Review and Measurements of Benchmark HPA4 Headphone Amp/Pre

[JohnYang1997]

I found another thing, why is hpa4 more noisy and quieter tham 789 at the same time?

 

[amirm]

I found another thing, why is hpa4 more noisy and quieter tham 789 at the same time?

It has higher baseline noise. However, it has so much less distortion that when you sum the two in those sweeps, it is better than 789.

 

[JohnYang1997]

It has higher baseline noise. However, it has so much less distortion that when you sum the two in those sweeps, it is better than 789.

It can't be distortion can it, linearly increased distortion at lower level? Probably different bandwidths? And some smps noise got into 789?

 

[JohnYang1997]

It would be interesting to get Amir-measurements for the Pass Labs HPA-1, which is around the same price and similar functionality, but no balanced function. No, I don't have one I can send him.

https://www.stereophile.com/content/pass-labs-hpa-1-headphone-amplifier-measurements

 

[amirm]

It can't be distortion can it?

No, baseline measurement is done using no input signal.

 

[Music1969]

A huge congratulations to Benchmark

Don't forget THX... their design is a huge part of this performance.

It's the THX 789 with a bigger budget to take things to the next (top) level. Plus balanced input can be handy.

 

[August]

Damn,it brings the bodies that have piled up into mountains and the blood that has gathered into the sea. (refers to other manufacturers)

 

[Blake Klondike]

Thanks so much for the fine review-- It really is clear that if you send Benchmark $7000, or whatever it is, they will send you a power amp, DAC and headphone amp that you can listen happily to for the rest of your life. Really great to know, and the standard, for me, by which all other products will be judged. Outstanding work.

 

[Music1969]

Headphone Listening Test
As usual, I started my testing with the Sennheiser HD-650. You guys know that I like to test headphone amplifiers at high volumes. Even if it is for a second or two, I try to up the volume to max to see whether the headphone or the amplifier give out first. Not here. I was too scared to get even close to -10 dB let alone +15 dB range the HPA4 has! The sound had incredible authority with superb bass and fantastic detail. It is a revelation to have this much clean power on hand to drive a headphone.

Does it sounds subjectively (to you) any different to your THX 789?

 

[maty]

Picture enhanced and rotated

from https://www.hifinews.com/content/benchmark-hpa4-headphone-amplifier-page-2

BTW, I can see thick walls again. Excellence must not be limited only to electronics, and more for the sale price.

 

[vkvedam]

Thanks Amir, excellent read!

 

[filo97s]

really impressive those measurements, my thought however is that it should be indistinguisheable from an Atom that costs 30 times less. Our ear it's not an analyzer, and it can barely spot the differences between the atom and a well made tube amp with 1% THD (like the WA22, at least for me), so imagine this kind of performance... (not even talking about individual tastes that maybe tend to prefer the higher tube distortion to the perfection of the transistor)
Still, it's nice to see that the money you spend, goes somewhere.

 

[JohnYang1997]

really impressive those measurements, my thought however is that it should be indistinguisheable from an Atom that costs 30 times less. Our ear it's not an analyzer, and it can barely spot the differences between the atom and a well made tube amp with 1% THD (like the WA22, at least for me), so imagine this kind of performance... (not even talking about individual tastes that maybe tend to prefer the higher tube distortion to the perfection of the transistor)
Still, it's nice to see that the money you spend, goes somewhere.

Come on seriously? WA22? It sounded "juicy" and "rich" but very dirty sounding. It is instant difference from a good solid state amp. Main issue isn't the tube tho it's the transformer.

 

[filo97s]

Come on seriously? WA22? It sounded "juicy" and "rich" but very dirty sounding. It is instant difference from a good solid state amp. Main issue isn't the tube tho it's the transformer.

well, at least for me. But i've seen also the zeos review of the WA22 and he also says that there's little to no difference in low gain compared to a ss amp. Measuring is good but we shouldn't overextimate our ears, and a perfect measure isn't everything. There's also lots of amps that measure worse (well actually everything else) but they are still a good choice. Even the Darkvoice 336SE that is an absolute crap from a measurement point of view, it turned out to be pleasant to listen to. Probably everything above 80dB SINAD is indistinguishable from perfect, especially if we're talking of speaker amps (where room noise is greater) and under 80dB SINAD, there's a subjective component that comes into play.

 

[JohnYang1997]

well, at least for me. But i've seen also the zeos review of the WA22 and he also says that there's little to no difference in low gain compared to a ss amp. Measuring is good but we shouldn't overextimate our ears, and a perfect measure isn't everything. There's also lots of amps that measure worse (well actually everything else) but they are still a good choice. Even the Darkvoice 336SE that is an absolute crap from a measurement point of view, it turned out to be pleasant to listen to. Probably everything above 80dB SINAD is indistinguishable from perfect, especially if we're talking of speaker amps (where room noise is greater) and under 80dB SINAD, there's a subjective component that comes into play.

I have heard wa22 2 years ago and wa33 1 year ago. The difference between them and good ss amp is huge. I mean huge. I doesn't take 2 sec to tell the difference. The thing is using resistive load for testing. These amps are far worse than it looks on measurements.

 

[JJB70]

A remarkable piece of equipment, as we would expect from Benchmark the design is first class and measured performance stellar. There are more and more expensive headphone amplifiers (such as the new high end offshoot of Lake People), many of which seem to be little more than audio jewellery. This is expensive but it is also superb. Does anyone truly need a product like this? No, but I do understand why people buy one of these as there is a pride of ownership in knowing you have something which is so well engineered (and in the bizarro world of high end audio Benchmark are not actually particularly expensive). Benchmark are one of the islands of sanity and first class engineering in the largely dysfunctional higher end of the industry.

 

[filo97s]

I have heard wa22 2 years ago and wa33 1 year ago. The difference between them and good ss amp is huge. I mean huge. I doesn't take 2 sec to tell the difference. The thing is using resistive load for testing. These amps are far worse than it looks on measurements.

resistive loading like a planar magnetic headphone, so what you measure is what you get if you have a planar or another headphone that has a flat impedance.
Still for me, past a certain league, the difference is way more subtle than it appears to be from the graphs. And i won't use the word "worse", just "different", otherwise how do you explain thousands of people buying tube amps even if they are worse on the paper? I'd call worse only broken designs, like the ones from Audio GD that objectively have something wrong, but not something that has an higher THD because with certain loads it's even better.
For example, the first gen HD800 for me it's better on a tube amp rather than on a ss one, same with the HD660s.

 

[maty]

Picture optimized

from: https://www.avforums.com/news/benchmark-hpa4-headphone-line-amplifier-coming-soon.14885

Closed Box, without holes.

Thick aluminum? walls.

SMPS protected and with small circular holes, as is usual in the professional world. Thus they will not act as small antennas, unlike what happens with long and narrow slots, present on the top of many devices (an example: the AVR), even just above the audio section!

In Benchmark they design very well not only electronics!

If you live in NA it is a great option. In Europe, with shipping, customs and taxes (Spain: + 21%) not so much. And in case of breakdown ...

 

[Snafu]

Benchmark's amps/dacs sure measure nicely but.... they are

So.
God.
Damn.
Ugly.

 

[maty]

The latter is easy to fix. A new line for the home and at a higher price for the aesthetic improvement.

The front is also available in black.