VOX AC100 - UPDATES AND NEW INFO
April - July 2019
Some details from AC100 serial number 241, black panel, unpainted shrouds to the Woden transformers: mains = part no. 72191, output = part no. 72192, and choke = part no. 72193, in other words the set used in the earlier copper panel amps.
Produced very late 1964 or early 1965. Sold and used in England. Converted in the early 1990s to run as an AC50 (2 x EL34) - so needs some putting back to original format.
Certain serial numbers were stamped with a prefixed "0" - 0185, 0221, 0241, 0254. Most, however, are just the three digit number.
Pot date code "JL" = November 1964.
Woden mains transformer, date code "KV" = November 1964.
Gold-coloured TCC 32uf capacitor, date code "VG" = July 1964.
Green TCC "Micromite" 32uf capacitor, date code "VF" = June 1964.
An advert for Egen potentiometers in "Wireless World", July 1952. Vox used Type 115. There is a general page on Egen Electric Limited here, and two further pages on the date codes stamped by Egen on their pots: one probably most relevant at present to the "100W Amplifier" (late summer 1965); and a second for the AC100 mark 2 (late 1965 to 1967).
Below, small images of two pages from the first Thomas Organ Vox Price List - "Effective April 26, 1965" - in other words ten or so days after the competition sponsored by Vox at the 4th Teen Age Fair - see this page. The leaflet has four pages: Front cover, Guitars, Amplifiers and Sound Equipment, Cases and Accessories.
Front cover, and page for Amplifiers and Sound Equipment. Sold on ebay in May 2011 - archived here.
Small though the pictures may be, they are just large enough to make out the text. Note that the amplifiers all have their new American names. Below, a copy (made in "Word") of the page.
Copy of the amplifiers page from Price List dated 26th April 1965. At this point, one could not buy an AC100 amplifier section separately, as one could in England. See the "NOTE" in box.
Below, details from the Thomas Organ Vox catalogue from late summer 1965 - the "King of the Beat" - the first to give the amplifiers illustrated their new designations - ie. the AC100 is the "Super Beatle" and so on. Since the Price List represents an earlier state of affairs, there are discrepancies - there is no "York" below, for instance, and no "Pacemaker", "Cambridge", "Berkeley" or "Essex Bass" above. The number of inputs mentioned serves as a useful means of correlation:
The "Viscount" is still the AC30
In the first illustrated catalogue - the "Million Dollar Sound" catalog - issued by Thomas Organ (in late 1964), items still have English names - see this page. The reference in the title is to the order for $1,000,000 of equipment placed by Thomas Organ in late August 1964.
Below, AC100 SDL serial number 954, with original cover for the amplifier section. Thanks to Michael for the pictures.
The amp is registered here, where there are further pictures.
And of course, the same amp again (as in the catalogues below) in the advert published in "Beat Monthly" magazine, April 1964 - "Vox went the Beatles, USA":
5th July (2)
Below, the thin-edged AC100 pictured in the JMI catalogue of February 1964. The page on which it appears is here.
A detail from the Vox dealer's catalogue, same date as above, showing the same AC100. Thanks to Martin Kelly for the image.
The amp cannot at present be identified in pictures from the period, but as more and more come to light, it may ultimately be possible to spot it in action. JMI initially kept a reasonable number of AC100s to lend out:
NME Poll Winner's concert, 26th April, 1964: two thin-edged AC100s on one of the wheeled platforms on stage.
Below, the well-known publicity picture of Billy J. Kramer and the Dakotas with an array of Vox equipment as printed in "Vox Teen Beat" magazine, no. 1, late March or early April 1965, though the shot was taken a little while earlier - late 1964 in the United Kingdom. This picture regularly features in Vox catalogues, brochures and so on. One also finds it as a framed print, part of a set supplied to dealers by JMI and Thomas Organ in 1965.
The thin-edged AC80/100 on end is actually the one used by the band (along with Gerry and the Pacemakers) on the T.A.M.I show, 28th-29th October, 1964. See the entry below, for 28th June.
As ever, compare the arrangement of diamonds on the grille cloth.
Pictures of the first edition (1960) of Shirley Douglas' "Easy Guide to Rhythm and Blues for Bass Guitar" now added here.
Along with her partner in music Chas McDevitt, Douglas was a long-standing Vox user and promoter, appearing in various flyers and brochures.
