Dating blackface amps

Posted by / 29-Jan-2018 10:56

Dating blackface amps

We also get calls wondering if we do repairs on vintage equipment; sorry, we don’t.

However, we do highly recommend David Kulka at for all 1176 and LA-2A repairs, or any other vintage UA/UREI or Teletronix equipment you may have. 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.

Production years 1964 -1967 “blackface” circuits AA864, AA165, AB165 1967 -1977 “silverface” circuits AA165, AB165, AA270, AA371, AA568, AC568, AA864 Tube layout AA864 Tube layout (Seen from behind, V1 is to the right side): V1 12ax7 = Preamp bass channel V2 12ax7 = 2’nd gain stage bass channel (and normal channel for AB165) V3 12ax7 = Preamp normal channel V4 12at7 = Phase inverter V5 6L6 = Power tube #1 V6 6L6 = Power tube #2 Summary The Fender Bassman is a legendary guitar amp known to both guitar and bass players.

So in this post, we're offering a complete revision history of the world's two most popular compressors, the 1176 Limiting Amplifier and the Teletronix LA-2A Leveling Amplifier. Anyone bought or sold one of these recently and can give me an idea? Hey all, I'm looking for a general idea of what a fair price is for a 1963 Fender Deluxe (Blackface, non-reverb, Pre-CBS).

I don't believe there was any difference between a '63 and '64 models, but they seem to be far less common. '63s were brownface, not blackface, and IIRC did not have the full complement of tone controls.

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 it 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 Design Date: 11/20/67 Serial Numbers: 125-216 Changed several resistor values in signal pre-amp stages; this improved stability as well as noise Circuit added bypass cap around the resistor feeding the gain reduction FET to improve stability Design Date: Not indicated Serial Numbers: 217-1078 Replaced FETs in the signal pre-amp with bipolar transistor (2N3391A) Tapped off of the emitter of the first transistor in the input stage; this provides a replica of the input voltage to the voltage variable resistor Design Date: 1/9/70 Serial Numbers: 1079-1238 Faceplate is anodized black Low noise ‘LN’ circuitry was added in the signal preamp; this reduces DS voltage on the gain reduction FET and keeps the FET within its linear range Modification to program dependency tuning Trimpot added to feedback circuit of audio FET, to minimize distortion The LN circuitry was built in a module that was encased in epoxy to protect the circuit A Modutec VU meter is used, with two lamps mounted above Design Date: Not indicated Serial Numbers: 1239-2331 Adds "UREI" branding to existing Universal Audio branding The LN module was no longer used and the circuit board was redesigned to accommodate the LN circuitry on the main board Design Date: 3/15/73 Serial Numbers: 2611-7052 Output amplifier changed to a push-pull (class-AB) configuration from the original class-A design Output transformer is changed to the B11148 type with 12 d B of gain (same transformer as the LA-3A) Push-pull design provided more output drive, and was based on the 1109 preamp Changed the metering circuit to an op-amp following the meter FET, instead of balanced bridge transistors Design Date: Not indicated Serial Numbers: 7652- 8000 Faceplate is brushed aluminum with red “Off’ button; this is the only revision with a blue UREI logo Removes Universal Audio branding VUi meter is changed to Modutec "light box" type, with two internal lamps Design Date: 6/04/08 Serial Numbers: 001-500 Faceplate is black anodized with blue paint Unique Rev.

A/E “hot-rod-mod" features, cosmetics and sonic signature Return to program dependency of legendary “Bluestripe” Rev.

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Numerous design changes followed, resulting in at least 13 revisions and variations on the 1176.

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