Review and Measurements of Massdrop THX AAA 789 Amp

[Rottmannash]

Hi all, yowzah just finished reading this thread from the start. So much information and terms go right over my head but what a relief to read straightforward and very advanced advice without all the snake oil involved on most audio sites.
So I turn to you with my very noob questions and confident it won't be littered with suggestions of wood blocks, insane cables, need to spend x amount etc....
I jumped on the Drop deals yesterday before they expired for the Sennheiser hd6xx headphones and THX 789 (179+199!) as they seemed like a great deal and a solid starting/end point in high quality headphones and amplification.

However now that I am doing my research I don't really see much info on how I am planning to use them in my audio system. I am running a 2 channel/vinyl/tape/streaming setup in my living room. I wanted the headphones for when I can't be using my speakers at night or mornings. My Amplifier is a Yamaha a-s801 and I was planning on running RCA from one of the line outs to the THX 789 and using that to power my headphones and bypassing the headphone jack on the Yamaha but leveraging it's built in DAC. Is there an issue I am missing with this setup? I ask because I've not read of anyone using it in this manner?
Secondly I am on my laptop usually and depending on where I am sitting it can be more convenient to use the headphones directly into my laptop rather than a long cable to the Stereo system. Would I be able to use the THX without a dac in that situation ,headphone jack out> THX>headphones ? Or just plug the headphones straight into the laptop and just not have much power to feed them?
I realize this should of been figured out before the purchase but I got it in me that I wanted to up my headphone game and it turns out 2 of the most highly recommended parts of the chain were on sale , so I jumped on them.
Thanks.

Good purchases-enjoy!!

 

[Rottmannash]

An inexpensive but quality DAC from your laptop>DAC>THX789>HP's would optimize your HP listening. That's what many, if not most do. I run laptop>Topping D70>THX789 and it sounds incredible. Also have run it through the Topping E30 and the D10B. All sound great.

Hi all, yowzah just finished reading this thread from the start. So much information and terms go right over my head but what a relief to read straightforward and very advanced advice without all the snake oil involved on most audio sites.
So I turn to you with my very noob questions and confident it won't be littered with suggestions of wood blocks, insane cables, need to spend x amount etc....
I jumped on the Drop deals yesterday before they expired for the Sennheiser hd6xx headphones and THX 789 (179+199!) as they seemed like a great deal and a solid starting/end point in high quality headphones and amplification.

However now that I am doing my research I don't really see much info on how I am planning to use them in my audio system. I am running a 2 channel/vinyl/tape/streaming setup in my living room. I wanted the headphones for when I can't be using my speakers at night or mornings. My Amplifier is a Yamaha a-s801 and I was planning on running RCA from one of the line outs to the THX 789 and using that to power my headphones and bypassing the headphone jack on the Yamaha but leveraging it's built in DAC. Is there an issue I am missing with this setup? I ask because I've not read of anyone using it in this manner?
Secondly I am on my laptop usually and depending on where I am sitting it can be more convenient to use the headphones directly into my laptop rather than a long cable to the Stereo system. Would I be able to use the THX without a dac in that situation ,headphone jack out> THX>headphones ? Or just plug the headphones straight into the laptop and just not have much power to feed them?
I realize this should of been figured out before the purchase but I got it in me that I wanted to up my headphone game and it turns out 2 of the most highly recommended parts of the chain were on sale , so I jumped on them.
Thanks.

 

[hwshi]

An inexpensive but quality DAC from your laptop>DAC>THX789>HP's would optimize your HP listening. That's what many, if not most do. I run laptop>Topping D70>THX789 and it sounds incredible. Also have run it through the Topping E30 and the D10B. All sound great.

Issue is I use my laptop on my....lap. Not sitting at a desk but usually on the couch or chair, so having 2 devices plugged in and needing power is not very conducive to keeping mobile. I'll have to wait and see just how they sound on their own without an amp/dac attached. Might not be usable in that situation. I do have a set of NAD HP50 but I just don't find them comfortable with glasses on.

