FourT6and2
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- Oct 4, 2019
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I've put about 18 hours on HPA4 and THX 789. DAC is Benchmark DAC3-B. Headphones are Meze Empyrean and Sennheiser 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. 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, both amps sound great and noticeably different than other amps I have here and have compared (Aune S7 Pro, Sennheiser HDV820, FiiO products, etc.). They are both 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.
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. 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, both amps sound great and noticeably different than other amps I have here and have compared (Aune S7 Pro, Sennheiser HDV820, FiiO products, etc.). They are both 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.
