Gibson, E-100 Guitar Amplifier (Style 3), 1939


E-100 Guitar Amplifier (Style 3)
Serial Number: 
The Story Behind

Following the musical “No longer is the electric Hawaiian Guitar restricted to professional players – here is a genuine Gibson instrument that costs only $100, complete with instrument, case, amplifier with slip cover, and cord.”

So introduced in Gibson’s Catalog X of very late 1936, the EH-100 Hawaiian set cost a third less than the company’s EH-150 set, which by this point had the updated six-tube chassis and “Echo” extension speaker.

Complementing these at the lower end of the market were the small line of 100 (and later 125) instruments and their matching amplifiers. 

Offered on its own at $50, the first EH-100 amps were promoted as the mate to the new EH-100 Hawaiian guitars. Dressed in “Strong imitation black leather covering” with a white Gibson logo stencilled on the lower right corner of the face, the box housed a 10″ field-coil speaker and a bottom-mounted, rear-facing chassis. Embossed lines framed the perimeter of the cabinet, with metal corner protectors on the bottom.

Like the early E-150 model, only two stages of amplification were employed, with a 6N7 twin-triode (amplification factor 35) handling the gain department (again, run in parallel for Class A operation, as specified by the RCA tube manual). Twin 42 power pentodes operating in push/pull were probably fed by a transformer phase inverter, although there are other, less-than-ideal (but cheaper) ways to achieve this function. It’s doubtful whoever was designing Gibson’s amps at the time would have chosen such a circuit for a high-fidelity amplifier (anybody have one of these black-covered models?).

Also like the first E-150 amps, the first 100s got their juice from an 80 rectifier, came fitted with two parallel inputs and had no controls in the circuit. A fuse was the only other “feature” of this bare-bones model. It’s interesting there was no tone control on the first EH-100 guitars either, though this would soon change as the last of the black-finished 100 Hawaiians had the modern two-knob arrangement.

1937-’38 (Catalog Y)

By the release of the next catalog (which were being cranked out annually during this progressive era), Gibson offered both a new look and a new circuit for the now $110 EH-100 set ($55 for the amp alone). The new model amp was covered in “Very handsome tan aeroplane cloth covering – this material is tough and can be washed.” Dark stripes running vertically accented the light coloured covering, as did the logo, the bottom-mounted leather corner protectors and the big brown leather handle, as seen on the EH-150 amp.

A three-stage circuit using five tubes was instituted, with the original 6N7 replaced by a 6C8 twin-triode (amplification factor 36) and a single-triode 6C5 (amplification factor 20). Again, two inputs were standard, but only one was for the instrument, with the second specified for use with a microphone. While not mentioned in the catalog, this version’s schematic shows a volume control operating on the mic input only (the AC power switch was shown built into the volume pot – turning the volume knob turned the amp on). Each channel used its own section of the 6C8 preamp tube.

Under “Tubes” in the “Electric Guitar Supplies” section of the catalog, the relatively new 6V6 beam power tubes were listed, implying a change in the output section occurred after the schematic was drawn up, but prior to the catalog’s release. This also suggests that either the first tweed 100s still used the 42 power tubes, or there were later version black-covered amps with the new five-tube circuit.

1938-’39 (Catalog Z)

A new look for ’38 featured “handsome dark brown Aeroplane cloth with harmonising yellow stripes,” and a matching logo. The pattern of the stripes was the same as previously used, only rotated 90 degrees, to the horizontal plane. Dimensions were given for the cabinet as 12″ high, 14″ tall and 7″ deep. An enclosed back was added, as seen on the 150s, and the leather corner protectors were replaced with metal, although these were not included in the catalog shot.

“Has six tubes and three stages of amplification with 8-watt output.” Unfortunately, the tubes were not listed (and somebody here didn’t do enough research!). Gibson made no mention of “seven (or eight) tube performance,” so it’s hard to speculate whether they used any twin triodes in the new circuit. An extra gain stage for the mic channel seems a safe bet, but as to whether a transformer was still being used for the phase inverter, as on the seven tube 150, or the function was performed by a tube, as on the ’40 EH-100, we’ll have to check and report back later.

By ’38, it was obvious to Gibson that electric Spanish guitars were a viable offering and they expanded that portion of the line to include the new ES-100. Like the EH-100 Hawaiian, the Electric Spanish model was “designed for use with the EH-100 amplifier” (the first of these guitars may have come with the earlier five-tube 100).

1939-’40 (Catalog AA)

Cosmetically, the ’39 model appears similar to the ’38, except for the number and spacing of the “harmonising” stripes. Again, the text also specified metal corners, although these were not included in the updated, retouched picture. The description of the electronics was unchanged.

Gibson provided their services to numerous wholesalers for “contract brand” instruments, e.g., Cromwell (C.M.I.) and Capital (Jenkins), who offered 100-style amps with the enclosed case. These are not to be confused with Gibson’s in-house bargain line, Kalamazoo. By the late ’30s, Gibson’s budget line had been expanded to include electrics, which allowed the company to put a better quality 100 line out and still offer a competitive line under it, as the cost of building amplifiers dropped in the second half of the decade.

This amp is from 1939 with the matching Gibson, EH-100 lap-steel guitar.

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