The second edition of the Guide (1963) was updated with newer pictures of bands with Vox amplifiers and guitars. The third edition (1970) preserved substantially the same text, but Vox no longer figured.
This copy was sold at Jim Marshall's shop (Marshall amps) in Hanwell.
Letter from David Turner at Jennings Musical Industries to Eric Easton, manager of the Stones, and the cover and back page of the programme to which it relates:
Programme front cover. The tour ran from 24th September - 17th October, 1965.
Dezo Hoffman photgraphs. Other photos from the session on the right (from 1963) show that the AC30 and T60 cabinets have no speakers in them. The T60 amplifier box is also empty. The advert as a whole was later recycled by Thomas Organ in the USA.
For info on UK package tours, 1959-1967, along with programmes, bills, and flyers, see the indispensable Bradford Timeline site.
Below, a rough print picture from NME, October 16th, 1964 - the Animals performing at the "KYA Swim Party", Cow Palace, San Francisco, 3rd October.
The amp indicated by an arrow is an AC100, perhaps belonging to one of the other bands on the bill, or a spare, as it is evidently not plugged in.
If anyone knows where the original photo is held now, do please let me know.
On the back panel: serial number plate in the centre, white warning plaque low down at left.
The other acts on the bill were: The Beau Brummels, Chuck Berry, Chad and Jeremy, Bobby Freeman, The Coasters, The Hondells, Lou Johnson, Sonny Knight, The Olympics, Roy Orbison, The Shirelles, and The Spearmints.
24th June (2)
Serial number 772 currently on Reverb - one of the nicest Mark 2s and an original set.
Further to the recent posts on thin-edged AC80/100s, details of the amp loaned to the Stones by JMI for the short European junket in October 1964: 18th (Brussels), 19th-20th (Paris). Pictures taken on the 20th at the Olympia Theatre. The first is held by Getty Images.
Photographs of this amp have so far only come to light from Brussels and Paris. Note that the speaker cab has corner protectors.
Paris, Olympia Theatre, 20th October, 1964.
The arrangement of the diamonds on the grille cloth of two of the amps used by the Stones in England in August '64 can be seen in the entry below for 11th June. For Bill Wyman's first amp, used intensively from late March to late July '64 and sporadically thereafter (well into 1965), see the entry for 11th May.
The T.A.M.I Show, 28th-29th October, 1964, Santa Monica Civic Auditorium, California. JMI provided an AC100 bass and two AC30s for Gerry and the Pacemakers and Billy J. Kramer and the Dakotas. The Rolling Stones had their own gear.
BASS flag on the speaker cabinet just visible.
The striking thing about the amplifier section is its rather stretched grille cloth, resulting in some bendy diamonds lower right. So far it has not been possible to identify this amp in other pictures or among the survivals (though two have lost their original box, and two have been regrilled). But it may be that further shots will turn up.
Below, a provisional list of numbers of *thin-edged* AC80/100s owned by bands in 1964 (attested in the photographic record), and amps seen to have been provided by JMI for particular concerts. Amps in the second category, however, may have served two or more events and at some point presumably found their way into the hands of groups or into shops.
OWNED BY BANDS
Rolling Stones - 4 - two serial numbers known at present.
Beatles - 5 (perhaps 6) - two serial numbers known at present.
Sounds Incorporated - 1.
Screaming Lord Sutch - 1.
Jonny Milton and the Condors - 1.
Featured in catalogues and adverts - 1.
NME Poll Winners (April '64) - 2.
Swinging Blue Jeans - 1.
"Ready, Steady, Win" competition (September '64) - 1.
Rolling Stones (October '64) - 1.
Arthur Howes/NEMS Package Tour (Oct. and Nov. '64) - 1.
Gerry and the Pacemakers / Dakotas (October '64) - 1.
Taken together these amps go some way to filling the gaps between the amps currently known to survive, the main gaps being: serial numbers 151 to 168, and 186 to 200.
Some better pics of the first sighting of serial number 225 in the States - Vox Teen Beat magazine no. 1, issued in California in late March / early April 1965. The magazine as a whole is available here.
It seems likely that amp and cab were flown to Sepulveda in late '64 or very early '65, perhaps (operative word at the moment) having been loaned out by JMI in England in November and December - see the detail of the photo of The Kinks in yesterday's post.
