[FunctionalDoc]

I was able to stop at the THX both at RMAF last year and heard both of the circuit amp designs and I spoke with Tim Dick an application engineer from company and heard 2 amps with these amp modules in tiny plexiglass boxes with external PSU's. I asked him then when would these come to market and he mentioned the Benchmark product and I asked anything not in big buck league. Tim said Monoprice would be coming out with amp next year.

I was throughly impressed with this amp design but waiting till Novemeber seems like a long time. I prefer that their is no DAC in this unit and it have more power and fully balanced output to power those power hungry headphones.

Lets be real what can you buy for this price point with this kind of power and design. I think that might be worth putting out $350 to see if Massdrop can excute a simple built highly engineered amp.

What would be some power supply options for this unit?

I do remember they had a nice mix of high impedance headphones and harder to drive ones and being blow away that a tiny boxed circuit could power all these headphones and sound very good.

I would like to hear this unit before I buy also .

I think I would take this over the Cavalli Liquid Carbon Massdrop version.

Here are my thoughts on what the amp design sounds like.

 

[negura]

I am not sure how this hasn't sold out yet.

OK there's a long wait. Besides that, even if this reaches 80-90% of the performance of the AHB2 (more on this below), which uses similar technology design, it can be a game changer at this price point and beyond. That said at least from measurements, which isn't everything of course, it shouldn't be too far from the AHB2 (consider AHB2 is measured for speaker loads. THD with this design decreases even further into higher impedance; i.e.: better with headphones), but who knows, since it's done at a different price target.

Also extrapolating from the AHB2, I don't expect this to be warm sounding, or bassy/rolled off, whatever. I expect it to be very revealing and transparent to the source, which is amazing given a good source. In practice most modern sources, including recent delta/sigma are way more performing than what most amplifiers can deliver. Fortunately, as opposed to a few years ago, I am hearing a real progress with delta/sigma, which is what's accessible at this price point and makes it worthwhile for someone wanting to hear what the source can deliver. There are also very good, and arguably better R2R alternative for sources, but unfortunately, the price of good R2R sources puts them way out of the budget this amplifier plays at.

Note: For frame of reference, I use 1 or 2 x AHB2 mainly with speakers, but also with most headphones - works flawlessly and sounds amazing, even with something relatively efficient as Utopia or Aeon Flow Closed and all the way to modded HE-6s. The overall performance of AHB2 with headphones (in most areas from transparency, driver control, resolution, lack of added artifacts), is well above end-game headamps like EC Studio or EC 2A3MK4 I had before, not to mention way beyond reach of some popular solid state headamps I had around like the Moon 430HA, Schiit Ragnarok, Audio GD HE-9 etc, let alone anything from Vioelectric, Burson, whatever

Note 2: It's not clear if this is a balanced design internally. The comments I've read from THX designer , it has a "true balanced XLR" output - how about the topology up to the output. Not sure. Does it matter a lot in practice - probably not. Also depends on the source used.

Note 3: Not sure how confident I can be in the included supply. I do not have anything in principle against a well-design SMPS for audio, again considering what was done with the AHB2. This could be a price saving point, but not necessarily.

Note 4: What are they using for volume control - can I assume it's a budget pot to meet the price point? This might hinder performance.

Note5: Although it's more than capable performance-wise with headphones, with extremely low output impedance and completely silent, I have some reservations to recommend the AHB2 for this use.
- It's a power amp and headphones people may not be used to the pitfalls of solving the preamp problem. It's not trivial. The performance of the AHB2 will be affected by underperforming preamps or weird source chain/preamp/power amp matches.
- 1xAHB2 has a lot of power for headphones use, even on low gain. Let alone two of them. Ones has to know what they are doing. HE-6 users usually know the caveats, but there's more than one or two who compromised their headphones. Have fun at your own risk.
- It's a speaker amp with no headphones output, so gotta work this one out
The Massdrop THX 789 solves all this for you.

Even if Note 2,3,4 have an impact, the performance of this could still be hitting MUCH higher than its price indicates.

