Monoprice Monolith Liquid Platinum Headphone Amplifier by Alex Cavalli

Edit - nvm it comes with a universal power supply.

I'm in, why not. I always have source noise problems from my PC, so I have been chasing balanced setups lately.

 

My recollection was that my LP produced the same volume from the balanced out whether I was feeding it from my Gungnir Multibit’s SE or balanced out. But there’s no doubt that gain is too high for many applications without attenuation of the input. I use a passive preamp.

 

This happened with my LAuX too, RD said he was told it was designed that way, to be run SE or Bal and have the same volume into the amp. I was so confused when my shiity RCAs sounded much the same as my Pangea XLRs.

 

Really? That's totally counter-intuitive. But if you guys report it happening, it definitely happened.

(puzzling)

My LGX works SO MUCH better with a high quality volume pot in line ahead of it...becomes a whole different amp, a tamed power beast vs an untamed one.

 

The other reason beyond gain to plan a preamp ahead of the Liquid Platinum is due to the QC issues with the volume pot. Early runs of the unit seemed ok, but somewhere along the line a lot of reports of bad volume pots have plagued this amp. Not just typical channel imbalance at extremes of the pot stuff, but strange non linear jumps in volume on the pot as well.

 

This plagued the Gold was well. The nonlinear jumps in gain. It was very strange, under 10oclock, you could barely hear anything, and then it shot right up at 10, and then you just sorta had to stay there unless you wanted to blow your ears out (unless you had a pre).

 

Is it hard to switch the volume pot on this?

 

I think Whitney tried on the Gold and he said it wasn't worth it. Just get a cheap SYS.

 

I've seen one or two mods done to replace the volume pot, but usually they opted for better (physically bigger) pots that required the mod the front plate facia as well, or machine a whole new plate cover. IIRC - heard it wasn't easy either. And as others have already mentioned - it was a desirable mod at one point due to the channel imbalance issues that plagued a good portion of units back then.

You could always ask @Ksorota for more details - he is very familiar with modding this amp.

 

I was going to go through the pain of swapping the pot but decided that it's not worth it.

You can find a few references and pics of the mod somewhere in the H-F thread.

 

Funny you'd say that. My LGX has a very strange (obnoxious) non-linearity at about 10 o'clock on the volume dial, where the volume jumps from one level to a higher level. It's bad because at about 10 o'clock on low gain, the amp is just getting to a moderately loud volume that is pleasing with planars. Then it abruptly jumps from almost loud enough to too loud. .

But when I used a DAC w/a high-quality, transparent volume pot and knock down the DAC's oubput volume by 25% (Audio GD R2R-11 MK2), the LGX is perfectly behaved because the discontinuity happens at a lower headphone volume where I typically don't listen. Above that non-linear portion, the pot's behavior is normal & predictable.

 

The non-linear volume on the LAuX seems to be pretty consistent between units...at least based on the few I have heard, and the experiences in this thread.

The volume pot on the LP is not overly difficult to swap, but unless you use a same size pot then you are stuck cutting the front face plate. I personally am not sure its worth going the route of custom mounting a Alps 4Gang after doing two of them.

The pre-amp route gives the most flexibility, but really you should be able to make the stock pot work for you unless the balance is very off, and in that case it makes the most sense to swap with Monoprice, assuming still under warranty.

The Freya N was one of the best audio purchases I have made in the last few years and makes the issue of volume pots basically non existent.

 

Thinking really hard about whether getting one of these when I have Lyr 3 and Piety is really just in "buy a better amp instead" territory. At some point I decided against it because getting balanced cables seemed annoying, but this price is... tempting.

 

I wouldn’t say this is better than Lyr 3, just different.

 

Well my LP arrived about 11 am this morning. Got the amp hooked up. No trouble getting the tubes in the tube sockets = no death grip. I do not have a balanced cable yet but I ordered one from Hart audio. So, I am using the amp SE in and SE out.

First impression is the amp is impressively quiet. Secondly, the sound is quite good IMO. I have read the SE output is decidedly inferior. I think in SE the amp sounds close to my Sunrise 3 with a NOS 7N7 for input or very good. I see why some people do not feel the need to tube roll with the stock tubes. The amp sounds good bone stock. However, after my initial listening session, being a tube junkie, I searched and found some good Jan Sylvania 6922's and ordered them.