The picture as printed in the magazine. No header or caption is given.
One also finds this - the original photograph composited with various bits of text, including the Teen Beat header and a highly inventive caption, both of which are here cut away.
A note on serial number 225, a JMI demonstration AC100 SDL (with early cab and basket-top trolley) found in Colorado around twenty years ago by a Korg representative and acquired by Mitch Colby.
Serial number 225 - brown grille cloth, thick edged box, no corner protectors. In some published photos serial no. 169, which does not belong, is shown on top .
Detail of the capacitor network protecting the Midax horns from low frequencies. The same arrangement can be seen in the bottom shelf of one of the Beatles' cabs - photo taken 20th June 1965, Paris.
Over the years, various comments about the AC100 were posted on the the "Plexi Palace" Vox forum (now sadly gone), the most interesting being that the speakers in the cab - Celestion alnico T1088s - had been found (ie. following inspection) to have "November 1964 date codes".
The cab is unlikely therefore to have been ready for use before the second half of November / early December. One suspects that both it and its amp were shipped to Thomas Organ - Sepulveda rather than the branch in Niles (572 Golf Mills Shopping Center) - at some point relatively soon after that.
As far as the amp is concerned, November is perfectly in order in terms of production. AC100s in thick-edged boxes are first seen around this time - photo of 20th November on this page. But one has to temper this with the fact that such boxes were being illustrated as early as September:
"Melody Maker" magazine, 12th September, 1964. The dimensions given are a little peculiar though.
Four cabinets with basket-top trolleys had already been produced in August 1964 and a number presumably followed, September to December, though quite how many is impossible at present to say. Probably only a handful.
Serial number 225
Detail from a picture of the The Kinks from Getty Images - "Top of the Pops", either 5th or 19th November 1964. On stage a loan AC50, an AC100 SDL and AC100 bass. Both amps are thick edged, apparently without corner protectors, and clearly not no. 225. Are the cab and basket-topped trolley those of no. 225? Very close if not.
The four early cabs
"Melody Maker" magazine, 25th July, 1964. "The four loudest amplifiers in the beat world...."
The amps in question were the AC100 SDLs designed for John Lennon and George Harrison. Paul's AC100 bass had been issued to him in late December 1963.
Two were given to the Beatles in the first week of August '64. The other two were evidently retained initially for promotional purposes, being shown at the "British Musical Instrument Industries" Fair (24th-28th August) while the Beatles were on tour (18 August - 20th September).
On the Fair, which took place at the Russell Hotel in London, see this page.
Just to signal that the black panel amp that recently came to light is not serial number 254 but 263.
Serial number 262 was exported to the States early on doubtless by JMI. Serial number 263 has always been in the UK.
A great pic. by John Taylor of Mary Wells and Sounds Incorporated on the Arthur Howes tour, Edinburgh ABC, 19th October, 1964. Top of the bill were the Beatles (one of their amps visible in the background. At least five thin-edged AC80/100s were present on the tour.
Edinburgh ABC, 19th October, 1964. For other pics taken on the tour, see John's site.
A third AC80/100 used by the Stones (Bill Wyman). Its distinctive back panel - with speaker sockets of various types - is known from a shot taken at the Wimbledon Palais, 14th August, 1964.
Wimbledon Palais, 14th August.
It is clear from details below that this was the amp that Bill had at the 4th National Jazz and Blues Festival, Richmond, 7th August:
Part of the amps's distinctive panel glimpsed on the Richmond stage through Keith's AC30 stand.
A sliver of the front of the amp caught in a picture of Mick Jagger.
This amp is clearly not the one seen on stage at Longleat on 2nd August (Bill's second AC80/100) - compare the arrangement of the diamonds on the grille cloth.
Longleat, 2nd August, 1964 - Bill's second AC80/100.
Below, Essen, Grugahalle, 13th September, 1965. Is this Bill's third AC80/100 (as seen at Wimbledon and Richmond, above)? - the white banana plug sockets removed, the serial number plate moved to cover the holes, and the chassis as a whole now in a thick-edged box.
Note far right on the back panel the Bulgin mains connector, a distinctive feature of the Wimbledon/Richmond amp. Bulgins are not common on AC100s.
A quick shot of two Thomas Organ catalogues side by side: "King of the Beat" from late summer 1965, and "The British Sound", from early 1966.
