Massdrop x THX AAA™ 789 Linear Amplifier - Impressions Thread
Sep 23, 2021 at 8:11 AM Post #2,401 of 2,613
I also picked one up at that price and have been trying it out with a couple of IEMs, namely the Andromeda 2020 and the Vega 2020. One thing I have noticed, and this is probably particularly true with really sensitive IEMs, is with the gain set to its lowest and the volume turned all the way down, I can still hear music playing. A minor annoyance, certainly not a deal-breaker, but I'm curious if others are experiencing this. I am using the Grace m900 as a DAC with the volume of the Grace set to 90, per the manual.
 
Sep 27, 2021 at 2:10 PM Post #2,403 of 2,613
I took advantage of the $200 sale and bought a 789 to compare it to my Schiit Heresy. I was amazed at the transformation, it was actually a game-changer for me. I think that I'd gotten used to my Heresy's quirks; loss of channel when lowering volume in low-gain mode, static when turning the volume pot, occasional hums & assorted other noise. The quietness of the 789 makes listening to my headphone collection a far more enjoyable experience. I did not expect that.
 
Last edited:
Nov 11, 2021 at 11:35 AM Post #2,405 of 2,613
Has anyone experienced the 789 picking up interference from mobile phone signal? It happens during every call even without any input plugged in. The phone is not even that close to it. I'm really surprised because I have never experienced anything like that with any amp.
 
Nov 11, 2021 at 11:41 AM Post #2,406 of 2,613
Has anyone experienced the 789 picking up interference from mobile phone signal? It happens during every call even without any input plugged in. The phone is not even that close to it. I'm really surprised because I have never experienced anything like that with any amp.

Nope my cell phone and wiresless router are in the same room as my 789 and 887 and I never had issues. The only thing I can think of is improperlly shielded connectors on your audio cables. I'd swap them out as an experiment.
 
Nov 11, 2021 at 11:48 AM Post #2,407 of 2,613
Nope my cell phone and wiresless router are in the same room as my 789 and 887 and I never had issues. The only thing I can think of is improperlly shield connectors on your audio cables. Id swap them out as an experiment.
Well, as I said before it happens even when there is no input plugged in so it can't be the RCA cables (which never did that before). And when I unplug the headphones (which never did that before) it cuts off immediately. The only thing left is to wrap up the 789 in aluminium to see if it helps, but even without that I have no idea how could the problem be anywhere else than the 789 itself.
 
Nov 11, 2021 at 11:56 AM Post #2,408 of 2,613
Well, as I said before it happens even when there is no input plugged in so it can't be the RCA cables (which never did that before). And when I unplug the headphones (which never did that before) it cuts off immediately. The only thing left is to wrap up the 789 in aluminium to see if it helps, but even without that I have no idea how could the problem be anywhere else than the 789 itself.
It stop when you unplug your headphone? Are they balanced or single ended? Are you able to swap the cable or remove the 6.3mm adapter if there is one? If you cant trace it to a cable or connector then its like a faulty 789.
 
Nov 11, 2021 at 12:41 PM Post #2,410 of 2,613
Has anyone experienced the 789 picking up interference from mobile phone signal? It happens during every call even without any input plugged in. The phone is not even that close to it. I'm really surprised because I have never experienced anything like that with any amp.
I have also noticed this. If I have my phone next to the amp I hear interference. It goes away if I put my phone further away from the amp.
 
Nov 11, 2021 at 1:00 PM Post #2,412 of 2,613
This is very unusual, must be a new batch of Drop THX 789. I bought my over 3 years ago when it was MassDrop and i also have THX 887 plus 3 other tube amps. I always put my cell phone in front of the THX 789 and 887 and nothing happens.
 

Users who are viewing this thread

Back
Top