Orange Squeezer Amplitude Modulation

[chumpito]

Hello, I've built an orange the orange squeezer from tonepad and it works fine.  I've also read the mods on the general guitar gadgets.  My question is this:

 I want to build a compression pedal with a slow attack time and noticable attenuation so that the guitar sounds loud right away then drops in volume and 'sustains' as long as possible.
 But the thing is I also want to increase the ripple.  I would guess that I could attenuate the signal in the envelope detector somewhere, but I'm not sure what part of the signal is the envelope detector.

 If anyone could help or suggest another compressor to start with I'd appreciate it.

[bwanasonic]

There is an untold wealth of info on the OS here if you use the search function.

Kerry M

[Mark Hammer]

Unfortunately, you'll need to revise your thinking a bit on this one.

When thinking about attack and decay, what happens in a simple analog compressor is not the same thing as what happens with a modular or digital synth.  When a new note is played in a synth, the entire envelope cycle is reset and starts from "the beginning".  In that instance, it doesn't really matter  how long your decay time is set for or where you are in that cycle at the moment.  

In the case of compressors, the time constants of the envelope are derived in another way, in that they are entirely dependent on what it is you fed the compressor.  This is distinct from a synth where attack and decay are set quite independently of how hard you press the key or how fast you feed it notes.

Why is this a problem for what you want to do?  It's a problem because a long decay almost implies a slowed or sluggish attack.  So much so that although the "attack" control on a great many OTA-based compressors is actually a decay control, it has enough of an impact on how the compressor recovers from the last note on the way to the current one that it FEELS like an attack control.  In essence, the "dust" has to clear from the last note envelope for the attack and decay portions to *not* be interdependent.

So, if you want a nice long sustain, you will have to sacrifice something that will enable those initial transients to slip through.  Either that or you will have to wait a long time between notes, so that the decay cycle has less impact on the attack portion of the envelope.  If you want to increase ripple (although lord knows why anyone would want to), you will want a fast attack and a fast decay, so that the FET responds to every perturbation and anomaly in the envelope that you can throw at it.  If that's your pleasure, drop the 4.7uf cap down to 1uf and hold on tight.

[chumpito]

Why is this a problem for what you want to do?  It's a problem because a long decay almost implies a slowed or sluggish attack.

Unless I am missing something again, this is exactly what I want to do.  Long decay & Slow Attack.

If you want to increase ripple (although lord knows why anyone would want to), you will want a fast attack and a fast decay, so that the FET responds to every perturbation and anomaly in the envelope that you can throw at it.

This is my problem, the two things I want to do seem to cancel each other out.  Maybe I will look at using a LFO on a VCA.  I’m guessing this won’t really be possible with an Orange Squeezer.  Thanks Mark.

[Mark Hammer]

Yeah, a pity.  The OS *is* a nice sounding compressor, and very moddable, but sadly it can't be turned into what you want.  The good news is there are lots more fish in that sea.

[gez]

Not really suitable for a OS, but I tend to use CMOS tube sound fuzz type circuits for rectifiers (usually half-wave 'precision').  Either that or just stick one of these circuits before a conventional op-amp rectifier (depends on the circuit).  

The natural compression and sustain that these circuits have means that you get the long decay you're talking about, but you can still achieve a quick attack (should you so want it).  Running CMOS from 5V regulators keeps the circuit battery friendly.