Later AC100 mark 2s - 1966


AC100 Mark 2s - serial numbers c. 1200-1800


Late 1965 saw two changes to the "standard" form of AC100 Mark 2: the introduction of the three-line serial number plate (the third line giving the power consumption), and a metal guard around the EL34s on top of the chassis as a means of directing the heat generated by the output valves upwards through the top vent in the wooden case.

Left, serial number 902 from late 1965. No metal guard around the valves. Right, serial number 1579 from 1966, guard plate in position.


Production seems to have been remarkably consistent. Tone circuits were occasionally wired up back to front, resulting in a strangely interactive bass and treble; and at one point in early 1966 (serial numbers in the mid 1300s), two-line plates crept back in, but that was largely it through to the circuit changes of 1967.

Probably around 800 "original circuit" Mark 2 amps with valve guards were made, starting with a serial number somewhere in the 1160s up to somewhere in the 2000s.

Unsurprisingly a fair few AC100s from '66 - '67 still survive - perhaps as many as 200, maybe more. Some of course had hard working lives. Number 1980 below, for instance, was in a particularly poor state, but not beyond the point of no return. It still packs a punch. Others are remarkably unscathed, no doubt having had only fitful use (or careful owners).

For 1960s bands with AC100s, see these pages. The standard AC100 mark 2 schematic is here. Information and pictures of cabs are on these pages.

SURVIVING AC100s 1966 - 1967

If anyone knows of any others, or would like his or her amplifier to be included on this page, please email me at click here for the address.

Serial number 1216 - currently in France

Chassis no. 1687 - this amp was previously (and wrongly) said to have a chassis number of 1887. A nice AC100 with very few changes. The cab is a fairly early Supreme cab, with jack plug socket, rather than an XLR. The rubbing on the sides indicate that it lived in a tilt-back stand, not a full frame trolley. Thanks to Julien for the pictures.

Serial number 1261 - currently in the UK

What remains of the three-line serial plate for number 1261 - attached to the box of a much later amp.

Serial number 1283 - currently in the USA

No pictures currently available

Serial number 1288 - currently in the USA

Recently sold (Jan. 2015), with a Super Beatle cab and trolley.

Serial number 1328 - currently in the USA

Probably with its original speaker cab (two T1088s have the solder tags on the spokes of the; two on a board between the spokes - ie. early and late style). The logo is a replacement for the original, the ghost of which can be seen on the cloth, which has faded from black to brown. Inside the amp, there is no guard plate around the EL34s; the transformers have silver shrouds; and the preamp tagboard is short, both indicating that this AC100 was assembled by Triumph Electronics in Purley, rather than at Burndept in Erith. There is no stamped chassis number. Thanks to Chris for the pictures.

Serial number 1337 - currently in the UK

Serial number plate attached to a small-box AC50 box with a late AC100 inside - probably built by Triumph, using left-over stock, after the official Vox/JMI run had come to an end. See the Triumph-made amps page. Another amp on that page has the number 1555.

Serial number 1375 - whereabouts unknown

Simply the two-line plate for the time being.

Serial number 1381 - current whereabouts unknown

Needing a bit of clean, this AC100 has already been repaired at least once. Difficult to tell for sure, but the mustard capacitors in the preamp may be original.

Serial number 1405 - currently in the UK (collection: Mike Handley)

Chassis number 2099. Excellent original condition, one of the best Mk 2s surviving. Note the mustard capacitors in the preamp.

Serial number 1410 - currently in Italy

Assembled by Triumph. Underchassis signed in pencil, perhaps by "Graham". No chassis number. Note the short tag board, the insulated stand-offs under the fuse-holder, and the large transformers with bare metal shrouds. Further pics on the Triumph-made amps page. Pictures originally posted here.

Serial number 1534 - currently in Italy

Chassis number 1918. A nicely restored AC100. An early instance of green TCC capacitors in the preamp (cathode bypass capacitors for the ECC83). Green TCCs occur next (or at least are next visible) on AC100 no. 2404. The white warning plaque is original; the voltage selector a replacement (the original was broken). Of great interest is the cab with its set of Goodmans speakers and horns - see page 7a. Note that the handwheel (picture 13) has incised letters in common with other later UK-made trolleys.

The restoration work was undertaken by the amp's owner: Andrea Spallone - Guitar Repairs, Campobasso - Italy. Thanks to Andrea for new details.

It should be said too that this AC100 can be heard on tracks by Nancy Cardo and the New Nervous Tic - http://www.nancycardo.com; and for a selection of tracks, click here.

Serial number 1540 - currently in Germany

Assembled by Triumph Electronics - registered on this page.

Serial number 1553 - currently in the USA

Chassis number C1902? Sold on ebay in 2007. Preamp extensively refurbished. Grille cloth later changed to brown to match a reproduction 2 x 15" cab.

