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

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#81
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. ...... high gain is whopping 18db.....
Thanks for posting this. I currently have an sp200, a JDS atom, and two versions of the O2. Sonically, (with single-ended output) the sp200 is by far my favorite, having significantly more LF fullness / solidity than the Atom, but the headroom is a nightmare. I'm feeding these from a pro computer audio system, so a balanced signla at a nominal +4 Dbu level, and driving various type of cans. But even if I drop the level to below 0 dbu, the high gain setting just folds. Massive compression & distortion. With my 600 Beyers, (my personal favorite for recording) there is simply no way to get enough clean volume, no matter how I tweak. With any other, from 32 ohm to 250 ohm, I can get good results, but only if I constantly tweak the balance between inout level and gain setting. It's bloody awful.

Great sounding amp, though.
If someone could come up with a detailed resistor swap, that would be heavenly. That is beyond my abilities, esp without a circuit diagram.
I've tried talking to the USA seller, but of course no response at all.
 
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#82
I'm also very curious if anyone has done sonic testing with sp200 vs the other brands of THX. I can't seem to find anything online at all.

- And can anyone explain the technical difference between THX 789, 888, and 889 ? Is this just a marketing thing, or are they actually different circuits?
 
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#83
Thanks for posting this. I currently have an sp200, a JDS atom, and two versions of the O2. Sonically, (with single-ended output) the sp200 is by far my favorite, having significantly more LF fullness / solidity than the Atom, but the headroom is a nightmare. I'm feeding these from a pro computer audio system, so a balanced signla at a nominal +4 Dbu level, and driving various type of cans. But even if I drop the level to below ) dbu, the high gain setting just folds. Massive compression & distortion. With my 600 Beyers, (my personal favorite for recording) there is simply no way to get enough clean volume, no matter how I tweak. With any other, from 32 ohm to 250 ohm, I can get good results, but only if I constantly tweak the balance between inout level and gain setting. It's bloody awful.

Great sounding amp, though.
If someone could come up with a detailed resistor swap, that would be heavenly. That is beyond my abilities, esp without a circuit board.
I've tried talking to the USA seller, but of course no response at all.
RETRACTED: I have a SP200 connected a ToppingNX4 as a DACline out). It's true that SP200 suffers some distortion and compression when go down the dac volume and go up the volume(low gain) a bit the distortion downs but don't disapears at 100%.
I don't know if the cheap Audio Equipment have compression and distortion but the fact that is than the Topping NX4 and the SMSL SP200 have good results in the reviews but in real life the two have this problems.
I tested this with AKG K701, HifiMan Sundara, Beyerdinamic DT990 600 and AudioTechnica R70x.

p.d: I'm retracted of this words, the SMSL SP200 and the Topping NX4 that I have don't have compression, sounds very well in good recordings.
In poor recordings the compression appears.
For example: In tidal hifi the coldplay song Hurts like heaven suffers some compression and in and blurred in others like Me & You Together Song of 1975.
cheers
 
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#86
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.
I actually got the Monoprice amp, using with Topping D90 and it’s whisper quiet! So the problem has disappeared and I am quite happy :)
 

JimB

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#87
Thanks, Jim, but that only compares the specs of the 788 and 888, with the 888 clearly being an improvement all around.

Nothing at all about the 789 or 889, though at least now I assume that they are, indeed, different chips or circuits. (Yes?)
My bad. Misunderstood the mystery. There seems to be little about the 789 that could be compared to the 788. But, in the ASR teardown of the Drop headphone amp, you can see that the PCB says THX 789, so not just made-up by Drop:
https://www.audiosciencereview.com/...eadphone-amp.5327/#lg=attachment17795&slide=0

This might have to do with specific implementation options. If so, that leaves us with comparing the offered specs on performance and features from the manufacturers, rather than on the number ("788" vs "789"). Where have you seen THX AAA 889? Monoprice does an "887" - seems to be "dual 888s". I give up.
 

Veri

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#88
Thanks for posting this. I currently have an sp200, a JDS atom, and two versions of the O2. Sonically, (with single-ended output) the sp200 is by far my favorite, having significantly more LF fullness / solidity than the Atom, but the headroom is a nightmare. I'm feeding these from a pro computer audio system, so a balanced signla at a nominal +4 Dbu level
Can't you lower the level to ~2Vrms over digital volume control?
 
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#89
Can't you lower the level to ~2Vrms over digital volume control?

Two problems with that.

First, it's not just 2dB, and (as posted above) when I reach an imput level that doesn't distort or compress, there isn't enough power to drive my 600 ohm cans properly.

Second: I use different cans & buds for different applications, plus that same output level haas to feed control room monitors, AND a live sound system. I cannot easily / safely be re-adjusting all the time. This amp sounds great, but it's gain structure is seriously problematic.

Still hoping someone can come up with a circuit mod.
 

JimB

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#94
You seem to have missed my point. What is actually under the hood?
As you said yourself: "Monoprice does an "887" - seems to be "dual 888s"
You mean you want circuit details for the 888? I’m not aware of any, but would be interested to see them if anyone shares them.
 
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#95
You mean you want circuit details for the 888? I’m not aware of any, but would be interested to see them anyone shares them.
Yeah, it would be great.

There may also be small gains to be made in the PSU, (like raising the voltage) but that would be hard given the space limitations. It might even be worth trying to bypass the internal psu completely. - But the small gains probably wouldn't be worth the trouble & expense. Adjustinng the basic gain structure would likely be almost as good.

Also, from what I'm reading elsewhere, that slightly recessed mid-range is due to the nature of THX circuit, in general. If that can't be fixed, then this should probably be considered a "buy it and just use it" amp. Maybe a future THX 988 will overcome this.
 

Celty

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#98
Yeah, it would be great.

There may also be small gains to be made in the PSU, (like raising the voltage) but that would be hard given the space limitations. It might even be worth trying to bypass the internal psu completely. - But the small gains probably wouldn't be worth the trouble & expense. Adjustinng the basic gain structure would likely be almost as good.

Also, from what I'm reading elsewhere, that slightly recessed mid-range is due to the nature of THX circuit, in general. If that can't be fixed, then this should probably be considered a "buy it and just use it" amp. Maybe a future THX 988 will overcome this.
No idea who your non attributed sources are, but would be interesting to see the evidence for your assertion of a "recessed mid-range".

Perhaps you missed the review of the 887 done by Amir in this forum, here is the Frequency Response he charted:
 
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Veri

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Yep it's in the manual. High gain can only take 2.1V input before clipping. Therefore a 'hot' single ended input could also cause it to clip in gain III.
 
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