[Tonybo]

Well, thank you for the clarifications.

My HPA 4 is shipping back to the distributors tomorrow, they have the kits, apparently. Would just point out that its possible to fit the foam formers in the packing box incorrectly and thus load the volume knob rather dangerously. The formers go front and back, not on the sides!

 

[esauseesaw]

Well, thank you for the clarifications.

My HPA 4 is shipping back to the distributors tomorrow, they have the kits, apparently. Would just point out that its possible to fit the foam formers in the packing box incorrectly and thus load the volume knob rather dangerously. The formers go front and back, not on the sides!

Glad you've got that the right way round! We'll get your unit turned around asap.

 

[Tonybo]

Thanks @esauseesaw!

 

[Tonybo]

The HPA4 is back! One week turnround, excellent. Measures perfectly now. The tuner connected to the rca’s sounds incredibly transparent with the small choral groups that they are broadcasting tonight on WDR3 FM (no sign of a ground loop!). Haven’t tried the Pi hat DAC that caused all this trouble in the first place yet, will get to that, but I am very happy now that the configuration is as intended. Many thanks Benchmark and SCV!

 

[Nicknick]

Hi,
for more than one week I try a HPA4 in my chain (Jplay dual-PC Setup and Bricasti M1 SE as DAC). If you don't mind, I would like to profit from your knowledge and your experiences, because I'm not an expert. Which headphones would match best with the HPA4 (according to the performance and potential of the HPA4)? Currently I'm driving a Beyerdynamic T1. Could you give me a small selection of some headphones which you would recommend?

Martin

 

[jsiau]

Hi,
for more than one week I try a HPA4 in my chain (Jplay dual-PC Setup and Bricasti M1 SE as DAC). If you don't mind, I would like to profit from your knowledge and your experiences, because I'm not an expert. Which headphones would match best with the HPA4 (according to the performance and potential of the HPA4)? Currently I'm driving a Beyerdynamic T1. Could you give me a small selection of some headphones which you would recommend?

Martin

Martin,

The HPA4 has become the demonstration platform of choice for a number of headphone manufacturers. It delivers consistent performance over a wide variety of load impedances and output levels. At the CanJam shows you will see the HPA4 at many headphone tables. Follow this link and scroll down to the bottom of the page to see the HPA4 with a variety of headphones:

https://benchmarkmedia.com/pages/rmaf

There are two specific reasons why the HPA4 is well-suited for a wide variety of headphone impedances and sensitivities:

1) The THX-888 headphone amplifier uses feed-forward error correction. This keeps the amplifier distortion free when heavily loaded by low impedance headphones. The no-load and 8-ohm load THD vs output level curves are virtually identical. Other amplifiers produce increasing levels of distortion as the load impedance is reduced.

2) The 256-step relay gain control maintains the SNR and THD performance over an extremely wide gain and attenuation range. This relay-controlled volume stage delivers the full performance of the upstream D/A converter over a very wide range of volume settings. It optimizes the gain staging between the D/A converter and the headphone amplifier.

Bottom line - there are lots of great choices.

 

[YooperAudio]

Hi,
for more than one week I try a HPA4 in my chain (Jplay dual-PC Setup and Bricasti M1 SE as DAC). If you don't mind, I would like to profit from your knowledge and your experiences, because I'm not an expert. Which headphones would match best with the HPA4 (according to the performance and potential of the HPA4)? Currently I'm driving a Beyerdynamic T1. Could you give me a small selection of some headphones which you would recommend?

Martin

I use Sennheiser HD800S phones with my HPA4. Until the HPA4 came along, I essentially never heard the potential of the HD800S, and I thought they were a tad sterile and "lacking" in tonal richness. Not anymore. I absolutely love them together (along with the Benchmark DAC3). Just incredible. The HPA4 lets you go farther into the volume range without any discomfort, which then opens up an entire new world of detail, imaging, and realistic immersion.

 

[Nicknick]

thanks for your advice! I think I will go for the HD800S. They have a reasonable price-performance ratio (in contrast to many headphones here in high-end audio!) and they not only set the benchmark but also serve as a kind of rule within the over ear headphones. I don't want to waste money for crazy headphones which - half a year after their release - eliminates their teething problems and let you know that you own the back-number.

Martin

 

[Christer]

I use Sennheiser HD800S phones with my HPA4. Until the HPA4 came along, I essentially never heard the potential of the HD800S, and I thought they were a tad sterile and "lacking" in tonal richness. Not anymore. I absolutely love them together (along with the Benchmark DAC3). Just incredible. The HPA4 lets you go farther into the volume range without any discomfort, which then opens up an entire new world of detail, imaging, and realistic immersion.

