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WolfX700 Measurement of Benchmark AHB2 Power AMP

WolfX-700

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#1
I have some power amplifiers, from Class A, AB to Class D. For some time in the past, I've been obsessed with making different types of power amplifiers for myself. There is no doubt that they have a variety of different sound labels.

But anyway, I think I need a "standard" amplifier to serve as a benchmark for my listening to music.

In terms of my values, it's hard to talk about good or bad without a benchmark (not a brand).

Unfortunately, I've been reluctant to invest too much in power amplifiers for a long time.

This is mainly because all kinds of lies and deceptions have long existed in the publicity surrounding power amplifiers (in fact, in almost all HiFi products). It's cumbersome to borrow a power amplifier to measure (they're often heavy and expensive). And almost all brands are promoting their "voice tags" --- I don't trust them.
The other thing is, I'm not rich enough to splurge thousands or even tens of thousands of dollars at will.

Until the last time, I made up my mind to welcome Benchmark AHB2.

There is no doubt that this is influenced (or stimulated) by Amir's measurements. Thanks To Amir!

Photo1.jpg


Photo.jpg

Rear.jpg



This is a fairly compact unit (and very light) for a power amplifier. In terms of construction quality, overall higher than the medium level. The front panel -- excellent, rear - is excellent, and I like the design of the output terminals very much, especially for the handling of bare wire connections. I'm using the NL connector to connect my speakers (very convenient and reliable way to connect).

To complain: the edges of the fins are not smooth enough, although not very sharp, but really do not feel good. Another is that this size is really a little too small, and my common product size is not matched---- A bit troublesome when stacked.

Although Amir measured this,but if I didn't do it again I would let my APX555 and the wolves very disappointed.

Ok, I also encountered a VCR(voltage coefficient of resistance) problem with the load.It took me some time to resolve this matter, and I also know that it may still not be ideal at the moment (due to the logistics problem of the Chinese New Year, attempts to buy better resistors are blocked).

Anyway, I can't wait! Measurement starts!(I set the gain to 14.2db i use)
First we start with the traditional 4R / 5W of ASR:
4R5W.jpg


4R1W.jpg

4R10W.jpg

4R100W.jpg

8R1W.jpg

8R10W.jpg

8R100W.jpg

4R-Linearity-(4.jpg

8R-Linearity-(4.jpg


8R-Relative-Level-(1.jpg

8R-THD+N-Ratio-vs-Measured-Level.jpg

4R-THD+N-Ratio-vs-Measured-Level.jpg


4R-THD-Ratio.jpg


8R-THD-Ratio.jpg


5WCrosstalk.jpg


8R1WMultitone.jpg


8R10WMultitone.jpg


8RMultitone.jpg



OI.jpg


Conclusion: No doubt this is an excellent amplifier! Although it is not cheap in my opinion, considering that the price often increases exponentially with performance, it does not seem to be so difficult to accept ...

Of course, it is eagerly hoped that the sought-after Chinese manufacturers can surpass this realization and sell at a more reasonable price. (In fact, more than one Chinese manufacturer has stated that they are developing a power amplifier that is less than half the price of AHB2 and meets or exceeds its performance)
 
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Matias

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#2
Great! Could you also show 32 tone at 1W and 10W? Always interesting to see those.
 

Feyire

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#3
Of course, it is eagerly hoped that the sought-after Chinese manufacturers can surpass this realization and sell at a more reasonable price. (In fact, more than one Chinese manufacturer has stated that they are developing a power amplifier that is less than half the price of AHB2 and meets or exceeds its performance)
Bold talk, who are these companies?
 

Nango

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All the great work and all the charts with no explanation is senseless at least to me. I noticed you mentioned you made bad experiences in the past but pls reconsider putting at least one sentence in the charts pls.
 
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WolfX-700

WolfX-700

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restorer-john

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#8
Bold talk, who are these companies?
They are reverse engineering the FPGA, give them time. ;)

It'll be a "BankMark BHA-2" in a lurid crimson and gold anodized finish at one third of the price with dubious mains wiring and lots of blue LEDs. ;)
 
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WolfX-700

WolfX-700

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They are reverse engineering the FPGA, give them time. ;)

It'll be a "BankMark BHA-2" in a lurid crimson and gold anodized finish at one third of the price with dubious mains wiring and lots of blue LEDs. ;)
I don't think so--although there are indeed many Chinese manufacturers copying or directly stealing some power amplifier designs and selling them. But the manufacturers I mentioned said they were not going to make such products-if they did, I would despise them.
 

jasonq997

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#13
When I hit it big, the first thing I am going to do is buy 2 of these as my stereo "monoblocks".
 
