[twoloszyn]

Thanks for your thoughts @MacedonianHero. I wish I had those four headphones to test on my HPA4 slowly but surely I’ll get there one day!

 

[nordkapp]

In short, I loved it so much that I purchased the review unit.

How am I not surprised? Great write up Peter!

 

[MacedonianHero]

How am I not surprised? Great write up Peter!

Thanks....not surprising at all once you get to hear this wonderfully transparent amp.

 

[MacedonianHero]

Thanks for your thoughts @MacedonianHero. I wish I had those four headphones to test on my HPA4 slowly but surely I’ll get there one day!

This amp can really power them all. I've just confirmed that the HPA4 is a peach with the Susvara as well! Very impressive indeed!

 

[JP281]

What about driving he6?

 

[MacedonianHero]

What about driving he6?

Haven't tried that one yet...but here are the specs:

Susvara: 60 ohm impedance and Sensitivity: 83 dB/mW
HE-6SE: 50 ohm impedance and Sensitivity: 83.5 dB/mW

So the Susvara are a tad harder to drive...in theory, the HE-6SE should be just fine.

 

[JP281]

I meant the OG he6 but I get your point. If it can power susvara then it shouldn't be an issue then. Did you have to set the line input +10db in the settings menu to power the susvara?

 

[Liu Junyuan]

In case any one is interested, here my my Benchmark HPA4 review:

https://www.headphone.guru/the-benchmark-hpa4-headphone-amplifier-the-leader-in-transparency/

In short, I loved it so much that I purchased the review unit.

I read the review and see it also paired well the Utopia. This corroborates Tobe's findings in this thread. Do you prefer the Utopia driven by the more neutral HPA4 or the slightly warmer GS-X Mini. I suppose this comes more down to tonal preference and system synergy since both have more than enough clean power to drive the Utopia authoritatively.

 

[MacedonianHero]

I read the review and see it also paired well the Utopia. This corroborates Tobe's findings in this thread. Do you prefer the Utopia driven by the more neutral HPA4 or the slightly warmer GS-X Mini. I suppose this comes more down to tonal preference and system synergy since both have more than enough clean power to drive the Utopia authoritatively.

Depends on my mood really. But if you are using the HPA4 exclusively, you have nothing to worry about!

 

[MacedonianHero]

I meant the OG he6 but I get your point. If it can power susvara then it shouldn't be an issue then. Did you have to set the line input +10db in the settings menu to power the susvara?

Using it with my Abyss Phi TC and Susvara, I usually run it at +8 dB.

 

[FourT6and2]

Have put about 18 hours of listening time on the HPA4 and DAC3-B. Also compared to THX 789, HDV820, and Aune S7 Pro. Aune has been returned. HDV820 has been my DAC/Amp for a while. Both 789 and HPA4 are punchier and more authoritative than the Sennheiser. The HPA4 and 789 are quite close to one another. Equal control and dominance over the audio. I'm listening to lots of hard rock, metal, prog rock, etc. with Empyrean and HD820 headphones. The DAC3B has internal pads that need to be adjusted when running into different amps. With the HPA4 you need to keep it at 0dB pad. With other amps, like the 789, you have to set them to -10dB. So it's hard to go back and forth quickly.

At first I didn't like the HPA4 at all actually. It sounded good, but lacked something I couldn't put my finger on. Whereas the 789 immediately jumped out at me as being powerful and delivery a visceral and clean sound. Albeit slightly brighter and snappier than the HPA4. But after some time either I've adjusted or the amp has "broken in" (I don't really believe that's a thing) and they sound nearly identical. But the HPA4 does sound every so slightly thicker and deeper. It's quite subtle. The 789 is very slightly brighter. For example, kick drum hits sound deeper and thicker on the HPA4 whereas on the 789 the note's attack has a slightly brighter "snap" to it. It's very subtle though. With either amp, the music sounds fantastic. And choosing one based on sound alone is really a crap shoot.

