Late AC100 mark 2s - 1966/1967

AC100 Mark 2s - serial numbers 1800-2050


Serial number 1800 - currently in Russia

Chassis no. 1927? Preamp repopulated with new capacitors, but three red Lemcos still survive. Original XLR sockets on the back panel.

Serial number 1804 - currently in Holland (collection: Reino Vester)

Chassis no. 1904. A nice AC100 with few changes. Red Lemco capacitors in the preamp, original XLR connectors on the back panel.

Serial number 1856 - current whereabouts unknown

Sold on ebay in early 2010. Chassis number 2099. Brimistor still in place, so too the original filter caps in the preamp.

Serial number 1857 - currently in the Netherlands

Chassis 2258. A really fabulous amp. Complete with preamp tag (as no. 1579). Thanks to Aart for the pictures. Extra capacitance on the underchassis perhaps because the amp was regularly used for bass. Logo has single letters V O X.

The amp, when acquired, suffered from excessive hum. New filter caps and a restored bias string were the cure. Thanks to Aart for pics of the sympathetic restoration.

Serial number probably in the mid 1800s - currently in Italy

Mains transformer rewound and some old replacements of components, but otherwise not too bad. Thanks to Francesco for the pictures.

Now in full working order.

Serial number probably in the mid 1800s - currently in Italy

A Triumph-style shroud to the mains transformer. Conventional black for the output. The same sort of long yellow coupling caps as in the amp above. A replaced fuse holder. The preamp is evidently in good condition. Sold originally by Musikhaus B. Hummel in Frankfurt, still going today.

Serial number probably in the 1800s - currently in Japan

Advertised for sale in Japan in July 2012 - - accompanying an early 1970s Defiant cab, doubtless great for guitar though not so hot for bass. Note that the cab has what looks like an original Amphenol socket on its back.

Serial number high 1800s or 1900s - currently in the USA

Probably a serial number in the high 1800s or in the 1900s. Red Lemco capacitors in the preamp - indicative of later amps. Replaced mains transformer (though it's hard to see from the pictures how this amp actually works). The speaker cabinet has been recovered, and the drivers, which are English Celestion alnicos, have Thomas Organ part number stickers, suggesting that the unit may have been intended for an American Super Beatle amp. Note too that the trolley has hooded castors. But the style of wiring, however, looks like standard JMI.

Serial number high 1800s or 1900s - currently in the UK

Chassis number 2128. Working well. Thanks to Gerry for the details.

Serial number 1903 - currently in Europe

Chassis no. 2210. In excellent condition. In the pictures above, paired with a Foundation Bass cab normally supplied with Vox solid state amps.

Serial number 1905 - formerly in the USA

Sold on ebay earlier in 2010. Chassis number 2263. Brimistor still in place, and perhaps the original Mullards. Square-cornered back panel; double-pin corner protectors (as no. 1966).

The date code of the blue Hunts 16uf capacitor in the preamp is "UYT" = 4th week of 1966 - as in two amps further down this page.

Serial number 1907 - currently in Italy

Control panel a little pitted, but otherwise not bad. Original Amphenol speaker XLR still in place.

Serial number in the 1900s - currently in the UK?

Sold on ebay in late 2010. Chassis number 2157, so a serial number somewhere in the 1900s. The backboard has square corners. Condition of the amp is generally good and easily enhanced. Few replaced components - most of the original capacitors appear still to be in place.

Serial number in the 1900s - currently in the USA

Chassis no. 2153. Replaced output transformer; underchassis electronics extensively changed. Red Lemco capacitors in the preamp. Speaker cab, less its original speakers, in good overall condition - horns and wiring are still in place.

Serial number 1938 - currently in the USA

Sold on ebay in late 2010. Amp cabinet recovered. Trolley and open-back speaker cabinet from a Super Beatle rig. The back panel of the amp has square corners - but the rounded inserts could easily come adrift when the recovering was done. Red Lemco capacitors in the preamp. The pairs of filter capacitors around the mains transformer are more recent additions.

Serial number 1947 - currently in Switzerland (collection: Maurice Cosandier)

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An immaculate rig from late Summer 1966. The first amp on this page to have a square-cornered back panel, a fact kindly pointed out by the owner. The corner protectors still have a single pin, however.

The date code of the blue Hunts 16uf capacitor in the preamp is "UYT" = 4th week of 1966.

Serial number *1948 - currently in the USA

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An interesting amp. Serial number 1948, yet chassis no. 1858 (which is more in line with amps with a serial number in the 1500s). Converted to cathode bias in 2009 by BLC - initials on the chassis underside. Fitted at some point with a modern replacement control panel - look at the fonts. It is not an original 60s JMI "make-do" black panel, as is suggested elsewhere. Mains transformer is of the sort normally used by Triumph, but the output transformer (with a Parmeko shroud, perhaps from an AC30) is of the type normally found in AC100s made by Burndept - code 66776 stamped on its underside. In the first three pictures, the amp sits atop an AC100 cab with new grille cloth and logo. Its cover is from Super Beatle cab, as are the speakers.

Serial number 1955 - currently in the USA

Sold on ebay in September 2010, and sold again with a closed-back Super Beatle trolley in October 2010 (last four pictures). A replaced mains transformer and choke, and replacement capacitors and resistors in part too. Box recovered and regrilled. No serial number plate or warning plaque on the new back panel. Rounded corners on the box for the original back panel still, but double-pin corner protectors. Close in date to number 1966, below.

