Monoprice Monolith Liquid Platinum Headphone Amplifier by Alex Cavalli

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by Vtory, Apr 4, 2018.

  1. AllanMarcus

    AllanMarcus Friend

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    Thanks for all the impressions. WRT to the tubes, it seems to me that a $700 awesome amp with $300 of tubes (assume one can get a "decent" set of NOS tubes for $300) is quite a bargain (one might even say a "deal" :) for $1000.
     
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  2. Walderstorn

    Walderstorn Friend

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    That's very subjective but some, like myself like the Crimson the most. My 2nd favorite is glass but the one that got Cavalli under my radar first was the Liquid Fire but it's not as enjoyable as the other 2 imo. The Crimson is my "will never sell unless I absolute must" gear.
     
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  3. Ice-man

    Ice-man Friend

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    Yes, I agree. No need to spend $300 on tubes though. I got two sets from members here after posting a WTB ad. I scored a holy grail set of Telefunkens originally from Upscale Audio, now selling for stupid money. Let's say that they were offered well under $200 and I had to snap them right up. They are exquisite. Tonally some of the very best tubes that I've heard. Very neutral with only a slight bit of warmth. I hope that they last a very long time.

    I also bought a set of Siemens pc88, which while not comparable to the Tele's, are very nice. I would have no trouble or regret running them as daily drivers, seriously. They are now my backup set.

    Both sets combined for right at $200. And I'm set on tubes for years!
     
  4. ButtUglyJeff

    ButtUglyJeff Stunningly beautiful IRL

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    Bob, we get it. Just understand you might be the only one here with the unicorn and the "baby, updated, new and improved, for the masses, last hurrah, new aged" unicorn replacement. Plan on being asked often, or have a party with @Torq and get him to do it...
     
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  5. xsuperxapplex

    xsuperxapplex Acquaintance

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  6. Sonance

    Sonance Rando

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    Quite intrigued by this amp..
    I saw the earlier post about gain being set by the tube mu (and I assume is therefore non-adjustable), and being a little on the high side (again, presumably for high efficiency cans like many IEMs). Probably doesn't help that the default levels for balanced outputs on DACs tends to be on the high side. Since most pots tend to throw away a lot at the low end and sometimes have slightly worse channel balances on the extreme low end (I have no direct experience with this particular amp), I'm wondering if the best option for those who have it available is lowering gain on the DAC where possible so that you have useful range on the volume knob when using high efficiency cans where the gain feels too high?
     
  7. dBel84

    dBel84 Friend

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    I spoke to Alex about this as I had been under the impression that most of the gain control was with local feedback and although this is not inaccurate, the amp does use a balance of global feedback to control overall gain.

    will go back and edit my original post to reflect this too.

    ..dB
     
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  8. songmic

    songmic Gear cycler East Asia edition

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    So this amp doesn’t have adjustable low-high gain as it was originally advertised? If it’s a fixed gain, how much is it? (I believe CTH had a gain of x8).
     
  9. AllanMarcus

    AllanMarcus Friend

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    14db(5x)
    It's right on the specs on the MP site.
     
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  10. Ice-man

    Ice-man Friend

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    This is one of the few real niggles I have with the amp. Of course there are various ways to circumvent the problem, some cheap and some not. At the end of the day, if the LP had high low gain, I would have gladly paid more for the versatility.

    The trend in headphones, for the most part, is more efficiency. I just don't see the reason for this much gain.
     
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  11. runeight

    runeight MOT: Alex Cavalli

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    Yes, I understand this problem intimately. It is not so easy to deal with as it seems.

    Amp designers are being squeezed at both ends. Many sources are really hot, hot enough that their voltage excursions are more than enough to drive modern headphones to hurt you if they were also equipped with enough power out. At the same time, the headphones are getting more efficient.

    The natural gain of the amplifying components in the amps is way, way higher than is needed for any situation. There are only a couple of ways to deal with this, the most common of which is adding global (and sometimes local) NFB.

