Surprise Coming Next Week!!! Monoprice Monolith THX AAA 887

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Re: Surprise Coming Next Week!!! Monoprice Monolith THX AAA 887
« Reply #20 on: 1 Dec 2019, 12:07 pm »
You made me smile this morning, up early listening with the new is good, quiet time here....great for listening, raining in Raleigh NC!

There is another person that is building Tom's DIY kit...should be neat as well..

I see Tom has a delay due to the case manufacturer?

« Last Edit: 1 Dec 2019, 06:19 pm by adydula »


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Re: Surprise Coming Next Week!!!
« Reply #21 on: 1 Dec 2019, 12:30 pm »
Well the surprise is out...and I am very happy that my wonderful wife got me this new amp for Christmas!!

Of course I had to open the box when it arrived today to make sure it was functional and I didnt have to return it for any possible defect. So far I have checked all the inputs and outputs for function. They all seem to work as designed, including the balanced and se jacks.

So why did I decide to get this particular amp, JohnR, one of the circles admins, started a thread about the THX AAA amps, and I really have not kept up with all the new technology out there, so as I was reading what Schitt has done to help solve the Class AB crossover distortion with their continuity implementation in the new ASGARD 3 and other amps, I learned that THX was working on this issue as well but with higher power speaker amps.

I watched and listened to a video with Laurie Fincham, who is Vice President of Audio Research at THX. He describes a 9 year process that led to this new THX AAA or Achromatic Audio Amplifier. In the video the focus is on the work of THX with Benchmark and the development of the Benchmark AHB2. The neat thing about this gentleman to me is he is an audiophile, engineer, music lover and a musician. So the background is he speaks to the Class A amp classification as "big, expensive, beautiful , but hot"....this again was focused on large 2 channel amps, but the parallels are there for Class A headphone amps. There are a few Class A amps that you can almost fry an egg on!! (can you say Asgard 1).

So they didnt invent or re-invent the amplifier but as he states, they looked at the shortcomings, the physics, and developed a technology to deal with these. They have been working on this since 2006. The result is an amplifier that stays within a fraction of its low distortion right up to 1db of its full output. Distortion in the Benchark amp was about 100x lower than was seen with existing amps and the S/N ratio is much higher. Another interesting part was for them to measure this new technology it turned out to be very difficult, and they only felt they had the correct or accurate result when at least three engineers using three different sets of measuring equipment "got the same answers"....

So they claim this technology provides a "clear window to the music". The aim of keeping the signal clear and pure was the inspiration for the new technology, AAA or Achromatic Audio Amplifier". Achromatic means "without color". The proverbial straight wire with gain.

For more info on this you can Google THX and Laurie Finchman and oh by the way he played the string bass in a band for 17 years.

So this is the reason I bought this amp, its a technology leader and has some of the best measurements ever to date. The techie in me had to listen with this new amp and its technology for myself.

So how does this technology stack up for us headphone word:  "EXCEPTIONAL".

I have had only six+ hours with the amp, and it doesnt take me long to know this is a really special amp. The magic in short is THX measures the distortion as the signal crosses the Class AB + to "0" to - swings....and inverts this and re-injects it to cancel this crossover distortion..voila distortion gone (or negated). But there is more to this than just always, great design and layout, power supply, low noise intergrated circuits or op the 9 year adventure evolved the quality of ICs and IC's designed and produced specifically for headphone audio amps appeared.

The sum of all these parts can make or break anypiece of gear and make it a stellar device or just another run of the mill device with all sorts of claims of audio nirvana.

New gear"itis" is always an issue, so I want to really be sure I am hearing what I think I I brought over some friends and my most severe critic my wonderful "wife"....going back and forth eveyone liked the immediate "clarity" of the amp...comments like "gosh those guitars sound so clear, that drum sounds so much like a real drum...her voice is magnificant", "hand c;aps that sound like a human being made them"...and most of these folks were not audiophiles and think I am abit strange with all my audio stuff!! I did some blind AB switching and asked everyone which one is "better" to them and why, and then which one was more clear....all but one picked out the THX amp over the other (won't mention this one ...but its a favorite here)...

So my first impression is this amp is so dark, or silence, you dont know its on, across all three gain settings with the volume turned up all the way. Its a brutally honest amp, it lets you hear how good or bad your source is, its all can easily discern music quality, compression etc...the often over used "garbage in garbage out" is here in spades! (in my second listening session, hour 7 I am up at o'dark thirty when the ambient noise is very low....I do detect a very slight hiss at high gain with 55 ohm Clears at the extreme position of the volume what I call never, never land...the your going to ruin your hearing land).