In the "King of the Beat" catalogue the text in the panel reserved for the details of "Your Vox Dealer" reads:
Manufactured by Jennings Musical Industries Ltd, England
Distributed in the United States by the Thomas Organ Co., Sepulveda, California
In the "British Sound" catalogue the text is:
Manufactured expressly for Thomas Organ Co., Sepulveda, California
under license from Jennings Musical Industries Ltd, Dartford, Kent England.
Although the "British Sound" catalogue still contains a good number of items assembled in and shipped from England (the AC50, AC100 and so on), production was clearly in the process of being reformulated - guitars farmed out to Italy, and the new Thomas Organ solid state amplifiers built locally at Sepulveda.
Thomas also came to make its own arrangements for the production of the Treble, Bass and Distortion boosters. The earliest Treble units in the States - as represented in the "King of the Beat" catalogue - were probably English made, however.
English-made boosters always have a hypen: "Treble-Booster". The second generation boosters made in the States have none. Details are being collected on this page.
None figure in the "Million Dollar Sound" catalogue from late 1964 / 1965 - see this page.
Bill Wyman's second AC80/100 - brown grille cloth, V O X in individual letters - pictures from the concerts at Longleat House (2nd August, 1964) and Olympia, Paris (20th October, 1964).
Longleat, the stage apron. The thin-edged AC50 is the PA amp, two microphones feeding into it. Brian and Keith have an AC30 each. The AC80/100, with two Foundation Bass speaker cabs, is Bill's.
A detail of the AC80/100.
At right, the top of the amp, one guitar lead plugged in. Detail of picture from Getty Images.
Paris, Olympia, 20th October, 1964. Detail of picture from Getty Images.
Pictures of Bill's first amp - with BASS runner and moulded VOX logo - can be seen in the entry for 11th May, below, and on this page.
As is well known, the potentiometers used by Vox in many of its amplifiers (and certain guitars) were made by "Egen Electric Limited", a subsiduary of the Ekco group based on Canvey Island. Egen also supplied pots to Selmer and other companies.
For the time being, some preliminary notes:
The Egen Electric works on Canvey Island, c. 1970. Photo from this page.
Standard Egen packaging.
Below, examples of potentiometers from 1964, 1965 and 1967. Distinctive features are the flat bottom; the solid metal shaft; the two small rivets on top of the terminal board; the two lugs extending from the body, one flat, the other upright, each pierced with a hole; and the notch in the body of the pot underneath the central terminal.
"EGEN" is generally stamped on the top of the body close to the shaft.
The volume pot from an early AC80/100 removed for cleaning. Date code is "AL" = January 1964.
The three pics above, a treble pot from an AC80/100 refurbished by Vox in mid 1965. The pot is a 1 Meg LIN (linear rather than logarithmic taper), date code "DM" = April 1965.
A tone pot from an AC100 with a serial number in the 1900s - date code "EN" = May 1966.
Egen potentiometers with printed part numbers are first seen in AC50s from early 1966 (amps with serial numbers in the 5000s). Volume pots (500K) were no. 66181; tone pots (1Meg) no. 66520.
The company presumably printed the pots for AC100s from that point too. Volume pot (500K) - number to be determined; tone pots (1Meg) no. 67030.
It is not entirely clear at present why the 1Meg pot for the AC50 should be no. 66520, and the one for the AC100 no. 67030 - they were identical as physical objects.
A new page begun on early Vox plug-in boosters. Further pics and new info to be added.
JMI boosters pictured in the solid state catalogue of mid 1967. First-generation boosters sold by Thomas Organ take the same form, but differ in a number of respects (different packaging, finish, legend, and so on).
Below, a Thomas Organ Vox document wallet from late 1965 / early 1966, produced for the use of dealers and representatives at Trade Fairs and so on - to hold catalogues, pricelists, flyers and hand-outs. Thanks to Arthur.
The American bands mentioned in the list of Vox users are: The Standells, Paul Revere and the Raiders, and the Sir Douglas Quintet. The list is typical of 1965.
Kenny Ball was evidently a sop to jazz fans.
An English wallet:
A couple of grabs from the film documentary on the The Beatles' concert at Shea Stadium, 15th August, 1965. On the field before the show, a brief glimpse of some of the equipment.
