Vox AC30 website updates

April 2024

27th April

A page on has now been set in motion. As ever, further material will be added shortly.

Of all the components embodied in an AC30, speakers almost invariably have the latest date codes. Final assembly by JMI - the point at which the AC30 became a usable amplifier - took place at some remove from the date recorded on the speakers - often well over a month after.

25th April

It appears that some Vox/Reslo microphones of the type illustrated in the entry for 22nd April were not stamped with a number. At least one survives without (thanks to Martin for the info).

It is probably worth noting too that mics with cylindrical bodies were never stamped by JMI. On the right below, an early RBH/TS microphone produced and labelled for VOX, Reslosound Limited not mentioned on the label. On the left, a later unit (now termed a RBTS/H), "Reslosound Ltd" in bold.

Below, the RBH/TS as illustrated in the Vox "Precision in Sound" newspaper-format catalogue of autumn 1964. The "VOX" above the switch is the draughtman's addition.

23rd April

A small update to yesterday's entry. Jennings had evidently added Reslo microphones to its roster of "accessories" by November 1960:

Melody Maker magazine, 19th November, 1960. The guitar accessories and three-input Meazzi Echos were relatively new also at this point. All else (as far as accessories are concerned) goes back to 1958.

22nd April

From late 1959 Jennings embarked upon a gradual expansion of its line of accessories - Meazzi echo units by late autumn 1959; followed around a year later (by January 1961 at the latest) by Reslo ribbon microphones. Chief among the Reslos was the "Celeste" - model "RBH", 30-50 ohms impedance. This was first illustrated in the brochure of early spring 1961 and remained in the Jennings catalogue through to 1963.

Mics supplied to Jennings were emblematised "VOX" rather than "RESLO". Mics supplied by Reslo to "GEC" were likewise given special badging.

Page 8. "Aids to Music" - Reslo microphone, Meazzi Echo, Volume Pedal, Accordion microphone, Vibravox, and PA speaker.

JMI catalogue, autumn 1963, detail, the Reslo "Celeste" still available

It is clear that early on Jennings stamped its mics with serial numbers. The one below, with a slightly worn roundel (originally black, not bright red), is number "125". Whether the sequence began at "0" or "100" is not known at present.

18th April

A new page has been started on in Celestion blues. It has long been thought that the number preceding "H1777" signifies week of production. But why "71" in December 1962? It is possible that Pulsonic, which was created in July 1961, simply counted forwards from its first week of business, the cone marked "71" having been produced in the 71st week, and production of cones (as a new initiative) having started around week 60, say (September '62).

It is worth saying that there will naturally have been some interval between the manufacture and stamping of a cone and its incorporation by Celestion in a speaker - in other words, some gap (note the imprecision) between the week of manufacture of the cone and the date stamp on the speaker's gasket (recording date of final assembly).

The new page will be kept up to date with new info, no further additions to be made to yesterday's entry.

17th April

Pulsonic cone code 71H1777, Celestion blue, December 1962.

18th April: the new page on now supercedes the entry below.

A provisional note on Celestion blues with Pulsonic cones (H1777). So far as one can tell 1962 has its own scheme, the (prefatory) numbers relatively high towards the end of the year. In 1963 (at some point) the sequence appears to start again. 1964 seems to be a continuation of 1963.

Charting these numbers with a view to divining the "system" may be a fool's errand. But it is probably worth collecting and collating the evidence as it arises.

Whether 1H1777 (February and March 1964) is a mistake or an indication of something else is unknown at present.

1962

18KG - 18th October 1962 - 65H1777.

19KG - 19th October 1962 - 64H1777.

08LG - 8th November 1962 - 68H1777.

04MG - 4th December 1962 - 71H1777.

1963

16HH - 16th August 1963 - 18H1777.

26HH - 26th August 1963 - 18H1777.

02JH - 2nd September 1963 - 18H1777.

07LH - 7th November 1963 - 40H1777.

02MH - 2nd December 1963 - 41H1777.

1964

14AJ - 14th January 1964 - 41H1777.

25AJ - 25th January 1964 - 51H1777.

29AJ - 29th January 1964 - 53H1777.

18BJ - 18th February 1964 - 52H1777.

20BJ - 20th February 1964 - 52H1777.

21BJ - 21st February 1964 - 1H1777.

25CJ - 25th March 1964 - 1H1777.

05EJ - 5th May 1964 - 9H1777.

06EJ - 6th May 1964 - 9H1777.

11EJ - 11th May 1964 - 53H1777.

16th April

Added to the list below, entries for two AC30s with serial numbers in the 6000s: 674x and 6758, which both have speakers dated 19th March, 1963.

15th April

Below, Part 3 of a gentle overview of original Celestion blues of known date in AC30s - in this instance, AC30/6s with copper panels. Part 1 will encompass TV Front AC30s, Part 2 will be AC30/4s and AC30/6s with black panels.