If your into specs well, they are indeed very, very good. You can take a look at the monoprice site or the charts I posted below. These will make the measurebators out there grin from ear to ear....I might note there are (2) versions of this amp, one from and this one from Monoprice. $399.

The battle for specs never seems to end, how low can you go and for what price (note the recent Schitt Magni Hersey $99 op amps). Well Monoprice went and outdid the Drop version by a small amount but enough for bragging rights!! :>) At least with the Monoprice they were available and didnt have to wait for the Drop etc...The folks at Monoprice indicate they looked at the competition and changed out many resistors, op amps to the 888 level and a few other things to glean a 2db advantage over the Drop version)..I know "crazy" but I like it....   :>)

Power, oh gosh, more than enough!! 16 ohms: 8800mw, 32 ohms: 6000 mw, 300 ohms: 700 mw...balanced. Less for SE. I used both no issue at all for low to high impedance T1's. Is there a difference between the two, to me not much if anything.

The unit has a soft on/off switch, no mechannical click, it starts a on/off sequence and the power led shines red then green then white. There is a mechanical push button switch for selecting balanced or SE inputs, so if you have a balanced dac your good to go. Three position gain switch, .66x, 2.0x, and 6.6x. 1 for IEM's, 2 for most headphones, 3 for those really hard to drive cans. The output impedance is less than 0.05 ohms! The freqyency response is ruler flat...really flat...crosstalk -127db at 300 ohms! This is the world of a distortionless amplifier....or so dang close its not funny...spectacular engineering IMO.

Absolutely no audible clicks or pops turning the amp on and off with the headphones plugged in. Headphone jacks are XLR 4 pin, standard 1/4 SE phone jack and the smaller 3.5mm SE. Very nice.

It weighs about 3.5 lbs, runs cool, hard to tell its on...class AB....there is a switch on the back that is a byass function or a switch that aftere 2 hours without an input signal the amp turns off, the bypass is there if you want to leave the amp on all the time etc. Build quality is good, the only small issue I have is the volume pot is small and I am wondering how well it will last over time, but the warranty from Monoprice is "3" years....with my useage I will find out within a years time. The low end tracking on this unit is spot on, listening this morning at low levels I can not detect any mis-tracking at low volume levels. I have had to replace a few pots in my DIY stuff over the years for scratchy and mistracking, my ODA and BH Crack. Low level listening is very nice as well.

So more on how does it "sound" or "not sound". I am trying not to be over-hyped but this unit is really that good...its a blanking really good amplifier, it "draws power to amplify the music signal without imparting any coloration or distortion"...this is a big claim, but it is the closest I have ever heard to this goal. Its alot like other experiences with other dont want to stop listening...but this is a new higher level. I would say this amp removes the "veil" once allows your headphones to really shine according to their design. What do I mean by Focal Clears I really love, now they shine even that they are producing what the recording has in it and to the best capability of the headphone. Its like hey I just got a new set of Beyer T1s' and HD600's never sounded so good. Live performances like Tom Petty and the Heartbreakers, The Live Anthology, Eva Cassidys, Live at Blues Alley, Sarah McLachlin, Fumbling Towards Ecasty, you can tell what the audience is doing, their reactions, just marvelous. The black background allow you to hear the drum swish's often overlooked or lost in a lesser amp. Patricia Barber has really well recorded and mastered stuff where she speaks and in between her diction you clearly hear the background instruments playing very subtley...and the room re-verberations. On early Beatles recordings its like your in the room with the "Boys"! Coupled with the Focal Clears its the best I have ever experienced and thats saying alot!!

This amp just makes everything else better for me.

At first one might think this amp is too thin, or bright, with no real weight, but as you play several tunes, you realize the tunes your playing are not perfect and vary all over the place, and the coloration of other amps does change the sound and the experience....this amp is brutally honest. Its ability to let small micro-dynamics thru is uncanny...Chet Atkins, Picks on the Beatles, "Shes a Woman" is a superb example of this....3 dimensional and the really in the background sounds are articulated well...

Some will love it and others will not...thats ok....this is about as far away from a soft tube amp as you can get. We can discuss that specs are important or not, do they make this amp as good as it sounds?? I honestly dont know, all I do know is as I listen to the music I am smiling alot...and this is good!

So what I am going to do is to start a comparison rotation and see how that goes...I also want to try out several dacs, for the first time I have an amp that will not get in the way and allow me to more objectively hear what the other pieces in the chain are doing or performing.

