Blind A/B test between (Benchmark AHB2+Topping D90SE/Pre90) and Hegel H190

[phion]

I have been an owner of Hegel H190 which I use in my living room and I recently started putting together my next system around AHB2 for my home office and as the pieces arrived I decided to A/B test the two stacks. I tried to be systematic as much as possible, but by all means critique my protocol.

Systems under test:
A: Qobuz via Roon core on Mac mini -> USB -> Topping D90SE 4V output DAC only mode -> Topping Pre90 -> Benchmark AHB2 in Low Gain
B: Qobuz via Roon core on Mac mini -> USB -> Hegel H190

I tested these two with my JBL L100 classic speakers.

I level matched both setups with a digital multimeter with both 300Hz and 1KHz tones up to +/- 5mv difference. This meant setting the volume on H190 to 35, and the gain on Pre90 to -33dB. The reason I also checked with 300Hz was that the specified frequency range for the AC input on the multimeter was 400Hz. Nevetheless the outputs were pretty similar for both test signals. I noticed that there is a slight (about 4mv) imbalance between the left and right channels of the Hegel.

To carry out the test I used a passive A/B switch box I got from amazon:

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I used two pairs of exactly the same set of cables to connect the speaker outputs of the two amps and routed them inside a "randomization" shoe box with holes on each side, and asked my partner to connect the other ends to the left most and right most terminals of the switch. So basically I had no idea which button was which amp. The speakers were connected to the speaker output of the switch box.

Both setups were visible in Roon, and I grouped them together as a single zone to play a playlist of test tracks to both at the same time. I made sure that the highest resolution track in the playlist was 96 Khz/24bit to be fair to Hegel H190 whose USB input cannot handle higher resolutions. These are the tracks I used (I am quite familiar with most of these) in Artist | Track | Result format. The Result field is either L if I prefer the sound of the leftmost button, R if I preferred what's controlled with the rightmost button, or N if I had no preference or I couldn't tell the difference.

1- Grimes | Vanessa | N
2- Nina Simone | Sinnerman | R
3- Air | Cherry Blossom Girl | N
4- Beethoven | Symphony No. 5, Carlos Kleiber Wiener Phil, Allegro con brio | N
5- Celeste | Tell me Something | N
6- Dire Straits | Money for Nothing | R
7- Moloko | The Time is Now | R
8- Daft Punk | Give Life Back to Music | N
9- Michael Jackson | Billie Jean | N
10- Judas Priest | Pain Killer | N

For the most part I couldn't tell the difference between the two setups no matter how much I went back and forth to moments in these tracks that I consider myself intimately familiar with. It was mostly as if I was listening to exactly the same thing. For three tracks, I did pick system R on a quite faint preference, but really kind of forcing myself to chose.

Now time to unveil what were L and R. I switched the output to system R and it was still playing the last track, and then pressed the off button on Hegel's remote. The music stopped.

I listened to the tracks that I had shown a preference for again and I am convinced I couldn't have heard a difference. I think psychologically I was rooting for Benchmark to win as it's my new system and I have been a bit sore about Hegel based on recent reviews. So I think subconsciously I may have tried to identify what sounded like Benchmark from my audio memory and pick that. Unfortunately once I made that choice the first time, I became kind of biased to it, so lack of randomness between songs is kind of the weakness of my protocol I think.

 

[pma]

As long as you do not get into clipping with one of the amps, it will be extremely difficult to hear a difference in a properly made A/B test, if both amps have flat frequency response and reasonably high damping factor.

 

[Mnyb]

In your setup did you ever noticed any differences in background noise levels ?
Distance to the speakers and speaker sensitivity ( and general background noise ) can make the noise inaudible for both setups even if one is quieter than the other.

Great execution of your test , very well done and as PMA states this is an expected result in most cases.

 

[phion]

In your setup did you ever noticed any differences in background noise levels ?
Distance to the speakers and speaker sensitivity ( and general background noise ) can make the noise inaudible for both setups even if one is quieter than the other.

Great execution of your test , very well done and as PMA states this is an expected result in most cases.

I just listened carefully with my ear next to the tweeter and I can't hear anything for either amps; both seem to be very quite when nothing is playing.

 

[BDWoody]

I have been an owner of Hegel H190 which I use in my living room and I recently started putting together my next system around AHB2 for my home office and as the pieces arrived I decided to A/B test the two stacks. I tried to be systematic as much as possible, but by all means critique my protocol.

Nice job!

Sooooo few go through this hassle, so Kudos. Kinda humbling, isn't it?

If you wanted to take a step back from preference, and just see if you can identify ANY difference, you could meld this into an AB/X test. However, I didn't do that either when I went through a similar exercise with DACs.

Is this your first listening test with controls? Will it change the way you read most 'reviews?'

 

[Kal Rubinson]

This is, of course, not a test to distinguish between the two amps but between two different DAC, volume control and amp configurations. FWIW.

 

[phion]

Nice job!

Sooooo few go through this hassle, so Kudos. Kinda humbling, isn't it?

If you wanted to take a step back from preference, and just see if you can identify ANY difference, you could meld this into an AB/X test. However, I didn't do that either when I went through a similar exercise with DACs.

Is this your first listening test with controls? Will it change the way you read most 'reviews?'

I kind of expected this to be more or less the outcome based on what I had read here, but still actually sitting there and not being able to tell which is which is humbling.

Yes, it was my first "proper" blind test. I had attempted something like this between two DACs before, but I only matched sound level acoustically with a SPL meter and had to ask my partner to do switches which made it hard to switch as frequently. I still couldn't tell the difference between them either.

As to reading reviews, I am pretty new to this hifi thing and honestly don't quite understand what people say in these audiophile reviews when they describe how something sounds

 

[phion]

This is, of course, not a test to distinguish between the two amps but between two different DAC, volume control and amp configurations. FWIW.

