Emerson Model 109 Bakelite Table Radio (1935)
The Emerson model 109 was introduced in the summer of 1935 with a price tag of $14.95, complete with RCA
tubes. It was one of Emerson's new models for 1936. It's a 4-tube superhet tuning the standard broadcast band
from 530-1620kc and using Emerson's U4A chassis, having tube line-up 6A7 (LO/mixer), 6F7 (IF amp & 2nd
detector), 43 (power amp) and 25Z5 (rectifier). The 6F7 tube incorporates a triode and a variable-mu pentode,
sharing a common cathode, into a single envelope.
The radio uses a resistance line cord ("curtain burner") to drop the line input voltage to the level required by the
series-connected filament string. Approximately 14W is dissipated in the line cord and when in use it should be
unravelled and stretched out to allow for adequate heat dissipation and minimal temperature rise. The problem is
that owners would sometimes overlook this and have the line cord coiled up beneath a household item such as a
curtain. The heat build-up supposedly resulted in numerous house fires - hence the name "curtain burner". Use of
these cords was soon discontinued by the radio industry! A further problem is that these cords would become
frayed and the wires exposed, creating a shock hazard.
These cords should not be employed today in their original form for everyday use. Instead there are alternative
techniques that can be used to provide the correct filament voltages without the accompanying heat dissipation.
For myself if the cord is good I'll leave it be but will use the radio only occasionally & never unattended.
tubes. It was one of Emerson's new models for 1936. It's a 4-tube superhet tuning the standard broadcast band
from 530-1620kc and using Emerson's U4A chassis, having tube line-up 6A7 (LO/mixer), 6F7 (IF amp & 2nd
detector), 43 (power amp) and 25Z5 (rectifier). The 6F7 tube incorporates a triode and a variable-mu pentode,
sharing a common cathode, into a single envelope.
The radio uses a resistance line cord ("curtain burner") to drop the line input voltage to the level required by the
series-connected filament string. Approximately 14W is dissipated in the line cord and when in use it should be
unravelled and stretched out to allow for adequate heat dissipation and minimal temperature rise. The problem is
that owners would sometimes overlook this and have the line cord coiled up beneath a household item such as a
curtain. The heat build-up supposedly resulted in numerous house fires - hence the name "curtain burner". Use of
these cords was soon discontinued by the radio industry! A further problem is that these cords would become
frayed and the wires exposed, creating a shock hazard.
These cords should not be employed today in their original form for everyday use. Instead there are alternative
techniques that can be used to provide the correct filament voltages without the accompanying heat dissipation.
For myself if the cord is good I'll leave it be but will use the radio only occasionally & never unattended.
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