I'm amazed that I can't find a thread discussing this

[Yorkshire Mouth]

I've been meaning to post on this for quite a while. The only (very brief) discussion I can see on it is in the thread on @amirm's review of the Behringer A500.

Ripe for discussion at a forum like this.

Matrix HiFi --> Blind testing high end full equipments

www.matrixhifi.com

 

[sergeauckland]

I don't think that Matrix article surprises anyone on here. There was also a Peter Aczel review of the A500 that said much the same. I have had three A500s in daily use for some 14 years now, with complete satisfaction. My own measurements indicated the amps are fine. Not SOTA, but perfectly adequate for transparency.

S

 

[Yorkshire Mouth]

So, just for reference, the A500 has been measured here at THD+N of c.67 dB, and SNR OF c.98 dB.

Review and Measurements of Behringer A500 Amplifier

This is a review and detailed measurements of the Behringer A500 "Reference" Power amplifier. I purchased this unit on suggestions from members from Amazon for just $199 including Prime shipping. Being targeted at the pro market, this is rack-mount unit with heft heatsinks on each side...

audiosciencereview.com

Question, can anyone find accurate, independent measurements for the higher priced amp?

 

[Yorkshire Mouth]

So, looking elsewhere…

The new WiiM Amp has THD+N of -93dB (streets ahead of the A500), and SNR of 98 dB (same as the A500). These are WiiM’s own figures, but Amir’s reviews of the Mini and Pro Plus suggest the company is pretty honest with these. They also look in line with the Fosi Audio V3 which uses the same amp chip, so I’m currently minded to accept them at face value.

That would make the WiiM Amp equal to it better than the A500, at least by those measurements.

Power-wise, the A500 is just a little beefier, at 160W into 4 ohms, with the WiiM claiming 120W (still not bad). The V3 is 60W or 140W depending on power supply.

Now here's what struck me. I'm possibly (just possibly) looking at a pair of Revel M106s. Does the WiiM look good enough - again, that's on face value and given what we've been discussing.

Cheers.

 

[Shadrach]

I've posted the link to the Matrix Audio site on a couple of occasions. From what I recall, not much discussion was forthcoming.
There is also a similar DBT report on an Italian audio enthusiasts site with similar results which I can no longer find.
What both show is setting up a DBT test isn't as complicated as some would have us believe if one has the equipment to be tested and a small group of enthusiasts to participate in such tests.
Even DBT and BT tests carried in less stringent conditions can help show that even if differences were identified they are small and probably of no consequence (barely audible) to the average listener.
Many years ago some friends and I carried out not particularly stringent BTs just by having a blanket between the listeners and the person who made the changes to the equipment being listened to. They were good enough to convince us that when it came to the electronics none of us could reliably pick one unit from another.
I think the sad fact is many audiophiles are just not interested in finding out just how unreliable their hearing is and just how similar the vast majority of audio electronics are in performance.

 

[daftcombo]

That link has been posted over and over again since the creation of this forum.

 

[Yorkshire Mouth]

That link has been posted over and over again since the creation of this forum.

I’ve searched a couple of ways, and only found it in the A500 review.

Any chance of links to the other mentions?

 

[Yorkshire Mouth]

I've posted the link to the Matrix Audio site on a couple of occasions. From what I recall, not much discussion was forthcoming.
There is also a similar DBT report on an Italian audio enthusiasts site with similar results which I can no longer find.
What both show is setting up a DBT test isn't as complicated as some would have us believe if one has the equipment to be tested and a small group of enthusiasts to participate in such tests.
Even DBT and BT tests carried in less stringent conditions can help show that even if differences were identified they are small and probably of no consequence (barely audible) to the average listener.
Many years ago some friends and I carried out not particularly stringent BTs just by having a blanket between the listeners and the person who made the changes to the equipment being listened to. They were good enough to convince us that when it came to the electronics none of us could reliably pick one unit from another.
I think the sad fact is many audiophiles are just not interested in finding out just how unreliable their hearing is and just how similar the vast majority of audio electronics are in performance.

I suspect that DBTs with different speakers is most difficult.

If all you have to do is swap two speaker cables, and you have one person for each, that’s pretty easy and quick.

 

[voodooless]

Search results for query: https://www.matrixhifi.com/ENG_contenedor_ppec.htm

www.audiosciencereview.com

 

[Blumlein 88]

More interesting is those Swedish AES series tests of amplifiers. More interesting because only two ever passed the test for transparency. A different result than you see elsewhere. They used a complex loudspeaker simulated load. Tapped that and fed into an amplifier attached to a speaker. Set up so you could switch the DUT in and out of the circuit instantly. There were only ever two amps that passed their sighted test as being transparent. One failed on the blind test. One passed both. They listened matched levels sighted and then blind. Oh, and their test signal was constructed to sound like a metronome. Don't know if it was more like a very quick sweep or more of an impulse that excited a wide band of frequencies. The amp passing the sighted test was a solid state Audio Research (yeah, the tube guys), and the one that passed both was a Bryston. Wish I knew more about the test signal and other details.

 

[mhardy6647]

I suspect that DBTs with different speakers is most difficult.

If all you have to do is swap two speaker cables, and you have one person for each, that’s pretty easy and quick.

they make switchboxes, you know?




