HoeDown (asymmetrical portamento?)

[Haible Juergen]

	> Just curious, has anyone ever made an asymmetrical portamento? One
where
	> the "gliding up" speed could be independently adjusted from the
"gliding
	> down" speed? (Or even turn off the effect in one direction.)

Emu built the "classic" one, with indepenent up and down times.
Today I (shamelessly) recommend the MOTM VCLAG. 

I think Roland had a kind of one-direction-only portamento on the SH-7
(switchable to up/down/both)
Serge has a slope generator with separate time constants for up and down.
(But I have never tested it, so I don't know if it's offset free for tuned
keyboard portamento)
*Some* VCADSRs might be usable as well (Keyboard CV goes into 
Sustain CV, and Attack / Release times control the up / down slope.
Offset Voltage is an issue here, and you want an ADSR that reacts to
Sustain CV changes in both directions (It's intentionally blocked in
some ADSR designs.)

Additional note: Various portamento types have different kind of symmetry
or unsymmetry by design. Linear glide on V/Hz CV is not the same as
expo glide on V/Oct CV for instance. (I've once built a log converter,
glide circuit, and expo converter to just get this effect on V/Oct.)

If you want full control over shapes and symmetry, it's useful to have
both, individual access to rise and fall times, and a 3rd knob for changing
the overall time (while preserving shape and unsymmetry). That's
what led to the MOTM VCLAG design.

JH.