Massdrop x THX AAA™ 789 Linear Amplifier - Impressions Thread
Sep 21, 2019 at 11:13 PM Post #1,801 of 2,591
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Sep 24, 2019 at 9:13 PM Post #1,804 of 2,591
Here we go

https://www.aliexpress.com/item/400...chweb0_0,searchweb201602_9,searchweb201603_52

Be sure to contact the vendor as 24v and 120 V USA supply needs customization - No extra cost Just extended delivery time
Good luck.
My 24v PSU has 2.89Amp peak current - I could have selected up to 4 over Amp. The transformer sizing and components arwe sized up accordingly. You pay more. But 2.89 amp is enough for the THX789. It sounds SMOOTH. With my Verum1 or the He560, no harshness. This weekend, I will hook up my 6n1p/45 tube Preamp to give the THX789 more harmonic richness and try my Abyss AB1266 Phi/CC and also my treble enhanced HP's like Senn HD800, Final Audio Sonorous VI....

Happy Listening
Kelvin
 
Sep 27, 2019 at 11:52 AM Post #1,805 of 2,591
If I use DAC for volume control would it be optimal to max the volume on 789? Not sure if there are any issues with the pot at max volume or other issues (e.g. gain 1 at max volume).
 
Sep 28, 2019 at 3:32 AM Post #1,806 of 2,591
If I use DAC for volume control would it be optimal to max the volume on 789? Not sure if there are any issues with the pot at max volume or other issues (e.g. gain 1 at max volume).
As per the measurements by Amir from ASR, the specs are ideal up to the max pot position so I guess it is well fine.
 
Oct 6, 2019 at 1:57 AM Post #1,807 of 2,591
Updated from the Fiio K3. My HD6XX and 58X never sounded so good. Lots of detail and separation and they even sound a bit more open or airy. Low gain is plenty for me and I don't need to go past 12 o'clock on the volume dial. I don't yet have balance cables between the SDAC and amp so that is next on the list. I bought this on Canuck Audio Mart despite having already on order from Massdrop (Drop) which will ship in November. I'll just sell one of them when that arrives. I didn't pay anything more for this than I did for the one from Drop. Running this off my MacBook Pro. Music being played in iTunes mainly in 320Kbps. Down the road I'll be interested to know how other headphones sound with this amp.
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Oct 6, 2019 at 8:39 PM Post #1,808 of 2,591
Thinking about grabbing one of these or the Monoprice version. Looking at a few other amps as well. And also trying to figure out which DAC to go with. If the 789 is described as crystal clear and analytical, would it make sense that the Empyrean would pair well with it since it's a somewhat darker and lush sounding headphone?

As far as DACs go, I'm considering Benchmark DAC3-B, Chord Qutest (no balanced out unfortunately), and a few others. Really hard to decide as there are so many options out there.

Other amps I'm looking at are the Violectric V280, Monoprice version (788), and Cayin iHA-6.
 
Oct 7, 2019 at 3:34 AM Post #1,809 of 2,591
Empyrean + 789 would be a good combo.
 
Oct 7, 2019 at 3:40 AM Post #1,810 of 2,591
Empryean & 789 is indeed a good combo. Add Qutest to the chain, even better. I am also curious about the GSX-mini and how the Empryean would sound off that amp.
 
Oct 7, 2019 at 12:41 PM Post #1,811 of 2,591
Thinking about grabbing one of these or the Monoprice version. Looking at a few other amps as well. And also trying to figure out which DAC to go with. If the 789 is described as crystal clear and analytical, would it make sense that the Empyrean would pair well with it since it's a somewhat darker and lush sounding headphone?

As far as DACs go, I'm considering Benchmark DAC3-B, Chord Qutest (no balanced out unfortunately), and a few others. Really hard to decide as there are so many options out there.

Other amps I'm looking at are the Violectric V280, Monoprice version (788), and Cayin iHA-6.

The 789 with Qutest is absolutely wonderful. I pair that combo with Senns HD660S.
 
Oct 8, 2019 at 5:43 AM Post #1,813 of 2,591
If you buy this amp using RCA inputs is probably better if there are no ground loops/hum because it bypasses couple opamps in the signal path.
 
Oct 8, 2019 at 10:02 AM Post #1,814 of 2,591
No way to know if there are or aren't any ground loops before you dive in, though. Buy a Qutest and discover you have a ground loop and you're screwed at that point. $1,700 for a DAC that only has RCA outs is inane.
 
Oct 8, 2019 at 11:00 AM Post #1,815 of 2,591
No way to know if there are or aren't any ground loops before you dive in, though. Buy a Qutest and discover you have a ground loop and you're screwed at that point. $1,700 for a DAC that only has RCA outs is inane.

Price point of the Qutest aside...ground loops can be resolved fairly easily. While I run balanced *everything* as a matter of choice, unbalanced signals are perfectly acceptable for short runs.

A few minor housekeeping steps will make for a happy listening experience:

1. Plug everything into the same outlet if at all possible. This keeps everything on a level playing field from the 'source power' side of things.

2. Try a different outlet. If everything is plugged into the same outlet, but that outlet creates buzz and another one does not.....the outlet needs to be checked.

3. If the outlet looks good (ground wise) but there is still hum... perhaps your circuit is getting interference from HVAC or another large appliance. Try again moving to another outlet NOT on the same circuit.

4. If none of this works or you cannot move your setup or afford an electrician to sort it.....buy an isolation transformer. Tripp Lite sells one on Amazon for around 120 bucks.

This will solve 99% of all ground issues. FWIW I have never had to resort to buying an isolation transformer. Dirty power is an issue that should be addressed regardless of if you are an audiophile or not. :wink:

Best of luck.
 

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