via this auction
"Here we have a RARE Oberheim OB-SX synth made in 1982/USA (sourced from New Jersey, July 2021). It was the second model in the OB range, slotted in-between the OB-X and the OB-Xa. This one is 4-voice polyphonic and has 56 programs on board. The model was introduced by Oberheim, tailored for live use. At the time, the OB-X was well expensive, so this was marketed at an attractive lower price. Its a wee bit smaller than the other OB models, measuring just 87 x 50 x 12 cms...weighing around 16 Kgs. The remit was "bring out a compact performance synth with THE best Oberheim sounds on board". Much of the same circuitry (80%?) as the OB-X was used to produce the distinctive polyphonic sounds. OB-SX is loaded with 56 presets, basically; but every sound can be "shaped" to some degree (eg adjusting the Filter Frequency control/detune of VCO 2). The left panel is always "live". There is a video on YouTube of me (KKGB/Doug McKendrick) playing an earlier OB-SX. You can hear some of the fat (phat) sounds and some rubbish playing at the same time. Lucky you! Hit YouTube and simply enter "OB-SX"......."
The only one I found with "McKendrick" is the following from Sue McKendrick on the previous grey faced model.
OB-SX 1970's demo Klassickeys GB
video upload by Sue McKendrick
The following are a few demos of a blue striped model from Pete Moulton that I found, including a run through the presets:
"Introduction to the OB-SX, a very underated synth that is a hybrid between the OB-X and OB-Xa. The OB-SX shares the voice architecture of the OB-X, but uses the discreet CEM chips later found on the OB-Xa. The OB-SX first appeared in 1980 as a preset/variable version of the OB-X.
A short demo demo of the brass sounds from A1, B1 and C1, using the variable controls. If the sounds in your OB-SX are different to mine, you could have a rare machine, as OB-X users could send in a tape of their favourite sounds to be burned into the OB-SX EPROMs. Also mine will have slightly different tunnings and voice calibrations to yours."
Playlist: 1. Oberheim OB-SX Part 1 (description above)
2. Oberheim OB-SX Part 2
Using only the A1 Brass Ensemble program as a starting point and the 7 variable controls on the front panel, a variety of sounds can be coaxed out of the OB-SX with considerable ease. The OB-SX might be your best bet it you cannot get your hands on an OB-Xa or OB-X. SHOW LESS3. Oberheim OB-SX Bank A Sounds
"Here I demo the 8 sounds from Bank A on the OB-SX.4. Oberheim OB-SX Bank B Sounds
A1 - Brass Ensemble
A2 - Clavinet
A3 - Low Strings
A4 - Electric Piano
A5 - Percussive Organ
A6 - Flutes
A7 - Harpsichord
A8 - Lead Sync
There may only be 7 controls on this "Poor man's OB-Xa" but you can tweak out some great sounds as this video demonstrates:
Portamento
LFO Rate
Osc 2 Detune
Filter Freq
Amp & Filter Attack
Filter Decay
Amp Release
Apologies for the sound quality as I was using the mics on the video camera
www.LoMountSound.org.au"
Demo of the 8 sounds from Bank B on the OB-SX.5. Oberheim OB-SX Bank C Sounds
B1 - Classic Horns
B2 - Celeste
B3 - High Strings
B4 - Brass In 5ths
B5 - Pipe Organ
B6 - OB-SX Choir
B7 - Harp
B8 - Calliope
Demo of the 8 sounds from Bank C on the OB-SX.
C1 - Trumpets
C2 - Pop Organ
C3 - Slow Strings
C4 - Resonance Sweep
C5 - Combo Organ
C6 - SX-6
C7 - SX-7
C8 - SX-8