Right at this stage with now 6 hours of play, would I buy this again: Answer: YES.

Smiling again

« Last Edit: 1 Dec 2019, 04:10 pm by adydula »


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Re: Surprise Coming Next Week!!!
« Reply #22 on: 1 Dec 2019, 12:34 pm »
Specs from Monoprice:

Discussion with THX designer:

This if from the THX site, the OPA 1688 I have used in several portable headphone amp designs...excellent op well as the OPA1622.



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Re: Surprise Coming Next Week!!!
« Reply #23 on: 1 Dec 2019, 04:33 pm »

Great review. I think part of your enthusiasm is that you have never heard an amp at these distortion levels. A lot of us Neurochrome builders and Benchmark/NCore/Orchard Audio/etc... owners have and are kind of used to it (in the loudspeaker world). We expect it. The Neurochrome HP-1 (discontinued) was somewhat the progenitor of this in headphone design and my colleague in the RTP area has one which he listens to everyday. What will be interesting is a shoot out between Tom's new budget kit, the Neurochrome HP-2 (which will be arriving to me in a few weeks), the original fully differential Neurochrome HP-1, and of course the Mass Drop/Monolith THX headphone amps. That should be an interesting comparison which we can probably arrange, since we live close to one another. I don't think there will be dramatic subjective differences at these distortion levels to be honest. But if we were to switch back and compare to any of your Bottlehead builds or Hagerman's recent unit, or Noir/T2, I think the differences will come back to being STARK! Whether that is subjectively better or worse is up to the listener.

Mind you, your achilles heel, or what is holding you back now, is your source or DAC. You cannot get any more detail, "downward" dynamic range, etc... than what your dac can deliver. So I'll haul over my dac too for the comparison which should be fun times.

Happy Holidays! And enjoy your new present!



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Re: Surprise Coming Next Week!!!
« Reply #24 on: 1 Dec 2019, 04:51 pm »
I would really like to compare to Schitts Asgard 3 as has a unique Class AB solution implemented for the crossover distortion, yeah the numbers may not be as good....but still I am

The Dac I have is the original Schitt Bifrost MB with their yet unreleased Unison USB interface, I have a beta board from very well.

As far as a dac upgrade I have thought of that, and have an ODAC and a HRT technologies Asynchronous MSII+ that I have used, and my ears prefers the Schitt MB.

But I am willing to try anything....but it has to really make a difference for me to spend the bucks...

The THX AAA 887 for $399 IMO is a very good price for this kind of performance!

So lets shoot for some time in early 2020 when you get your stuff built, I have a very good possibility of getting a loaner from another member here in this timeframe.
It would be neat to have Toms's DIY and retail version of his stuff to compare to the THX AAA amp...

Need to get thru December and the maybe in mid Jan or early Feb?

You can PM me later etc..



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Re: Surprise Coming Next Week!!! Monoprice Monolith THX AAA 887
« Reply #25 on: 2 Dec 2019, 02:01 pm »
Ok so this morning I put up the Focal Clears, T1's and HD 600's...and plugged in the Audio Technica MSR7's that Tyll H at Innerfidelity really liked a few years ago and
went on his wall of fame.....the ones with this new "Hi-Res" moniker!!

I have had them for a few years and have worn the headband simulated leather but they still work well....

At 35 ohms, these are the lowest impedance headphones I have at present.

For lower impedance cans the gain position is set to 1 as recommended and there is no hiss at full volume....

On gain position 2 I hear a very slight hiss or noise when i rotate to volume position 2 pm and it stays the same until full volume at approx 5pm.
In gain position for use with the 300 ohm and higher stuff....I hear this hiss at 12 midnight ...

So its important to match your headphones to the proper gain level for the best experience....that said I cant even go there in normal listeing because at
these extreme volumes hearing damage could occur.

So the claim for "Dead silent" made above is tied to the proper gain setting.

That said, the MSR7's are the first set of headphones I prefer less than the others so far...Why?

I said this amp is "brutal" and very unforgiving for less than stellar source and or headphones downstream...

The tone and freq response characteristics of these MSR7's add up to a very sharp overall presentation IMO....on the high end especially.

Its not that its sibiliant, but really, really "crisp"....and not so well recorded, mic's or mastered stuff is hard to listen to....

But with really good stuff its great...go figure...

Now what I did hear this morning suprised me several time, listening to Rachael Yamagata's Happenstance, and "God Rest Ye Merry Gentlemen" I kept thinking my chair started to develop
a squeaking sound!! Turns out it was the chair Rachael Yamagata was sitting in as she played, rocking back and forth!!! OMG..ha!! I have listened to this many times and now I hear this
for the first time....

