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. svperstar

    svperstar Acquaintance

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    Sorry people took the time to reply to me so I answered back.

    That appears to be the common wisdom. I am pairing it with the Audeze LCD-2 luckily and not the HD800
     
  2. penguins

    penguins Friend, formerly known as fp627

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    I've also been able to do some limited tube rolling now (see Ice-man's posts #292 and 293 as well). Long story short, I agree with his posts and feel that tube rolling makes a pretty noticeable difference with this amp.

    EH 6922 (stock, new mfg) - ~30 hours burn in, mids felt a little to moderately bloated depending on the music. slightly warm tilt. OK in most other aspects; no glaring faults or strong positive points.

    Genalex Gold Lion 6922 (new mfg, from upscale audio) - only ~15 hours of burn in but so far I don't like these - can't place my finger on it, but these have an unnatural sound//everything sounds slightly artificial. Mids are present but missing body and some instruments almost sound out of tune (this won't with other tubes here). The soundstage feels a little smaller and more forward than stock EH although this smaller soundstage is also more clear than the stock EH. Hopefully more white + pink noise burn-in resolves some of the above as I understand some new production tubes need 50-100 hours before they start to sound good.

    Amperex Bugle Boy E88CC (advertised as and appear to be NOS, from vivatubes) - ~15 hours burn in. IMO these don't do anything for (or against) the lows and mids, but are amazing with treble. Found myself continuously turning up volume on sections I wanted more bass/mids but they never came. Very airy upper end without messing up balance or making music too sibilant, fatiguing, etc. Neutral (not forward or withdrawn) presentation. Clear/transparent throughout and opens up the sound stage the most as well. Oddly - it almost feels like these tubes are projecting a sound on top of another sound - much like superimposing what should be the same image on top of the original image (maybe this makes no sense, but it's the only way I can think of the impressions/feeling I get with these tubes). Easily my favorite of all 5 so far for treble heavy/oriented music. Probably won't use these often though, will come out when I want to listen to treble heavy music for a while.

    Telefunken E88CC (advertised as and appear to be NOS, from vivatubes) - ~25 hours burn in. Does well across entire FR, very smooth, more forward/not as laid back sound signature but the sound stage is bigger. Iceman's post matches some of my other thoughts, especially hearing all of the color/reverb when guitar strings are strummed (or the color in other string instruments). Added a little extra slam to the bass vs above (without adding more bass). However, and this is not a + or - for my own preference, overall, LP + these tubes have a "polite" sound. It doesn't feel as "colored" as most other tubes on this amp - like they don't bring as much of their "own personality". I don't feel this way about the LP with the other tubes nor Telefunken E88CC with other amps. Favorite overall.

    Matsushita (advertised as and appear to be NOS, from upscale audio) - No burn in yet, only ~2hrs listening so far. Clear throughout with tighter bass than the above but some of the low bass seems slightly rolled off - may just need burn in though. Slightly sibilant and shouty(?) to where I probably won't be using these with my Focal Clears which are also a little sibilant to me already with most gear. Will use these tubes in other gear to see if this sibilance goes away.

    Edit: Grammar
     
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    Last edited: Dec 8, 2018
  3. Biodegraded

    Biodegraded Friend

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    Matsushita 7DJ8 (purported NOS from Vivatubes, I think the same as the ones from Upscale) in MCTH seemed too warm after 1 day but pretty nice after 2. I didn't hear the sibilance & shout you mention (with Modi Multibit & HD6XX though).

    It won't displace the Telefunken ECC88 (#1) or A-frame Amperex (#2) for me, but it might get some more listening. Suggest you give yours a bit more time.
     
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  4. penguins

    penguins Friend, formerly known as fp627

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    After burning in the Matsushitas for about 55 total hours, the shouty sound is ~90% gone. Unfortunately the sibilance is still there but about 1/2 of what it was before (which wasn't too much to begin with). Low bass is still a bit rolled off unfortunately.

    Edit: Gold Lions are also a bit better after about 40 hours of burn in. Artificial sound is ~60% gone. Mids have more body now, but not hugely so - this issue is maybe 30% fixed vs before, but not resolved by any means. Good thing is sound signature is retained, i.e. the mids are not 30% more. Rest of my comments still stand. Not as good as vintage tubes (NOS or in otherwise good working condition) in a similar price range but given the improvement in 40 hours I'm hoping these will continue to get better.

    Overall, I agree with Biodegraded, these aren't as "good" as Telefunkens for me, but for a set of readily available matched NOS tubes under $100 where you don't have to worry about fakes, people passing off crappy tubes, etc. I would still consider these.

