The UA-1 Class "A" Amplifier

Designed by Dick Sequerra

The UA-1 is an all Triode Class A Vacuum Tube Power Amplifier of a very low feedback design. The UA-1 is unconditionally stable with any capacitive or inductive load and will easily drive speakers with the most difficult resistive loads.

UA-1 PROPRIETARY DESIGN FEATURES

• Balanced differential DC Amplifier circuit topology for the input and driver stages.
• Only one capacitor coupling to the output stages.
• Unique ultra wide band output transformer.
• Amplifier power bandwidth of 10 Hz to 120 kHz.
• Built in digital volt meter to check the output tubes for balance.
• Separate regulated power supplies.
• All power supplies have choke input filtering.
• greatly reduces the interference from AC power lines as well as stabilizing the voltages prior to regulation.

UA-1 AMPLIFIER TECHNICAL SPECIFICATIONS

• Power Output: 100 Watts continuous.
• Amplifier Class A.
• Dynamic Head Room: +4dB.
• Power Bandwidth: -3dB - 10Hz to 120 kHz.
• Frequency Response: -3 dB - 8 Hz to 130 kHz.
• Input Impedance: 10K ohms.
• Signal to Noise: unweighted > 120dB.
• Input Sensitivity: .565 volts for full output.
• Negative Feedback: 4.5dB.
• Harmonic Distortion: @ 1kHz
- 100 Watts: - .36%
- 50 Watts: - .2%
- 20 Watts: - .07%
- 10 Watts: - .038%
- 1 Watt: - .01%
• Harmonic Distortion: @ 80 kHz
- 80 Watts: - 2.1%
• Harmonic Distortion: @ 20 kHz
- 80 Watts: - .4%
• NOTE: all outputs to 100 Watts have a 3rd order harmonic distortion product. There are no measurable 5th , 7th or 9th order distortion products.
• CCIR intermodulation products are below our measurement ability.
• Phase Shift at 100kHz is 20 degrees.
• Peak Soft Limiting.
• Output impedance available: 4 ohms - 8 ohms.
• Input connectors: 3-pin XLR and RCA Jack.
• Dynamic Linearity > 120dB.
• Number of Vacuum Tubes: 15.

UA-1P POWER SUPPLY TECHNICAL SPECIFICATIONS

• Power requirements 120-240, 50Hz - 60Hz:
@ 7.5 Amps for 120 volts.
@ 3.8 Amps for 240 volts.
• Mains Power Switch Heineman Magnetic Circuit Breaker.
• All Regulated Supplies individually fused.
• All Power Supplies are choke input.
• (6) ea. Regulated Power Supplies. - (2) ea. High Voltage Plate Supply with Time delay Relay.
• (4) ea. Vacuum Tube Regulator.
• (7) ea. Solid State Filament Regultaors.
• (1) ea. Zener Regulator.
• Low Stored Energy Rectifiers.

UA-1 AMPLIFIER MECHANICAL SPECIFICATIONS

• Width: 19 - (482 mm)
• Depth: 24 - (610 mm)
• Height: 12 - (305 mm)
• Weight: 50 lbs. - (23 Kilos)

UA-1P POWER SUPPLY MECHANICAL SPECIFICATIONS

• Width: 19 - (482 mm)
• Depth: 24 - (610 mm)
• Height: 12 - (305 mm)
• Weight: 120 lbs. - (55 Kilos)

LIMITED WARRANTY AND MANUFACTURING INFORMATION

• UA-1 Amplifier Warranty: Unconditionally to the original owner for a period of (5) years against any manufacturing error or defect EXCLUDING TUBES.
• Sequerra Associates, Ltd. Reserves the right to change and/or modify the UA-1 Amplifier and/or UA-1P Power Supply at anytime without notice.

UA-1 PRICE AND PURCHASE INFORMATION

• The UA-1 Amplifier is part of the Sequerra Music System.
• SMS components are availlable in a variety of exotic wood cabinets.
• The UA-1 is made To Order on a Custom Basis Only.
• Price: US$ 90,000.00 (per stereo pair).
• Please contact Sequerra Associates to audition the UA-1 in the Sequerra Music System.