Douk P1 DAC/Preamp/Headphone Amp review

A few weeks ago I decided to build a fun sound system for my home office (see this post for details). The goal was something that looked interesting, sounded good, and was expandable. The Douk P1 DAC/Preamp/Headphone Amp serves as the centerpiece of the system. After using it for a few weeks, I can say that it is a decent piece of equipment.

Pros:

• Small size
• Switchable tone controls
• Good Bluetooth (stable, easy connection, APTX support)
• Built-in DAC

Cons:

• No optical input
• Unnecessary bright blue light on power supply
• Clicks when turning amplification on and off on Bluetooth

It has a good build quality. The tone and volume knobs turn smoothly with soft clicks. It feels sturdy and all the connectors are solid.

Setup is easy - plug in the tubes, connect to the speakers, plug the PS into the wall, and hit power. The tubes that came with my unit went right in - I didn't have to mess with the pins, but YMMV. Pressed power, flipped the switch to Bluetooth and the unit went into pairing mode. Connected my phone and played a few songs. This is where I would hear the clicking - when not actively playing sounds, it seems the amp switches power modes (?) so you hear a click when it goes to low power mode, then a click when you do something on your phone that causes sound again as the amp powers up. Really not an issue, but it made me think something was amiss until I figured out what was happening.

Sound is great out of the box. Running with tone off, it is a nice balanced sound - no muddiness. Tone off is roughly equivalent to both tone knobs at the 50% (straight up) position - if they are both turned down it has the effect of lowering the volume. It did a good job driving my Sony MBR-7506 headphones, and was able to provide full-spectrum sound with no issues. When I plugged them in it switched off the RCA out, which is nice as it means I won't have to turn off my speakers if I want to do some headphone listening.

I find the Bluetooth connectivity to be rock solid. I have it paired with a transmitter connected to the Zone 2 preamp of my receiver that is about 20 feet or so away and I haven't had any issues with the connection.

USB worked like a charm for both my PC and my Android phone. The included DAC is better than either device's built-in option, which is a plus.

When it comes to the tubes, there is some question as to what they actually do in the signal chain. As close as I can tell from my research and looking at the circuit board, they are a tube "buffer" - not used to amplify the sound (that's handled by chip-based op-amps) but they "color" the signal. Some people report that changing tubes has an effect on the sound - I don't know as I updated the tubes before I used it the first time. If I get around to doing a test and comparing the sound signatures of the stock tubes with a different set, I'll update this post. The upshot is that if you're looking for an amplifier that uses tubes to actually increase the gain as opposed to color the sound, you probably want something else.  

My only real complaint about this unit is the super bright LED on the power supply. It's unnecessary. Plus, did I mention it's bright? Because it's bright. I ended up doing the "electric tape mod" to cover the light.

If you are looking for a unique DAC/headphone amp, this would be something to consider.