Gemtune APPJ PA1502A 6N4+6P6P tube headphone amplifier (Black)

I've only had a couple of hours on the amp so far but it does sound nice. There was no documentation with the amp but it is simple enough, only line in on the back and a switch, phone plug, and volume on the front. The switch is labeled H and L. I wasn't sure if this was for impedance or gain. My Fidelio X2s are 30 Ohms and worked fine in either position, just much more drive in the H position. I did email Gemtune and asked about the switch, they got back to me promptly and said it was for high or low impedance but didn't say what the switch over point was. At 30 Ohms, I would call my X2s low, but for 150 Ohm, who knows. I did notice some hum when set to high and no audio input, could just be the mismatch. In the low position there is no hum. Even right out of the box with no burn in, the amp sounded fine driven by my iPod. Max volume in the low position was plenty for my ears. In the high position, I could really drive the phones and did not notice any bad behavior ( less the hum, which may change with time on the tubes, and is not perceivable once playing ). The amp has solid brass feet which let it slide around easily. I would have liked rubber feet better but not a big deal. For now I'm just running the tubes that came with the amp. The only reason I give it 4 stars instead of five is lack of documentation

I can't say what this would sound like with the stock tubes but with JJ 6L6's and a Gold Lion 12AX7 running into a pair of Audio Technica ATH-M50 headphones, this amp sounds wonderful. It has power and command. Whether I listen to vinyl via a tube preamp or if I'm running it via a bluetooth receiver listening to Sirius XM or YouTube, this amp sounds better than I'd ever thought it would. I also changed the knob to a more knurled type to make it easier for adjusting. It comes with a smooth knob that was difficult for me to adjust with one finger when sitting in my recliner.

This is a great little amp. Sounds good right out of the box, but I put in some nos Ratheon 6v6's from 1958 and a Sylvania 12ax7 from 1961 and it made a huge difference. It would get 5 stars if it had decent tubes. A great buy. I hooked it up to my computer also, and the audio significantly improved, which shows that my computer's sound interface does not handle power well - even the small amount to power headphones. Same with the laptop. I suspect most digital devices are this way. If you buy this do yourself a favor and buy good tubes for it. I'm using it to power regular dynamic over the ear cans - not cheap, not expensive.

This is an outstanding headphone tube amp. I upgraded the original tubes with a Genalex SINGLE Gold Lion 12AX7 ECC83 B759 Tube Gold Pins, and Genalex Factory Platinum Matched PAIR Gold Lion 6V6GT. I'm using an Elfidelity Sound Sourced PCI-E Hifi AK4396 DAC 2.0 Channel Internal Sound Card into a REAL pair of Sony MDR V6's. The warmth and clarity of this amp is amazing and money well spent for up and coming audiophiles.

Just received this and couldn't be more happy! Rolled the stock tubes for upgraded electro harmonic and genalex tubes and could not be more pleased! Build quality is great. Amp arrived from China very quickly and well packed! Will likely change the feet, but that is my only quibble so far.

Always blown away by the sound of this amp! The stock tubes are alright, but rolling some different tubes makes drastic changes in sound. I ended up using Genalex Gold Lion 6V6GT for the power tubes and a reissued Mullard 12AX7 for the driver tube. Amazing clarity and black background.

I am no self-proclaimed audiophile, just a hobbyist who loves relaxing sessions of headphone music in my recliner after a long day of work. I have had this amp for 4 years and still impressed by it enough to write a review of recommendation. It might not be as powerful as my Gustard H10, but it's powerful enough to drive all my headphones - dynamics and planars, to satisfaction and they all sound great. It's certainly a winner in looks with those bottle Tung-sol KT66 tubes. Always a great conversation piece for anyone who sees it for the first time.