: Look for large electrolytic capacitors near the tubes; these filter out ripple noise from the power supply to ensure a quiet audio path. 4. The Output Stage
The Universal Audio (UA) 610 modular amplifier, originally designed by Bill Putnam Sr. in the 1960s, is a dual-stage tube preamplifier famous for its "warm" and "harmonically rich" sound [15, 18]. The schematic for the original
The signal path typically follows a cascading design: Ua 610 Schematic
The schematic is a masterclass in 1950s broadcast design. It prioritizes iron (transformers) over silicon.
) dual triode acts as the second gain stage and driver [3, 8, 28]. Output Stage: Employs an output transformer (originally a UTC PA-5946 ) to balance the signal for line-level output [3, 8]. Key Component Values (from 610-A Schematic) : Look for large electrolytic capacitors near the
Before diving into the resistors and capacitors, let’s look at the signal flow common to all Ua 610 schematics (Solo, 2-610, LA-610):
If you are cloning this schematic, be aware of these documented issues: in the 1960s, is a dual-stage tube preamplifier
★★★★☆ (4/5) Deducted one star for noise floor and gain staging quirks, but the schematic is a legendary piece of audio history. If you build it, use a regulated heater supply.
: A separate, lower voltage line (usually 6.3V or 12.6V) powers the heaters of the tubes, which is what makes them glow.
: This is the primary voltage amplifier. The schematic will show the audio signal entering the grid of the tube. This stage provides the bulk of the "tube character" and gain.