 

[dan.gheorghe]

It's a long time to wait indeed. This seems like a kickstarter project to me, where they get the money from the buyers then they produce the units. Well...if the specs are true it might very well worth the wait time. I bought one for myself. At 350$ it's not much of a gamble ... Can't wait to hear it. I agree with negura, this might be a game changer!

 

[a1411832]

How does this amp compare to say audio-gd products? I am very much interested in audio-gd NFB-1?

I have a Oppo 105D, and the headphone amp is not that powerful. I am expecting my order of 6XX delivered soon

Or, should i stop worrying about integrating it to my 105D and get a R2R 11 instead?

Thanks!

 

[tizman]

Thanks FunctionalDoc and Negura. Based on your comments, comparisons and listening impressions, I am joining the drop. I had a strong feeling that it would be a great value for the money, and you two have confirmed that feeling for me. Thanks!

 

[tizman]

From what I remember reading, Andrew Mason was involved in designing the power supply, and he also did so for the one in the AHB2. I believe that it is an area of specialty for him. This is a good indicator to me that the power supply unit will be of good quality.

 

[sebna]

Guys (and girls),

Do you think it may be a competition, in same league or better to violectric v200 or gustard h10 albeit with different sound signature, precision vs warmish laid back?

I have read comparisons of v200 to most expensive shitt amp and it was blow for blow while i have read comparisons of AAA vs cheapest shitt and it was also a draw... Lol that should tell me a lot...

 

[FunctionalDoc]

Jude has the amp for doing testing so should get results soon.

I joined the drop and I beleive that once Jude puts out his review this will sell out. I watched the video on Home Theater geeks with the Vp of THX talking about design and said thius amp will be punching much above its price point. Let the wait begin.

 

[mtmercer]

Deleted.

 

[baiyy1986]

After a couple of days I would say Andrew Mason is very helpful, he almost replies every question that people confused.
I would say they must know what they are doing, and in the price range, this may be the most powerful headlamp. I asume it would be more like audio-GD NFB-1 type of amp, which is smooth and neutral sounding, also they are the same output specs on the paper. Differents is NFB-1 is Class-A and 789 is class-AB, which is more efficient and don't get warm.
But everything just guesses

 

[CEE TEE]

I haven’t found a review yet. If anyone has a review unit, this would be a good time to put out a review, considering the drop. If anyone does know of a review, or finds one, please post a link to it in this thread. It would be appreciated.

Hi Tizman,
Thanks for your interest.
There are two units out for review and measurements, Jude has one and just got his Audio Precision back up and running after an upgrade. Hope to have some 3rd party graphs and impressions soon...

 

[GenEricOne]

Joined the Drop earlier today. Looking forward to Jude's measurements and impressions.

 

[mtoc]

reaches 80-90% of the performance of the AHB2

no, using AHB2 to drive headphones is not a good idea, it has more than ten times output noise than headphone amps', as a speaker amp, the noise is pretty low, but with this much higher noise it doesn't suit to be a headphone amp, different things entirely.

so what are you trying to say is that if we use this 789 headphone amp to drive speakers, could we get 80% of AHB2? I have no idea, but I'm sure it could output 2.83v or even 5v (highest gain) under speaker load, and its output z = 0.1 ohm (at 1k Hz, this value isn't a constant number), would not be a problem at all.

yes, we could use this little amp to drive speakers (ignore those hard to drive ones)

 

[mtoc]

any massdrop folks here? just posted the THD+n vs output power graph, would be more professional

here's an example, try to be more professional, guys (62 ohm load, not 300 ohm)

http://www.funk-tonstudiotechnik.de/LPA-2S-englisch.pdf

 

[smallcaps]

Haven't posted on head-fi for around 5 years but came back because of this amp. Very much looking forward to Jude's impressions. Needless to say, I joined the drop, and the addiction is back in full swing. Now shopping for an appropriate DAC for this baby. What are people thinking of pairing with this?