Jeroen Allaert a écrit :Without further ado I present you the first synthesizer downgrade: The REV -1
This modification for the Sequential Circuits Prophet-5 reverts the Rev 3 sonically to the earlier, much bigger-sounding Rev 2!
Fully working prototypes have been built and tested, and have the following features:
No mods to the Prophet 5 PCBs are required.
It simply plugs into the IC sockets, replacing each CEM3320.
Only 1 extra wire for the -15V supply needs to be soldered.
Electronics have been added that cancel out the pollution from the CEM3320’s level shifting circuitry. The little that remains (30 to 100dB attenuation depending on frequency content and Prophet component tolerances) is also moved entirely to the filter's input. So, it get's further attenuation of 24dB per octave beyond cutoff.
Extras:
The input signal has been increased a bit, since the 2040 likes to be driven a bit harder. This is no issue for the purists as it can be attenuated in the ‘mix’ section of the prophet-5.
By design the SSM2040 is also self-limiting, so the output level has been increased a lot as ample headroom was available, and this gives a much better signal-to-noise ratio and dynamic range.
REV -1 also adds two new features not present in the original Rev 2:
variable Q-compensation that restores the loss of bass when resonance is increased (14dB is lost at the onset of self-oscillation in the original filter design).
the option to use the REV -1 as 2-pole filter instead of the original 4-pole configuration. Most non-linear effects happen in the first two filter stages, and the 2-pole mode lets you hear these effects unfiltered by the last two stages.
The combination of these two extra features will make a Prophet 5 sound absolutely monstrous!
Switches to select 2-pole or 4-pole mode and the amount of Q-compensation will be included with mounting hardware.
A short demo can be seen here:
https://www.youtube.com/watch?v=nUc5dsV ... u.be&t=480" onclick="window.open(this.href);return false;
And, skip to the beginning to see how it is installed.
Note: those switches in the video are by no means final. Much better looking hardware is coming.
More info here:
http://www.analoguerenaissance.com/rev-1/" onclick="window.open(this.href);return false;