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.

I really wanted to love this dac/amp, I really did. I wanted a full tube amp (not a hybrid like most on the market) with an integrated dac, and this is one of the only models available.However, there is a constant electrical buzz (mostly in the right channel, but present in both) that changes with the volume. It's always there, and very distracting. I tried to fix it in every possible way: new tubes (Russian military grade imports), a power conditioner, better shielded cables, and isolation from emi sources. None of these changes has effected this noise, so I'm guessing its the wiring/interference from inside the device itself.Monoprice always has great ideas, but their QC is hit or miss from product to product. This one is a definite miss, that's why it goes on sale for $280 from the $400 msrp often. It does sound great, and the external housing and controls feel nice, but the constant noise is too much for me.

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.

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.

This is an excellent headphone amp. That's why it's such a disappointment to return it.The amp is very well built and all the knobs have a solid feel when turned. Sound quality is comparable to more expensive tube headphone amps. It sounds spacious, solid, and three dimensional, and it has effortless power. This amp worked especially well for my inefficient and higher impedance headphones.So what's my problem...the volume control. My amp has a left sided imbalance. Oddly, it improves greatly after about 45 minutes of warm up. To make matters worse, the volume control itself is poorly calibrated. It goes from soft to really loud within millimeters of a rotation. By 9 o'clock on the volume dial its too loud, even on 600 ohm Beyers. It's very hard to dial in the proper volume. The 100$ Monoprice Liquid Spark ( or Schiit Magni 3 for that matter) has a superior volume control.Also, the impedance selection knob makes barely any change to the sound regardless of headphone choice. Very odd. This amp just missed the mark and its a shame since its so nice. Monoprice needs to remove the impedance selector and replace it with a gain switch. That would fix the volume loudness, and then remove the internal dac and just install a high quality volume control. I would imagine most people with this amp will want a separate dac anyway.Maybe I just received a dud. But something tells me...No. Hope this helps others. Send me any questions if you have them.

Was not expecting much given the price but was blown away by the quality of this tube amp. Was also skeptical because of the reviews, but was surprised as I took a first listen from the usb input. Didn't hear any humming, buzz, noise,etc. Driving my 600 ohm Beyers, I finally feel like I'm getting the full potential out of them.Update 2021-01-13Theres a slight hum sound and when turning up the impedance knob, it gets louder.Its always there and is lowest in volume at 32 ohms while using my hd650's. So slightly annoying but when music plays, you won't hear it unless the music is very quiet. I tried a different outlet and it still remains. I docked a star off for this reason.

is worth every penny