Zesto Audio Bia 120 Class A Stereo Power Amplifier : 

The tubes are always on, so you have power when you need it. Class A is fast and responsive. There is no lag, providing your music more punch, transient response, better dynamic range and transparency. 
The unsung hero of a power amp is its power supply. That’s why my design incorporates a custom Toroid power transformer and a choke-based, dual-mono power supply to deliver all the “slam” you can handle.

Features

• Plenty of power to drive your speakers
• Pure Class A power is fast and musical
• 4, 8 & 16 Ohm taps gives you options for your speaker preference
• Dual Mono gives you less cross talk and better stereo imaging
• No adjustments with Auto Bias. Its safe, consistent and settings are always perfect
• Provides enough gain for most standard preamps and accommodate most speakers
• Choice of either Single Ended RCA or Balanced XLR to suit your needs or cable preferences
• Transformer balanced XLR input offers true noise rejection and isolation from the preamp
• Left and Right ground switches on the XLR balanced inputs to help eliminate ground hums
• No Negative Feedback provides for virtually no compression to your music
• Custom Toroid provides lower noise with plenty of available power
• Global mains power supply can work all over the world
• KT120 compatible
• Push-Pull circuit design gives you more power
• Ultra-Linear circuit design provides lower distortion
• Low noise levels allow really dark black quiet musical passages
• Non inverting polarity retains the same phase as the input (so your trumpets blow and don’t suck)
• Gold pin sockets are more reliable because gold doesn’t’t oxidize when it heat cycles
• Matched quad output tubes retain the stereo balance
• It’s ready to enjoy with 50 hours of factory burn in on all circuits and vacuum tubes.
• Elegantly designed, heavy duty 14 &16 gauge zinc plated steel enclosure
• Each unit is hand built “Made in the USA”
• The wide frequency response allows you to hear the finest passages in your music.
• High quality gold plated RCA, XLR connectors and 5 way binding posts
• All fuses are easily accessible

Specifications

Output

• Pure Class A
• 60 Watts per channel
• 4, 8 and 16 Ohm output taps
• 8, 5 and 4 Amp Slow blow fuses for outputs
• Eight 5 way binding post
• Non inverting output polarity
• Push-Pull and Ultra-Linear design

Inputs

• RCA single ended inputs Left and Right with an impedance of 100K Ohms
• Transformer floating XLR balanced inputs Left and Right (pin 2 hot) with an impedance of 12K Ohms
• Independent ground lift switches on left and right balanced inputs
• 2 Volts RMS input to reach rated output

Detailed Specs

• Dual Mono
• Auto bias
• No negative feedback
• Frequency response 20Hz to 50Khz ~ 2db
• Total Harmonic Distortion ~ 0.22% at 1W output into 8 Ohms
• Gain of 23dB
• Noise level > 0.2 mV RMS into 8 Ohms with input shorted
• 1% metal film resisters throughout
• Polypropylene capacitors throughout the audio path

Power

• Custom Toroidal power transformer with global mains
• Choke based power supply design
• factory installed 220V, 230V, 240V 50/60Hz
• Power consumption at rated output 300 Watts
• On/Off switch conveniently located on front panel
• 3 pin IEC power connector with fuse

Active Components

• Matched quad set of four (4) KT88’s vacuum tubes
• Four (4) Gold pin ECC82s (12AU7) vacuum tubes
• High quality gold pin ceramic sockets

Other Features

• Each unit is made by hand
• 50 hour factory burn in on all circuits and vacuum tubes
• Dimensions 17″ W X 20″ D X 10 ” H
• Weight 66 lbs. (30Kg)
• 16 and 14 gauge Zinc plated steel enclosure