Conversions and reproductions

As the title indicates, this page collects together amps that were converted to perform as AC100s - AC50s being the natural starting point - and reproductions made in recent years.

Converted AC50 - whereabouts unknown

Sold on ebay in late 2007, a converted AC50. Just two pictures showing the redesigned panel, and a rat's nest of wiring (a Health and Safety inspector's field day). The preamp seems to have been modelled in part on the AC125, with frequency sweep controls. Sold as being in working order.

Converted AC50 - currently in the UK

Pictures by kind permission of John Chambers, who restored the amp to working order. See his website - An interesting conversion. The transformers are replacements - note how the power transformer overhangs the chassis - and the paired rectifier diodes sit on two insulated standoffs on the underchassis - no attempt to provide further tagboard.

Currently in the U.S.A

A beautiful reproduction of the AC100 Mk I (the AC80/100) - Mercury Magnetics transformers and other quality components throughout. Note the white input jack sockets, and the "sideways" Cannon LNE-11 power socket on the back panel - just as in McCartney's first AC80/100 (see ).

Reproduction - made by JMI Amplification (Music Ground) - 1st version

The first version of Music Ground's reproduction AC100, probably late 1990s or early 2000s. More accurate cosmetically than version 2 (below): old-style grille-cloth; a good repro panel; conventional handle; and no option for beige tolex, as Music Ground had not yet sourced a supplier. Although there are no detailed pictures of the electronics, one can see a small choke (smaller than the original) through the top mesh, and what appears to be a slightly larger than original output transformer. There is no standby switch.

Reproduction - made by JMI Amplification (Music Ground) - 2nd version, current production 2010

A modern "take" on the AC100 Mk II - an example in beige covering and brown grille cloth, another in black (last two pics). The fixed bias has been circuit brought up to date with a standby switch and bias pot. For the sake of convenience (presumably), the preamp valves have been moved low on the aluminium upright; and the use of a double-section filter capacitor, has obviated the need for a second cut-out in the chassis.


with a MusicGround repro AC100

Mark Griffiths with the AC100 bass rig and repro trolley. The set up was offered for sale by MusicGround on ebay in November 2010.

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