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Oberheim/Viscount OB3-squared

Tonewheel Organ Module By Nick Magnus
Published September 1997

In 1995, Oberheim released the OB3, a little‑known drawbar organ module, subsequently eclipsed by Hammond and Roland's advanced electronic tonewheel organ emulations. Now Oberheim have teamed up with Italian organ specialists Viscount to produce the enhanced OB3<sup>2</sup>. Nick Magnus squares the difference...

The Oberheim OB3 squared (OB3<sup>2</sup>) follows hot on the heels of the Hammond XM1/XMc1 (reviewed SOS May 97) in a bid to satisfy those looking for the famous vintage tonewheel organ sound in a rackmounting format. Both the XM1 and the OB3<sup>2</sup>, unlike the standard 19‑inch rack modules to which we are by now all accustomed, offer the benefit of physical, hardware drawbars that can be manipulated in real time whilst playing, or used to create various registrations to store within user memories. The principal differences between the Oberheim and the Hammond are twofold:

(1) Whereas the Hammond XM comes as two separate items (the sound module and a remote drawbar unit), the Oberheim takes an all‑in‑one approach; it's a single unit resembling the sawn‑off left‑hand control panel of a keyboard‑based organ, such as a Hammond XB2, Korg CX3, or Roland VK7.

(2) The Hammond offers extensive editing of many parameters, while the Oberheim offers 'take‑it‑as‑it‑comes' features — parameters available for editing are kept to a minimum. If that sounds disparaging, it is not meant to be — a real Hammond organ has no means of customising certain features, and as such the design of the OB3<sup>2 </sup>can be regarded as more faithful to the original Hammond.

The OB3<sup>2</sup> is in fact Oberheim's second product of this type — as the name OB3<sup>2</sup> suggests, there was a previous model called the OB3 (released late 1995, reviewed SOS March 1996.) The newer OB3<sup>2</sup> offers significantly improved functionality, and dramatically improved sound. The panel legending displays the words 'Viscount joint venture' so it doesn't take much to deduce that Oberheim sought Viscount's not inconsiderable organ‑building experience to assist in the voicing of the OB3<sup>2</sup>.

Construction & Layout

The OB3<sup>2</sup> is solidly built and reassuringly heavy — hence it's unlikely to be pulled from the top of your master keyboard by the weight of its own connecting cables. The livery is unmistakably Oberheim, featuring the famous logo and black legending on a white background — no low‑lighting visibility problems here. The 'keyboard off‑cut' appearance is enhanced by the polished wooden end cheeks, and the overall effect is very stylish.

To the left of the drawbars are six rotary knobs that cover treble/bass EQ, master level/overdrive and effect selection/level, and below those is one larger knob to select vibrato type. In front of the drawbars are 22 rectangular LED‑embedded buttons that deal with selecting presets, user patches, percussion settings, vibrato assignment, the rotary effect and MIDI functions. Rounding off the hardware tour, the rear panel has stereo and headphone outputs, MIDI In, Out, and Thru sockets, a master tuning pot, three footpedal jacks for overall volume, rotary fast/slow speed selection, and one to alternate between the currently selected preset or live drawbars. Last on the list are the power switch, power cable anchor and a 10.5‑volt input from the wall‑wart power supply.

Let's See What's Out There

The OB3<sup>2</sup> operates in one of three MIDI reception modes: Monotimbral (Upper, Lower and Bass sounds all on the base MIDI channel); Duotimbral (Upper on base channel and Lower on base channel +1); or Tritimbral (as duo mode but with the addition of Bass tone on Base channel +2).

On powering up, the OB3<sup>2</sup> presents itself in the mode in which it was last left. The manual states that the six user memories have been pre‑programmed at the factory — though on the review model, these locations were actually empty. No problem — the OB3<sup>2</sup> is, in the main, very self‑explanatory, so I pressed the Drawbars button and pulled out a mittful of bars. The sound that came up was as close to that of a Hammond XB2 or XM1 as makes no difference — a promising start. To verify this, I set up the same drawbar registration on my beloved XB2, and indeed the comparison held up — a double‑blind test would most likely yield no better than 50/50 results.

Having made a drawbar registration, saving it is a simply matter of holding the drawbar button down while pressing one of the six memory location buttons — and that's it.

In A Spin

Those of you who have bravely waded through my previous 'ersatz Hammond' reviews may well be expecting the usual hyper‑critical assessment of the built‑in rotary speaker effect. So, here it is... and it's great. The effect benefits from use of the stereo outs, with plenty of depth and swirl at the slow speed, and a satisfying throb when running at full speed. Editing parameters such as upper/lower horn balance and stereo separation are not available, but the basic rotary settings have been judiciously chosen, which is just as well — as mentioned earlier, editing is kept to a minimum on the OB3<sup>2</sup>. However, Oberheim have provided the means to alter the acceleration/deceleration times between slow and fast settings. This is done using MIDI control change messages. Slow to fast time is varied using controller number 12, while fast to slow falls under the command of controller 13. This appears to work fine, and these parameters are variable over a wide range. The chosen settings are also retained at power‑off, so your favourite 'mass' of Leslie is available to you next time you play the OB3<sup>2</sup>. Controller 14 is supposed to provide MIDI selection of fast/slow speeds, but here (as with other occasions mentioned later) I suspect the MIDI implementation of the OB3<sup>2</sup> is not yet complete; controller 14 values which are below 64 select the slow speed, as expected, but a value of 127 only manages to crank up the effect to about half of full speed. Hopefully Oberheim will rectify this fault before long.

