Fosi AudioP3 Tube Preamp Headphone Amplifier Home Audio Preamplifier Mini Vacuum Pre Amp Receiver with Bluetooth aptX LL HD Bass Treble Tone Controls for HiFi Stereo Active Speakers with RCA AUX Jack

The media could not be loaded. I may not be using this in my system to it's full extent, or as intended, but the Fosi P3 is doing exactly what I need it to do. No need for the Bluetooth, not using the tone controls or the volume control... BUT I needed to take the edge out of the top end of a Fosi BT20A Pro. While I've been very happy with the BT20A Pro, certain tones in the upper octaves can catch you by surprise... a little clangy, zingy, edgy (worsened by the speaker I use). I went with the P3 because I read so many times over how it's well paired with Fosi amps.Inserting the P3 between sources and the BT20A is all it needed. Edge rounded off nicely! BUT there's more! Unexpectedly, the P3 has brought more fullness to the sound from bottom to top. Instrument separation is clean... focus is tight. Class D amps get a rap for vocals being forward. I notice the depth is back a bit more now... vocals seem more precisely placed in the sound stage. I was using tone controls but I am now back to flat, where it "should" be. Now tone controls add juice instead of getting it to flat... flat is flat now. I don't know how "tubey" this bugger is... it's not "yummy" or "syrupy" or whatever the audiophile head words are... it took the edge off and left all of the precision and beefed up the bottom and top. For me, a fantastic addition to the kit.Why no tone controls or volume control? I'm glad you asked...I use a WiiM Pro Plus as a hub of sorts. That way I can control volume and use the EQ in the awesome WiiM app. Fluance RT 82 with an AT VMN30EN cart upgrade, into an iFi Zen phono, into the WiiM... clean pass through RCA to Fosi P3 and finally RCA into Fosi BT20A Pro with Sparkos SS3602 op amp upgrade. Streaming and phono go through the P3. The BT20A feeds Sony SSCS5 and Elac 1010 Sub (crossover is about 70) very nicely. Someday I'll upgrade that Sony, but for now, it works well for me. Full recommendation for this Fosi P3 use case.I'll also add that the biggest impact upgrade in the kit was the Sparkos op amps. Those little bad boys do amazing things for class D amps.

I picked this up to have a headphone amp that I could use with my Sennheiser 58X Jubilee and Sony MDR 7506 headphones. None of these headphones are hard to drive or super high end, but I feel they are budget appropriate for this Fosi P3.Setup was an issue with the first unit I received. The included tubes have to be inserted by lining up the C shape of the pins with the socket and pressing them in. This was no issue with the right side and I could insert either of the included tubes. However, neither would work on the left socket. After some frustration and bent pins on the tubes, I returned it and got a replacement. The replacement had no issues. The pins were easy to maneuver into place and insert for both tubes.The only other setup needed is screwing in the bluetooth antenna and attaching the small power adaptor. If you want to use it as a preamp you can run a source into the RCA in and out to a stereo or powered speakers.I first tested the headphone amp. I was impressed with the amount of power this has. The 58X Jubilee are easy to drive but I couldn't even reach a quarter of the volume without it being too loud. This should easily drive most headphones out there. Maybe something crazy like magnetic planar headphones might need more power, but those are at a price point way outside of something you hook up to a sub $100 amp.Sound quality is excellent through RCA. I did an A/B comparison between it and my Schiit Magni+ Heretic. The Heretic is a bit more expensive and is known for measuring very well. This P3 held up next to it and there honestly was only a slight difference in sound between the two. This is a slight issue though. Where was the tube sound? I can confirm the tubes work and are not just for show, but they have the electronics in the amp keeping the distortion the tubes cause to a minimum. This makes for an excellent sounding amp, but it doesn't really sound like a tube amp at all. Why include tubes if you are going to still design an amp that measures well? It is confusing as the tubes seem like a mostly cosmetic decision. Perhaps different tubes might have stronger distortion and give more of a warm tube sound, but in the stock configuration this doesn't sound like a tube amp at all.I tested it as a preamp using a DAC hooked up to the RCA In, out to my stereo. Sound is just as good as through the RCA out and I can't imagine finding something better under $100. The P3 also has tone controls that click when they are centered and seem to only adjust the highs and lows while leaving the mid range mostly alone. Use can use the Aux out on the back to send audio to a powered subwoofer for 2.1 sound.Another feature I was happy to see is the bluetooth receiver. It easily connected to my Android phone and the sound was very good using AptX. The bluetooth in the P3 also supports AptX HD and Adaptive. This adds some options for the P3. You can use your phone and the P3 to connect to a stereo or powered speakers in any room. The more I use it as a bluetooth receiver the more I have drops and distortion. I'm not sure if the cause is the Fosi or my Samsung S22 but I don't have these issues using bluetooth headphones. The music will sound great and then have interference for a brief second. I have not been able to solve this issue and it happens in any room I use the P3.The quality of the sound through RCA was very good and makes this a good value as a headphone amp and preamp with its nice metal construction and attractive look. The tubes don't add much to the sound, but they are attractive with their red glow and blue LEDs underneath. I wish the bluetooth had been more reliable as that and the pointless tubes caused me to knock a star off the score. This seems well made and should be a great companion device to a desktop DAC or speaker amp like the Fosi V3.