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Massdrop 789 vs. Monoprice 887 vs. SMSL SP200: THX amp measurement comparison

Celty

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#63

Celty

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#65
Jesus ****ing christ this is amazing.

Thanks to all who helped guide me here! And sorry for cluttering up this thread with my questions / build update.
No need to be sorry, sharing here is what the forum is for :)
 

Inkey31

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#66
I believe MediumRare was asking for a comparison of the headphone amp section of the DX7 Pro (not the DX7s) vs. the Monoprice 887. Both are top performers from a measurement perspective, although as Amir says in his conclusion about the DX7 Pro: "The headphone is a step below state-of-the-art from measurement point of view." The upside is you also get the DAC with the DX7 Pro. Perhaps the major knock against DX7 Pro (depending on your headphones) is the somewhat high output impedance of the 1/4 jack at 6.2 Ω.



Up to you, but my advice is don't hold your breath. That's the point of doing this type of comparison: the measurements show these are both SOTA headphone amps. In a blind level-matched A/B test the highly likely outcome is that it would be impossible for you to tell the difference. So considering the prices are the same between the two you can decide on features, warranty, customer service, etc.
Sorry, I misunderstood, thank you.
 
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#67
Hello everyone,
I bought the SMSL SP200 a week ago and noticed a hissing sound. In that forum, there are few others who have similar experiences. I was contemplating buying the Monoprice amp, when I came across this review at Amazon:

"The THX amps are ok, they're clean, as advertised, but they suffer pretty badly from compression, this is something very few people are willing to talk about, or just don't realize. By compression I mean the dynamics are heavily lacking, this is generally a problem with headphones, but amps should not be contributing, and the SMSL THX 888 has this problem quite a bit worse than the THX 788 and 887 from monoprice..."

I tried googling for THX compression but could not find any. So my question is what is THX compression, and is it going to be a problem when using HD 660S with the Monoprice amp for movies and music? Also if anyone can confirm that the hissing problem does not exist with the Monoprice's (or the Drop's) amp, that would be great
 

Celty

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#68

Veri

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#69
Hello everyone,
I bought the SMSL SP200 a week ago and noticed a hissing sound. In that forum, there are few others who have similar experiences. I was contemplating buying the Monoprice amp, when I came across this review at Amazon:

"The THX amps are ok, they're clean, as advertised, but they suffer pretty badly from compression, this is something very few people are willing to talk about, or just don't realize. By compression I mean the dynamics are heavily lacking, this is generally a problem with headphones, but amps should not be contributing, and the SMSL THX 888 has this problem quite a bit worse than the THX 788 and 887 from monoprice..."

I tried googling for THX compression but could not find any. So my question is what is THX compression, and is it going to be a problem when using HD 660S with the Monoprice amp for movies and music? Also if anyone can confirm that the hissing problem does not exist with the Monoprice's (or the Drop's) amp, that would be great
That review is utter bullshit. It's probably posted to promote other (non- THX) products ....

I can confirm both drop and monoprice amps are less prone to the hissing, it's only the SP200 that is so sensitive to this.
 

JohnYang1997

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#70
That review is utter bullshit. It's probably posted to promote other (non- THX) products ....

I can confirm both drop and monoprice amps are less prone to the hissing, it's only the SP200 that is so sensitive to this.
We just made measurements with sp200 as well. It's prone to the issue because the low gain option is 6db. There is no 0db or -10db option. There can be noise from the mains that got coupled into the amplifier. Also these designs are really supposed to run with balanced input. The 789 has horrible mains hum(in high performance standard) with rca input. The smps is part of the issue. The leakage current is always too high that there must be a path to short out the secondary side.
Due to the high resistor values, smps, and higher gain(for sp200) the noise is actually much higher than some other designs. Oh most importantly high gain is whopping 18db..... almost as much as the power amplifier I'm designing. So what we see on ASR is sometimes a snapshot or just one angle, a lot more are hidden or not brought to the surface.
 

Celty

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#71
Well as far as the 887 goes, I listen to it with all my headphones, and use it daily at various volumes with a variety of sources and I have never run into any hiss at all. The background is dead silent.
 
