Monolith Tube Amp Headphone Amplifier - Black with ESS ES9018 Sabre Chip DAC | Impedance Selector | Tube Sound

I bought this directly from Monoprice for 199 free ship!Great value for the money, built literally like a tank over 20lbs, plenty of power and the sound, even stock, is very good.Roll some tubes in there and SQ gets even better!Glad I got one.FYI mine has no hum or other extraneous noises from USB or any other input.UPDATEAfter some tube rolling I can say I did get a buzz from some tubes like the beautiful RCA 6AS7G I bought for 35 dollars! And a fabulous Svetlana... Oh well, if you want some advise on this go with a CEI 6080 and the Russian 6N3P tubes.No noise and sound is fantastic! There are many different 6N3P driver tubes out there so do some research, I got mine from fleabay from a guy called tubes_old70 and they are legit. Takes a month to get them but well worth it.This is a powerful amp that with the right tubes preforms exceptionally well.

This is an updated review. My first impressions were very good. Seemed built like a tank, heavy (it has 3 transformers inside). The metal knobs and switches are a nice touch, and so is the little screwdriver to open the tube compartment and remove the packing foam that protects the tubes.The sound is clear, with punchy lows, clear highs, and no detectable noise or distortion other than the desirable non-linear artifacts that comprise "tube sound". The honking power tube cranks out 1W per channel, which is in excess of that's needed to drive any headphone. One complaint is something a previous reviewer mentioned, and it is the volume control knob. Only about half the range is useful, as anything above 11:00 is just too loud. Perhaps a pot with a different response (linear perhaps?) would have worked better in this amp.I was re-organizing my desk, and needed to move the amp. When I picked it up from the bottom, I noticed a loose screw. Upon further investigation, I discovered that it was just one of four identical screws arranged in a square, that are very loose and cannot be tightened because they just turn indefinitely. They are pretty hefty so I assume they hold a component of some weight in place. Perhaps a transformer.Really too bad that such as lovely piece of equipment should be marred by sloppy assembly.

OK, so I've had this amp for several months now. I've waited to post a review for quite a while. First off, the bad. The quality control issues with this amp are real. I bought mine on Amazon, and when it arrived there was something heavy clunking around inside the unit and it wouldn't power on. The usb input for the DAC on the back was slanted at a 45 degree angle. Not wanting to deal with an exchange from Amazon, I figured I'd open it up and take a look inside. There is a large, approximately 2lb power transformer mounted directly to the frame over the DAC. When this unit was assembled, I'm assuming that they never tightened the 4 screws that hold the transformer. During shipping, the nuts worked lose, and the transformer dropped on the DAC. The DAC is mounted on thin, stamped steel brackets so the transformer bent the brackets down, hence the angle for the USB input. The transformer had come unplugged when it fell. I remounted the transformer, plugged the connector back in, and straightened the DAC brackets, and hoped for the best and powered it up. After that the amp worked perfectly. Now the good. This amp is sounds amazing. No hum or noise at all unless you are using a source with a cheap power supply, or you have some ground loop issues in your house. It is also the only full tube amplifier that I''m aware of that will drive a full 1W per channel even into low impedance headphones. This amp is seriously built, it has a giant torroidal multi-tap impedance matching transformer in the bottom. The transformer alone has to weigh at least 5 lbs, this is where most of the weight for this amp comes from. The power stage is all very heavy duty, and all the wiring to the tube sockets is heavy, solder joints all looked good, etc. This amp will drive any tubes you throw at to their full potential. It has also paired well with every set of headphones that I've thrown at it without blinking. Anything from 30 ohms to 600. It sounds good with the Chinese tubes out of the box, but I agree with the previous poster that the GE's make a marked difference, and are the best preamp tubes that you can get for this amp without paying more than the amp for tubes. However, I find that the power tube has more of an impact on the sound than anything. I've tried an RCA Octal 6AS7G, a GE O getter, and a GE 5 star 6080 in it so far. My favorite by far is the RCA, it is just a magic combination with the GE pre's. It really tighten up the bass and lowers the bass extension by quite a bit, and also gives it a higher, warmer treble extension. No noise or hum at all, my second favorite tube is the GE 6080 5 star. I didn't care for the O Getter at all, it was much more compressed overall. I actually like the Chinese power tube that it came with better than the O getter. The Chinese tube actually has a nice, wide transparrant top end, it is just a little clipped in the bass region. The DAC in this is fantastic, I actually like it better than the DAC in my LG G8. It is in the same family of Sabre DAC's but it is superior to the DACs in the LG phones, and they are the best in the business. The DAC work perfectly with my phone with an OTG driver, or with my computer with the Savi driver. It is a pretty neutral DAC and is a great pairing for this amp. So, at the end of a long winded review, I would have to say that other than the ridiculous process of having to repair a brand new purchase, this is as close to an end game amplifier that you are going to get without a much more substantial investment then even the full list price of this. And if you want tubes, and the ability to properly drive low impedance phones, it is pretty much the only game in town without going to a hybrid like the Liquid Platinum.

Read through the bad reviews but decided to gamble anyway since it is the only amp that enclosed the tube. Seems like there is quality issue for sure on this item. only one of the channel work. Like one of the poster mentioned here there was something moving in the back. Took the top off and the transformer is unmounted and laying there on the dac chip. the two screw is scattering inside the case. Took a while to remount but still doesn't fix the issue. All the tube light up fine. It is going back.