Serial number 1561 - formerly in Denver, USA, now in Seattle

Chassis number C1885. Pictured with a Vox 4 x 12 cab. Restored seven years ago and brought back to full working order, this is the main gigging amp of Hank of "Hank and the Hankstirs". Normally, as one hears it in the clip above, the amp is run through a Vox Essex cab (2 x 12). A really fine sounding (and nice looking) AC100. The band's website is http://www.hankandthehankstirs.com/.

Further images

The amp in 2012, having been expertly tidied and restored, accompanying a great AC100 cabinet. Thanks to Tom for the pictures.

The amp now in Seattle - thanks to Walt for the pictures.

July and August 2013 - currently with Thunder Road Guitars in Seattle; and advertised on gbase.


Sold through Emerald City Guitars.

Serial number 1569 - currently in the USA?

Sold on ebay in 2010. Old style white warning plaque. A strange array of speaker output jack sockets added.

Serial number in the 1500s - currently in the US

Chassis number 1850. An AC100 inside an AC50 box. Thanks to Matt for the pictures.

Serial number 1579 - currently in the UK
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579
Vox AC100 no. 1579

Chassis no. 1846. An amp with few changes. An inspection tag is still attached to the preamp tagboard. Probably made May 1966. Pot codes are KM and AN = November 1965 and January 1966; and capacitor code XB = February 1966.

Serial number 1584 - currently in the UK

Chassis no. 1810. Probably used by a Birmingham (UK) band. Repaired in 1969 and 1971 - a new valve socket, Bulgin plug, jack plugs for speaker outs. The output transformer was mounted upside down, such that the primary leads had to be passed through holes on the upper chassis. Similar transformers occur in serial no. 1099 and in two amps with numbers probably in the 1000s and 1100s - see the early fixed bias amps page. The date codes of the preamp filter capacitors are unfortunately hidden, but one of the pots has AN, signifying January 1966. The main filter caps have the code XB = February 1966. The amp is currently (25th June 2011) being tidied up and returned to working order. The first ten pics are from the ebay auction, the next twelve further details of the original state.

3rd July 2011: the amp is now in working order again (last seven pictures). The wiring has been tidied up, and the output transformer remounted the right way round. The EL34s that came with the amp, presumably put in c. 1970 - two Mullards and two Matsushitas - are still good. This AC100 has a huge thump. My theory is that amps that were used for bass for most of their working lives always sound fuller than those used primarily for guitar.

Serial number 1591 - currently in the US?

A nice looking MacCartney-ised rig - repro brown grille cloth, covers and stand. Note that the amp (or rather its box) still has its hangtag. The white warning plaque may be a modern replacement, or original to an older box that has been used to rehouse the amp.

Serial number 1600 - currently in the US?

Sold on ebay a few years ago. Box in excellent condition, as is the amp. Few changed components. A pair of jack sockets (rather than a single? original Amphenol XLR socket) now on the back panel.

Serial number 1638 - currently in Spain

A Triumph-made amp, signed off by Graham, whose signature appears in other amps. See this page for further details. Thanks to Juan for notification of the existence of this amp.

Serial number 1654 - currently in the USA

Sold in early 2012. A replacement (Fender) output transformer, and large-format "VOX" logo, but otherwise in good condition. Original mains connector on the back panel.

Serial number 1669 - currently in the UK

Sold on ebay.uk, 2015. A nice rig. Only a few changes - mains transformer replaced, white Bulgin mains connector on the backboard, a few capacitors renewed, and a US silver alnico in the speaker cab (presumably a replacment for an original that had blown.). The wiring in the speaker cab is intact. Terminals on the Celestions are still on the struts, rather than on tagboards. The connector on the cab is a rectangular Cannon, not a round Amphenol.

Serial number 1674 - currently in Connecticut

Another nice AC100, original XLR and mains connectors still on the back panel. The mains and output transformers have the unpainted tops typical of Triumph-made amps. See for instance the AC100s on this page.

Serial number 1677 - current whereabouts unknown

Only the serial number plate for the time being.

Serial number 1708 - currently in Italy
Serial number 1740 - currently in the USA

Chassis number 1878. A nicely restored AC100. Thanks to Jimi for the pictures.

Serial number 1752 - currently in the Uk

Amp built by Triumph Electronics and registered on this page.

Serial number 1769 - currently in Europe

Perhaps with its original 2 x 15" cab. The amp has been modified, as the pictures indicate: the original warning lamp has been rejected in favour of an extra control, and a small switch sits beside it - presumably either a boost, or a means of switching a middle control in and out.

Serial number 1777? - currently in the USA

Chassis no. 1918. Note the two-line serial number plate and the sticker "Vox Room Guitar Center. Put back into full gigging order, with adjustable bias to cope with the vagaries of modern valves. Thanks to Chip for the pictures.








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