June 2011: three more pictures - the amp now with serial plate 1955 and a repro NCM 2 x 15 cab. Notice that the jack sockets have been replaced by Amphenol XLRs, but a voltage selector is still absent.

Serial number 1966 - currently in Paraguay

Chassis number 2259. Late 1966? Capacitor codes XD and XE = April and May 1966. At some stage in the amp's life, one of the main filter capacitors blew, and the plate resistors caught fire, flaming out part of the tagboard. But with a few repairs here and there - apparently made three years ago - the amp now runs well, good and loud. The box appears to be on its third handle. Red Lemco capacitors in the preamp. The sockets on the backboards are old style replacements for the Amphenols (evidently removed some time ago). Rounded corners to the back panel; but double-pin corner protectors. Pictures from summer 2008.

The date code of the blue Hunts 16uf capacitor in the preamp is "UYT" = 4th week of 1966 - as in an amp further down this page.

Above, photographed November 2013. The original mains transformer revarnished and new filter caps to replace the existing dud ones.

Serial number 1979 - currently in Sweden

Chassis number 2271. Resident in Sweden from the late 1970s, perhaps earlier. Nice condition: a few changes here and there, for the most part in order to conform to Swedish legislation (note the absence of the voltage selector and brimistor), but otherwise all good. Square corners to the chipboard backpanel (as one can see in the second picture); metal clamps for the screw. Chalked on the back panel: "134/61". Thanks to Lars for the pictures.

The date code of the blue Hunts 16uf capacitor in the preamp is "UYT" = 4th week of 1966.

Serial number 1980 - currently in the UK

Chassis number 2149. Early 1967? Pot code EN = May 1966. Woden choke code DX = April 1966. A bit of a mess when it arrived from Italy - dry and dusty, an added bias transformer, and a dead short due to incorrect wiring in the output stage, meaning that after all the trouble that had been taken at some stage in the 70s to judge by added capacitors, the poor old thing would not have worked. It's fine now. The back panel has square corners on the left-hand side, rounded on the right - the corner protectors are replacments. The first three pictures show the amp in Italy. The next 12 show the amp in the United Kingdom before restoration; and the rest illustrate the present state, after restoration.

Serial number unknown - currently in the UK

Chassis no. 2039. The serial number plate (bearing the number 1261) is not original. The number on the plate originally affixed to the box was probably close to the amps above and below. The date code on the filter capacitor is "XF" = June 1966. The pots have the code 87030 - or perhaps 67030 - which may indicate a date early in 1967. See picture 14, reversed to show the reflection of the code the right way round.

The date code of the blue Hunts 16uf capacitor in the preamp is "UYT" = 4th week of 1966.

The pictures show the chassis stripped back, more or less, to original parts - an attempt was made some years ago to turn the amp into a 60 watter - but it was not successful. The box has a square edged back panel; two Amphenol connectors; and one corner with two pins - all the others are single - see the final picture.

Serial number in the 1900s - currently in Holland

Sold recently in Holland. Good external condition. Square back panel; double-pin corner protectors. Original Amphenol XLR connectors in place.

Serial number in the 1900s - currently in the UK

Chassis number 2029. The serial number plate looks like an original, but the stamping of "AC100" and "0227" must have been done later. The "Rating" pane underneath it, which normally gives "319", was originally left blank but ater lightly inscribed "100W". A good AC100 with few changed components. Once owned and used by Andy Pyle, bassist of Blodwyn Pig, Chicken Shack, and many other bands. For a short bio, see his and the . The Woden choke has the code DX = April 1966. There are square edges to the backboard and bulbous red Lemco capacitors in the preamp - consonant with the arrangement of the amps immediately above. Note that this amp has the same type of yellow Lemco decoupling caps (0.1uf, 400v) as serial no. 1938.

The date code of the blue Hunts 16uf capacitor in the preamp is "UYT" = 4th week of 1966 - as in three amps further up this page. The date of the 32uf cap is "IYS" = 30th week of 1965.

All holes for connectors on the back panel (made of chipboard and typical of later amps) have been enlarged. The red warning plaque has been moved to cover the hole formerly occupied by a second speaker connector. The amp's 4x12 cab survives too (picture 14), though somewhat changed internally. At some point the bias circuit was adjusted slightly to accommodate KT77 power valves instead of the usual EL34s - in the final picture, one can see one of the quad with the date and factory code 7824 Z, which translates as 24th week of 1978, Hammersmith Factory. The stencilled initials "G-R" indicate the box was made by the Gla-Rev company, which provided most of the other boxes on this page. The protective carrying case has been with the amp for the past thirty years.

Serial number 1994 - currently in the USA

Accompanied by one T60 cab and one 2x15" (with double pin corner protectors).

Serial number 2007 - currently in Switzerland

Thanks to Jogi for the info and pic.

Serial number 2036 - currently in the UK

Chassis number 2215 (?). Still single filter capacitors (rather than pairs, as in the later schematic). Red Lemco caps in the preamp; Brimistor still in place on the upper chassis. Only a few replaced components here and there. A small slot is visible in the control panel - possibly for some sort of tone boost switch.

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