WODEN TRANSFORMERS
The Woden Transformer Company Ltd.
Woden was based in the West Midlands - the "Black Country" - first in Wolverhampton (1939, Thornley Street), then after a move, in Bilston, a little to the south east. The initial premises there were on Moxley Road. By 1957 a second site had been acquired or set up on Oxford Street, on the edge of the massive Loxdale Industrial Estate.
Aerial views showing, left, part of the Loxdale Industrial Estate, and right, heavier industry. It is regularly said that the term "Heavy Metal" was coined by West Midlands bands, many of whose members had worked, on leaving school, in iron and steel plants. At least one member of Slade's road crew worked for Woden Transformers from 1964 - 1969.
Woden's principal business seems to have been industrial transformers, some fairly gargantuan,
along with transformers for hifi units:
Images from this page.
The company also marketed its own range of amplifiers - the "Woden Super Sound Apparatus Amp":
The transformers that Woden made for Vox were commissioned units. They are not to be found in any other maker's amplifier. Manufacturing began in late 1961, as Jim Elyea has noted, for the AC30. No doubt instructions came directly from Dartford Road. But consultation with Westrex, who assembled AC30s for Vox under contract, may have played a part initially too.
From 1961 - mid 1964 the units had distinctive green / blue-green shrouds.
Two earlyish Wodens in Vox AC30s - August (date code "HT") and October 1962 (date code "JT").
By 1963 more detailed codes appear. Mains Transformer: 66309 & J/82. Output Transformer: 66310 & J/83. Choke: 66311 & J/81. Examples in an early Burndept-made amp (Burndept were also contractors for Vox), below.
"AU" signifies January 1963. The amp is now in full working order.
By late summer 1964, the shrouds of the transformers were no longer painted, but bare metal:
"HV" and "JV" signify August and September 1964.
"JV" and "KV" are respectively September and October 1964.
A mixture of transformers in a single amp: two made by Albion, the other by Woden (output). Note the new code: 76853. "KV" = October 1964.
Orders evidently continued through 1966, and well into 1967:
AC30s from 1966 with Woden transformers. Codes: 76852, 76853 and 76854. "GX" = July 1966.
Batch 1
AC80/100s were initially equipped with green-topped Wodens. All three units - mains and output transformers, and choke - have the date code "LU" = November 1964, or "MU" = December 1963. Part codes are: 72191, 72192 and 72193.
So far as can be judged, the first order was for around 150 sets, ie. for amps with serial numbers running from 101 to 240, with a few "spares" that were used later - in late 1964 / early 1965.
Batch 2
In late summer 1964, AC80/100 control panels changed from copper to black, and at much the same time, a second batch of Wodens was ordered. The choke was still the 250H lay-down unit.
The shrouds were unpainted (bare metal), and probably bore date codes ranging from "JV" to "KV", much as in the AC30s pictured above. Part codes remained 72191, 72192 and 72193; and the transformers were still fixed to the upright of the chassis by means of a bracket.
Mains and output transformers have gone, but the shroud from the former remains, turned by 180 degrees
- one can see the shadow left by the bracket on the fore-edge.
It seems likely that this second order was only for around 60 units each of mains, output and choke, in other words raw materials for AC80/100s with serial numbers running from 240 to 300.
Batch 3
Coinciding with the change to grey panels, Vox ordered a third batch of transformers from Woden. These were delivered to the Burndept factory at Erith, which had taken over production of the AC80/100 from Westrex.
Around 150 sets were ordered, enough for amps with serial numbers between 300 - 440 and spares. The mains and output units had date codes "BW" = February 1965. The chokes had "AW" = January 1965. Part numbers were 72191, 79806, and for the new "stand-up" choke, 76854, as in AC30s. The shrouds of the two larger units had "ears" to facilitate fixing to the upright of the chassis.
In this batch, the design of the output transformer was simplified (hence the new part number - 79806 instead of 72192). The four primary windings of the green Wodens were reduced to two, as in the schema below.
On the left, a green Woden (date code "MU"). Note the four yellow wires of the primaries. On the right, a later Woden (date code "BW" = February 1965), with only two primaries - red and blue wires.
Above, serial number 392, showing the disposition of the new transformers.
Later batches
Small batches of output transformers seem to have ordered from Woden from from late 1965 - 1967. These have unpainted shrouds and bear the standard part code - "79806". Occasionally they crop up in later AC100s (as in serial number 2098 below) and in AC50s. For the latter the tranformers will have been well suited. For the former, only just, as the Woden 79806 had only twelve secondary windings, whereas the standard black-shrouded AC100 unit had fourteen.
The code "JW" indicates September 1965.
Observations
1. The ordering of new sets of transformers in 1964 and early 1965 generally corresponded with a change in control panel colour.
2. The second batch of around 60 units seems to indicate that Vox had ideas to do something different at serial no. 300. Perhaps this was simply the transferring of production to Burndept (which did happen).
3. From August 1964, all three guitarists in the Beatles had AC80/100s, and Vox must have realised that production would need to be ramped up and costs tightly controlled - a slightly less complex output transformer, and a smaller choke were therefore commissioned from Woden (batch 3). No schematic showing the smaller choke seems to have survived, however.
4. A question. Why did Westrex still have, in late 1964 / early 1965, green-topped Wodens? At least two amps with grey panels were fitted out with them. A third amp, which also has a grey panel and these transformers, is probably much older, a copper-panelled AC80/100 that was refurbished at some later date.
