From lyonsrm1@teomail.jhuapl.edu Sat Sep 28 08:19:01 1996 28 Sep 96 11:18:48 +0500 28 Sep 96 11:18:24 +0500 Comments: Authenticated sender is 26 Sep 96 13:54:46 +0500 Date: Thu, 26 Sep 96 13:00:17 EST From: "LYONSRM1" Encoding: 97 Text Subject: Re[2]: Odyssey Models ( was B & G ) Cord posted this wonderful info, but because of the way I would search the AH archive I would have never found it because the subject did not contain the word "Odyssey". So I though I would re-post it for future benefit. I hope I'm not out of line, but this is something to think about when posting. No offense. Russ L russell_lyons@jhuapl.edu +++++++++++++++++++++ Joachim Verghese once wrote me the full line of ARP Odysseys. Here is the information. You will see that there are black&gold Odysseys identical with the white face (like mine). 1972 - 1974 Model: 2800 Face panel: White with black legend Osc board: B-I Filter: 4023 Interface: None Pitch bend: Rotary knob 1974 - 1975 Model: 2800 Face panel: Black with gold legend Osc board: B-I Filter: 4023 Interface: None Pitch bend: Rotary knob 1975 - 1976 Model: 2810 Face panel: Black with gold legend Osc board: B-I or B-II Filter: 4035 Interface: None or CV & gate+trig Pitch bend: Rotary knob 1976 - 1978 Model: 2810 - 2813 Face panel: Black with gold legend Osc board: B-II Filter: 4075 Interface: CV & gate+trig Pitch bend: Rotary knob or PPC (Proportional Pitch Control) 1978 - 1981 Model: 2820 - 2823 Face panel: Black and orange with white legend Osc board: B-II Filter: 4075 Interface: CV & gate+trig Pitch bend: PPC The newer B-II oscillator/S&H/LFO board features the famous stable ARP oscillator design which was used in practically all late '70s models. The B-I oscillators aren't bad either, but they may have slight high frequency tracking problems, and are trickier to repair. The original 4023 filter is a 2-pole (12dB/oct) OTA-based biquad design somewhat similar to the Oberheim SEM/OB-X filter. This filter has a very smooth behaviour, and unlike most 4-pole filters, does not attenuate the low end with increased resonance settings. Good for bass and bright lead sounds. A bit noisy, though. The 4035 is rather rare because it wasn't installed into many units. This is a slightly modified 4-pole (24 dB/oct) Moog ladder design very similar to the one used in the ProSoloist (4034) and the Axxe I. The sound is Moog-ish, as one might expect, but (fortunately) doesn't make the Odyssey sound like a Minimoog. The 4075 filter was probably the first high-fidelity dynamic filter to emerge in a commercial synth. This is a 4-pole (24 dB/oct) cascaded integrator type filter featuring very low noise and distortion. The 4075 sounds very similar to the Moog filter at low resonance settings, but remains very stable at high resonance, and will even pass the input signal while self-oscillating. The trade-off is that it doesn't perhaps sound as interesting at high resonance, or when the input is being overdriven. What's more, due to a design mis-calculation, the cut-off frequency cannot typically be made to exceed 12...14 kHz. This is not much of a problem, and can fairly easily be corrected by changing four resistors in the non-epoxied 4075 submodule (assembly number 7210500/7210501). Cord gestatten, mein Name ist Wischmeyer, Dieter Wischmeyer! ...Radio FFN ___________________________________________________________________________ Cord Mueller cord@lance.colostate.edu Colorado State University, Department of Chemical & Bioresource Engineering Fort Collins, CO 80523 home (970) 206-1215 off 491-3451 fax 491-7369 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^