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Fosi Audio P2 Headphone Amplifier Vacuum Tube Headphone Amp Mini Hi-Fi Stereo Audio with Low Ground Noise Output Protection

  • Based on 849 reviews
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Availability: In Stock.
Fulfilled by Amazon

Arrives Tuesday, Dec 24
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Style: AUX + RCA


Features

  • Excellent Sound Performance: Low ground noise, built-in output protects the circuit, no buzzing or ringing noise, Audiophile-level sound quality, exclusively designed for the customers who pursue HiFi sound; and safe for your expensive headphones.
  • RCA and AUX Input: The compact amplifier for home theater speaker systems will drive the signal from your music player via RCA or AUX input and increase both its volume and detail. There's a selector for you to switch the mode you want.
  • High-performance: The stereo preamp supports 16-300 ohms of headphones and comes with a 6.35mm to 3.5mm adapter. THD: 0.1%; SNR: 95db
  • Easily-swappable Tubes: The twin 6K4 tubes deliver the sound that makes an impact, and the amp can bring out the high-quality sound in most headphones. It can be replaced by 6j1/6J4/GE5654/6AK5/6*1n/ E180F/69/EF861/6688 tubes etc.
  • What You Get: P2 Tube Amplifier x1, 6K2 Tubes x2, 6.35mm to 3.5mm Adapter x1, power supply x1, user manual x1, our worry-free 24-month warranty, and friendly customer service.

Product Dimensions: 5 x 3 x 1 inches


Item Weight: 8.8 ounces


Item model number: P2


Date First Available: May 14, 2019


Manufacturer: Fosi Audio


Country of Origin: China


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Tuesday, Dec 24

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews


  • Great for getting a feel for how tubes affect sound
Style: RCA
This little preamp provides a great introduction into tube amplification, both the benefits and drawbacks of using tubes. First of all, as this is a preamp, it is very easy to set up direct A/B comparisons with commodity recording equipment (namely USB recording interfaces). Run a line out recording through the preamp, and again direct, match the output levels, and you now have a better insight into what these tubes are actually doing to the sound with A/B testing (preferably blind ABX testing). The good news - this preamp is pretty quiet and does a good job amplifying the signal coming in. I've had zero issues with noise including this in my playback chain. For a component containing tubes it is surprisingly quiet. The bad news (depending on your point of view) - the EQ knobs on this device affect the sound output far more than the tubes themselves. This is not a knock on the quality of the EQ, no, in fact, the EQ knobs are actually very useful given there is only a treble and a bass knob. In fact, the preamp is almost worth the price of the device given how well these work. The tubes themselves work as advertised. Sending a sine wave through the preamp, I definitely see way more second-order harmonic distortion through the preamp than through a direct output without the preamp. For instance, with a 440 kHz sine wave, I see the expected bump of 880 kHz at -30dB from the main signal. And there is noticeable compression running high-volume sounds through the preamp, particularly when running into the preamp at higher outputs. In short the expected effects of the tube (even order harmonics and compression) are measurable with sufficiently juiced inputs using relatively inexpensive measuring equipment. The real question is whether these effects are noticeable by your ears. For me at least the answer is yes, but the effect is pretty subtle, nowhere near what I was anticipating. For better or worse the stock tubes actually perform very well and have a good amount of headroom available before you notice any obvious changes in the sound. You kind of have to go out of your way to hear obvious changes, though, whether that be with bass-heavy music (Sublime's 40oz to Freedom works great for this) or by deliberately overdriving the inputs. A fun quantification of how this preamp affects sounds is to do a null test. First capture a recording of music played through the preamp tube, and then do the same exact source without the preamp tube. Line up both recordings *exactly* to the sample and to the same level, then invert the phase of one of them. Play them together and you'll get an exact audio representation of the difference between both input modes. This is more difficult than it sounds but if you do it you will hear the obvious distortions being introduced by the tubes. The interesting part is that they are both almost inaudible (unless you are carefully listening for them), and that even though these distortions sound not so great by themselves, when mixed into the output they can actually improve the sound of the music. OK, enough navel-gazing for now. Is this worth purchasing if you want to understand what "magical" tubes do? Absolutely. Is the effect going to be obvious? Probably not, unless you swap in tubes that are either busted or have very low headroom. Oh, and if you want to get an easy check for whether the tubes are actually in the signal path, grab a pencil and (gently) tap on each tube. As long as you don't have a fake you should hear the taps through your output speaker/headphones. There shouldn't be any ringing from the taps - that would indicate the tubes have gone bad and are microphonic - but you should be able to hear something with the volume up high enough. And the sound volume should increase gradually after a cold start like any self-respecting tube would. Speaking of tubes, I wish the silly LEDs under the tubes were not included. Even though this is just a preamp there is enough voltage running through the tubes to emit a slight glow after the tubes have warmed up. The red LEDs that turn on when powered up are *sort* of useful to make sure the device is working, but ultimately silly as it looks super fake compared to a real tube glow. ... show more
Reviewed in the United States on July 30, 2022 by Alan Smithee