Reverb And Delay Effects

Five types of reverb/delay effect are provided on the OB3<sup>2</sup>, selected via a rotary switch on the panel. These are Delay, Spring, Plate, Room and Hall. Of these five, only the delay is editable. As in the case of the Rotary effect, these edits are performed using control change messages. Unfortunately, the owners' manual is rather at odds with the truth; it states that Delay Depth (which I take to mean level) is varied with controller number 91, which seemed to do nothing at all on the review unit. As it happens, reverb/delay level can be set manually with the dedicated pot on the OB3<sup>2</sup>'s panel. The manual also states that Delay Feedback (ie. number of repeats) is altered by controller 102. The reality is that controller 102 alters the delay time, not the feedback amount. Experimentation revealed that feedback amount is actually governed by controller number 103 — a fact not documented in the manual. Once again, these settings are retained on power‑off.

The four reverb algorithms are fixed, but perfectly pleasant and useable. The Hall algorithm is considerably louder than the other three, so you may need to adjust the effect balance when switching from one to the other.

The OB3<sup>2</sup> also receives pitch‑bend messages, but only with a fixed range of +/‑1 semitone — a curious restriction. Two semitones would be a more logical, useful choice for a fixed value. I'm sure some irrefutable logic was applied to arrive at that executive decision!


Situated alongside the master level control, the Overdrive effect is intended to simulate the valve distortion of an overdriven Leslie cabinet. So far, I've been awarding the OB3<sup>2</sup> high marks in all other departments for authenticity. In the case of the overdrive, the marking echoes the comment regularly written at the foot of my school Maths homework: '3 out of 10 — see me'. This particular overdrive effect suffers from the same problem that's found in a number of other organ‑based instruments: that is, it sounds like muddy filtered white noise layered over the organ sound, rather than producing the pleasing, growly interference of valve distortion. The timbre of the OB3<sup>2</sup> overdrive stays constant, regardless of the pitch played, which is, again, something that would not occur with a real Hammond. The only occasion when the effect becomes vaguely believable is when low octaves or octave/fifth combinations are played — and even then the 'muddy white noise' quality is relentlessly present.

...sounds absolutely great, with bags of punch and authority.

This presents a problem (if the overdrive is important to you) in that it comes before the rotary effect. This is as it should be, but if you want an overdriven rotary sound, you are stuck with the overdrive effect provided by the OB3<sup>2</sup>. This would not be such a stumbling block if Oberheim had followed the example of the XB2 and the old Korg CX3. Both of these provided a pre‑rotary send/return jack, meaning that you could output the signal to a suitable external distortion device, and back into the instrument to be 'Leslied'.

I don't wish to seem unreasonably critical over this point, but (as previously mentioned in the XM1 review) there are plenty of half‑decent digital (and analogue) overdrive representations to be found amongst the many effects units on the market. Sadly, it's probably way too late in the day to suggest that Oberheim do a little extra research into redesigning this effect — it's really the only sonically negative aspect of the OB3<sup>2</sup>.

Vibrato & Percussion

The vibrato section is very straightforward — vibrato can be assigned to either or both of the upper/lower manuals, and the classic Hammond choice of three 'V' settings (plain pitch vibrato) and three 'C' settings (the throbby type) are provided. They are fair representations of the effects they seek to emulate.

The percussion is available only to the upper manual, and is in the traditional Hammond format of 2nd harmonic, 3rd harmonic, normal/soft and fast/slow. The 2nd and 3rd harmonics are mutually exclusive — you can only have one or the other, a restriction the OB3<sup>2</sup> has in common with Roland's new VK7, whereas the Hammond XM1 and XB organs allow both together. Tonally, the OB3<sup>2</sup> percussion is spot on, having the lovely 'ponging' marimba‑like quality of a real Hammond.

Sadly missing (but not too critical) is the facility to vary the level of keyclick, or spit, that characterises the dirty key contacts of a vintage organ. The spit is certainly present, but at a fixed level. However, you can take consolation from the fact that changing this sonic artefact on a genuine Hammond would require alternate applications of Coca‑Cola and Servisol to achieve the same control.

On a similar note to the above point, it should be mentioned that some other more expensive units allow detailed editing of parameters such as percussion decay time, keyclick level, rotary horn balance, vibrato speeds, and more. The OB3<sup>2</sup> foregoes these luxuries (presumably to hit a target price) but whether it was the intention or not, it ironically makes the OB3<sup>2</sup> more faithful to the real thing, as none of those editing options are possible on a pukka Hammond, nor are the percussion, vibrato, or rotary settings storable in a user memory. It's all up to the player to set them going when required — and so it is with the OB3<sup>2</sup>. However, it should be added that the OB3<sup>2</sup> has the added advantage (over the pukka item) of sending out all such performance manoeuvres, including drawbar movements, as SysEx messages to be recorded as part of a MIDI sequence. This is another of the major improvements over the original OB3, which had no MIDI Out socket at all.