That said... since they sound so similar, it's hard for me to justify $3,000 for the HPA4 vs $400 for the 789. The build quality on the Benchmark is better for sure. The features are better for sure. I don't need those features though. I don't need multiple inputs and outputs and pass-thrus. I don't need a touch screen. I don't need a fancy digital stepped attenuator. I don't need level presets and adjustability. All I need is XLR input from a DAC, XLR output for headphones, and a volume knob. So really, it's going to come down to sound quality. I haven't made a decision yet, as I have 30 days thanks to Benchmark's trial period. I am going to keep the DAC3-B for sure though. I was actually surprised that it does sound better than the built-in DAC in the Sennheiser HDV820. I ran that DAC into the 820 and I could hear parts of familiar songs I hadn't heard before. Like subtle echo/reverb/FX/noises in the background that were previously obscured.

So... conclusion?
I need more time to suss out the differences, if any, between 789 and HPA4. But the HPA4 certainly sounds great. Especially for heavy prog rock that requires complete control to not sound like mush.

For anybody curious, with the DAC3 set to 0dB, HPA4 is at about -30dB with Empyrean for loud, immersive listening and HD820 is at -23dB for about the same volume. This is about 3/4 on the volume display.

 

[stemiki]

the HPA4 has a marked improvement after about a month of use (2-3 hours a day). Have them do a good burn-in.

 

[Arniesb]

Have put about 18 hours of listening time on the HPA4 and DAC3-B. Also compared to THX 789, HDV820, and Aune S7 Pro. Aune has been returned. HDV820 has been my DAC/Amp for a while. Both 789 and HPA4 are punchier and more authoritative than the Sennheiser. The HPA4 and 789 are quite close to one another. Equal control and dominance over the audio. I'm listening to lots of hard rock, metal, prog rock, etc. with Empyrean and HD820 headphones. The DAC3B has internal pads that need to be adjusted when running into different amps. With the HPA4 you need to keep it at 0dB pad. With other amps, like the 789, you have to set them to -10dB. So it's hard to go back and forth quickly.

At first I didn't like the HPA4 at all actually. It sounded good, but lacked something I couldn't put my finger on. Whereas the 789 immediately jumped out at me as being powerful and delivery a visceral and clean sound. Albeit slightly brighter and snappier than the HPA4. But after some time either I've adjusted or the amp has "broken in" (I don't really believe that's a thing) and they sound nearly identical. But the HPA4 does sound every so slightly thicker and deeper. It's quite subtle. The 789 is very slightly brighter. For example, kick drum hits sound deeper and thicker on the HPA4 whereas on the 789 the note's attack has a slightly brighter "snap" to it. It's very subtle though. With either amp, the music sounds fantastic. And choosing one based on sound alone is really a crap shoot.

That said... since they sound so similar, it's hard for me to justify $3,000 for the HPA4 vs $400 for the 789. The build quality on the Benchmark is better for sure. The features are better for sure. I don't need those features though. I don't need multiple inputs and outputs and pass-thrus. I don't need a touch screen. I don't need a fancy digital stepped attenuator. I don't need level presets and adjustability. All I need is XLR input from a DAC, XLR output for headphones, and a volume knob. So really, it's going to come down to sound quality. I haven't made a decision yet, as I have 30 days thanks to Benchmark's trial period. I am going to keep the DAC3-B for sure though. I was actually surprised that it does sound better than the built-in DAC in the Sennheiser HDV820. I ran that DAC into the 820 and I could hear parts of familiar songs I hadn't heard before. Like subtle echo/reverb/FX/noises in the background that were previously obscured.

So... conclusion?
I need more time to suss out the differences, if any, between 789 and HPA4. But the HPA4 certainly sounds great. Especially for heavy prog rock that requires complete control to not sound like mush.

For anybody curious, with the DAC3 set to 0dB, HPA4 is at about -30dB with Empyrean for loud, immersive listening and HD820 is at -23dB for about the same volume. This is about 3/4 on the volume display.

Well Hpa4 sound thicker because it have better power supply that can deliver better dynamics and quieter background.

 

[FourT6and2]

the HPA4 has a marked improvement after about a month of use (2-3 hours a day). Have them do a good burn-in.

Well Benchmark has a 30-day return policy. I'm certainly not going to wait until after that period is over to make a decision.
Also, Benchmark themselves say there is no "burn in". They designed the thing so I'll have to trust what they say.

 

[twoloszyn]

I suppose if it takes 2-3 hours a day for 30 days to burn it in you could just leave it on for 4-6 hours for 15 days haha. I do believe there is some validity to a higher quality power supply that leads to any discernible sound quality differences between the 789 and HPA4. Had they been identical I think it would be impossible to tell the difference between the two..