Some preliminary notes:

(i) the date codes are NOT the date of the amp - they simply record the day on which the speakers were manufactured at the Celestion Works in Thames Ditton;

(ii) there is in most cases no firm evidence to indicate how long the speakers sat on shelves at Celestion or JMI before being fitted in an AC30 (final assembly);

(iii) where component date codes in AC30s are concerned more generally, speakers are regularly the latest, sometimes a matter of weeks later than the latest date codes in a chassis, occasionally as much as three months;

(iv) remember that prior to final assembly, chassis, speakers, and cabinets were simply stock parts sitting on shelves, useless on their own.

(v) final assembly was not the end of the process though. Thereafter the amp would be tested, and only after that a serial number plate stamped (by Jack Jennings) and affixed.

(vi) reckon on adding three to four weeks *at least* to the date of the speakers to allow for final assembly, testing, and the assigning of a serial number by Jack and his team. In some instances, getting the amp ready will have taken longer.

The list below is by no means comprehensive, necessarily just a series of "stepping stones" if you like - further material to be added in the coming days and weeks. In some instances, only the RIC cone codes are known for some speakers at present. As these codes tend to go in alphabetical sequence by date, links have been provided to the .

Provisional versions of Parts 1 and 2 will be posted shortly.

Final assembly, testing, assigning of serial number - 1962

4981 - 22FM (should be 22MF) - 22nd December 1961.

4988 - 22FM (should be 22MF) - 22nd December 1961.

4995 - RIC cone code known, Dec. 1961 - .

5002 - 22FM (should be 22MF) - 22nd December 1961.

5169 - RIC cone code known, early 1962 - .

unknown - 24EG - 24th May 1962.

5327 - 24EG - 24th May 1962.

5329 - RIC cone code known, May 1962 - ..

5392 - 14FG - 14th June 1962.

5482 - RIC cone code known, May/June 1962 - .

unknown - 20JG and 21JG - 20th and 21st September 1962.

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Final assembly, testing, assigning of serial number - 1963 (to late spring)

6000 - RIC cone code known, early 1963 - .

6097 - 31KG and 08LG - 31st October and 8th November 1962.

6364 - 04MG and 18MG - 4th and 18th December 1962.

6372 - 18LG - 18th December 1962.

unknown - 11AH and 15AH - 11th and 15th January 1963.

6529 - RIC cone code known, Jan./Feb. 1963 - .

6534 - 31AH - 31st January 1963.

66xx - 28BH - 28th February 1963.

674x - 19CH - 19th March 1963.

6758 - 19CH - 19th March 1963.

6887 - 03DH - 3rd April 1963.

14th April

Thanks to Andreas, pictures of AC30 serial number 5392, mid July 1962. The Celestion blues have the date code "14FG" = 14th June, 1962, for their manufacture. Further pictures .

AC30 serial number 5392.

Also added to the page, a slightly earlier Twin, no serial number, cabinet recovered - .

13th April (2)

A couple of updates to the page on AC30s with - (1) an entry for serial number 20203, still in excellent condition, thanks to Lothar; and (2) a note on the JMI owner's manual supplied with serial number 20899. The manual bears the print date November 1965.

Rear cover of the owner's manual supplied with AC30 serial number 20899, its print date "11.65". The manual, along with the warranty documentation, was sold in Germany separate from the amp earlier this year.

13th April

Thanks to Stephen, pictures of , early 1964, complete with original speaker cabinet and fixing hardware. The speaker is a Fane, probably a 122/10, sprayed blue for Jennings.

Vox Domino Bass, serial number 1451.

12th April

Currently on sale on Marktplaats (Netherlands), a pair of early Celestion blues, one speaker apparently with only a checker's stamp on its gasket (no date code or model number), the other with all three stamps, date code "21BF" = 21st February, 1961.

The page on Celestion blues .

11th April

Thanks to Steve, a shot of the Haddon mains transformer of an AC1/15 from early 1959 (capacitors dated August and October 1958). The visible legends are:

SCREEN - 0 - 115 - 145 - 160 - 212 - 237

350 - 0 - 350 - 6.3V - 3A - 5V - 2A

In the centre, what may be the part number, its first letter hidden - "xL. 113". A slightly later AC1/15 transformer has "215" and "245" instead of "212 and "237" and the screen terminal after "237" instead of first left. Its part number appears to have been "KH" followed by three numbers (obsured by wires in the photo) - , section on "Transformers".

10th April

A quick detail of the preamp of TV Front single speaker AC/30 serial number 4158. The main electrolytics are TCC Micromites, date codes January and March 1960. Signal capacitors are for the most part black WIMA Tropydurs, date codes February and May 1960.

At some point in the later 1960s, a few repairs were made, the pots replaced, among other things, with newer ones (also Egens) with date codes "EM" = May 1965, perhaps by JMI.

AC30 serial number 4158, detail.

2nd April

Thanks to Ilpo, pictures of Italian-made AC30 serial number 30182, late summer 1971. The reverb stage of these amps was solid state. Further details .

Reverb in these amps, and presumably also in those with serial numbers in the 6000s, was solid state:

Solid state reverb stage, the board date stamped July 1971.

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