[lator]

Interesting comparison in Benchmark HPA4 thread with THX https://www.head-fi.org/threads/ben...fier-impressions.876705/page-35#post-15279648

 

[mixman]

Interesting comparison in Benchmark HPA4 thread with THX https://www.head-fi.org/threads/ben...fier-impressions.876705/page-35#post-15279648

Gotta admit I did not find that an interesting comparison at all. I would be much more interested in an MJ2 vs THX vs LP vs Cayin IHA6 comparison or an HPA4 vs V281 vs GSX (Mini or MK2) vs SPL Phonitor comparison. If the HPA4 didn't sound better than the THX then I would be shocked.

 

[lator]

If the HPA4 didn't sound better than the THX then I would be shocked.

IMO with Ether Flow THX achieves very good sound balance and I have considered HPA4 as a possible next upgrade the "heavier" sound signature is not exactly what I would be looking for.

 

[FourT6and2]

Have put about 18 hours on HPA4 and THX 789. DAC is Benchmark DAC3-B. Headphones are Empyrean and HD820.

They are quite close in sound. THX 789 seems to be a tiny bit brighter. Like the attack on bass and drum notes has a bit more of a snap to it. Whereas the HPA4 is overall slightly deeper/thicker sounding. More weight behind everything, though. And this is with me trying to nitpick. They are really quite similar. Features aside, it's hard to justify $3,000 for the HPA4 when the 789 is $400 and they sound equally good.

That said, does anybody know what XLR input level the THX 789 likes to see? 4v? 2v? Higher? Lower? The DAC3 at 0dB output puts out something like 13v. And it has two pad settings: -10dB and -20dB. -10dB is close to 3v - 4v I think. And -20dB is around 1.5v. Benchmark says you want to set the DAC up such that your headphone amp's volume control is close to maxed out when at a comfortable listening volume. But the 789's gain control is a bit weird in that Gain I attenuates the signal, Gain II and Gain III both boost. There is no unity gain setting... Been using the DAC3 at -10dB into the 789 on Gain I and my listening volume is between 11:00 and 1:00.

Either way, the 789 sounds great. Authoritative and punchy and clean. What goes in, comes out. Listening to something like Tool's "Invincible" is a visceral experience, especially when the bass comes in at the end of the first verse. It's like I'm standing right next to Justin Chancellor on stage, the drums and guitar and bass swirling around me. Fantastic.

 

[AndrewM888]

Have put about 18 hours on HPA4 and THX 789. DAC is Benchmark DAC3-B. Headphones are Empyrean and HD820.

They are quite close in sound. THX 789 seems to be a tiny bit brighter. Like the attack on bass and drum notes has a bit more of a snap to it. Whereas the HPA4 is overall slightly deeper/thicker sounding. More weight behind everything, though. And this is with me trying to nitpick. They are really quite similar. Features aside, it's hard to justify $3,000 for the HPA4 when the 789 is $400 and they sound equally good.

That said, does anybody know what XLR input level the THX 789 likes to see? 4v? 2v? Higher? Lower? The DAC3 at 0dB output puts out something like 13v. And it has two pad settings: -10dB and -20dB. -10dB is close to 3v - 4v I think. And -20dB is around 1.5v. Benchmark says you want to set the DAC up such that your headphone amp's volume control is close to maxed out when at a comfortable listening volume. But the 789's gain control is a bit weird in that Gain I attenuates the signal, Gain II and Gain III both boost. There is no unity gain setting... Been using the DAC3 at -10dB into the 789 on Gain I and my listening volume is between 11:00 and 1:00.

Either way, the 789 sounds great. Authoritative and punchy and clean. What goes in, comes out. Listening to something like Tool's "Invincible" is a visceral experience, especially when the bass comes in at the end of the first verse. It's like I'm standing right next to Justin Chancellor on stage, the drums and guitar and bass swirling around me. Fantastic.

Hi! DAC3 B is a great pairing with AAA and we use the two together to demonstrate AAA on the road.

789 XLR inputs can tolerate:
up to +19dBu input (XLR or RCA) in Gain 1/2
up to +8 dBu input (XLR or RCA) in Gain 1/2/3.

When paired with DAC3 I recommend:

a) set DAC3 XLR Output Pad Jumpers to -10dB (+14 dBu) (see P. 25 of the manual), and using 789 in Gain 1 or 2 depending on your HP sensitivity. This will give you optimal SNR for the system. Use 789 knob as your volume control.

b) if you find a) too loud e.g. not using much range on the 789 volume control, then set DAC3 pads to -20dB (+4 dBu). In this setup you can use any 789 gain setting 1/2/3 without risk of clipping. Use 789 knob as your volume control.

c) if you find a) too quiet and you want to squeeze out 5-6dB higher output power from the 789, then:
- set DAC3 pads to 0dB (+24 dBu).
- introduce -5dB digital attenation e.g. in your PC player software, to bring the DAC3 output back down to +19dBu
- use 789 in gain 1/2 to taste. Use 789 knob as your volume control.

Above guide remains same regardless of unbal/bal output.

Happy Listening!

 

[FourT6and2]

Hi! DAC3 B is a great pairing with AAA and we use the two together to demonstrate AAA on the road.

