The Vox UL730
The power amp schematic is OS/114 (shared with the 430), and the preamp schematic OS/117 (shared with the 715, 760 and 7120).
The 7120 aside, the 730 is perhaps the most well known of the 7-series guitar amps. All sorts of things have been said about numbers remaining - even that only 26 survived a "cull" carried out by Vox in 1967 - the premise being that a large number of unsold amps, and amps recalled from owners and distributors (exchanged in some cases for new solid state units), were destroyed in Dartford. That is wide of the mark unfortunately. Probably around thirty or forty exist today.
The Beatles had at most two - not two each, or six each, but two in total. The serial number of George's amp is known, and it is not either of the two! now claimed. Watch out!
Also watch out for conspiracy theories and the fluffy stuff that's regularly ventured about UL730s.
Triumph Electronics, which assembled the amps for Vox, was a small place and produced work of the highest quality - but not always in an orderly linear fashion. Elements changed as production proceeded. Wiring was copied from sets of component boards not designs on layout sheets.
The schematics as we have them were for the repairmen and service departments, not the wirers and assemblers at Triumph.
A number of 730 cabs produced around October 1966 evidently had Celestion T1225 ceramic speakers, rather than silver alnicos. The cabs that the Beatles had on stage at the Savoy Theatre for the Hello Goodbye promo video (10 Nov. 1967) certainly had T1225s. See 2/3rds of the way down this page.
Amps are registered in two sections: (1) by serial number if known; and (2) lower down the page, serial numbers unknown.
Serial numbers begin at 3000 or 3001. Note that they are not a reliable guide to relative date, ie. amp no. 3030 could be later than amp. no. 3040.
The Finnish band Tetetermite with a 730 set just visible in the background
An early 730
Pictured above with a 715 cab - the original is to be seen below.
Pictured with its original cab. Currently in the UK. Sold on ebay in 2016. Restored to full working order. Various things indicate that this amp was part of a small pre-production run, c. May/June 1966 (it is not a prototype). Points to note: the early style of panel; the different arrangement in places of the electronics - notably the lights over the front panel; the filtering in the power section; and some of the under-chassis elements. The original footswitch has a different style of lettering from what came to be standard. The back panel is removable (early style of box).
SERIAL NUMBERS KNOWN
Not necessarily the second issued, though perhaps still early - see the note on the unreliability of Triumph serial numbers.
The amp alone (no cab, no trolley) sold on Gumtree in 2009. Above, pictures from the auction.
Currently in Australia. A good tidy amp. Visible pot codes are "GN" = July 1966. Thanks to Guy for the pictures.
Currently in the USA. 12 June 2016: This amp is currently for sale.
Currently in Italy. Formerly owned by the band "The Royals".
Formerly in the UK, now in South America. Thanks to Steve for the pictures. One of the pots has the date code "GN" = July 1966. The mustard capacitors are by and large old stock with date codes from 1963 and 1964 - Triumph had large batches of these.
Currently in the USA. Main amp in picture. To the left, on the floor is 730 serial number 3029. Number 3078 came from Germany. The cabinet is an original, the trolley a NCM reproduction.
The Celestion T1088s have date codes 10LL and 02ML = 10th November and 2nd December 1966, respectively.
Existence reported by J. Elyea.
SERIAL NUMBERS UNKNOWN
Currently (12/06/2017) in France and for sale on the Leboncoin auction website.
Currently (12/06/2017) in Denmark and for sale on Reverb.
This is probably an old picture of the same amp.
Currently in Holland, with original cab and trolley.
Poor pictures from the late 1990s. Advertised for years on Marcus Hardy's now defunct toneheaven site.
Currently in the USA. Accompanied by a repro NCM cab.
Currently in the USA - ex Sentience Studio. In the last pic, the amp is shown either with another 730 or a 715.
Paired with a North Coast Music repro cab and trolley.
Note the pair of T1225 speakers instead of the more usual alnico T1088s.
Sold on Gumtree UK in September 2016, but for a long while resident in Holland. Possibly another 730 in the background. Note the T1225 as in the amp above.
Grabs from the Hello Goodbye promo video, shot at the Savoy Theatre, London, 10th November 1967. The amps on stage were Conquerors, and the cabs 730s with ceramic T1225 speakers.
Paired (doubtless not from point of origin) with a closed back 460 cab. A nice amp with original footswitch.
Formerly in Germany, currently in the US.
In pre-restoration condition. Currently in the UK.
Currently in Holland.
Currently in France. A nice set, missing though the top bar of the trolley.
Offered for sale by Music Ground in the mid 2000s. Music Ground more recently also used pictures of this amp to try and sell a "7120" with four KT66s!". Perhaps it was accidentally converted.