  • Great Value
Style: RCA
I currently have this connected to some small JBL amplified speakers and a Rotel RD 955AX cassette deck. I was stunned by the smooth & rich sound this thing is producing. The Bass & Treble controls work well and add the needed enhancement. I will eventually try this with my Adcom GFA-545 amplifier. I am confident that this thing will continue to impress. It sounded quite nice with the Chinese tubes that came with it (although the pins on these tubes were thin and the tubes fit a bit looser in the sockets that I would like), I replaced them with some Vishkod Rockets and am VERY happy with the sound. The pins of the Rockets fit better in the tube sockets. ... show more
Reviewed in the United States on September 26, 2023 by Paul S. Kasten

  • A great amplifier at an unbelievable price
Style: AUX + RCA
I never thought I'd buy a tube amp. I felt that the "tube sound" did not justify the typical high price. So when I needed a headphone amp, I had no intention of buying one based on tubes. But when I saw the Fosi P2 for only $50, I thought why not try it. I couldn't go wrong at that price. So when I got it, I wanted to determine its sound, so I first plugged it into the headphone jack of my amplified speakers and gave it a listen. Not bad at all, I thought, and more than ample volume for my 32 ohm headphones. Then I bypassed the speakers and plugged it directly into my computer. Wow! The sound was warmer and more detailed, not what I expected from a tube amp. Disturbed's cover of Sound of Silence raised goosebumps anew. This little amp is definitely worth your money. ... show more
Reviewed in the United States on August 28, 2023 by Walter J. Maslowski

  • Works well but NOT a phono pre-amp
Style: RCA
My own fault here… when you search phono pre-amp on amazon you get this as one of the top results. And while it is a nice tube style pre-amp capable of coloring your audio and making it sound warmer, despite what some of the reviews say, it will not work as a pre-amp for an older style turntable without a phono pre-amp built in. So it’s going back for another Fosi that is actually a phono pre-amp. But I did try it out first and as long as you aren’t routing an older style turntable through it, it’s a pretty nice bargain for warming up your music at around $40. ... show more
Reviewed in the United States on September 5, 2023 by Friendly Consumers

  • Very simple but well sounding unit.
Style: RCA
I accidentally broke a tube when removing them from the box. I was sent a matched set from the seller without question. Very please with this little pre-amp.
Reviewed in the United States on August 28, 2023 by Amazon Customer

  • Worth the $ PERIOD
Style: AUX + RCA
I'm using Sennheiser HD 599 on a Marantz Rx. Without the Fosi amp they were muddy & dead on the highs. Now with the Fosi amp they're clean, crisp, and not needed to be CRANKED to get just ok sound. I'm very pleased with this amp. I DEFINITELY would recommend this tube amp to someone.
Reviewed in the United States on July 16, 2023 by cypher

  • Another Fabulous Fosi Product
Style: RCA
Fosi products are one of the best values in audio today. I purchased the P1 preamp to go with my Fosi V3 amplifier. I chose the P1 for its price and performance as well as the tone control feature. Works flawlessly in my bedroom setup. Excellent company, products and post sales support. Highly recommended. ... show more
Reviewed in the United States on August 9, 2023 by James Minotto

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