![](https://cdn.shopify.com/s/files/1/0672/2283/1394/files/the-listening-chair-logo.png)
Earlier this year, I received a sample of xDuoo’s MT-604 fully-balanced tube headphone amplifier from online retailer Apos Audio. At an asking price of $169, it offers more sexiness per dollar than almost any audio component I’ve seen. I couldn’t wait to photograph it, and find out if it delivered on its promise of delivering enchanting tubed sound at a very low cost.
The MT-604 is a class-A, hybrid tube/solid-state amplifier. It’s rated to an output up to 200mW (at 32Ω) of power, which is said to work with even hard-to-drive headphones. Its features include a built-in mute circuit and independent left and right volume controls. A solid-state amplifier is said to provide “large dynamics, high speed, and resolving power.” On the MT-604’s rear is a pair of stereo balanced inputs. Front-facing output terminals are XLR and 4.4mm. The MT-604’s tube complement is four 6J1s, all located in its preamp section.
Not surprisingly for its cost, the MT-604 is not the most resolving or tonally accurate headphone amp out there. Instead, it delivers a beautiful and warm midrange and has an overall presentation that’s extremely fun and easy to listen to. It would be fantastic choice for a new audio hobbyist or even a solid-state veteran who to wants to experience a little tube magic in their audio pursuits for little money. Let the tube rolling begin!
![The xDuoo MT-604's tube complement.](https://cdn.shopify.com/s/files/1/0672/2283/1394/files/c-xduoo4a.jpg)
![The MT-604 can drive a wide range of headphones via its dual outputs.](https://cdn.shopify.com/s/files/1/0672/2283/1394/files/c-xduoo3.jpg)
![The warm glow of tubes provides an appealing sonic signature.](https://cdn.shopify.com/s/files/1/0672/2283/1394/files/9_2023-01.jpg)
Howard Kneller’s audiophile adventures are documented on his YouTube channel (The Listening Chair with Howard Kneller) and on Instagram (@howardkneller). His art and photography can also be found on Instagram (@howardkneller.photog). Finally, he posts a bit of everything on Facebook (@howardkneller).