    Anyways, point of all of this feedback with tubes - this is the first amp where I wanted to "try more" tubes after a 3rd set. If 6922 tubes weren't so relatively expensive I'd probably get another 2-3 ($350-450) sets for experimenting.
     
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    Last edited: Dec 21, 2018
  5. Aeron

    Aeron Facebook Friend

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    My LP, with stock tubes, @36 hours of continuous music is fantastic. Listening to Monk’s Dreams, with the Vinshine R2R>LP>Abyss 1266. Tone is quite good and continues to improve over my last listen at 16 hours.

    Experienced something new, on the track Ba-lu, Bolivar, not only can you hear the reed, I felt it, vibrating my dumbo ears!
     
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  6. songmic

    songmic Gear cycler East Asia edition

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    [​IMG]

    After being stuck in customs purgatory for 2 weeks, the Liquid Platinum finally found its way home just in time for Xmas. As the Monoprice website doesn't seem to ship overseas directly, this would not have been possible had it not been for @Cspirou's generous help. Thanks Gaël!

    I've only listened to the amp for a couple days, so these are my initial impressions. They are subject to change if prolonged burn-in makes a noticeable difference. Since I heard reports that LP is more responsive to tube-rolling than CTH, I swapped the stock EH tubes with Amperex 6922 PQ, which are my personal favorite 6922 tubes (smoother than their European, specifically Telefunken, counterparts). I didn't bother fiddling with 3rd-party LPS and used the stock SMPS. DAC was Yggdrasil A2 and headphone was Code-X.

    To provide some context, the Code-X is my reference planar headphone, and from my experience, seems to have a special synergy with Cavalli amps in general. The LG/Code-X remains the best planar system I've heard to date, and the CTH also boasted terrific performance with a sound signature similar to that of LG for a measly fraction of the price. So it goes without saying that I had high expectations for the LP, which is a supposedly balanced version of the LC (which I never had the pleasure of hearing, unfortunately). Although I know it's not very important in the grand scheme of things, the OCD side of me always have had a soft spot for fully balanced gears, since they take advantage of Yggdrasil's superior balanced outputs.

    LP vs CTH:

    The LP is clearer, faster, and more resolving than the CTH. Rather surprisingly, I expected the LP to outperform CTH in soundstage, but they were close and neither could touch the LG in this regard. As for tonality... I've read some people claiming the LP to have a smoother, more laid-back presentation than the CTH, but I actually thought the opposite is true. Although I've never heard the LC, I remember @purr1n saying that it is more exciting than the LG. Personally, I thought the LG and Code-X's tonal balance to be perfect (with the right tubes, of course), and since the LP shared the LC's DNA, I also found it to be a bit brighter and more aggressive for the Code-X. A darker headphone might yield different results, but for the Code-X, I honestly preferred the CTH's politer and wetter tonal presentation. Of course, YMMV.

    LP vs LG:

    I don't have the LG for a direct A/B comparison against LP right now, but if memory serves, the LG outperforms the LP in almost every aspect conceivable. Not really surprising, given the x4 difference in price. The gap in resolution might not be significant, but the LG throws a much deeper and more holographic stage. End-game performance, especially with the Tung-Sol BGRP. Though I haven't tried any other 6922 tubes than Amperex, I don't think any tube rolling from here would change my opinion since the Amperex are pretty much my holy grail of smooth sounding 6922. Even with these tubes the LP already sounds more aggressive than I had hoped for. If the LP has any redeeming value against the LG, it's that it's a lot quieter in balanced operation, while the inherently single-ended LG suffered from ground loop hums at higher volumes. Also, for people who enjoy a more exciting presentation, they might prefer the LP's tonality.

    LP/Code-X vs Carbon/SR-007A (port mod):

    Not a fair comparison at all, but I had both at hand so why the hell not. Again, considering the huge price gap, there was no competition at all. The stat system utterly destroyed the planar system. In resolution, soundstage width/depth, and even bass which is supposed to be one of planar headphones' typical strengths. But then again, I didn't buy the LP so I could listen to both at once, it was intended to be a secondary desktop system at the workplace while the Carbon/SR-007A remains my reference home system.

    At any rate, I'll need to look for a separate DAC to move the LP/Code-X to my work. Although Yggdrasil is usually the be-all or end-all of DAC's, I found the Yggdrasil/LP/Code-X to be a bit bright for my tastes, so maybe a warmer R2R DAC or even a NOS DAC might be the ticket. The Denafrips Ares fits the bill here without breaking the bank, so I'll start from there.
     
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    Last edited: Dec 26, 2018
  7. purr1n

    purr1n Building Magnis part time because it's peaceful.

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    You'll come back to traditional dynamic headphones and SET amplification in a year or two.