From background to middle-ground: the brown-fronted amp is probably one of the early AC50s (there as a backup); to its right, a thick-edged AC100. In the middle-ground, two amps placed front to front. Nothing much can be seen of the furthest one, but it may be another AC50 (given its apparent smaller size). The amp with its rear panel showing is an early thin-edged AC80/100. To its right a thick-edged AC100.
The amp with its back to the camera is not seen on stage at any point during the proceedings, so may have been a backup either for The Beatles or Sounds Incorporated. The arrangement of elements on its panel shows that it was not the early AC80/100 that Sounds Incorporated regularly used, however. See the picture and detail below. Note the positions of the mains socket and outermost speaker socket in relation to the screws on the lower edge of the back board.
A further shot of the early AC80/100 belonging to "Sounds Incorporated" - caught from rear of stage. c. 1966 (venue at present unknown). At least one of the AC50s pictured has a three-line serial number plate and red warning plaque.
It is the front of this AC80/100 that probably features in the picture of the band with Mary Wells (entry for 15th May, below).
Salient features of the rear of the amp: twin Cannon XLR sockets; the rounded off corners to the white warning plaque (also on serial number 173); the metal Arrow ball-end mains switch; and the absence of screws on the top edge of the backboard.
Thanks to Ruth for the image.
A new page begun on Vox (Thomas Organ) adverts in "Downbeat Magazine", a jazz bi-weekly that cast its net wide. Most of the ads are well-known, but their source is seldom noted.
The front and a portion of the reverse of a Burndept flyer for an airborne transceiver. Aviation and military communications devices were the company's main lines of business in its Erith premises - the works on West Street, shared with Vox from early 1965, and the Riverside Works beside the Thames.
Both Burndept and Vox were part of the Royston group of companies, a controlling share in Vox having been taken towards the end of January 1963 (380,000 one shilling shares). What eventually brought the group down, Vox included, was Royston's insistence that Burndept develop its Midas black box flight recorder. Profits from the member companies were effectively siphoned off in Burndept's direction, and when the recorder failed to find commercial success, Royston and its holdings rapidly collapsed.
The telephone number originally printed - Erith 33080 - is that of the West Street Works. One also finds it in Vox literature from 1965. The fact that the number is crossed out in the Burndept flyer (dated 2nd Dec. 1964) probably indicates that the department concerned had moved out to make room for Vox.
Full page advert in "Flight International" magazine, 30th August, 1962, giving the Erith 38121 telephone number at foot and the line "A Member of the Royston Industries Group".
Below, the well-known picture of Mary Wells with Sounds Incorporated, last third of 1964, from Getty Images. The amp caught at right is certainly a thin-edged AC80/100 - its grille cloth 3 diamonds tall. The grilles of thin-edged AC50s are 2 2/3 diamonds tall.
The amp is seen on stage accompanied by two Foundation Bass cabs during the Arthur Howes/Epstein package tour of Great Britain, 9th October - 10th November, 1964, Mary Wells, Sounds Incorporated, The Remo Four, et al. supporting The Beatles.
Belfast, King's Hall, 2nd November, 1964. The amp and one of the Foundation Bass cabs (the other is behind the curtain) can be seen at right of stage.
Below, a detail from the picture of the Barron Knights published in "Pop Weekly", 2nd January, 1965. The amp on the ground is an AC100 (AC80/100) in a thick-edged box, not a small-box AC50, as suggested earlier (entry for 5th May).
AC100s in thick-edged boxes with BASS runners (lower right hand corner on the grille cloth) are extremely rare birds - indeed, this so far seems to be the only example. As BASS runners are, as far as AC100s go, a thin-edged box thing, the amp in view is probably an early thick-edged AC80/100 with a copper control panel.
11th May (2)
The page on the Stones, 1964-1965, has now been overhauled, long overdue. Further details will be incorporated soon.
Dayton, Ohio, 13th November, 1964. The settings of Bill's amp - everything at 1 o'clock.
Further shots of Bill Wyman's first AC80/100 - at Alexandra Palace, 26th June, 1964, road manager Ian Stewart sorting out cables; and on stage, NME Poll Winner's concert, 11th April, 1965.
The front of the amp, currently in Florida.
The original box and plate of serial number 215, currently in the USA - thanks to Mike for the pics. Although the back panel fittings have been removed, shadow outlines show how it was arranged.
