Review and Measurements of Massdrop THX AAA 789 Amp

[amirm]

@amirm / @AndrewMason , can you see if you're able to replicate this?

Replicated:

 

[L-Train]

Replicated:

View attachment 17759

Thanks for taking the time to reproduce this Amir. I'll send an email to Massdrop with a link to these posts to get their opinion on this issue. I have a feeling that this degradation in crosstalk is related to the change in selectable gain from 0/+12/+18 dB to -10/0/+10 dB since Andrew mentions that the "architecture doesn't permit gain much lower than 0dB" here: https://www.massdrop.com/buy/massdrop-x-thx-aaa-789-linear-amplifier/talk/2007668, and so perhaps they had to resort to another method of attenuating the signal which is causing this increase in crosstalk.

 

[amirm]

Yeh, the circuit path is likely different with higher capacitance, causing loss of channel separation.

It is not an audible issue but I agree it should have been something that was measured and fixed prior to release.

FYI I am finishing testing of a very high performance amp that competes with this unit and it doesn't have this issue in any of its three gain settings. But then again, it doesn't go down as low in gain as the THX unit does.

 

[BurritoJustice]

FYI I am finishing testing of a very high performance amp that competes with this unit and it doesn't have this issue in any of its three gain settings. But then again, it doesn't go down as low in gain as the THX unit does.

HPA4?

Probably the review I am most looking forward to.

 

[rajapruk]

Thanks for taking the time to reproduce this Amir. I'll send an email to Massdrop with a link to these posts to get their opinion on this issue. I have a feeling that this degradation in crosstalk is related to the change in selectable gain from 0/+12/+18 dB to -10/0/+10 dB since Andrew mentions that the "architecture doesn't permit gain much lower than 0dB" here: https://www.massdrop.com/buy/massdrop-x-thx-aaa-789-linear-amplifier/talk/2007668, and so perhaps they had to resort to another method of attenuating the signal which is causing this increase in crosstalk.

Good that you found this.

 

[amirm]

HPA4?

Ah, no.

 

[Veri]

HPA4?

Probably the review I am most looking forward to.

I think it might be March's amp? or maybe some newly discovered superb amp that would be cool too.

 

[Noob]

Yeh, the circuit path is likely different with higher capacitance, causing loss of channel separation.

It is not an audible issue but I agree it should have been something that was measured and fixed prior to release.

FYI I am finishing testing of a very high performance amp that competes with this unit and it doesn't have this issue in any of its three gain settings. But then again, it doesn't go down as low in gain as the THX unit does.

This is like a movie teaser. "Coming soon to a theatre near you."

Also, hello everyone! I just found this website a few days ago and have greatly enjoyed adventuring through the many charts, graphs, and enthusiastic comments. The more I immerse myself in the audio enthusiast community, the more I like being part of it.

 

[badboygolf16v]

Ah, no.

Tom's I guess.

 

[Noob]

Been doing some back and forth comparisons between this and the JDS Atom. It seem that when considering just the single ended output, the Atom is clearly superior. The only substantial advantage this amp has is when it is run through the balanced out. So for those like me who are not interested in running balanced to headphones, the Atom seems the clear winner here.

 

[Headphonaholic]

Been doing some back and forth comparisons between this and the JDS Atom. It seem that when considering just the single ended output, the Atom is clearly superior. The only substantial advantage this amp has is when it is run through the balanced out. So for those like me who are not interested in running balanced to headphones, the Atom seems the clear winner here.

Wow you got the Atom really quick! When you ordered yours did you get faster shipping?

 

[rajapruk]

Noone opened the 789 up yet? I want to see naked pictures.

 

[Headphonaholic]

Noone opened the 789 up yet? I want to see naked pictures.

I could have sworn someone found pictures of the internals somewhere, guess I was thinking of something else.

 

[amirm]

Noone opened the 789 up yet? I want to see naked pictures.

I was hoping I would get mine to do that but it won't be here for another 9 days. I will ask the owner and see how he feels about me operating on his.

 

[Noob]

Wow you got the Atom really quick! When you ordered yours did you get faster shipping?

Sorry for the misunderstanding. I was comparing the measurements side by side. I have not actually decided to purchase either amp at this moment.

 

[Headphonaholic]

Sorry for the misunderstanding. I was comparing the measurements side by side. I have not actually decided to purchase either amp at this moment.

Oooh ok. No worries, I got excited that they shipped em quick. To my knowledge they weren't going to ship right away, I haven't gotten tracking info anyways.

 

[amirm]

Noone opened the 789 up yet? I want to see naked pictures.

OK, received kind permission from the owner of the loaned unit and I did my teardown. See: https://www.audiosciencereview.com/...n-of-massdrop-thx-aaa-789-headphone-amp.5327/

 

[AresHarvest]

Same deal here. Paid extra for expedited shipping, and then they took three days to create a shipping label.

Same. Bought it Tuesday morning, paid extra for 2-day shipping. Ordered Tues morning last week, received Tues this week (today).

To their credit, Fedex got it to me quickly. Technically I did get the 2-day shipping I paid for... Massdrop just added a 3-day sit-on-hands period before they actually shipped it. Seems to be par for the course.

Anyway, it arrived in good shape, and so far it's working out great. Happy to have it here, and happy my HE560 v2 came with a balanced cable in addition to the SE cable.

 

[mi-fu]

Just to update that I also received mine today. I bought it on the first day of the latest round with normal shipping. Hope you guys will get it before thanksgiving

 

[amirm]

Mine is still 7 days away...