Appendix: Confusions

Occasionally there have been comments posted online to the effect that the Stringvox is just a rebadged ELKARhapsody 610. The confusion probably arises from the fact that the original Hohner String Vox (with a space) was in fact a rebadged ELKARhapsody 490, and both the K2 Stringvox and the 610 are Piano+Strings. However, the 610 does not have a separate Bass voice (except by connecting the optional bass pedals), and in many ways is quite different in controls and circuitry. Since the 610 came first, the rumour may have started with someone commenting that ELEX/Hohner were doing a copy. Copy of the basic idea, yes, but expanding on it and altering just a bit; and they weren’t the only ones producing Piano+Strings keyboards at the time.

Another point of confusion seems to be with the Vox String Thing, of which there may also be two models. It doesn’t help that Vox initially marketed their rebadged Jen J‑600 electronic piano as the “Pianovox”.

And then there’s the String-Orchestras. This r3 is not so easy to confuse, but it is a revision of an instrument that was sold as a String-Orchestra. But not so far as I’ve able to tell, by Hohner. (Or if otherwise, evidence needed.) The other actual String Orchestra was by Logan, also rebadged by Wersi.

Appendix: Capacitor Tests

Appendix: Voicing Board Variations

Those components which vary between the different envelope groups are as follows. Non-varying components are not listed. Capacitors C4, C5, and C6 are not always present.

Appendix: K2 rev.2 and 3 Boards

Some boards appear to have been changed between the K2r2 (based on detailed photography provided by Sebastian of the Silvertop String-Orchestra) and the r3. It is not currently known what changes other than the position of the tuning trimmer and bass pedal connector occurred between the K1r1 and r2. Some of the boards found here also appear to have been used in the K4r1 (which is likely to have been similar to the K2r1 in those ways), but this is based only on the rather faint schematics. No information so far about later versions of the K4.

Appendix: Controls

The left four buttons are a four-way exclusive group, i.e. pressing any one cancels the others. They set the four operating modes for the K2:

• Split Keyboard Mode has no direct switching function but mechanically cancels the other three. Pressing it places the Stringvox in Split mode with normal voices, i.e. both bass and treble range have their four pianos and strings voices available, controlled independently with the bass and treble faders and cancels.
• Full Keyboard Mode applies the settings of the treble-range faders and cancels to all keys.
• Ensemble Mode might be described as a strings unison mode — each key in the bass range plays its basic pitch plus the second and third octave up. The bass-range pianos are also still playable. However, in the treble range, the strings voices become unavailable and you’re left only with pianos.
• Bass Mode replaces all other voices on keys 1–24 with the Bass voice.

(It is possible to keep more than one of the Full Keyb., Ensemble, and Bass switches on at once, but nothing very interesting seems to result from that, although it is useful to have all three in when removing the top panel.)

The other eight buttons are cancels for the four voices in the bass and treble ranges.

Appendix: Switch Functions

All switches on the K2-110 board. Terminals as numbered there.

Decay on/off switching occurs by switching the transistors on K2-110 off and on for each key group: Q1 — Cello (treble), Q2 — Cello (bass), Q3 — Strings (bass), Q4 — Strings (treble).

Appendix: TOG Pitches

TOG chips are not perfectly accurate to the 12-ET chromatic scale. On the K2, the 50240 will produce IPN A6 with the clock tuned to 667,040Hz, and the other pitches as below:

(50240s also produce a /478 division which here would be F6, but the K2 produces that as a division of F7.)