The distinctive feature of no. 215 is the low position of its warning plaque - close above the paired Cannon XLR speaker sockets (which are not uncommon on amps with numbers in the 200s, but rare earlier on).
An overview of the arrangement of the back panels of various AC100s is available on this page.
"Pop Weekly" magazine, 2nd January, 1965. The Barron Knights pictured with a full set of Vox gear: two AC30s; an AC50 Mk 1 in thick-edged box with BASS flag; two Foundation Bass speaker cabinets (with no side handles) and an AC100 on top; two LS40 columns.
Given the date of publication, the AC100 (AC80/100) will have had either a copper or black panel. The picture doesn't particularly look like one taken in the depths of a British winter - more late summer / autumn - but there were certainly some warm days in the south of England, December '64 - synopsis.
2nd May (2)
A quick shot of the lower half of a full-page Vox ad in "New Musical Express", 10th December, 1966:
Below, a paper runner, one of two said to have been given to a group visiting the Dartford Road factory in early 1967. Stacks of these were probably printed during the course of 1966 - note the similar arrangement of items (not quite the same) in the ad placed in "Beat Instrumental" magazine, February 1966.
Whether anyone really put these in a van window....
Printed paper runner, c. 1966.
"Beat Instrumental" magazine, February 1966.
"Melody Maker" magazine, 9th May, 1970 - three AC100s on sale. The Orange shop on New Compton Street regularly had secondhand Vox amps, and not uncommonly AC100s. Occasionally the line was "Vox AC100....choice".
9th May 1970
A couple of Vox 200 watt (custom) valve amps listed for sale in "Melody Maker" ads, late 1970. These are unlikely really to have been produced by "Vox Sound Limited", which had only just come into being, or for that matter by its predecessor, "Vox Sound Equipment Limited" (mid 1968-early 1970). VSEL mainly supplied solid state equipment, its only valve amps being the AC30 and AC50. If the 200 watt amps were indeed made by Vox, they are more likely to have been produced by JMI. Could they have been akin to the massive PA amps given to The Who in late August 1965? See this page for more.
19th September 1970
5th December 1970
Below, pictures taken by Michael Ochs on the "Shindig" national package tour of the U.S.A., 29th April - 26th May, 1965 - three AC100 SDLs on stage. It seems unlikely that these amps belonged to Gerry and the Pacemakers and had been shipped from England for (or by) the band to use in the States. In all probability they were supplied for this leg of the tour by Thomas Organ.
Pictures from Getty Images.
Advert for the Philadelphia show, 21st May 1965.
With a little delving, it may be possible to identify the venue in the Ochs pictures above. For further details of the various legs of the Shindig package tours, see this page.
17th April (2)
"Melody Maker" magazine, 22nd February, 1969 - Jennings Electronic Industries promotion for its showing at the forthcoming Frankfurt Musikmesse.
A quick group shot of three of the old ones. Left to right: serial numbers 178, 173, and 254 (the JMI promotional amp never given a logo).
A little more on JEI. Below, a short note on the Jennings showing at the Frankfurt Musikmesse in April/May 1975 from the general coverage given in "International Musician" magazine.
"International Musician and Recording World", April 1975.
"Melody Maker", 16th August, 1969 - entry on Jennings Electronic Industries (JEI) in reference to the Associated Musical Instrument Industries Trade Fair at the Russell Hotel:
Interesting to find mention of the planned expansion of the premises at Dartford Road, and production at Byfleet and Ascot in collaboration with A.P.T. Electronics Ltd.
A.P.T. Electronics, originally All Power Transformers Ltd, manufactured test equipment, among other things, under the trade name "Lektrokit". Its headquarters were at Chertsey Road, Byfleet - see this page. The company entered receivership in 1974.
Two further AC100s - SDL sets from late 1966, serial numbers in the 1800s - have come to light:
Serial number plate missing. Currently in Australia. Thanks to Adrian for info and pics. An entry will posted soon.
Serial number 1886. Currently in Germany and on offer at Oldenburger Vintage. The amp was owned for some years by a well known collector in N. Germany.
Two further amps now known to exist - serial number 252 (hand-stamped 0252 like 0254), black panel, late 1964 / early 1965, currently in the process of being restored; and serial number 691, a "100W Amplifier", late summer 1965.