 

[Rottmannash]

Issue is I use my laptop on my....lap. Not sitting at a desk but usually on the couch or chair, so having 2 devices plugged in and needing power is not very conducive to keeping mobile. I'll have to wait and see just how they sound on their own without an amp/dac attached. Might not be usable in that situation. I do have a set of NAD HP50 but I just don't find them comfortable with glasses on. Ah. Then perhaps look into something like the 9038D. It's a dongle, it's is SE 3.5 mm and very well measuring and powerful. plug it into your laptop and drastically improve your sound.

 

[hwshi]

Issue is I use my laptop on my....lap. Not sitting at a desk but usually on the couch or chair, so having 2 devices plugged in and needing power is not very conducive to keeping mobile. I'll have to wait and see just how they sound on their own without an amp/dac attached. Might not be usable in that situation. I do have a set of NAD HP50 but I just don't find them comfortable with glasses on. Ah. Then perhaps look into something like the 9038D. It's a dongle, it's is SE 3.5 mm and very well measuring and powerful. plug it into your laptop and drastically improve your sound.

Oh that looks interesting, unfortunately I can't find it in stock anywhere (I'm in Canada). It is available from Ali express but I'm a little leery of ordering off of there, not that I've had bad luck in the past but they were never items of much value.

 

[Rottmannash]

Oh that looks interesting, unfortunately I can't find it in stock anywhere (I'm in Canada). It is available from Ali express but I'm a little leery of ordering off of there, not that I've had bad luck in the past but they were never items of much value.

The 9038D was reviewed here. I'd go read that thread and ask @staticV3 for advice on where to order.

 

[hwshi]

I have it all set up now, Yamaha A-S801>THX789>HD6XX and I have to set the gain on the THX at 3 to not have to max out the volume. Is this normal? Seems like it should be getting a strong signal from my Amp (line out) and not need to boost it so much. Going straight into the headphone jack on the Yamaha it has no problem getting the headphones too loud fast.

 

[Dunring]

I have it all set up now, Yamaha A-S801>THX789>HD6XX and I have to set the gain on the THX at 3 to not have to max out the volume. Is this normal? Seems like it should be getting a strong signal from my Amp (line out) and not need to boost it so much. Going straight into the headphone jack on the Yamaha it has no problem getting the headphones too loud fast.

On the Yamaha do you have a spare RCA pair out to run to the amp? For the headphone jack out do you have the volume set high enough on it? Ideally I'd get an RCA cable to run to it, but the headphone out at high volume should be good enough for normal gain. I tried it with a Soundblaster play3 which is less than 2 volts and ran into the same thing, it was just not putting enough and I had to compensate quite a lot on the amp.

 

[Jimbob54]

OK friends. I freely admit being an absolute liability regarding all things electrical.

The power brick for my (oldest, out of warranty) 789 has died. I know its the brick as a) the light on the brick is out and b) I have a second 789 and the PS from that powers the old amp fine.

Given the cost of even asking Drop to send me a new one to the UK, assuming they even would, could any bright spark tell me what 3rd party option I could buy. Its a 5.5 x2.1mm plug, 100-240v 50/60hz input, 24v 1.8A DC output. Ideally one from the UK or europe but if the right one is on Aliexpress, happy to buy there.

Ideally if someone has already bought one that has worked without issue for a while, link me please. Looking on amazon I can find plenty of 24v 2a with the right connector for £20 or less

 

[guzkiy]

Hi all,
I've got this amp recently given good reviews and measurement but I have to say it falls short of my expectations (or my expectations were unreasonable).
I compare it to simaudio moon 430HA (which was 7 times more expensive when i bought it), and I can tell the difference straight away. The sound stage collapses and the drums are less detailed. So i don't like it that much.
The stack is as follows:
Tidal/Roon->USB->Topping D90SE->( either [Drop THX 789] or [Moon 430HA] ) -> Sennheiser HD800S
Music: classics, a bit of soft rock, vocal

Any ideas are appreciated. Do i expect too much from the 789? the review/measurements are excellent.