Yes, it's true and yet the result is still difficult to discern for me, even though the DAC in Hegel is a weaker link compared to the other stack.

 

[pma]

This is, of course, not a test to distinguish between the two amps but between two different DAC, volume control and amp configurations. FWIW.

Something must be left to be properly reviewed in a qualified review .

 

[Kal Rubinson]

Something must be left to be properly reviewed in a qualified review .

Reviewed perhaps but this is an apples-to-oranges comparison.

 

[phion]

Reviewed perhaps but this is an apples-to-oranges comparison.

I think your point is moot. I would proceed to somehow isolate and compare the amps only if I could discern a difference in this first test. Given that Hegel amp with its inferior DAC still sounds the same to me renders additional tests unnecessary.

Also I only wrote AHB2 in the title mostly for brevity. My objective has been to compare this stack of SOTA SINAD products with something integrated and mediocre, to see how much better measurements matter. I also argue that this test is more relevant to the potential end user more than if the Hegel amp was isolated.

 

[Kal Rubinson]

I also argue that this test is more relevant to the potential end user more than if the Hegel amp was isolated.

OK but I wonder how many potential users would be considering these as alternatives.

 

[phion]

OK but I wonder how many potential users would be considering these as alternatives.

Mostly existing Hegel owners entertaining exchanging their units for something that measures better can chill now

 

[Chrispy]

Mostly existing Hegel owners entertaining exchanging their units for something that measures better can chill now

But that really goes for most amps

 

[Mnyb]

Something must be left to be properly reviewed in a qualified review .

A magazine or pro reviewer could spend more time and maybe even hire help. OP did great and much more than most home user included myself .

But a pro with time on his hands for a proper test . Could test more scenarios.

OP did the most important one he used the products inside thier “envelope” or comfort zone and proved yet again when not driven outside their capacity reasonably designed products ( well Hegel has decimals in its THD numbers and low output impedance ) does not sound very different.

A magazine could then spend time finding the corner cases . High sensitivity speakers if the product is noisy.
Low sensitivity low impedance speakers in a large room to what’s happening when driven hard.
I agree that some of this can be inferred by the numbers, but the readers might benefit from real world examples .

An ad financed mag could even splurge for a power cube ( which is outside Amir’s budget ) and see if something odd shows and then go find a real world speaker that provokes the amps under test in that manner .

And both amps in this case actually provides power I think it’s underestimated, you need power . A boutique amp with 15w class A would surely sound a bit different

 

[Kal Rubinson]

A magazine or pro reviewer could spend more time and maybe even hire help. OP did great and much more than most home user included myself .

But a pro with time on his hands for a proper test . Could test more scenarios.

I do agree with you that the OP did great with his testing of the devices that interested him. I am not criticizing his work.

OTOH, I do not think that a typical "magazine or pro reviewer" has any more time (always deadlines) nor the ability to hire help (unheard of, afaik).
Now, don't get me started with "time on his hands."

 

[Head_Unit]

For the most part I couldn't tell the difference between the two setups

Not a shock to me, and kudos on a good setup. I don't believe amps sound the same, but the differences aren't always huge and can be fleeting. Maybe illusory. Here was a more extreme humbling instance
https://forums.stevehoffman.tv/threads/denon-vs-parts-express-round-1.984507/
In the next part a Denon AVR-X3600H (purchased due to @amirm's test results) was swapped for an Integra DHC 60.5 + ATI 525NC. Sounds a bit different, though we would not say "better" just different. Quite probably explained by the Integra's Audyssey not being adjustable; on the -3600 I had turned off their goofy midrange notch and gently boosted the upper mid 1 dB using the App. Some day I gotta compare versus the AIYIMA A07 TPA3255 from another house (also purchased due to ASR review, danke schoen!). Mostly I don't worry about differences between amps and cables. If there ARE differences, they're small or at least I've never heard a huge "BETTER!!!" so I just enjoy the music

 

[radix]

I do agree with @Kal Rubinson that this is a test between the Topping/AHB2 stack and the Hegel stack, not really amp-to-amp. I do applaud you for taking the time and testing it in a thought out manner.

What was the SPL at your listening position? It seems like you were driving the amps at a modest setting (i.e. -33 dB on Pre).

Based on this result, I'd say return the more expensive gear and stick with the Hegel.

 

[phion]

I do agree with @Kal Rubinson that this is a test between the Topping/AHB2 stack and the Hegel stack, not really amp-to-amp.

Yes, I also agree with Kal; though this was intentional. I should probably reword the title of the thread to make this explicit.

I do applaud you for taking the time and testing it in a thought out manner.

What was the SPL at your listening position? It seems like you were driving the amps at a modest setting (i.e. -33 dB on Pre).

SPL for the first track was between 55-65dB with my sound meter (not a very good one tbh) at the listening position, which was about 2m away from the tweeters; Being a relatively low volume listener, this was actually slightly louder than how I usually listen.

Based on this result, I'd say return the more expensive gear and stick with the Hegel.

As I mentioned, I bought the new gears for a second system in my home office; so I intend to keep both actually. I will be getting Revel M105 speakers for that room, which will arrive soon so I may also repeat the test with those speakers as well.

 

[abdo123]

55-65 dBSPL is above the average for you? Wow lol.

I thought i was on the responsible side for keeping peaks (0dBFS) on about 85dBSPL.

You’re basically running the amplifiers on below 100mW if we take the sensitivity of the speakers as 85dBSPL/W and we took the high end of that 55-65 dBSPL range.

To put that in perspective, Amir’s SINAD measurements are at 5W, your use case is almost in the realm of headphone amplifiers.

Edit: the sensitivity of the speaker is actually 90dB/W.