers

[ulysses]

hey rg

do you think this moog noise circuit will work ok with 9v+ and 9v- ?

i might just use 2 9v batteries and wire them up together to give 9+ and 9-

what do you think? that way i wont have to muck about with a max chip

cheers

[artifus]

Somewhere on the Web I ran into a composition which has been playing continuously for 12 or 13 years...

as slow as possible?

The actual performance commenced in the St. Burchardi church on September 5, 2001... The performance is planned to continue until September 5, 2640.

[slacker]

There's also Jem Finer's Longplayer started in 2000, supposed to play until 2999 before repeating.

[R.G.]

do you think this moog noise circuit will work ok with 9v+ and 9v- ?

It might work on a single 9V supply, with some juggling of DC levels and part values. It's a fairly simple broken-base-emitter noise generator with transistor amplifier after it. The two transistors and RC networks that follow it are a pinking filter and a .. ? .. redding filter?  then recovery amplifiers to get back the level lost to the filters.

[PRR]

> do you think this moog noise circuit will work ok with 9v+ and 9v- ?

The plan you posted is marked +/-10V, is all +/-20% design, it won't know the difference +/-9V.

As R.G. says, *single* 9V operation is *barely* possible, if the 9V is full 9V (not a saggy battery). It takes ~~7V to break-over the transistor, and a bit more for steady current through its supply/load resistor. Might need to select transistor and resistor for reliable single-9V operation.

That's why I liked the MM chip, it ran good-enough from over 12V down near 5V, battery health was never an issue.

But at +/-9V you are golden.

[R.G.]

Latest iteration:PIC, runs at 16MHz internally, outputs values at 250kHz, recycles every 1.8M years, feed it from 9V with a resistor and a zener. Runs from 2.6V up to 5.5V, so maybe a power supply could be concocted... 

Operating current about 25uA except for whatever you put out to the pinking filters.

In fact, its signal would be a good one to feed the moog filters if suitably attenuated first.

[ulysses]

very good

i will make a vero board and wiring diagram when i get the time

cheers