    In the meantime, when Aegir comes out, might be worth trying that out with the HE-5.
     
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  8. songmic

    songmic Gear cycler East Asia edition

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    Ha! Maybe I'll start bitching about wanting moar bass from my stats in less than a year. My custom title says it all.

    There is no denying Studio T + HD650M is my favorite headfi system of all time.
     
  9. nickwin

    nickwin Acquaintance

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    I just noticed I got two different looking tubes with my Liquid Platinum, is this normal? The first thing I noticed was one was glowing much brighter than the other, but then I noticed they have different shaped plates also (one is kind of round and the other is star shaped).

    @songmic


    https://send.firefox.com/download/c38116f923/#TrLLBvvMtETrFYUBRFrjeg

    Im on the phone with Monoprice support right now and they are saying both tubes should have "star shaped" plates.
     
    Last edited: Dec 26, 2018
  10. jexby

    jexby Posole Prince

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    1. I have been sitting at the table of dynamic cans + SET and can't seem to give it up.
    2. Aegir could deliver amazeballs to vintage Hifiman cans. @zerodeefex loans me his code-X sometime in 2019 to confirm this theory. ;)
     
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  11. songmic

    songmic Gear cycler East Asia edition

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    Normally I wouldn't worry to much about differences in tube brightness, but if they have different shaped plates or getters inside, it could imply that they are of different builds. It would be helpful if you could provide a photo showing the difference.

    However, even if they look different, they could measure as a matched pair. If you swap the channels and don't hear an audible difference, you should probably be fine.
     
  12. purr1n

    purr1n Building Magnis part time because it's peaceful.

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    Either @brencho or @E_Schaaf has the unofficial SBAF Marvey HE-5 Code-X wannabe edition for less than the price of the HE-5 reissue. You get first dibs on it. @brencho mentioned it secretly somewhere, but no one bit or saw it. (I wasn't aware but @brencho already made the sale). The downside is if the headphone ever needs service, you might get back an HE-X instead from HFM.
     
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    Last edited: Dec 26, 2018
  13. purr1n

    purr1n Building Magnis part time because it's peaceful.

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    haha.jpg

    Sorry, this is Monoprice right?

    It's not normal because different type tubes (or very differently aged tubes of the same type) will have different distortion and subjective sound characteristics. At least the tubes work.
     
  14. nickwin

    nickwin Acquaintance

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    @purr1n, thanks for the info. I figured that was the case but I just wanted to make sure. The first person I talked to at monoprice said I had to deal with eBay for product/tech support since the item was purchased through eBay (sold by Monoprice official ebay account). I can't imagine that's correct though. I can see it for returns, but tech support?
     
    Last edited: Dec 26, 2018
  15. purr1n

    purr1n Building Magnis part time because it's peaceful.

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    Oh geez. I am imagining a Chinese granma: What you complain? It all same. It work. Go away

    I'm really good at imitating my mom. One day, I'll tell you guys about the "pie / pine" incident which got my American wife into deep doo-doo with my mom.
     
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  16. nickwin

    nickwin Acquaintance

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    @purr1n, hahaha that was pretty much the case. Took 3 calls but they are going to stand behind it and will replace the tubes. As far as I can gather Monoprice will provide tech support directly (assuming you get a good agent) for sales through eBay but they require all return/exchange requests to go through eBay. That makes sense... The first person I talked to said I had to deal with eBay for any/all support, which is very different than dealing with Monoprice through eBay.

    I was planning on spending some time with the stock tubes first, but I guess Ill be swapping in my Amperex PQs right away. Hopefully its a good match. Initial impression with the stock tubes, Modi Multibit and he500s is pretty good.
     
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    Last edited: Dec 26, 2018
  17. dBel84

    dBel84 Friend

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    Platinum should be shipping with stock JJ tubes.

    I wonder if someone messed up and sent you NOS tubes.

    The brightness variance is not a big deal and quite normal (and common) in vintage tubes.

    .. dB
     
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  18. HotRatSalad

    HotRatSalad Friend

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    Did you get JJ's with yours ? It's listed as non gold pin EH tubes which is what I got. Just curious if monoprice is sending with different tubes. Alex has mentioned JJ's have quality issues and prefers EH and Genelex. I actually enjoy the JJ golds in the platinum and haven't had any issue.
     
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  19. dBel84

    dBel84 Friend

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    No, I was going off early discussion with Alex. They must have switched to EH. Either way, modern production 6922.

    The Genelex Gold Lion tubes are some of the best modern production tubes.

    ..dB
     
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  20. aamefford

    aamefford Nothing like chamberpot coffee

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    I concur from the little bit of 6dj8 variant rolling I’ve done.
     

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