I got this tiny unit to replace an older JVC micro-system in our bedroom. I matched the T20 with a set of older British Gale Reference Monitors, and the results are astounding, to say the least. The sound from the T20 is tremendous. The BT connection works well, and perhaps my only quibble with the design is that the BT/RCA input switch should be on the front panel, rather than the back. But at least the T20 gets an actual switch, whereas the BT30D (Pro & non-Pro) models do not.

The little valves which come in the box are easy to fit, but use a torch to make SURE you have them oriented correctly. It is OK to touch the valve glass - these are not Tungsten flood lamps.

The tiny speaker terminals at the rear accept banana plugs, and that is the way you should connect to this unit - and to your speakers, as well.

At night I found the blue LEDs under the valves to be complete overkill, along with the incredibly bright power indicator, which is far too bright. This was fixed by 3D-printing a tiny plug which fills the hole above the LED and below each valve. This reduces the brightness, so that the natural orange glow from the valves can be seen. A piece of tape now covers the power LED.

The headphone output seems to sound just as good as the speaker outputs - so that's good! And my wife loves to connect to it via BT when she is doing her hair and makeup each day. The quality of the BT connection seems to be excellent.

It is more than capable of some pretty high sound pressure levels, too. Not enough to shake the house, but certainly more than adequate to fill our large bedroom with cruisey tubey sounds.

This is the fifth FOSI amplifier I have purchased, and all of them are extremely well made, and produce superb sound for their price. I've also grabbed the BT30D (Pro & non-Pro), ZA3s, ZD3, T20, and I have a GR70 and a GR40, and a V3 power amp on the way.

Thank you very much, Fosi, for re-kindling my passion for 2 and 2.1 channel audio again. For 15+ years I have been all about the 5.1 and 7.1 surround for gaming and movies. But now with the new Fosi stereo gear all my old speakers sound brand new again, and all my old music also sounds brand new. I'm so excited to listen to music again, and it's all because of the brilliant quality and amazing prices of their new Class-D gear.

10/10 - Thoroughly recommended.

Fosi Audio T20 Bluetooth Tube Amplifier

Does a nice job of powering my Audio Technica ATH-40 headphones. I wasn��t able to pair it to my Sony tv though, so that took a star off its score.

I bought a couple of Polk audio bookshelf speakers at a yard sale and was looking for a small, relatively inexpensive amp to power them. Your T20 fills the bill quite nicely, with enough power to make these speakers a real upgrade from my cheap computer speakers. The sound is clear and distinct. The Bluetooth option is a plus.