... and in the olden days, AVID made a switchbox ("Comparator") that provided level matching. I suspect these would be a little hard to find and pricey today.

source: https://www.worldradiohistory.com/Archive-All-Audio/Archive-Audio/70s/Audio-1978-11.pdf

 

[Yorkshire Mouth]

Search results for query: https://www.matrixhifi.com/ENG_contenedor_ppec.htm

www.audiosciencereview.com

Well, that's me being stupid not searching the actual URL - many thanks.

Funnily enough, whilst I've looked at most of those results and found mention of the Matrix HiFi test, I didn't see much discussion per se. Sometimes it's one post with no reply, or just the odd one or two replies.

Thanks again for taking the time to look it up.

 

[voodooless]

I didn't see much discussion per se.

So, what more do you want to discuss about this?

 

[Sokel]

Question, can anyone find accurate, independent measurements for the higher priced amp?

Found some here:

Classe Audio CAP-80 Integrated Amplifier and CDP.3 CD Player

YBA 2 HC power amplifier Measurements

Sidebar 3: Measurements All measurements were made after the YBA 2 had been preconditioned by running it at one-third full power into 8 ohms for an hour, which thermally stresses the amplifier to the maximum. Its heatsinks were very hot at the end of this period. Interestingly, however, those...

www.stereophile.com

Close to 60s for the pre and worst if I can read the tiny pictures well and the same for power amp.

2 sets are not far from each other.

 

[Yorkshire Mouth]

So, what more do you want to discuss about this?

What people thought of the test, and what it says and doesn’t say. What we can extrapolate from it and what we can’t.

 

[Yorkshire Mouth]

For me, and I’m happy to hear contrary opinions, what it seems to suggest is the following. Firstly, Amir’s ‘limits’:

Understanding Amplifier Measurements (Video)

Continuing the series on learning measurements, I recorded one last night on power amplifiers. Alas, my external microphone got disconnected and internal one to the camera was used. So the sound quality is rather poor. A personal note: as you may know, I don't allow advertising in my...

audiosciencereview.com

He suggests that the limits of human audibility are THD+N of -115 dB and SNR of 108-114 dB. I’m sure he’s right - the limits of human hearing are well-documented.

But the A500 falls some distance short. So what we’re into is the gap between the theoretical limits of human hearing (presumably listening to distortion of a sine wave on a pair of headphones - probably closed back, so no other sounds) and the real-world limits when listening to music.

When I read Amir’s reviews, I’ve always focussed on those figures for DACs amps. But I’d like to see more focus on real-world limits, as well as theoretical ones.

 

[Blumlein 88]

Well there are those Mr. Clark amp challenge rules. To win $10,000, you had to discern the difference in his amp and yours 12 of 12 twice. Rules were flat frequency response, all amps operated within the power capabilities of the lower powered amp, and THD of 2% or less from 20-10,000 hz. Hundreds attempted it and no one came away with the cash.

Some indications that 3% on music is about where it becomes audible. Or distortion of -31.5 db in other words. Masking makes a big difference. Hearing noise above threshold with no music is one thing. Hearing it with music very much another. That SNR of 108 db or so depends upon a quiet place, efficient speakers and no masking. Basically everything so low nothing could be heard at all is certainty. Less certain, but effectively the same is much higher. Going with certainty means no worries.

It is reasonable to go with certain limits because so many various other things we hear vary with material, the situation and the exact signal. It also means much lesser performance is often just fine.

 

[Deleted member 48726]

For me, and I’m happy to hear contrary opinions, what it seems to suggest is the following. Firstly, Amir’s ‘limits’:

Understanding Amplifier Measurements (Video)

Continuing the series on learning measurements, I recorded one last night on power amplifiers. Alas, my external microphone got disconnected and internal one to the camera was used. So the sound quality is rather poor. A personal note: as you may know, I don't allow advertising in my...

audiosciencereview.com

He suggests that the limits of human audibility are THD+N of -115 dB and SNR of 108-114 dB. I’m sure he’s right - the limits of human hearing are well-documented.

But the A500 falls some distance short. So what we’re into is the gap between the theoretical limits of human hearing (presumably listening to distortion of a sine wave on a pair of headphones - probably closed back, so no other sounds) and the real-world limits when listening to music.

When I read Amir’s reviews, I’ve always focussed on those figures for DACs amps. But I’d like to see more focus on real-world limits, as well as theoretical ones.

Can you hear a difference between dac+amp path with 92dB vs. 78dB SINAD? (test)

Can you hear a difference between dac+amp path with 92dB vs. 78dB SINAD? Quite a lot has been said here about “audibility” of SINAD, or existing/non-existing sound differences between amplifiers or DACs. Quite often we forget to evaluate SINAD of the whole audio chain consisting of a DAC, power...

audiosciencereview.com

 

[Sgt. Ear Ache]

I've linked to this on many occasions in threads here over the past few years. It's one of my favorites...

 

[Sgt. Ear Ache]

What people thought of the test, and what it says and doesn’t say. What we can extrapolate from it and what we can’t.

what we can extrapolate from it is that you have to work pretty damn hard to make really notable audible differences with equipment other than speakers. You aren't going to do it by buying more expensive speaker wiring or a boutique usb cable.