Monoprice Monolith THX 887 - Impressions Thread
Dec 3, 2019 at 8:49 AM Post #122 of 359
I have noticed with 55 ohm Focal Clears there is no audible hiss with gain positions 1 or 2, but with gain 3 there is hiss at the 2pm position....granted the high gain 3 position is meant for those
higher impedance headphones, just wondering if any of you have heard this?

With low impedance cans, 35 ohms I can hear this hiss in gain position 2 at 2 pm as well, but not in gain position 1.

Alex

I haven’t experienced any hiss with mine, but I only have the 300ohm Verite at this time. However, when I owned the 789 I don’t remember getting any hiss on any gain.

What output level/ volume is your RME on, out of interest?
Usually I run the RME at -5.0db with the Mj2 and 887. This leaves me with gain 2 and volume between 10 to 12 o’clock on the 887. But I don’t have a particular reason for -5.0db. I would like to test the line voltage of the RME’s XLR at that volume but I’ve never got around to it.
 
Dec 3, 2019 at 9:08 AM Post #123 of 359
With HD600 300 ohm or T1 600 ohm no audible hiss on any gain, use gain 3 for these.
Its only as the impedance gets lower that you hear the hiss at the higher gain positions of 2 and 3..

I think this is a design limitation and a corner case where its really what I call a "dont care"...
But being in software and hardware test for many years we go out of our way to test these corner cases and see what happens.

Alex
 
Dec 3, 2019 at 11:30 AM Post #125 of 359
With the 789, I owned Clears (55ohm) and Ether 2 (16ohm), neither had any hiss on any gain from memory.

789 and 887 share nearly identical internals. Seems odd.
Monoprice desktop and Drop 789 have nearly identical low noise floor.
In gain 3 position, both units have higher noise floor due to gain * (amp preamp noise) + gain * (upstream DAC noise).
To lower the noise floor, use the lowest gain knob setting that still achieves the SPL you need at the headphone without running out of volume knob.
 
Dec 3, 2019 at 3:00 PM Post #126 of 359
To clarify; I do hear a hiss when I have the gain on 3 and the volume pot maxed out (with Verite).

I would be terrified of how loud any actual signal coming through would be at this amount of amplification considering loud listening levels are at gain 2 around 12o'clock.
 
Dec 3, 2019 at 3:12 PM Post #128 of 359
Yea, if I set my computer system output volume to 100%, Spotify to 100%, and the RME to 0.0db....

Gain 1, Volume knob at 10 to 12 o'clock max.

I tend to keep Spotify volume around 90% cause I remembered seeing my system sound clipping sometimes in eAPO with everything set to 100%
 
Dec 10, 2019 at 12:12 PM Post #129 of 359
I have listened to a second Monoprice 887 and it has the same hiss I hear with the first one...again this is not a real issue
in that effects the sonic character .....its just a corner case that I wanted to make sure this is normal with this amp.

With such low specs I as curious as to why I was hearing this hiss at extreme high volume positions of the vol pot.

Its only with lower impedance headphones on gain 2 and 3 at 2pm or higher volume knob position.

Andrews comment makes sense to use the lowest gain and the lowest vol position and you should never be aware of this anonomoly.

Alex

An excellent amp for the price, brings world class peformance down to an affordable level...
 
Dec 12, 2019 at 1:23 AM Post #130 of 359
Having listened to my Monolith 887 for a month, paired with my SU-8 DAC, I really could not be happier. I have not found a single thing to complain about in terms of performance / sound. It just brings out the full potential of my current headphones, giving them all the clear, clean, accurate power they could ask for. The combination of totally silent noise floor and soaring dynamics capability is really something.

I'm really looking forward to hearing how the Auteur's sound when it arrives.
 
Dec 12, 2019 at 9:39 AM Post #131 of 359
Having listened to my Monolith 887 for a month, paired with my SU-8 DAC, I really could not be happier. I have not found a single thing to complain about in terms of performance / sound. It just brings out the full potential of my current headphones, giving them all the clear, clean, accurate power they could ask for. The combination of totally silent noise floor and soaring dynamics capability is really something.

I'm really looking forward to hearing how the Auteur's sound when it arrives.
Awesome, enjoy your setup! Auteur will be very relaxed with 887 :)
 
Dec 12, 2019 at 11:30 AM Post #132 of 359
I just exchanged my THX AAA 887 with a different one.

My concern was the hiss I was hearing at high volume levels with low impedance headphones.

Monoprice when asked this just offered to replace the unit...so I took the chance and did.

Monoprice's customer service to me was excellent...

That said the second unit has the exact same hiss, so this is indeed a trait of this amp.

That said it doesnt affect any listening with any headphone when used with the appropriate gain level.

Alex
 
Dec 19, 2019 at 1:29 PM Post #135 of 359
My concern was the hiss I was hearing at high volume levels with low impedance headphones.

I tried low impedance headphones and IEMs (shure 846) with the 887 amp. There was no hiss whatsoever.
 

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