Listening to Chris Rea's Still So Far to Go, "You Can Go Your Own Way", the combination shines very nicely....good stuff in good stuff out....

Ah the magic thats done in the recording studio!!

Good Morning!

Update: As I sit here with these cans and listening to some really nice stuff....the thought came to me that when you are close to an actual instrument and experience the
actual brutal strike of a snare drum or close to a guitar amplifier, its a very loud experience....well not an acoustic guitar...but this is what its like at times with these cans.


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Re: Surprise Coming Next Week!!! Monoprice Monolith THX AAA 887
« Reply #26 on: 2 Dec 2019, 07:42 pm »
80 ohm Beyer DT1350's no hiss or noise on gain 1 or gain 2, slight hiss at 2pm on gain 3...


Jon L

Re: Surprise Coming Next Week!!! Monoprice Monolith THX AAA 887
« Reply #27 on: 6 Dec 2019, 10:15 pm »
Received the cheapest THX tech headphone amp, SMSL SP200, $260-280.
Already sounding mighty good driving Senn HD600/ALO cable  :thumb:

SMSLsp200 by drjlo2, on Flickr


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Re: Surprise Coming Next Week!!! Monoprice Monolith THX AAA 887
« Reply #28 on: 6 Dec 2019, 11:53 pm »
Hello Jon L,

Nice looking piece of gear...very interesting design approach compared to the other two variants....

The toggle switches for gain, you have a high or low, and on the other two there are three positions, 1, 2, 3.

I assume the XLR / RCA switch looks like it selects one or the other? While the other two have three output jacks, xlr, 1/4 and 3.5mm.

The other functional addition on the Drop and Monoprice are the addition of a rear 2 hr / bypass switch that allows the powering down after 2 hours or not.

The other noticeable difference is in the Monolith variant they used the "888" op amps (5 in total) to help get the extra 2db margin of performance as well as upgrading 50+ resitors and caps.

Yeah I know its crazy but its what folks do for bragging rights.

Warranty is three years for the Monolith, only 12 months for the SMSL.
(this is the one that I really like, 3 yrs).

6 watts vs 3 watts @ 32 ohms...

But the price is $400 vs $270.

That said I would think they must sound close?

Please post more listening as you use it and have you compared to your existing amp?




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Re: Surprise Coming Next Week!!! Monoprice Monolith THX AAA 887
« Reply #29 on: 12 Dec 2019, 06:38 pm »
Well I just went thru an excercise I didnt want to to....

I seny my Monoprice THX AAA 887 back to Monoprice..

Why...there was a hiss I could hear at high volume levels (music player paused) using low impedance headphpones in gain
position 2/3.

It was noticeable when the volume pot was at 2pm and higher....way out of the normal listening level I might add.

So why would I return this wonderful amp?

After a few converstations via email to a THX person for Monoprice we decided to swap out or replace it with another "new" unit to be sure
this unit was not defective in anyway...

Well the replacement arrived in a few days from Monoprice, which I have to say their customer service was questions lets just replace the unit.

So after a few days now with the other unit, I have concluded there was nothing wrong with the first unit!! #^&^&)(&*&% Yup, anal retentive side....kicked in.

But I wanted to be sure and  now know that this is a trait of this amp...if you properly match the impedance to the proper gain all is well inaudible, no hiss...

This only happens using low impedance 55 - 80 ohm cans typically on Gain 2/3...but I never go past 12 pm with these cans, so no real issue.

This was confirmed from my contact in THX land.

So the good news the second unit is performing very well....same great overall performance...almost a perfect straight wire with gain...

Listening last night I kept taking off the cans (Clears) because I was hearing a thumping sound, only to learn it was the sound of the bass pedal striking the bass drum
softly....OMG good detail retrieval....I have listened to this song many times and for the first time I was really made aware at the resolution the combination of this amp and the
Schitt Bifrost MB provides!

I went back to the Magni3 and the sound is there, just not as discernable....again amazing..


Jon L

Re: Surprise Coming Next Week!!! Monoprice Monolith THX AAA 887
« Reply #30 on: 12 Dec 2019, 07:48 pm »
These THX units defy price:performance ratio.  Talking about bass, Abyss 1266 Phi TC planars powered by SMSL SP200 THX amp produces probably the most defined, impactful, extended, and violent bass I have ever heard in headphone land  :eyebrows:

AbyssSMSL by drjlo2, on Flickr