Monoprice Monolith Liquid Platinum Headphone Amplifier by Alex Cavalli

I picked this amp up as well. received it yesterday. I really like it a lot. Ice-man hit it on the head when he said neutral with some warmth added. Bass is also very good. The packaging was terrible. The box showed up with a huge gash but luckily the actual amp box was not affected by the external damage.

 

The right socket looks slightly offset, but it's hard to judge now that the tubes are installed. I'll check again when I remove the tubes for rolling.

I had a two month loaner on the Crimson but it was over a year ago. Just from memory, this amp sounds very close to the Crimson.

 

Monoprice really did a crap job on packaging this amp. The shipping box was half a length larger the amp box and came with four sections of plastic air cushions. Not adequate at all to keep it from moving around. Haven't tried the E-Mu Teaks with the amp but if the gain is the same as the MCTH you're going to hit too loud very quickly. Haven't checked the default tubes that came with the amp. I'll do this later today.

Here's a quick copy and paste from my post at Head-Fi:

Received my unit yesterday and along with the Hifiman Ananda loaner.

Initial impressions are that the Liquid Platinum pair very well with planars. It gives the Ananda a nice and tight low end rumble on just the single ended connection. Loaner didn’t come with a balanced cable unfortunately. AFO sounds great out of it on a balanced connection but I’ll need more time with this pairing. Auteurs also have a “good” pairing with it but sounds magical from an OTL. Haven’t had a opportunity to try it with the HD650s.

The LP isn’t as fast as the Jotunheim but it has an ease to the way it handles music. Tubes affect the sound moreso than the MCTH. I found my Siemens too bright with the Ananda and Auteurs but the Phillips SQs gave me a great middle ground. I’ll share more thoughts later next week as this week is packed with after work functions.

 

SE may help?

<edit> Gungnir NB I know is a bit gimped on SE out, but worth a try if you have cables handy.</edit>

 

The sockets loosen up after a few swaps. I moved the amp a couple times already, and removing/inserting the tubes is easier now. It's definitely not loosey-goosey like the DNA Sonett 2.

As far as sound, I find it a bit thick and bloomy down low. I think I prefer the Lyr 3 with the Clear. Haven't tried the LCD-2C.

And yeah, there's too much gain. I'm at the bottom of the pot with the Clear. Speaking of which (the pot), it has this interesting behavior where no sound comes out (or it's very, very faint) until about 10 degree rotation.

On the plus side, the hiss is significantly less than the MCTH. Testing with the Andromeda + IEMatch on High I can only hear a very faint low frequency hum. The MCTH has an audible white noise in the same condition.

 

I'm not hearing anything that resembles "think and bloomy" on the bottom end yet. More like tight and extended. This is not a "tubey" sounding amp. Pretty clean and clear so far. Maybe things change as it breaks in.

@GoodEnoughGear I will try your suggestion and try to SE outs on the Gungnir Multibit and see if that makes a difference and gives me more volume swing. I kinda hate to do that because I prefer the sound of the Gungnir Multibit over balanced, but it's worth a shot.

This amp gets VERY hot along the bottom edges. Like original lyr hot. Makes me a little nervous TBH. We'll see how it plays out.

 

SE did not help. It made only a tinny difference on spl level.

 

Could also add a Sys (or equiv.) to tame gain. I have my MCTH hooked up to Freya and basically leave the volume knob at 1'o'clock on MCTH as per @atomicbob 's measurements.

 

It's too bad they didn't make this amp $50 more expensive to give it a decent build quality and a gain switch. This socket problem is going to end up affecting resale value too.

If the opinion that it sounds almost like a Crimson bears out after the hype dies down, they'll sell a lot of them regardless.

 

Just to give another data point, I didn't have any problems with bent pins with mine. The tube sockets were not perfectly aligned, but I didn't have any problems installing the tubes (I had more difficulties installing the tube in the MCTH) and there was enough clearance so that the tubes weren't touching up against the chassis when installed.

I won't say much about sound yet since I just got mine yesterday and need to let the tubes burn in longer, but it drives my LFF modded HE-5LE well, improving the headstage and low end compared to the MCTH and the RME ADI-2 Pro built in balanced amp. I also like how it improves the headstage of the PMx2, though with the high gain there wouldn't be a lot of wiggle room with the volume pot if I didn't have a DAC with volume control.

 

Production unit or one you were sent in advance for testing?

 

Interesting that our packaging was different. I’ll post pics later today on how I received my box and it could possibly match what Ice-man sees as well. Regardless the package was pristine and I did not see any damage to it.

 

Listening now. Quite impressed. I really the the tube thing is being over hyped. Has Hands stated tube sockets new are very tight. Pushing down firmly mine when right in. Sound is thick but I don’t find it bloomy at all

 

As long as the pins are not bent, you can get the tubes in the socket. The real concern is the difficulty in getting them out.

So far, the sound of the amp has woo'ed me. I really do like it. But there are still areas of concern. The lack of a gain switch could be a deal breaker for me. I don't like living between 8-9 on the volume pot.

The fitment of the tubes are a smaller issue. And I don't plan to tube roll much at all. Plus I have socket savers.

I'm also concerned about the operating temperature of the amp. It's continued to rise in temperature for about three hours and now it seems to have settled. The chassis is super hot to the touch. In no way would I want to leave the house without turning off the amp. This might be a non-issue, but it concerns me.

I guess I'll see how these things play out over the course of the next few weeks.

 

Can you rest your hand on it for a long time or are we talking 80's Pass Labs hot? The temp of this is unfortunate-sounding given how cool the MCTH runs.

 

Yes, I can rest my hand on the chassis. But not comfortably so.

 

The MCTH runs an order of magnitude cooler than any electronics gear I've ever had. I can run if for hours and not only comfortably rest my hand on the chassis, but can firmly grasp the tube without any discomfort. If I tried that on the Valhalla 2 I'd be in the ER.