And I have been using my orginal HD800 for years with my DAC2HGC and it's been very good.

But quite honestly ,not until I started using my HD800 with a Chord Qutest/M Scaler have I come to realize its full potential since hearing it for the first time used as monitoring headphones at a series of classical music recording sessions just after it had been released around 2009.
There and then the HD800 sounded very good and quite close to what I could hear live in the hall at the sessions.

And now playing those masterfiles again for the first time I can say it's almost like being back at the sessions again.
No other consumer dac combo has managed that.

It would of course be very interesting to hear if the DAC3/HPA4 will sound as good as an M Scaler.

Without having heard the DAC 3 or HPA4 yet, all I can safely say so far is, my DAC 2 is NOT at all in the same league as Chord's M Scaler in any of the combinations I have head it with.
The M Scaler is very clearly and obviously,more resolving than the DAC2.
The DAC3 would have to be a very obvious audible improvement over the DAC2 to really compete with an M Scaler combo to my ears.
I would also be interested to hear if the HPA4 could improve SQ over my other headphone amps,one of them being the one in DAC2HGC.
But having just read reviews in the British HIFI mag HI FI NEWS of both the Qutest and HPA4 in the same issue I am a bit confused about the SNR figures quoted there.
Both get good, even raving reviews.
But they mentioned 109dB SNR A weighed for Qutest and only 103db SNR A weighed for HPA 4.
If those figures are correct I would assume that Qutest is capable of delivering a larger dynamic range ie has notably better SNR than HPA4?
Under listening conditions a 5dB difference is huge in loudness levels at least.

Until reading that review I was under the impression that HPA4 had some of the, if not the ,lowest noise levels of any headphone amp on the market?
As I read and interpret those figures the limiting factor as far as noise levels are concerned in that chain, would be the HPA4 not the dac?
Correct me if I am making any wrong assumptions.
All the above written with interest of getting the best possible SQ and lowest noise levels with large scale acoustic symphonic hi res music as a reference.
Not at all intended in any way as a criticism of products I have not even heard yet. Only my curiosity.
Cheers Controversial Christer

 

[YooperAudio]

And I have been using my orginal HD800 for years with my DAC2HGC and it's been very good.

But quite honestly ,not until I started using my HD800 with a Chord Qutest/M Scaler have I come to realize its full potential since hearing it for the first time used as monitoring headphones at a series of classical music recording sessions just after it had been released around 2009.
There and then the HD800 sounded very good and quite close to what I could hear live in the hall at the sessions.

And now playing those masterfiles again for the first time I can say it's almost like being back at the sessions again.
No other consumer dac combo has managed that.

It would of course be very interesting to hear if the DAC3/HPA4 will sound as good as an M Scaler.

Without having heard the DAC 3 or HPA4 yet, all I can safely say so far is, my DAC 2 is NOT at all in the same league as Chord's M Scaler in any of the combinations I have head it with.
The M Scaler is very clearly and obviously,more resolving than the DAC2.
The DAC3 would have to be a very obvious audible improvement over the DAC2 to really compete with an M Scaler combo to my ears.
I would also be interested to hear if the HPA4 could improve SQ over my other headphone amps,one of them being the one in DAC2HGC.
But having just read reviews in the British HIFI mag HI FI NEWS of both the Qutest and HPA4 in the same issue I am a bit confused about the SNR figures quoted there.
Both get good, even raving reviews.
But they mentioned 109dB SNR A weighed for Qutest and only 103db SNR A weighed for HPA 4.
If those figures are correct I would assume that Qutest is capable of delivering a larger dynamic range ie has notably better SNR than HPA4?
Under listening conditions a 5dB difference is huge in loudness levels at least.

Until reading that review I was under the impression that HPA4 had some of the, if not the ,lowest noise levels of any headphone amp on the market?
As I read and interpret those figures the limiting factor as far as noise levels are concerned in that chain, would be the HPA4 not the dac?
Correct me if I am making any wrong assumptions.
All the above written with interest of getting the best possible SQ and lowest noise levels with large scale acoustic symphonic hi res music as a reference.
Not at all intended in any way as a criticism of products I have not even heard yet. Only my curiosity.
Cheers Controversial Christer

There are some things about the post above that confuse me. Seems like you're comparing apples to oranges here.