789 XLR inputs can tolerate:
up to +19dBu input (XLR or RCA) in Gain 1/2
up to +8 dBu input (XLR or RCA) in Gain 1/2/3.

When paired with DAC3 I recommend:

a) set DAC3 XLR Output Pad Jumpers to -10dB (+14 dBu) (see P. 25 of the manual), and using 789 in Gain 1 or 2 depending on your HP sensitivity. This will give you optimal SNR for the system. Use 789 knob as your volume control.

b) if you find a) too loud e.g. not using much range on the 789 volume control, then set DAC3 pads to -20dB (+4 dBu). In this setup you can use any 789 gain setting 1/2/3 without risk of clipping. Use 789 knob as your volume control.

c) if you find a) too quiet and you want to squeeze out 5-6dB higher output power from the 789, then:
- set DAC3 pads to 0dB (+24 dBu).
- introduce -5dB digital attenation e.g. in your PC player software, to bring the DAC3 output back down to +19dBu
- use 789 in gain 1/2 to taste. Use 789 knob as your volume control.

Above guide remains same regardless of unbal/bal output.

Happy Listening!

Perfect, thanks!

 

[Ultrainferno]

Today we published a guest review from Jana on the Drop THX AAA 789 headphone amplifier.
A ladies point of view on this special amp: https://www.headfonia.com/drop-thx-aaa-789-review/

 

[ReAlien]

I came to report that, recently, I have sold my THX AAA 789, which I have listened to since January this year. It was a very good audio friend of mine who supported me in my melomaniac endeavors with various headphones (even the 8 Ohm ones though it is not recommended in the manual). It is indeed a neutral, powerful, transparent amp that is hard to beat at that cost. Thank you Massdrop and THX for this wonderful product, I have found a new audio love, however.

 

[Sukotto85]

Hi All,

I have recently bought the THX AAA 789 and now I am wondering which dac to pair it with? Currently I only own single-end headphones, DT 1990 Pro's and th AKG K712 Pro's. With he headphones I own should I buy a unbalanced or balanced dac? A couple of dacs I have been looking at are SMSL SU-8 and the Topping D50S. My budget is £300, although I can increase this if necessary.

Thanks in advance.

 

[adeadcrab]

Topping D50 / D50S is a great little starting DAC for the price.

 

[bequietjk]

Hi All,

I have recently bought the THX AAA 789 and now I am wondering which dac to pair it with? Currently I only own single-end headphones, DT 1990 Pro's and th AKG K712 Pro's. With he headphones I own should I buy a unbalanced or balanced dac? A couple of dacs I have been looking at are SMSL SU-8 and the Topping D50S. My budget is £300, although I can increase this if necessary.

Thanks in advance.

Hey! I have a 789 on its way to my house and i plan to use my K712 after the balanced mod. Ill give my impressions after its all said and done, and evaluated.

Im stoked!

 

[Sukotto85]

Topping D50 / D50S is a great little starting DAC for the price.

Would I hear any differences between single-ended and balanced, other than an increased volume? Should I be buying a balanced dac for future proofing? Or would I get more for my money on an unbalanced dac?

Hey! I have a 789 on its way to my house and i plan to use my K712 after the balanced mod. Ill give my impressions after its all said and done, and evaluated.

Im stoked!

Thanks for that! How much did the mod cost?

 

[bequietjk]

@Sukotto85 The only thing I came up with was the $10 for the 4pin male connector here https://www.amazon.com/gp/product/B00BYE8R5G/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

I still need to buy a cable with a 4pin female connector to plug that part into the headphone, and the other end preferably would have a standard 4pin xlr but I can't find any cable like it. So, either I have to make one or buy an assortment of connecting cables and make sure the polaritys are correct.

Here's a reference https://www.head-fi.org/threads/the-akg-k712-pro-support-and-impressions-thread.659251/page-233

I can't wait. I'll try the SE end of the 789 first, create the mod and experience the difference.

Hope that helps :]

 

[eeagle]

Hi All,

I have recently bought the THX AAA 789 and now I am wondering which dac to pair it with? Currently I only own single-end headphones, DT 1990 Pro's and th AKG K712 Pro's. With he headphones I own should I buy a unbalanced or balanced dac? A couple of dacs I have been looking at are SMSL SU-8 and the Topping D50S. My budget is £300, although I can increase this if necessary.

Thanks in advance.

I have the SU-8, but far prefer the X Airist R-2R DAC with most amps I own, especially the more sterile THX 789. Not much reason to go full balanced with the 789 as it is not a true balanced amp internally so SE DACs are fine and make little difference. I primarily use my 789 with HiFiMan HE560's in balanced mode as the extra power benefits planar HPs.

 

[Sukotto85]

I have the SU-8, but far prefer the X Airist R-2R DAC with most amps I own, especially the more sterile THX 789. Not much reason to go full balanced with the 789 as it is not a true balanced amp internally so SE DACs are fine and make little difference. I primarily use my 789 with HiFiMan HE560's in balanced mode as the extra power benefits planar HPs.

I've spent around 8 hours looking through forums and I am still no closer to making a decision!

So there's literally no point in getting a balanced dac for the 789? What about if I get a balanced tube amp in the future, would it then be a good idea to get balanced? Does a balanced dac truly make a difference in sound compared to a unbalanced dac when paired with a balanced amp? Another user suggested that it won't make any difference to the sound. After all the time I have spent reading into this subject, I am not closing to finding an answer. To be fair, the more I have looked in things the more confused I am. Why can't it be simple haha!