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#72
Well as far as the 887 goes, I listen to it with all my headphones, and use it daily at various volumes with a variety of sources and I have never run into any hiss at all. The background is dead silent.
This is really helpful. What headphones are you using?
 

Celty

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#73

phoenixdogfan

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#75
" ... but things have kind of changed for me." Well, it's not just you; the market has changed. The Monoprice THX 887 and the SMSL SP200 are new entrants to the market, both use THX technology, and both are in the same price range as the Drop THX 789. Having 3 units like this wasn't a thing a year ago. And what you mention in your post is sort of the point of why I put Amir's measurements side-by-side. I wanted to show how closely these products measure against each other, and other than receiving a defective unit there wouldn't be any audible difference between any of them. All three are SOTA headphone amps. Which means that potential buyers should focus on:
  • output impedance (depending on what headphones you're driving)
  • output power
  • features (e.g., 2 gain settings vs. 3 gain settings, XLR headphone out, etc.)
  • price (although all three are very close in price)
  • build quality / warranty / customer service
  • aesthetics
So while we're not at the limit of what can be engineered, you're right: we're at or getting very close to the limit of what matters in terms of human hearing. You can buy and be happy! You don't have to worry about upgrade-itus every 2 years or so.

For me personally I hope that the continued engineering advances result in a few products that have the same basic form factor, same ballpark price range (higher, but not significantly higher), and same performance but as stereo / power amps -- for low power desktop speakers, not HT -- instead of headphone amps.
Having purchased the Massdrop (I refuse to call it "Drop") 789 before either of the other two units came out, and finding it entirely adequate to power my LCD X and HD800, I don't see myself replacing it in the forseeable future, if ever.
 

JohnYang1997

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#77
@amirm The Drop THX 789 was tested at 5,8V level and Monolith THX 887 was tested at 4V. Does this make a difference in the results?
Yes. It does. APx555 tend to change step around 5.3V. Meaning the 5.3V before changing to a higher step will give best noise performance. 5.4 (or 5.5) is going to give much worse noise performance. 4V should be give better measurements than 5.8V.
 
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#78
Hello everyone,
I bought the SMSL SP200 a week ago and noticed a hissing sound. In that forum, there are few others who have similar experiences. I was contemplating buying the Monoprice amp, when I came across this review at Amazon:

"The THX amps are ok, they're clean, as advertised, but they suffer pretty badly from compression, this is something very few people are willing to talk about, or just don't realize. By compression I mean the dynamics are heavily lacking, this is generally a problem with headphones, but amps should not be contributing, and the SMSL THX 888 has this problem quite a bit worse than the THX 788 and 887 from monoprice..."

I tried googling for THX compression but could not find any. So my question is what is THX compression, and is it going to be a problem when using HD 660S with the Monoprice amp for movies and music? Also if anyone can confirm that the hissing problem does not exist with the Monoprice's (or the Drop's) amp, that would be great
Hi! I have The SP200 too and I think your problem is your dac or dac drivers, the SP200 only amplificate the sound that recive of the the dac without any coloration, if your dac is harsh/compressed the problem it's in the dac or dac drivers, I recommend using the original drivers (better in windows).
I have Topping NX4 for dac (I use the line out without any amplification) and in android(UAPP app) the SQ it's much compressed and harsh but in windows 10 with the original drivers of the NX4 the SQ is smooth and without harsh.
 
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#79
Yes. It does. APx555 tend to change step around 5.3V. Meaning the 5.3V before changing to a higher step will give best noise performance. 5.4 is going to give much worse noise performance. 4V should be give better measurements than 5.8V.
How much worse would that be?
 

JohnYang1997

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#80
How much worse would that be?
Difference can as big as 0.00006% vs 0.00013%. In this case, there's chance that the noise of the devices is comparable of that of AP's so it's at a pretty critical level where it can make a difference. However you should refer to the distortion vs level graph in which you can calculate the noise as well as read if the distortion is rising with power output. Dashboard is just one measurement which can tell you something but there's a reason that there are many more graphs.
 
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