In case anyone cares, I've been listening to the McIntosh MHA150 and comparing it (with my bad ears) to the Monoprice THX AAA 887.
I tried to volume match them as carefully as I could using a decibel meter on my iPhone, held firmly between the earpieces and a 30 second average reading of 83.3dB during the same passage of a compressed to hell pop song. This was fed from 320k mp3 via iTunes at 100% and the volume attenuator on my MacBook at 100% for both USB targets. On the THX side, we go into the SMSL SU-8 v2 which is also at max volume and hands off to the THX using short (1ft) balanced cables. The THX was on low gain with volume at 12 o'clock (~50%) to establish the 83.3dB baseline. On the MHA150 side, we go into the built-in USB DAC and ended up setting the volume at 35% to hit an average of 83.3dB. This was using the Normal 8Ω-40Ω headphone output. Okay, enough science.
Impressions.
- At 83dB, these were both very loud and very clear. I don't want to listen to them very long at this volume because I know it's going to harm my hearing... but I could listen all day because they are both very, very clean.
- Bass comes through very well in my MDR-V6 Sony's. I want to say the McIntosh is more pronounced in the ultra low bass, but I'm not certain. It just seems to have more ... rumble to go with what I can hear. Like I can hear/feel the drivers pushing just a bit harder at those long wavelengths.
- I want to say the THX AAA 887 is a bit brighter in the mids and highs, but I'm not certain. Song after song just seemed a bit more brilliant and loud when switching back to the THX. Was this a loss of bass or an increase in mids? Going back to the MHA150 consistently seemed to quiet down a touch in the mids, but pick up a bit more low rumble.
- I really want to say the McIntosh is "better," but I'm not sure that's fair or just my wallet speaking. No one wants to admit they don't like or understand the million dollar painting they just "won" at auction.
After listening to many different pieces from unnamed female pop clones to Diana Krall, Röyksopp, Steely Dan, A Perfect Circle, Sade, and Beck I keep making the same assessment: These two amps are basically the same.
To be thorough, I ran a quick and less scientific comparison with my Behringer UMC22, Elgato Dock headphone output, and MacBook Pro headphone jack. I would like to say I could hear a slight reduction in quality with those. The elgato headphone amp is very noisy, it's the worst and the reason I bought the UMC22. The MBP headphone amp is quiet and at full volume comparable to the THX and MHA150 with less presence in the bass. The UMC22 continues to be impressive for $35, easily the equal of the MBP, but just not as much power in the low end as the THX or MHA150.
If I had only bought one of these two amps, I would be very happy with it. They both sound incredible. Knowing I overpaid for one of them is a bit of a pinch, but... I like the McIntosh more. This bezel is ridonculous:
I'll be keeping them both. The MHA150 will get home office duty while the THX is going to my employer's office so I'll be using it regularly. Right now with a choice between them both, I keep plugging into the McIntosh.
I hope one day this write-up helps someone else considering doing the stupid thing and overpaying for a headphone amp.