The Qutest is a DAC, and it has no volume control, and no HP amp. The recent Stereophile review of the Qutest looked pretty favorable, but it seemed to settle in at the Brooklyn/iFi Pro level of DAC performance (with is very good). But Stereophile seems to consistently rate the Benchmark DAC3 to be at a higher level of performance than the Brooklyn/iFi. (I realize the Stereophile reviews are just a data point and aren't always to everyone's tastes.) Too bad the Qutest is limited to unbalance outs, but not the end of the world.

The M Scaler is just an upscaler that sits between your digital source and the Qutest - correct? And of course, it has no volume or HP amp. So I assume you're piping the output of your M Scaler/Qutest combo into some kind of HP amp so that you can listen via your HD800 phones?

And from everything I've read and heard, the Benchmark DAC3 is a definite improvement over the DAC2 - so it's unfortunate that you're not comparing your Chord stuff with the DAC3.

The way I see it, there might be some advantage in putting an M Scaler in front of a DAC3/HPA4 stack if the upscaling would produce a notably more accurate (realistic?) sound. That would be a fun thing to try out. But given the way the DAC3 is designed, I'm not sure how much the massive upstream upscaling would get you.

As for the HPA4 - it's not really relevant to your comparison, since it's neither an upscaler or a DAC. Both the DAC3 (HGC) and the HPA4 have volume control. The HPA4 is just a superb HP amp and preamp that, when combined with the DAC3, works really well with the HD800S phones. The great thing about benchmark is that you can get all of their stuff and try it out for 30 days risk-free and hear for yourself.

For $5K, the Chord M Scaler would need to produce some pretty amazing digital source improvements in my Benchmark stack for me to justify buying it. But I've said that before, and ended up spending the money.

 

[Christer]

There are some things about the post above that confuse me. Seems like you're comparing apples to oranges here.

The Qutest is a DAC, and it has no volume control, and no HP amp. The recent Stereophile review of the Qutest looked pretty favorable, but it seemed to settle in at the Brooklyn/iFi Pro level of DAC performance (with is very good). But Stereophile seems to consistently rate the Benchmark DAC3 to be at a higher level of performance than the Brooklyn/iFi. (I realize the Stereophile reviews are just a data point and aren't always to everyone's tastes.) Too bad the Qutest is limited to unbalance outs, but not the end of the world.

The M Scaler is just an upscaler that sits between your digital source and the Qutest - correct? And of course, it has no volume or HP amp. So I assume you're piping the output of your M Scaler/Qutest combo into some kind of HP amp so that you can listen via your HD800 phones?

And from everything I've read and heard, the Benchmark DAC3 is a definite improvement over the DAC2 - so it's unfortunate that you're not comparing your Chord stuff with the DAC3.

The way I see it, there might be some advantage in putting an M Scaler in front of a DAC3/HPA4 stack if the upscaling would produce a notably more accurate (realistic?) sound. That would be a fun thing to try out. But given the way the DAC3 is designed, I'm not sure how much the massive upstream upscaling would get you.

As for the HPA4 - it's not really relevant to your comparison, since it's neither an upscaler or a DAC. Both the DAC3 (HGC) and the HPA4 have volume control. The HPA4 is just a superb HP amp and preamp that, when combined with the DAC3, works really well with the HD800S phones. The great thing about benchmark is that you can get all of their stuff and try it out for 30 days risk-free and hear for yourself.

For $5K, the Chord M Scaler would need to produce some pretty amazing digital source improvements in my Benchmark stack for me to justify buying it. But I've said that before, and ended up spending the money.

Hello Yooper Audio, and thanks for your take on this.Yes my post may seem a bit confusing.And that is because I am a bit confused especially regarding those SNR figures I quoted from that review.

But I am generally interested in THE BEST POSSIBLE SQ with acoustic music.

Nice to read that you feel the DAC3 is better than the DAC2.
I also want to audition it.

But at the end of your post it seems like you are basically asking almost the same questions I did?

We don't know which sounds best until we have actually auditioned things right?

In my case the DAC3/HPA4 would need to be a very clear and obviously audible improvement over my DAC2 HGC to begin with.

And if that is clearly established, then it would need to take on the Chord M Scaler which I can only describe as so far on my journey in digital audio to be the most obvious and clearest improvement with acoustic music I yet heard.

I heard it first in its orginal form in the BLU2/Dave combination and have now heard it extensively with the new TT2 as well and Qutest which I own.
And with complex heavily scored symphonic or for that matter any well recorded acoustic material it is in a completely different league than my DAC2.

I am very familar with the DAC2 having owned one for over 5 years.