 

[jani80k]

I just got this device. Significantly less bass than SP200. Sharper treble tho, but not in a good way.
I cannot recommend it with HD800s. All the criticism HD800s received over time suddenly becomes true (lack of base, fatigueing treble, weird timbre). With SP200 this wss not the case at all.

 

[Selarom]

Hello All,

I also started to experience the scratchy volume potentiometer issue...looking around I found on the Drop forums a post indicating that the pot has lubrication inside... recommendation is with the amp OFF, turn the volume knob fully up and down. Then use the amp as normal.. This has mitigated the issue for me for now and I can go back to enjoying this little gem. However... once any of it's parts, kick the bucket... I'll probably go A90...But again, for now, as it stands, this is a nice little gem of a unit. I am enjoying it a lot with my SU-9n DAC.

I wonder if the cheap knockoff pot, and capacitors could be replaced with higher quality components that last longer but don't change the sound signature. I wish we could get a better quality version of this amp with better components, however, now we have the A90 and the Singxer SA-1.

 

[Prism24]

I’m looking to buy this amp and use the balanced output, but for the time being I want to use the DAC in my Fiio K5 Pro and run that into the 789.

Does anyone know how much that will affect the balanced power output of the 789? All of the stats I can find has the power ratings measured with a balanced DAC running in. I’m going to be driving Mk3 Argons.

 

[Selarom]

I’m looking to buy this amp and use the balanced output, but for the time being I want to use the DAC in my Fiio K5 Pro and run that into the 789.

Does anyone know how much that will affect the balanced power output of the 789? All of the stats I can find has the power ratings measured with a balanced DAC running in. I’m going to be driving Mk3 Argons.

Well, I can tell you that the 789 is internally unbalanced… so it takes balanced signals and converts them to single ended for amplification.. I don’t think feeding it an unbalanced signal will do a huge difference. The amp is powerful, and although the Argons do require power, I think you will be fine. Just my opinion, I haven’t heard the Argons. Good luck

 

[ssmith3046]

I just bought a like new Drop 789 and I'm loving this amp.

 

[jani80k]

I just bought a like new Drop 789 and I'm loving this amp.

I got used to the way it sounds, now. I am loving it, too.

 

[ssmith3046]

I got used to the way it sounds, now. I am loving it, too.

I've been using a Schiit Asgard 3 and it's a great amp but the 789 has a much more open soundstage to my ears. I've used the new Modi 3E with my HD600's and they've never sounded better. With my Focal Clear Pro's and Avantone Planar headphones I like the Modi multibit with the 789.
Need help here please. I'd like to use my Asgard 3 as a preamp for my powered monitors. Is that possible with the SE pass on the 789?
All in all, the best $120 that I've spent audio in a long time.

 

[FrantzM]

Recently acquired this amp... Didn't even realize it was this particular model, until I looked carefully. It is used with the HifiMan HE-6SEv2. Endgame. May move to a balanced DAC, just ... because

Peace.

 

[AVKS]

Recently acquired this amp... Didn't even realize it was this particular model, until I looked carefully. It is used with the HifiMan HE-6SEv2. Endgame. May move to a balanced DAC, just ... because

Peace.

Moving to a balanced DAC (Topping E50 in my case) allowed me to get the maximum headroom from my 789 and took care of the compression I was running into when using my V2s. However, my prior DAC was only putting out and estimated 1V so you may not be having the same issue.

 

[ssmith3046]

I'm using the Schiit Modius balanced with mine. From what I've read this isn't a "true" balanced amp but I like the Modius with this amp. Also using the balanced headphone plug gives me extra juice for my HD600'S. I like some DACs and headphones with my Asgard 3 but I really like the clean sound this amp provides.