    But, too much NFB can be really detrimental to the sound, depending exactly on the topology of the amp. Most of the time an amp designer has to make a compromise between the final (closed loop) gain of the amp and the non-feedback (open loop) gain. There is a balance that has to be achieved between these two parameters and the SQ.

    For example, most of the opamps which are used in headphone amps have gains of 100db-120db (100,000X to 1,000,000X). To use one of these opamps and then reduce the gain to 0db (1X) requires global NFB of 100db-120db. MHO is that this amount of NFB is often too much and is detrimental to the sound.

    Discrete amp designers can try to control the open loop gain so that it is not so high, maybe 100X-1000X. If the open loop THD is good then applying 40-60db of NFB can yield a better sound with low THD numbers.

    If we are trying to achieve a gain slightly higher than 1X then the amount of NFB goes down even further.

    Thus, there are two reasons why the Platinum has the 5X gain. 1) I felt that any more NFB would cause it to begin to lose its sound signature and 2) after compressing a very large SE Liquid Crimson amp into a fully balanced version in 1/4 or less the space, there just wasn't any room to fit the additional comps for gain switching.

    Maybe we could ask the source manufacturers to stop making their output voltage swings so freaking high and headphone manufacturers to stop making their headphones so damn efficient. :) :D
     
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  12. Ice-man

    Ice-man Friend

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    @runeight I appreciate you taking the time to explain this. It's quite a treat to get a thorough explanation directly from the creator. Like I said, it's not that the gain is a deal breaker, the LP is one of my favorite headamps. I've found a solution to get around the gain issue.
     
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  13. jmpsmash

    jmpsmash Acquaintance

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    After my disappointment with the Mjolnir 2 I went and order the Liquid Platinum. Excellent service from monoprice, ordered Friday, delivered Saturday 8:30am.

    Haven't even have 2 hours on it yet and it already sounding very very good. I think we have a winner here. I will wait for another couple days of breakin before giving more detailed thoughts and evaluation.

    But before then, I have to put this here... Why is the left balanced input on the right side and vice versa?

    [​IMG]
     
    Last edited: Nov 17, 2018
  14. Ice-man

    Ice-man Friend

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    Just look at it from the other side. :p
     
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  15. jmpsmash

    jmpsmash Acquaintance

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    Oh, and a couple more comments on the non-sonic side.

    The Liquid Platinum does get warm, but not overly so. It is a tube amp, tube amps gets hot. That's just the way it is, get over it. :)

    The case looks much better in real life than on photos. In fact, IMHO it look rather handsome. It is an extruded aluminum case with screened cutout on the top and on the bottom, for ventilation I am sure. It is done quite well and the amp feel very solid. Any improvements would be to have a black face plate instead of the dark grey, and something more "expensive" looking than just the silk screened name (though I am sure that will actually be more expensive to execute).
     
    Last edited: Nov 17, 2018
  16. lcmusiclover

    lcmusiclover Acquaintance

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    Can you tell us about your other equipment, music genres and sound preferences?

    I assume you still have your Terminator and Ares (from other posts), but I can’t find any mention of your cans.

    Thanks
     
  17. jmpsmash

    jmpsmash Acquaintance

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    Yeah. The plan is the LP will eventually end up at my office with the Ares, it will drive a pair of LCD2cb. Right now it is plugged into my hifi at home as the preamp to burn in. Driving Nucore nc400 and a pair of Focal/Jmlab Mezzo Utopia when I am around so I can get familiar with the sound. When I am out, it drives the LCD for some lower impedance load.

    I listen to mostly classical and a little bit of jazz. I like tube sound. Can't stand anything that sounds bright.
     
  18. Elnrik

    Elnrik Super Friendly

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    LCD2Cb? Has there already been a silent revision by audeze?
     
  19. Jozurr

    Jozurr Almost "Made"

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    LCD-2 Closed Back
     
  20. jmpsmash

    jmpsmash Acquaintance

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    Yes. Unfortunately with the trend of more open cubicles these days, closed back is the only way to not annoy my co-workers.
     
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