Zesto AudioEros 300 mono ampsusedZesto Audio Eros 300 mono ampsselling our demos newer 500 watt models out now about 2 years old 200 to 300 hours on tubes add 3% for paypal a super clean sounding musical presentation great bass and dynamics https://www.thea...6500.00

Zesto Audio Eros 300 mono amps

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Ships fromJersey city, NJ, 07307
Ships toUnited States
Package dimensions25.0" × 20.0" × 19.0" (82.0 lbs.)
Shipping carrierFedEx
Shipping cost$400.00
Original accessoriesBox
AverageResearch Pricing

selling our demos newer 500 watt models out now

about 2 years old 200 to 300 hours on tubes 
add 3% for paypal

a super clean sounding musical presentation great bass and dynamics

To sum up, the Zesto Eros 300s proved to be amiable listening partners. They were completely reliable and silent in operation. They look good too, though this is not a necessity. Through several months of living with the 300s, listening to music was always a pleasure and each session lasted longer than planned. My notes reflect my overriding perceptions that the 300s are extremely transparent, lush, warm in the way that live music is, and more powerful than their rating would suggest. Their only downsides, in my view, were heat output (par for the course with higher-powered tube amplifiers) and a slightly reduced soundstage compared with much higher power (and generally more expensive) amplifiers. Some may feel that the often cooler presentation of solid-state amplification is more accurate, but not to my ear. Moreover, I have not heard any other amplifiers in this power and price range reproduce the sense of orchestral space and three-dimensionality that are second nature to the Zestos.

Where this sonic mix will end up on a given user’s personal score card will vary, but it is undeniable that the Zesto Eros 300s offer an intriguing and inviting alternative to the army of solid-state amps out there. I can envision many music lovers being thrilled with these amps—indeed, even feeling that they have “arrived” musically. My review pair has been sold and must be returned to Zesto tomorrow. I will miss them.


Key Features

  • Class A topology is the most musical of all amplifier designs because it has the lowest distortion.
  • Unlike solid state, this tube amp efficiently transfers power by matching the output transformer to the impedance of your speakers using 4 & 8 Ohm taps.
  • Two parallel options for your speaker cables; the binding posts or the SpeakOn connector.
  • The Eros 300 is easy to use. There are no adjustments or tweaking with Auto Bias technology on the output tubes. It’s safe, consistent and the settings are always perfect so you can relax and enjoy the music.
  • Transformer balanced XLR input offers true noise cancelling and rejection as well as ground isolation from the preamp.
  • Should you need to eliminate a hum? The Eros 300 has a XLR ground switch installed for your safety. This eliminates the dangerous temptation to lift the ground from the mains.
  • The combo of Push-Pull – Ultra Linear output circuit design gives you more power & lower distortion.
  • No Negative Feedback in the circuit design provides better dynamic range because it doesn’t compress the music.
  • Non Inverting Phase Polarity retains the directional information from the original source which gives your system punch.
  • A robust choke based power supply creates maximum immediate power with no compression.
  • Custom Toroid power transformer provides lower noise with plenty of available power.
  • The circuit design creates low noise levels with a wide frequency response. You will notice this in the really dark, quiet passages in your music.
  • Gold pin sockets are more reliable because gold doesn’t oxidize when it heat cycles.
  • A matched sextet (6) output tubes provides a synchronized balance for the lowest distortion and maximum output of power.
  • An extensive grounding scheme is designed into the power supply, wiring and all tube circuitry.
  • Elegantly designed, heavy duty 14 & 16 gauge zinc plated, fully grounded steel enclosure isolates external noise and vibration.
  • All fuses are easily accessible
  • It’s ready to enjoy with 50 hours of factory burn in on all circuits and vacuum tubes.
  • Each unit is hand built “Made in the USA”


Specifications per Amp


  • Pure Class A
  • 150 Watts per amp
  • 4 and 8 Ohm output taps
  • 8 and 5 Amp Slow blow fuses for outputs
  • Three 5 way binding post
  • One SpeakOn connector
  • Non inverting output phase polarity
  • Push-Pull and Ultra-Linear design



  • Transformer floating XLR input
  • Balanced inputs with pin 2 hot, impedance of 12K Ohms
  • Single Ended input, impedance of 100K Ohms
  • XLR ground lift switch on balanced input
  • 1.8 Volts RMS input to reach rated output


Detailed Specs

  • Monaural
  • Auto bias
  • No negative feedback
  • Frequency response: 20Hz to 50Khz ~ 2db
  • Total Harmonic Distortion: ~ 0.43% at 1W output into 8 Ohms
  • Gain of 26dB
  • Noise level > 5 mV RMS into 8 Ohms with input shorted
  • 1% metal film resisters throughout
  • Polypropylene capacitors throughout the audio path



  • Custom Toroidal power transformer with global mains
  • Choke based power supply design
  • 120 Volts AC mains
  • Optional factory installed 220V, 230V, 240V 50/60Hz
  • Power consumption at rated output: 360 Watts
  • Power consumption at idle: 348 Watts
  • On/Off switch conveniently located on front panel
  • 3 pin IEC power connector with fuse


Active Components

  • Matched sextet, set of six (6) KT88’s vacuum tubes
  • Two (2) 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: 64 lb (29.03 kg)
  • Shipping weight: 80 lb (36.28 kg)
  • 14 and 16 gauge zinc-plated steel enclosure
  • Two year limited warranty
  • Six month warranty on vacuum tubes


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