This is an early look of the Monolith by Monoprice Desktop Headphone Amplifier and DAC with THX amplification technology. The unit was kindly purchased by a forum member and drop shipped to me. And that is where the trouble began but more on that later. The Monoprice THX amp and DAC retails for USD $480.The Monoprice THX amp and DAC has the same design language of other "monolith" units which translates to a serious look. There is brushed metal on front and very shiny and glossy enclosure which instantly shows fingerprints:Let's backtrack a bit. I have ordered three products from monoprice. The first one never came and I only found out about it a few months later. I then ordered two other products from them both of which were sent to a remote neighbor. Their street and house number are one digit off from us. Hard to imagine how someone could be this bad at reading addresses yet be in delivery business.Worried that this unit would also face the same fate, I contacted the carrier and monoprice. With the latter, I read them the riot act for sending the last shipments to wrong address. No response came back. The carrier sent me a form response a couple of days later saying "we will get back to you." Well, they didn't and today got notification that the package was delivered at the front door. Searched everywhere and no sign. Called the carrier and they started to investigate. A few phone calls later and then neighbor calls and says the package is once again delivered to her.Thankfully it was double boxed or it would have been soaked in the rain.I unpack the unit and find no manual of any type -- just a code to put in online to find it. I know we have moved away from paper but come on, for a $500 device, I expect a little cheat sheet on how to power the unit on. Yes, how to power it. Look at the front panel: there is no indication of how you turn it on! Fumbling I hit the enter button and I see the monoprice log and the unit lights up.I hook up a USB cable to it, select that input and run a quick dashboard test. I get to SINAD of 107 in best case scenario. Where is that output you ask? Well, I usually run a few quick tests before doing a formal review and I don't save those. I went on to test output power and with 300 ohm, and single-ended, I get half the rated power before clipping (and less than Topping DX3 Pro). I then test 33 ohm, and here I get about a watt of power which is decent.I thought I test the amplifier section by itself so I hook up a set of analog cables to its inputs. In the midst of switching things around, the protection circuit kicks in which is fine. But on the second instance this happened, the unit shut itself off. Hmmm. This is never a good sign. I turn it back on and now it is acting crazy. Menus work but changing the volume causes it to update the new value 0.5 dB every few seconds! Changing inputs no longer works as you see from the stuck "RCA Line" in the above picture. Factory reset does nothing.There is an about menu so I selected that and see this:0.82 beta? Really? With all the delay in production of this unit they couldn't finish the firmware?Seeing the dismal usability of the firmware, my suggestion is for them to throw it all out and start over. It is maddening to navigate. Why isn't there a single button press for changing inputs? Once you go into menus, the rotary volume control goes through different options. But when you go into settings, the enter button does that! Why or why? Between it crapping out and poor usability I am tempted to throw it into the bay. But then it is not mine so I better not do that.And oh, the purpose of messing with it was that I was getting the two channels completely out of phase with each other when feeding it analog input! I ran out of options with the thing breaking before trying everything. I doubt the issue is at my end though.Back to functionality, any desktop product in this range should have a remote control for volume so that you can use it in your equipment rack.I was all excited to get this review out quickly for you all. But the company didn't allow it. Between poor delivery, customer service, firmware functionality and reliability, I am not sure I have any motivation left to test the product anymore. And can you imagine my mood if they replace this and it goes to the neighbor again? She was ready to shoot me had it not been for the joyous holiday mood!The bit of performance that I did measure was good but not exceptional. At nearly $500, that is not acceptable. You can get excellent $100 DACs and pair them with the Massdrop THX 789 or JDS Labs Atom and be in business for less than what this unit costs. And they would be a lot easier to use.Anyway, I feel bad for the owner who actually lives in Europe and ordered this just for the good of the community. I think I am going to ask him to get a refund instead of replacement.My suggestion is to buy the Massdrop THX, JDS Labs Atom or Neurochrome HP-1 if you need high performance headphone amplification and a DAC of your choice. Otherwise, there are excellent all-in-one choices like Topping DX3 Pro which cost less than half of this unit.-----If you like this review,using Patreon ( https://www.patreon.com/audiosciencereview ), or upgrading your membership here though Paypal ( https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054 ).