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1W:0.003347% 10W:0.002689% 100W:0.002680% 8R
Thank you! That's:

1W: -89.5db 10W: -91.4db 100W: -91.4db

I'm a bit surprised at the large difference of -89.5db versus -108db THD+N at 1W. That's the most indicative number for me since most of my listening is < 1W and multitone is closer to music signals.
 
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WolfX-700

WolfX-700

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Thank you! That's:

1W: -89.5db 10W: -91.4db 100W: -91.4db

I'm a bit surprised at the large difference of -89.5db versus -108db THD+N at 1W. That's the most indicative number for me since most of my listening is < 1W and multitone is closer to music signals.
But with 1W power, you have 90dbspl even if ideally. Your environment is unlikely to have background noise below 0.5dbspl ...
 
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#16
But with 1W power, you have 90dbspl even if ideally. Your environment is unlikely to have background noise below 0.5dbspl ...
Oh I agree that at 90db distortion at 1W is good enough, but AHB2 is the best of the best, so other amps might be only 50-60db multitone distortion if Amir's SINAD chart is any indication.

Most of my listening is 70-80db so I care most about the 10-100mw range. Note that this is also AHB2 designers' philosophy:

"the first 10 milliwatts are the most important"
https://benchmarkmedia.com/blogs/application_notes/power-amplifiers-the-importance-of-the-first-watt
 

anmpr1

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#19
They are reverse engineering the FPGA, give them time. ;)

It'll be a "BankMark BHA-2" in a lurid crimson and gold anodized finish at one third of the price with dubious mains wiring and lots of blue LEDs. ;)
I think we will witness in China an evolution (and close acceptance) of the idea of IP, intellectual property. We saw this sort of thing in Japan during the '50s where knock-offs predominated (contrast the then 'high end' Gray Research tonearm made in Hartford Connecticut with the mostly identical Grace Oil Damped arm--Shinagawa Musen, Tokyo). Pretty soon Grace was making their own designs, better than (or at least as good as) anything made in the US. Now there's Accuphase, etc. and no one can afford Japanese electronics.

One can see a transition within popular Sino-culture. For those following such, there is recently aired a mainland television show (精英律师, 2019) starring famous Chinese actor Jin Dong, whose character is a high profile attorney. Some of the episodes turn on intellectual property and patent infringement. This indicates that the idea is entering into the popular consciousness. So while it is just and appropriate to judge/critique cultural norms based upon present circumstances (where IP is an often questionable thing) one must be cognizant of nascent/gross attitudinal cultural shifts and what they may portend. As China becomes more technologically independent, a lot of the questionable stuff one now finds will recede. I think that is a fair observation of a likely trend. At least based upon post WWII Japanese manufacturing history.

PS: Would really like a Huawei phone. But now I have to go Korean if I want anything high end. Used to be you could get an American phone. LOL
 
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Tks

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#20
Of course, it is eagerly hoped that the sought-after Chinese manufacturers can surpass this realization and sell at a more reasonable price. (In fact, more than one Chinese manufacturer has stated that they are developing a power amplifier that is less than half the price of AHB2 and meets or exceeds its performance)
Thank a lot for the review and a few more metrics tested Wolfman! Also nice to see more images :D

I got into audio a year and a half ago or so. I saw this amp reviewed, and looked up the company and the product, and realized it was the thing that brought THX to the consumer fore-front. We've now had headphone amps that have made THX a serious name, while also others like Geshelli and JDS proving they can make perhaps an even cleaner amp without their feed-forward error correction approach perhaps (unless they are also doing it themselves in a custom manner).

One thing I simply do not understand is, seeing as how this power amp was being shown off nearly half a decade ago. Why not a single contender has shown interest in surpassing it, or if they have, they've failed in some fashion or another. Is the scaling of the typical power usage that power amplifiers are made for, simply something that doesn't scale very well with the massive fidelity disparage between them, and headphone amps? I understand it plays a factor, but is the factor THIS BIG where for essentially half a decade no one has been able to dethrone this Rolex of the amplifier world?

I have never seen a piece of electronics maintain it's supremecy for this long, especially considering no newer SKU's or revisions of it were ever released(aside from blacked-out front plate).

But more interestingly, how hasn't anyone used the THX tech in any other power amp? We have multiple in other types of amps, heck even in mobile DAP devices now as well. But power amps, it seems just this only one, for some reason.
 
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