The Gibson ES-340TD was launched in early 1969, and was available until 1974. It was very similar to the ES-335TD with a couple exceptions: the woods used, and the wiring - which allowed an out-of-phase configuration for a "snarly type sound, in demand by today's players". The birch body with maple neck of the ES 340 contrasted the maple body with mahogany neck of the 335 at this point; though it did have the same body size and profile.
But the 335 was only available in Cherry, Sunburst, Walnut and Sparkling Burgundy at this time. The ES 340, crucially was Natural (or Walnut). In fact some late 1968 Gibson publicity briefly offers a Natural finished birch bodied ES-335 with five-ply laminate maple neck, at an unspecified price. Shipping totals do not show these, and they almost immediately became the ES 340.
ES stood for Electric Spanish, and TD stood for Thinline Double pickup, though this was often omitted; it is often referred to as the ES 340, or just 340
Whilst the 335 had a typical pickup selector switch; neck/bridge/both pickups, the 340 three way switch was wired to be in-phase/out-of-phase/off. So pickups would not be selected the using the switch. When set 'in-phase' the blend of pickups could be adjusted with a separate 'blender' control, allowing either pickup alone or any blend of the two. An 'out-of-phase' tone works best with an equal amplitude signal from both pickups; the blender consequently does not function in this setting. Finally there were volume and tone controls. Phase switching guitars were pretty new for Gibson at the time; 1969 is also the year they launched the Les Paul Personal and Professional models, also with a pickup phase switch.
Details of the potentiometers used in this guitar are reproduced here.
The ES340 was more expensive than the ES335, (see the table below for relative pricing) and comparatively few were shipped; just 1561 instruments compared to 17346 335s (not including 12 strings) in the same period. In 1976, a couple years after the ES-340s discontinuation, the ES-335 was fitted with a coil tap switch that could emulate the out-of-phase wiring to some extent.
The following description is taken from the 1970 Gibson thinline catalogue
The Gibson ES-340TD introduces a new dimension in electronic sound versatility. A thin archtop, semi-acoustic body with double venetian cutaway design. Selected birch body with white pearl binding.
FEATURES: Semi-acoustic body, with solid hard-rock maple center piece. Laminated maple neck. Beautiful Brazilian rosewood fingerboard with miniature block pearloid inlays. Exclusive adjustable truss rod. Decorative, inlay mother-of-pearl peghead. Chrome-plated parts. Tune-O-Matic bridge. Twin chrome-plated Humbucking pickups. Master volume control. Master mixer control. Three-position toggle switch. 1: Normal position for standard guitar sounds, 2: on or out phase tonalities, 3: stand-by position. 16" wide, 19" long, 1 3/4" thin: 24 3/4" scale, 22 frets.
ES-340TDW - Walnut finish
ES-340TDN - Natural finish
519 - Faultless plush case
304 - Archcraft plush case
ZC-19 - Zipper cover for 519 case
The recommended string set for the ES-340 TD was Gibson GE-340 - medium gauge nickel "sonomatic" strings .012-.056 with a wound 3rd.
Shipping figures are split by colour for the ES-340TDN (Natural) and ES-340TDW (Walnut), and come from Larry Meiners book . Original zone 1 (USA) prices are displayed in the third row. Prices in brackets are the prices of the ES-335TD from the same price list