Electrokinetica The Electro-mechanical Museum

Model 357

Player’s view

The model 357 is arguably the archetypal post-war Electrone, developed from the 352 in response to the need for a low-cost church instrument. The basic versions share many of the principal features of the 352, including the case design and circuit arrangements, although the voicing is based conventionally on a Diapason chorus. Alternative voicings were made available in due course, with the 357CS being the standard ‘romantic‘ specification, the 357CT a classical or ‘baroque’ variation, and the 357ET a dual-purpose instrument. None of these included the 352’s Vibraphone, although mixtures and mutations were introduced. The attack and release were lengthened for a more sedate sound, whilst to give an impression of a vast cathedral acoustic a sustain feature was added, allowing the normal stops to be subjected to a very long release time. Also in the 357 we see a variety of tremulant mechanisms emerging in place of the separate motor-driven pulley of the 352, giving the options of variable speed and depth adjusted by two internal controls.

357CS Specification


  • Contra Bass 16
  • Bourdon 16
  • Echo Bass 16
  • Octave 8
  • Flute 8
  • Harmonics IV
  • Trombone 16
  • Trumpet 8


  • Double Diapason 16
  • Diapason 8
  • Harmonic Flute 8
  • Gemshorn 8
  • Octave 4
  • Twelfth 2 2/3
  • Fifteenth 2
  • Tromba 8


  • Bourdon 16
  • Geigen Diapason 8
  • Stopped Diapason 8
  • Salicional 8
  • Principal 4
  • Stopped Flute 4
  • Flautina 2
  • Sesquialtera 2
  • Mixture III
  • Contra Oboe 16
  • Cornopean 8
  • Clarinet 8


  • Tremulant
  • Rotofon Celeste
  • Reverberation
  • Balanced swell pedal to great and pedals
  • Balanced swell pedal to swell

A further variant, the 357CP, added features to extend the capabilities towards those of the older 347, albeit with the tonal limitations of the simplified generator system. Four double-touch combination pistons per division were included, plus Pedal and Swell-Great couplers. The latter necessitated the use of relays for the manual key action, since it was not practical to control the Swell voices directly from the key contacts of the Great. As a result, the 357CP is internally rather different, despite its external similarity.

Many technical changes occurred throughout the model lifespan of the 357. The metal chassis inherited from the 352 was replaced by a wooden one, lined with sound-deadening fibreboard inside the generator compartment. This was apparently to suppress an unacceptable background noise level experienced with the older arrangement during the quiet parts of a church service. In 1961 the amplifier was slightly updated to an ultra-linear configuration, which in turn was replaced by a solid-state unit of much greater power shortly before manufacture came to an end. The original double-sided generators were ousted by the better single-sided design, and as a cost-saving measure a simplified form of stopkey was introduced.

Overhauling our first 357

357 console nameplate

Our first 357 CS was obtained in non-functional condition from a church in Essex. Although the console was readily accessible the Rotofon needed retrieval from atop an entrance porch: This was a ‘four-man job’ owing to the massive construction of the cabinet. The organ and Rotofon were taken to the workshop where they were first thoroughly cleaned and dusted. The amplifier was found to be a solid-state unit built by Fred Allen which, according to the maintenance record book, was supplied in 1989 after a spate of irritating faults occurred in the original valve amp. Like many of Fred’s amps, it is built on a modified Compton valve amp chassis distinctively resprayed in green. The organ had failed due to one of its mains transformers burning out, unusually without any other fault in evidence to cause this - possibly due to a minor winding damage. A suitable transformer was within arm’s reach of the bench; fitting it returned the amplifier to operation. The Rotofon wiring, severed during removal, was replaced and connected to the console. Electrical safety tests were made, power was connected and the generators lubricated and set running. The organ gave forth some reasonably promising sounds, and a pleasant lack of nasty noises from the electromechanics. A few issues were immediately apparent; some keys were stiff or did not sound at certain footages or harmonics; the tremulant was jerky; there was a thickening of tone near the middle of the compass; ciphers (continuously sounding notes) occurred on the pedals. Nothing was amiss, however, that couldn't be fixed with a soldering iron and a few hours work.

Faulty transformer

Faulty transformer

Servicing the key action

Servicing the key action

Condition as found

Condition as found

Most of the missing notes and harmonics were caused by faulty or fatigued connections to the wiring looms and cross-connections under the manual key contacts and these were all rectified quickly. The stiffnesss of a few keys was caused by friction between the return-spring hook and the key itself; increasing the clearance by 1/64 of an inch cured this fault. The pedal ciphers were simply the result of damaged springs on the jacks (levers operated by the pedals themselves) which were removed, reshaped and refitted. A bad connection and failed capacitor were responsible for the unsatisfactory tremulant behaviour, along with mechanical maladjustment which might have occurred while a previous attempt was made to find the fault. The irregularity in tone across the keyboard was brought about by a simple but sneaky mistake; the colour-coded bodies of the amplifier audio connectors had been interchanged at some time in the past. Reconnecting them according to Compton's convention after repairing the amplifier had resulted in the treble and bass amplifier channels being interchanged. Since these have different frequency response characteristics the entire tone of the instrument was upset. Once all these minor items were attended to, the organ was found to be eminently playable in every respect, with just a small amount of background hum remaining as a nuisance. This was eliminated by making some improvements to the earthing arrangements around the generator area.

An earlier 357

It had been our intention to re-equip the above instrument with an original valve amp as an example of a typical 357. However we have since obtained an early 357 with double-sided generators and valve amp in original condition. Although at the moment lacking its speakers, this organ is more suitable as an original example of the model, leaving us the option of keeping the later one in its modified form to show how Fred Allen’s very popular conversions and upgrades kept instruments working and in regular use. The early 357 has gone direct to the stores without a stop in the workshop, hence we don’t yet have pictures of it. More info on this organ follows soon.


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