Lower And Bass Sounds

So far, I've dealt primarily with the upper manual and drawbars. The lower manual sounds consist of five fixed presets (much like the reverse‑coloured key presets on a B3 or C3) which cannot be changed. These presets can either be accessed via MIDI on the base channel +1 (in Duotimbral mode), or from a master keyboard played below the designated split point (in Monotimbral mode). The split point between upper and lower sounds can be set, with a maximum upper range of C4 for the lower tone (again, the manual's instructions for doing this were at odds with the behaviour of the review model). Incidentally, Oberheim use the same MIDI note name/number convention as Roland — but why must manufacturers differ over this basic point?

The Bass preset is a single fixed tone, as on a Hammond L100, and can also be given its own split point, with the caveat that it cannot exceed the upper range of the lower manual.

I made certain comments earlier about the possibly incomplete nature of the OB3<sup>2</sup>'s MIDI implementation. In addition to the curious behaviour (or non‑behaviour) of a few of the MIDI controller functions, try as I might I could not set the OB's base MIDI channel to anything other than channel 1. I followed the manual's instructions to the letter, and even improvised a bit when that failed, but channel 1 (and its sub‑channels) seemed to be it for the present.


OK, the OB3<sup>2</sup> lacks some of the editing finesse and features of machines such as the Hammond XM1 or the mighty Roland VK7, but the bottom line is (and very importantly) that it sounds absolutely great, with bags of punch and authority. There is real‑time hardware control of all the major performance functions, and all this comes in a good‑looking, compact unit. Despite my own reservations concerning the overdrive (in common with the XM1), I think many people will be pleasantly surprised at how good this instrument sounds. It's also around £400 cheaper than Hammond's XM1/XMc1 package. In short, if the absence of detailed editing and the limited number of user memories doesn't bother you, I recommend giving the OB3<sup>2</sup> a serious listen.

Squaring The Difference — OB3<sup>2</sup> & OB3 Compared

Power supplywall‑wartfixed lead
Rotary effect editablerise/fall timesno
Reverb/delay effectsyesno
Vibrato types63
EQ (global)Hi & Lono
Multitimbrality3 partsmonotimbral
Presets accessible from panel6 Up, 5 Lo, 1 Bass6
User programmable presetsyesno
Total number of presets126
Panel functions TX/RX via SysExyesno
SysEx bulk dumpyesno
Variable keyclick amountalways 'on'on/off

Oberheim OB3<sup>2</sup> & Hammond XM1 Compared

Stereo outs yesyes
Phones yes yes
Send/return jacks no no
11‑pin Leslie connectornoyes
Rotary effect editablerise/fall timesdetailed
Rotary edits storableon power‑off yes
Reverb/delay effectsbothreverbs only
Rotary cabinet simulations110 user
Effects editable Delay only no
Effect edits storable on power‑off no
Overdrive level/status storable nono
EQ (global) Hi & Lo Hi & Lo
Multitimbrality 3‑part 3‑part
Patches accessible from panel 6 Up, 5 Lo, 1 Bass128 scrolling
Total number of patches 12 128
Panel functions TX/RX via SysEx all except EQlimited
SysEx bulk dumpyesyes
External control pedal inputs 3 2
Patch naming no yes
2nd/3rd perc. available together no yes
Velocity sensitive percussionno yes
Percussion triggeringSingle Single/Multi
Drawbars 'live' for patch editing'drawbar' mode only yes
Customisable drawbar wraparoundno yes
Variable keyclick amountno yes
Variable percussion levels soft/normal onlyfully variable
Variable percussion envelopesslow/fast only fully variable
Variable organ sound A/R envelopeno yes


  • Great tonewheel sound; competes well with the best of the current market.
  • Very good Leslie simulation.
  • Three‑part multitimbral.
  • Extremely easy to use.
  • Sturdy, chunky construction — looks very stylish.
  • All controls (barring EQ) are transmitted/received via MIDI.
  • Instant hardware access to drawbar settings and performance controls,


  • Overdrive disappointing considering |the otherwise excellent sound.
  • Limited editing available for some parameters.
  • Percussion, Vibrato and Rotary on/off status not saved within a program.
  • No pre‑rotary send/return jack for outputting signal to valve preamp.
  • No custom drawbar settings available for lower manual sounds.
  • No global transpose (or octave shift for lower manual).
  • Owners' manual misleading in parts.


A quantum leap, both sonically and operationally, from the original OB3. Not the cheapest dedicated organ module, but great for those who seek an authentic sound plus hands‑on control of drawbar settings. If you can forgo some of the minutiae of editing available on more expensive units, this instrument should satisfy most, if not all of your requirements.