Quirks, cont'd
2001-12-21 by petergrenader
OK, I only own one rack of Doepfer modules, and in truth, some of that space is inhabited by Analog Solutions and Analog Systems modules, gut I have run into a few 'funny' things in the A100 mods I do own, to wit: First off, let it be known that I am using these analog modules expressly to create control streams to manipulate analog modeling synth's via the Doepfer A-192 module. So, I've got ADSR's, Slews, LFO's, gate delays, sample and holds (many), CV Sources, DC mixers, gates, switches and some other goodies. So, outside of the limits of the LFO, my analog machine is silent. But I have still run into small hick-ups: A-192 Bleeding: The A192 is s teriffic module. It allows you to convert CV's (up to 16 at once) into midi information which can then be used to attack's a given midi instrument's midi implimentation list. Sometimes however I will get bleed - meaning that a CV connected to an agacent input will sometimes creep over to another input in which that signal is not connected...which is a little weird. Further explanation. Let's say I've got a sine LFO opening and closing a filter center frequency from port 2. Let's say I also have a sample and hold controlling the oscillator freq from port 3. Let's say I pull the rigger input of that sample and hold out, which makes that hold at whatever voltage last stepped. I may hear a slight vibrato in the oscillator, which is the LFO signal into port 2 which is controlling the filter freq. A-192 Midi Weirdness: Beware of anyone who dares to update the operating system of another midi intrument connected to the same chain as an A-192 - make dang sure you disconnect the A-192 out of that chain first, or you wil more and likely effect the operation of the A-192 permanently until you set it's functions back to the factory defaults. I updated my Waldorf Q with OS 3, and when I did, I also unknowingly turned the midi thru function on the A-192 off which, unitil I realized what I had done, rendered my keyboard, MAQ 16/3, and other thingy's useless. A-192 Voltage raange: This isn't a bug, as much as it's a oversite in their design. The A-192 only responds to positive control voltages, within a range of 0 to +5. The rest of the A-100 otherwise is bi-polar, producing mostly AC voltages in about a +/- 6 volt range. This means if you plug an unprocessed AC signal into the A-192, you will only hear the positive side of that signal having an effect. This modifies you otherwiswe sweeping control to a series of little bumps. To fix this, you can either by another module from Doe which has three channels of voltage offset/processing, which will allow you to offset these AC's into full saweep DC's, positive only -or- you can do what I did and make a circuit that does that (it's a very simple circuit). My problem is I couldn't afford the rack space the Doe. option required, it's a (relatively) huge module designed for use with their vocorder. My circuit took a whopping two ICs, is two channels and takes up 4 spaces (as narrow as their VC switch). Personally, I think that these offset converters should be part of the A-192 inherently. CV Source Wierdness: It seems that the '0' (i.e., no voltage out) of two of my three CV Source channels have offset themselves so that ground is actually at about .5 on the pot settings. I haven't opened it up to see if there is an internal adjustment pot. General Weirdness: Anyone who owns a A-100 has been faced with intermittant jacks. There is an easy fix to this, which you can find on their site, but I personally think they should do this BEFORE the modules leave their facility. Other than that, I love this thing. Peter