Two new postings - Steve, you'll love this

[Mark Hammer]

http://hammer.ampage.org

A while back, someone here posted a large archive of scans of some Japanese project books from wayyyyyyyyy back (many have 1978-1980 copyright indications (please step forward and accept the applause).  I stuck the zipfile in the wrong directory and neglected it all this time, stumbling onto it the other day.

I posted two projects at my site that I thought would be appealing to people, based on previous threads and requests.

One is a flanger that has about as many modulation parameters as a person might want.  Envelope control, waveform shaping, the works.  Steven Giles, this one has your name written all over it in dayglo Sharpie pen. :lol:  Ton's name is scrawled on it as well. :wink:

The other project is a noise-gate/expander.  A traditional problem with noise gates is that by virtue of their on/off action, one tends to lose the attack and tail of notes/chords if you set the on-threshold too high (to keepnoise at a minimum), and have to put up with noise if you want to hang onto the attack and tail.  Tough tradeoff to make.  

An expander essentially does the mirror opposite of a limiter.  Where a limiter downplays the volume differences between higher and lower amplitude sections of a signal above a certain threshold level, an expander exaggerates volume differences for louder and softer signals below a certain threshold.  No on or off, just softer than it used to be.  The result is that ALL attack and note tails are preserved, but hiss is reduced when you're not playing.  Not a perfect solution, but an improvement over gating.

As with a lot of stuff I scan, I have tried to digitally touch up the image so that things are more legible, and so that the PCB patterns are flipped around for PNP purposes. I thickened up the traces.   And, as per usual, I can't vouch for the scale of the PCB patterns, you may have to enlarge or reduce them to print out your patterns to scale on transfer paper/sheets.

I have not attempted to build either of these, but a glance at the design suggests they might make some of you very happy indeed.  At the very least, they are different from a lot of things out there.  More comments are posted along with the circuits at my site.

Many thanks to the person who provided the scans, and of course even greater thanks to the Japanese designers who originally drew up the design for wherever they originally happened to be posted.  Me, I'm just the messenger.

Enjoy,
Mark

[cd]

Was the Japanese book poser ExpAnonColin?  I know there's a complete japanese book posted on the experimentalists anonymous website.

[nelson]

WHy do you do this to me, I have no money I am a student! Why must you tempt me!  

[puretube]

bookmarked for educational purposes...  :lol:

[Mark Hammer]

Was the Japanese book poser ExpAnonColin?  I know there's a complete japanese book posted on the experimentalists anonymous website.

That sounds about right, so props to Colin.  There is a wealth of stuff in that archive, though a lot of it I'd seen before in one format or another.  The two I selected represent the tip of the tip of the iceberg, but tghey struck me as of particular interest here.  The rest of it IS good, just perhaps not as topical.

Thanks for the heads-up CD.

[puretube]

...there have been heavy discussions here, incl. locked threads, cc. IP issues with that book...  :roll:

[toneman]

hey Mark,
i think it's *compressors* & expanders.
not *limiters* & expanders.
a limiter has nothing 2 expand....

[Mark Hammer]

...there have been heavy discussions here, incl. locked threads, cc. IP issues with that book...  :roll:

Which is pretty much why all you're gonna see of it on my site is two schems, and why you won't see my Anderton collection.  A taste here and there to get people interested in someone's book is one thing; giving the book away quite another.

hey Mark,
i think it's *compressors* & expanders.
not *limiters* & expanders.
a limiter has nothing 2 expand....

Nah.  I pit the two as polar opposites in that they both apply a change in input-vs-output curves to things beyond a given threshold/level.  Limiters do what they do to things OVER a given level, and expanders do it to things BELOW a certain level.  What most folks here encounter as "compressors" is generally something that does not discriminate with regard to level, except by coincidence.  The Ross/MXR compressor and CS-2, the OS, the Anderton, the Supasustain, et al, all apply a fixed gain boost and reduce either gain or input signal down from there as the input signal increases.  There is no real "changeover point" as such where they start or stop doing that, just more and less of it.

On the other hand, if one is talking about something like a compander chip where the level reduction in the compression half is the mirror image of what happens with the expansion half so as to restore the dynamics of the input signal, then yeah, you're right.

Which brings up an interesting point, and that is the difference between upward and downward expansion.  In a compander chip, what gets "expanded" is the higher-amplitude signals; i.e., they get restored to be as loud as they were originally.  

When it comes to the limiting-vs-downward-expansion contrast , limiters tame the highest amplitude signals but try to stay out of the way of the dynamics of everything below that, all for the purposes of avoiding the traditional concerns of tape saturation or blowing speakers with transients, etc..  Downward expanders work on the *softest* parts of the signal and leave the dynamics of everything above that alone, all for the purposes of making any hiss/hum left in the signal when the musician stops that much less noticeable.

I suspect the distinction between these two approaches to or uses of dynamic expansion is where we got our signals crossed; meaning that we were BOTH right!

[StephenGiles]

Just when I thought it was safe to buckle up my holiday electronics bag!!!!
Thanks for that Mark - having done Grandfatherly duties at my 2nd Grandaughter's 1st birthday party this afternoon, I can now relax with the A3 size print out I now have of this circuit.
Stephen

[toneman]

here R some "actual definitions" 4 any1 that might B comfused--

http://buzzwiki.wipe-records.org/index.php/Expander

http://buzzwiki.wipe-records.org/index.php/Compressor

http://buzzwiki.wipe-records.org/index.php/Limiter

lots of other good stuff 2!!.......