The sound is warm and smooth, very musical but not the last word in detail or resolution. I have the Stones famous 1973 live boot Brussels Affair on right now. The sound is big and captures the venue. Just very nice to listen to. Good dynamics and very nice with vocals too. No channel imbalance.

The pot . The pot does jump in volume at 10 o'clock or so. But SE my Senn 599 is set about noon and my M1070 is set at 1 o'clock so no issue. I have read the input level from the source is the same SE and Balanced so this should not be an issue. I have a 23 ohm Senn 598 Cs and the volume knob was still above that 10 o'clock threshold and I am not a loud listener.

All I can say for $289 this was an absolute steal.

Note: I am driving the amp with a Modded BF1 OG so maybe the quality of my source is giving better than expected results.

 

A short follow up .....

I am still using the LP single ended waiting for my Hart balanced cable to arrive. I received my NOS Jan Sylvania 6922's yesterday and even single ended the sound is now even more engaging. More detail, but not in your face. A very clear, clean treble that is delicate and in the right proportion to the rest of the sound spectrum. Vocals are nicely fleshed out but not to forward. Bass is very dynamic but again in the right proportion. I do not know how the sound is going to be much better in balanced mode but the consensus is the amp is clearly better balanced. We will see.

I have modded MP M1060 and M1070's and excellent sources so maybe that is some of the synergy. But the extra power should definitely benefit the M1070's low end and overall dynamics. Maybe the M1060 too but the 1060 is a lot easier to drive.

 

Well I received my Hart balanced cable for my Monoprice M1070. The 1070 is my hardest to drive headphone. I thought the extra power would make a definite difference and that turned out to be true. Balanced is noticeably more dynamic and slightly more aggressive = less laid back. Bass hits harder and is slightly better resolved. There is just a more realistic quality to the amp but the wonderful signature of the amp basically sounds the same. Balanced operation is better as most have stated

Moreover, the Sylvania Jan NOS 6922 is a good step up from the stock tube .... which is good in its own right. The more I use the amp the better it sounds as everything is breaking in. Great match with my MBF1OG dac too. I was surprised the volume pot is positioned in exactly the same place balanced and single ended. This was pointed out too in earlier posts. But, I forgot.

 

One more discovery .... the sound stage is clearly larger laterally and instrument and vocal placement is more precise. As I went through familiar recordings the placement of instruments and vocals was different and sometimes starkly different. There was naturally some differences before but balanced they were more evident . For instance, Mick Jagger's vocals on the Brussels Affair boot are noticeably more forward and Mick Taylor's fantastic guitar playing is better fleshed out. Keith's rhythm guitar does not get lost at times when the music gets busy.

I am not always sure I like the more forward character on some vocals but there is no doubt more size and resolution in the sound stage and like it or not I believe balanced is more representative of how he recording is supposed to sound.

 

I seem to have my own personal thread here. LOL!

Well today I remembered my old Zhalou DAC has an add on class A output stage that has single ended and balanced outputs. So, I managed to find some XLR cables and hooked it up. WOW! The sound is even better. The sound stage is really large now and the resolution is fantastic.

For instance, listening to the Derek and The Dominoes "Live At The Filmore" full show boot from 10/24/70 had Bobby Whitlock's B3 and vocals joining the band. Normally he is way to the left and you only sometimes hear the B3 and bits of his backing vocals. But going balanced in/ balanced out he magically reappeared and provided some wonderful contrast to Clapton's guitar and vocals. This was the best I have ever heard this recording sound.

Dynamics were better with just balanced output. Now balanced in and out the bass hits harder and macrodynamics are big and bold throughout the spectrum. The sound is more open and clear sounding. No downside either. Love this amp.

 

I haven't listened to enough stuff with measurements in mind to know how to interpret everything here, but I was looking at atomicbob's measurements of this a few days ago and it struck me that really the SE in XLR out and SE in TRS out looked more similar than different, and the XLR in XLR out looked much, much cleaner than both. Just so much grass with the SE circuits.

I'll set mine up and listen for a while when everything I need comes in (I'll just hope the fact that it showed up missing a foot doesn't reflect on the quality of anything else...), but I guess I'd be surprised if balanced all the way weren't better somehow. Although maybe it's hard to compare, since you'd need a DAC that sounds the same with RCA out and XLR out to really do apples to apples.