The DAC 2 tames digital glare compared to many other DAC combos like the one you mention, but is not as resolving as the M Scaler which upscales 16/44.1 to 705.6 khz and 24/96 and anything above to 768khz.
I am not sure there would be much, if anything, to gain from adding an M Scaler to a Benchmark DAC?
Benchmark have their own way of upsampling internally,don't they?

But an M Scaler with a compatible Chord DAC even makes well recorded 16/44.1 sound very good to me. No other digital reproduction link or cd player has managed to do that!
16/44.1 does NOT sound good via my DAC2.

I still suspect that for digital to sound as close as currently theoretically/technically possible to live acoustic music in a real hall, 24/192 which is the limit with Benchmark's DACs even with DAC3 as well, may not be enough?
I may be wrong.

But having both heard DXD 24/358.2khz raw at recording sessions and now what M Scaler does by upsampling DXD to 768khz I still suspect that the target may need to be set at 768khz?

Back on topic.
Anyway my interest in HPA4 which is the actual topic of this thread is because I already have the DAC2 HGC and the headphone amp in it is already one of the better I have heard.

And I have even heard its headphone amp used at classical music recording sessions as monitoring amp with the HD800 but bypassing its digital section.
The sessions were recorded in DXD.

And if the HPA4 clearly and audibly improves on my HPA2 I might be interested in using it with my Qutest /M Scaler instead of the DAC2 headphone amp.
The partnering ABH2 power amp is also an amp I would want to audition.
But those SNR figures still remain an open question.

Cheers Controversial Christer

 

[Tobes]

Both get good, even raving reviews.
But they mentioned 109dB SNR A weighed for Qutest and only 103db SNR A weighed for HPA 4.

Just going by the brief measurement summary, part of the reason for the disparity between Benchmark's figure and the Hifi News result is the measurement level.

Hifi News measures at 0dBV (1VRMS or 2.28dBu) and Benchmark measure at +24dBu (12.28VRMS or 21.27dBV) - which is the nominal output level for the HPA4 balanced outputs and ideal for the low gain setting of the Benchmark AHB2 amp.
24dBu is also the nominal output of the DAC3, though there are pads available to ensure compatibility with typical (low) consumer levels.
Maintaining high voltage from DAC to pre to amp maximises SNR.

 

[Christer]

Just going by the brief measurement summary, part of the reason for the disparity between Benchmark's figure and the Hifi News result is the measurement level.

Hifi News measures at 0dBV (1VRMS or 2.28dBu) and Benchmark measure at +24dBu (12.28VRMS or 21.27dBV) - which is the nominal output level for the HPA4 balanced outputs and ideal for the low gain setting of the Benchmark AHB2 amp.
24dBu is also the nominal output of the DAC3, though there are pads available to ensure compatibility with typical (low) consumer levels.
Maintaining high voltage from DAC to pre to amp maximises SNR.

Hello Tobes and thanks for your explanation.
So now all I have to do is to figure out who measures most honestly from a user and buyer point of view?

Obviously Benchmark's own measurements deliver a better higher value than the 0dBV measured value from HIFI NEWS.

But how do I know which is the most quiet least noisy link in absolute terms in say the chain I am thinking of possibly using a HPA4 in, ie a Chord DAC which theoretically has 5dB less inherent noise then the HPA4 measured the same way they measured the HPA4?

It also seems like Stereophile measures dynamic range /SNR differently than both HIFI NEWS or Benchmark do as well?
In their review of the Qutest they mentioned 124dB dynamic range for the Qutest and I can't remember their SNR for my DAC2 or DAC 3.
There seems to be no conscensus on how to best and most accurately measure SNR/dynamic range?
Would it be correct to assume that manufacturers measure in a more advantagous way to make their product seem as excellent as possible and at least some HIFI Mags do the opposite?
Or deliver factual figures that are more relevant for a user not necessarily connecting a given product to another product from the same brand maybe?
I am still confused.
Cheers Controversial Christer

 

[Tobes]

There may be other reasons for the differences in Benchmark vs Hifi News measurements, obviously the output level I mentioned will have an effect on SNR - as will the instrument being used to make the measurement, environment etc.
The +24dBu output is the nominal output level for the DAC3 and HPA4 and how they will be used in a Benchmark system, so it's relevant I think.

Magazines use different test procedures and there's something to be said for them maintaining a consistent standard that allows readers to compare reviews more easily. Stereophile is pretty good at this - though sometimes you have to read the graphs carefully.
I don't have the full test data/method and have no idea whether the HiFi news derived SNR measurement for the Qutest is comparable at all to the measurement of the HPA4.
Do you have the full measurement explanations to share?

 

[Jozurr]

If anyone would be willing to sell their HPA4, Please do PM me. Thanks