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Monoprice Monolith Liquid Platinum - By Alex Cavalli

Discussion in 'Headphone Amps (full-size)' started by ufospls2, Apr 4, 2018.
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  1. jinxy245
    You can put one of those polls up top, but I have a feeling we all know thew outcome (more or less). There would be a LOT of interest in an affordable fully balanced version of the Liquid Platinum.
    Phantaminum likes this.
  2. Jim N
    I burning one in right now. Manual says nothing about using variant tubes. After 2+ hours of running a burn-in disk (mix of XLO and others) the thermal protection circuit kicked in. I was driving Fostex TH-X00 and it turns out the manual suggested doing burn in without driving a load, which I am doing now. Unit runs quite warm on the cover by the tubes.

    Good solid feel to the unit with nice case work. Will post more later on. I have Massdrop Focal Elex (balanced), HD600 (balanced) and the aforementioned Fostex amongst other cans. My current amp inventory is Auralic Taurus Mk II, Questyle 600i, Yulong A8.
    sorrick and alphanumerix1 like this.
  3. runeight
    Liquid Crimson --> Liquid Platinum

    OK. Let's see how this goes. :)

    First thing is, let's have a look at the Crimson. It is an embedded hybrid with no coupling caps. It uses 1 triode per channel, hence a single dual triode.

    It is SE only with about 4-5W per channel into 50R. It has four supplies: Heater, HV, LV Rails, and Housekeeping.

    It has a pretty beefy linear supply using a custom RCore transformer. It is all through hole components except for some housekeeping circuitry like the offset detector.

    It uses a custom TKD volume control, Cardas RCA jacks and Neutrik headphone jacks.

    It's also pretty big. Here's a photo:

    Notice that the sides are entirely heatsinks. These sinks make it possible to make 4-5W SE. The output mosfets are biased at 150mA keeping in class A mode for a very long time as power demand goes up. Each mosfet burns about 5W at idle creating a minimum of 20W that has to get out of the box. There are also hot regulators attached to the heatsinks so let's say 25W.

    The Crimson is made on a single board (I can't find the interior photos offhand).

    So the engineering question is, how do we take this and turn it from SE to Balanced (which would increase the original size by at least 50%), then take the balanced version and make it 1/4 the size of the SE Crimson, and then get the cost to a more affordable level?? We'll get into that in the next post.
  4. runeight
    I know I've mentioned this in other threads. MHO is that extended burn in is not necessary. The amp should sound ok out of the box and will slowly improve as you listen normally. When I do a new amp, I don't really burn in anymore, I just use it. Just my thoughts.

    Also, performance really is better out of balanced out for all the reasons that you guys know. If you don't have balanced cables I highly recommend that you get some if you can.
  5. Jim N
    Thanks for the info. It's a little rolled off on top right now and bass is a touch woolly so I'll give it a bit of time. I run balanced from my Gumby into the Auralic and now the Liquid Platinum. Busy doing other things so I'm letting it do it's own until a bit later on.
  6. BearlyPizza
    I have to say.. The all metal casing looks a lot better in person than the photos on the monoprice site! It feels quite sturdy too!
    Sadly, i'm listening to it through SE until my balanced cable comes in! i'd like to give impressions, but i'd rather do that when I have my balanced cable =).
    It does run a bit hot compared to what i'm used to though! Not hot enough to burn, but hotter than warm for sure when i'm touching the case.

    Here's some photos!
    [​IMG] [​IMG]
    Last edited: Nov 2, 2018
  7. Allanmarcus
    Just to clarify for everyone. Alex said balanced out has better performance. I assume there is one amp for each polarity for each channel (4 amps) vs 2 amps for SE out.

    As for balanced vs SE in, they should be the same. Balanced sources will output more power to their balanced out, so using balanced in might sound louder than SE in from the same DAC, but unless there is RFI, it should pretty darned close, if not identical. Of course this assumes that output is the same quality from the source.

    @runeight : Any comments on balanced in vs SE in WRT the Liquid Platinum?
    Last edited: Nov 2, 2018
    omniweltall and Rattle like this.
  8. PopZeus
    Is there a big difference between running the input balanced versus SE? I only have one balanced out on my DAC, so I'm torn between the idea of running this (potentially) SE or the Liquid Carbon X.
    displayname and Rattle like this.
  9. runeight
    The Platinum uses two differential amps, one per channel. The Balanced is, obviously, taken between the two outputs of each amp. The SE, however, is taken from one output of each amp to ground. This means that SE can only output 1/4 the power into the same load. This is shown in the specs on MP website.

    Human hearing, being logarithmic, doesn't really notice the power difference that much, especially when listening power is usually quite low and you can always change the volume setting. But I think the Bal out is a hair more dynamic than SE. And I have a general philosophy that a balanced amp should be run fully balanced in and out to get the best. Though this last idea is more of a personal thing than something measured out in detail.

    At one point a while back I almost decided to remove the SE jacks from any future Balanced amp that i would make. A little extreme, I know, and others talked me out of it. :ksc75smile:

    If you use the Platinum SE I think you'll be very happy with what it's doing. It sounds great. I just think Bal out adds just a tad more to the experience. Subtle but hearable if you really try.

    Input doesn't matter. The amp should perform the same regardless of Bal or RCA ins. The RCA in has a built-in splitter so that the lower level SE signal is doubled to be more consistent with the Bal input. I have a DAC where the Bal out outputs twice the amplitude of SE. When using the Carbon (with a similar arrangement) I can live swap from one input to the other and I, honestly, can't even tell that the switch has occurred.

    Oh. One interesting thing. With the Carbons there were quite a few questions about not being able to switch the output from Bal to SE and back using the input switch. So, just to maybe anticipate one or two of these, the button on the right only swaps the input selection. Both output jacks are live all the time. :L3000:
  10. runeight
    It does run a little warm. Just be sure to give it lots of surrounding ventilation. Don't put it on top of something that is also hot. :)
  11. BearlyPizza
    Definitely going to be giving it a lot of ventilation and its own spot on my desk! It's a lovely amp to listen to !
  12. Jim N
    I just realized who responded :wink:. Thank you for taking the time here! I was greatly anticipating this amp!

    I am running my Focal Elex balanced from the LP. I also have HD600 balanced. I had a long listening session last night with the Auralic driving the Elex balanced. I will listen to the same, very familiar CD's (Chick Corea / Ultimate Adventure, Dave Grusin / One of a Kind, Flim & The BB's Tunnel, Steely Dan /original issue MCA CD's of Aja and Gaucho) that I did last night. I know audible memory is quite short but I know these recordings very well and what details to look for.
    Eagle13 and displayname like this.
  13. alphanumerix1
    Most definitely
  14. runeight
    First post made a few posts back. Second one coming. :)
    Last edited: Nov 3, 2018
    displayname and cardeli22 like this.
  15. Jim N
    Quoting oneself does seem a bit tacky but.... amp is settling in quite nicely. Getting ready for the night's listening session. Will use the Elex balanced.

    Alex, anything you wish to share would be greatly enjoyed and appreciated.
    alphanumerix1 likes this.
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