Benchmark HPA4 and a RME ADI 2 DAC

[ShiZo]

What line out volume should I use for external headphone amplifiers? I just recieved my Benchmark HPA4 and want to use the RME as a standalone dac.

 

[BurritoJustice]

+24dBu, so maximum level. The HPA4 is designed for the +28dBu output of the Benchmark DACs, so it will work best with the highest voltage you can pump into it. Should show the ideal performance of both systems.

 

[watchnerd]

What line out volume should I use for external headphone amplifiers? I just recieved my Benchmark HPA4 and want to use the RME as a standalone dac.

Why not just use the headphone amp built into the RME?

It's a damn good headphone amp as is.

 

[ShiZo]

+24dBu, so maximum level. The HPA4 is designed for the +28dBu output of the Benchmark DACs, so it will work best with the highest voltage you can pump into it. Should show the ideal performance of both systems.

SO it's not powerful enough?

 

[BurritoJustice]

SO it's not powerful enough?

Absolutely not. +28dBu is the maximum input voltage, not what is required or necessary. The ADI-2 is extremely competitive at 24dBu with the DAC3 at +28dBu. You should always use the maximum voltage that your DAC and amp both support. The HPA4's ability to accept input voltages up to 28dBu is actually quite a nice feature, the semi-equivalent THX AAA 789 clips above +19dBu.

 

[ShiZo]

I feel like I will see an improvement. Everybody always questions it though.

 

[watchnerd]

I feel like I will see an improvement. Everybody always questions it though.

Because you're just as likely to have a sonic degradation as an improvement.

If you don't need the extra power, and you probably don't, you're just adding more circuitry and noise.

 

[BurritoJustice]

Because you're just as likely to have a sonic degradation as an improvement.

If you don't need the extra power, and you probably don't, you're just adding more circuitry and noise.

To be fair, the THX AAA amps are a substantial step up over any other designs. Replacing the amp in the ADI-2 with the HPA4 does lower distortion and noise. The HPA4 also has an insanely accurate resistor ladder line amp that will likely work a lot better than the digital/relay combination in the ADI-2, without the dynamic range compression.

There is certainly an argument for it being not audiable or necessary, but it won't degrade performance.

 

[ShiZo]

Because you're just as likely to have a sonic degradation as an improvement.

If you don't need the extra power, and you probably don't, you're just adding more circuitry and noise.

Would a stand alone dac be different or you just think the upgrade is unnecessary?

 

[BurritoJustice]

Would a stand alone dac be different or you just think the upgrade is unnecessary?

The amp in the ADI-2 is good enough to be totally transparent, you honestly won't be able to hear the difference with the HPA4. It certainly isn't worth another three grand.

 

[watchnerd]

To be fair, the THX AAA amps are a substantial step up over any other designs. Replacing the amp in the ADI-2 with the HPA4 does lower distortion and noise. The HPA4 also has an insanely accurate resistor ladder line amp that will likely work a lot better than the digital/relay combination in the ADI-2, without the dynamic range compression.

There is certainly an argument for it being not audiable or necessary, but it won't degrade performance.

Have you measured the SINAD of the RME standalone vs the RME + HPA4?

 

[BurritoJustice]

Have you measured the SINAD of the RME standalone vs the RME + HPA4?

Read Amir's review of the THX AAA 789, which uses a scaled down version of the AAA 888 used in the HPA4. In short, it exceeds the SINAD performance of any DAC on the market. The internal headphone amp on the ADI-2 is good, but it isn't THX AAA good. Of course the difference is only academic, however.

I own an ADI-2 Pro Fs and will measure this exact thing for you, though with a THX 789 instead, when mine arrives next week

 

[watchnerd]

Read Amir's review of the THX AAA 789, which uses a scaled down version of the AAA 888 used in the HPA4. In short, it exceeds the SINAD performance of any DAC on the market. The internal headphone amp on the ADI-2 is good, but it isn't THX AAA good. Of course the difference is only academic, however.

I've read those reviews, but the pieces in isolation are not the same as the pieces in combination.

But, yes, entirely academic and waste of cash no matter what.

 

[maverickronin]

But, yes, entirely academic and waste of cash no matter what.

Unless you've got an HE6 or really need an analog input on your headamp...

 

[watchnerd]

Unless you've got an HE6 or really need an analog input on your headamp...

Or get the Pro version with built in ADC?

 

[maverickronin]

Or get the Pro version with built in ADC?

I don't doubt that it's transparent, but an extra conversion is inelegant.

The HPA4 is mostly just bragging rights though.

 

[BurritoJustice]

Unless you've got an HE6 or really need an analog input on your headamp...

I've actually got a HE-6 on the way, I'll see how it goes.

And yeah if I had the money I'd love a HPA4 too, there is something alluring about excessively perfect performance.

 

[ShiZo]

The only way you couldn't tell the difference between the HPA4 and the rme amp section is if you were deaf.

 

[andreasmaaan]

The only way you couldn't tell the difference between the HPA4 and the rme amp section is if you were deaf.

Or blind