The "Long Beach Press Telegram", 15th March, 1965.

The earliest pictures to have emerged so far of AC100s in the States - ie. of amps not belonging to the Beatles (or any other English band) - come from April 1965: from the 4th Teen Age Fair at the Hollywood Palladium, venue for the LA stage of a "Battle of the Bands" stretching over Easter week '65. The competition was won by Captain Beefheart. A sizeable amount of Vox equipment was provided for the event by Thomas Organ.

For the background to the association of Thomas Organ and Vox / Jennings, see this page.

On the left, "The Santa Ana Register", 12th March, 1965; on the right, "The San Mateo Times", 19th March. Auditions for the events evidently began well in advance. Marv Kaiser continued in his role as representative of the Vox division of Thomas Organ at least until October 1966.

During the LA leg of the event at the Palladium, The Challengers, a surf group, served as the house band, providing music during the interludes between the competition rounds for the broadcast coverage of the days.

An AC50 in the foreground, and an AC100 further up stage. This picture and the one below from this thread.

The cabs belonging to the two Vox amps at left.

The first Vox Teen Beat magazine, produced slightly in advance of the Teenage Fair, had this to say:

"Pierced ear drums are expected to be the only casualties this week as 80 torrid teen combos battle for the Vox sound crown at the Teen Age Fair. Forty groups will vie at the Bay area show in Vox "Battle of the Bands" while the other forty will fight Vox "Battle of the Beat" at the Palladium in Los Angeles.

This advert had been first published in late 1964. The magazine as a whole is available here.

Captain Beefheart, winner of the Los Angeles competition, on stage at the Palladium, April 1965. Note at front of stage the "Dave Clark Five" and "Jumping Beatles" standees,

San Francisco / San Mateo "Battle of the Bands"

"San Francisco Examiner", 9th April, 1965.

The San Franscisco Battle, April 1965 - probably Santa Clara County Fairgrounds, San Jose, Santa Clara County, California. Foundation Bass to left, an AC100 (or possibly a thick-edged small-box AC50) on a large-box AC50 cab, and at right an AC30SRT. Picture from this article.

"San Mateo Times", 22nd April, 1965.

The Brothers Grim in Teen Beat magazine, no. 1, early endorsers of Vox.

A fake advert commonly found on the web these days, the banner head and text added.