The Smallest Tube Amplifier in the World
High Fidelity Magazine Product of the Year 2010 Award
Switching Power Supply Technology

Choose Your Favorite Color:

A $40 USD shipping expense will be added to your payment. The total payment will be $278 USD. Your order will be shipped from China within 5 business days.

Technical Specifications:

  • tubes: triode/pentode 6F3
  • power connector: standard IEC with 2A fuse
  • power voltage: 100-240V AC
  • power consumption: 33W
  • dimensions: 132mm (w) x 96mm (d) x (100+70)mm (h)
  • weight: 1.7kg
  • color: gold, gray, black, silver, pink
  • noise: < 0.6mV AC
  • input: 1 x stereo RCA
  • input impedance: 10kΩ
  • input sensitivity: 800mV
  • output: banana jacks
  • output power: 2.5W+2.5W/8Ω
  • output impedance: 16/8/6/4Ω (Japanese output transformers Z11-Ei48*24)
  • frequency response: 30-40kHz (+/-1dB)
  • The 6F3 vacuum tubes can be replace with ECL805, 6GV8, ECL85, or 6F5P.

    Product Description:

    APPJ-6F3 is a small stereo tube amplifier, working in Single-Ended Triode (SET) mode. This is currently the smallest tube amplifier available in the world. Tiny as it is, its performance is comparable to a full size high level amplifier. The enclosure is made from bent aluminum elements, and the top cover from a sheet of aluminum. The interior is made from steel plates. The whole unit is finished with sanding and anodizing to one of the five colors (gold, gray, black, silver, and pink).

    On the front panel there is only one knob – a silver, chrome plated one – used for volume control. On the back there are one pair of RCA inputs and two pair of loudspeaker outputs. Those are not standard terminals, but accept only banana plugs. There is also a full size IEC power terminal with a mechanical power switch and a fuse.

    The circuit is mounted on two PCBs, mounted atop of each other, with distances. The top PCB has two small output capacitors and a part of the audio circuit. Amongst those there are also very nice RIFA coupling capacitors. On the bottom PCB, separated from the upper one with a shield, is the switching power supply. This is a proprietary solution from PPJ Acoustics Studio, which allows the power supply voltage to be between 100 and 240V AC. PPJ Acoustics Studio is the first to make good use of switching power supply in tube amplifiers. Without switching power transformer, it is impossible to make tube amplifiers in such small size because traditional power transformers are big.

    The sound of the APPJ-6F3 is clearly shaped.  It takes full advantage of the fact that the signal is amplified in tubes. It does nothing wrong – it does not warm the sound, does not mud anything, does not "forgive" everything, etc. Rather, it shows a much richer palette of timbres, better transients and is much quicker in differentiating the shape of dynamics. The cymbals from discs, especially with good jazz, are nicely lit, but not underlined, or sharpened. This is actually one of the characteristics of this device – it does not sharpen anything, even in the slightest way.

    This is probably why APPJ-6F3 won the Product of the Year 2010 Award in the category of integrated amplifiers by High Fidelity Magazine.

    Reviews and Discussions:

    2011-02, Continuation of APPJ-6F3 AMP Story

    2011-01, Synergy HIFI APPJ-6F3 Class Single Ended Tube Amplifier

    2010-12, Online Discussion: Smallest Valve Amp?

    2010-11, 6moons Audio Reviews: Synergy HIFI 6F3

    2010-10, High Fidelity (October 2010):  Cover story

    2010-10, A Creative 6F3 Mini Tube Amplifier

    2010-08, Porland / Seattle Head-fi Meet at 32-ohm Audio Store -- Many Photos

    Photo Gallery:

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    APPJ-6F3-08.jpg APPJ-6F3-18.jpg 06.jpg APPJ-6F3-26.jpg APPJ-6F3-41.jpg