While the 1176 has seen a huge number of revisions in its
history, the most significant revision to the 1176 circuit was designed by UREI
engineer Brad Plunkett in an effort to reduce noise —
hence the birth of the 1176LN (LN stands for low noise) at revision C.
Numerous design changes followed, resulting in at least 13 revisions and variations on the 1176. Most units include the revision letter with the serial number. Revisions C, D and E (the first three with the LN circuit) are all very similar, and are historically the most beloved.
hence the birth of the 1176LN (LN stands for low noise) at revision C.
Numerous design changes followed, resulting in at least 13 revisions and variations on the 1176. Most units include the revision letter with the serial number. Revisions C, D and E (the first three with the LN circuit) are all very similar, and are historically the most beloved.
Revision A (AKA “Bluestripe”)
Design Date: 6/20/67
Serial Numbers: 101-125
Faceplate is brushed aluminum with blue paint and red power light
Original 1176 designed by Bill Putnam for broadcast use, class A design
Signal Preamp: Used FET (field effect transistor) in a voltage divider configuration for gain reduction, a technological first
Used FET as voltage variable resistor to control the gain
Used ‘T-pad’ resistive attenuator to drop the input voltage
Input Stage used a 600 ohm input transformer
Used FET followed by bipolar transistor as preamp
Output amp used essentially the same circuit as in the preamp, but followed with a 2N3053 operating in class A
Output transformer was the UA-5002; this transformer has split secondary, tertiary winding for negative feedback, emitter winding; the design was basically that of the 1108 preamp
A Weston meter is used
