Topping B100 Amplifier Review

[terryforsythe]

I suspect that the vast majority of people commenting that 86W/ch is not enough power have never measured the SPL of their system when listening to music, and have no idea of how much power they actually are using.

 

[shuppatsu]

Unless someone is using really inefficient speakers or playing the speakers in a really large room, they probably don't need more power.

Moreover, many people will use the B100 for bookshelf speakers. With a couple of exceptions (e.g., KEF Reference One), most bookshelf speakers will be exhibiting high levels of distortion and high compression by the time the power limit of the B100 amplifier is reached, and should not be played that loud.

I'm in the market for an amp, actually, for my PSB Platinum M2 speakers. I finally have a space in my house for them; they've been sitting under my basement stairs for several years.

The PSBs are fairly efficient at 88dB, 4ohm nominal. PSB recommends 100WPC for these, but back when I was using them I powered them with a 30W Rotel RA-930AX, and they got loud enough for me. I have no doubt that the B100s would be more than adequate.

I will probably get a Wiim amp for the functionality. But if I only cared about sound quality, what would be your case to get the B100s over the Wiim Amp? Or if balanced is important, what would be your case to get these over the Fosi monos or PA5 II?

 

[ryanmh1]

Of course, the only problem with a paper assessment such as this is will one get 100 dB SPL across the full bandwidth of which the loudspeakers are capable, playing actual music, and -- if so -- for how long before thermal shut-down or other, similar sequelae?
I mean... maybe...

This being said, I fully (!) support the notion that 50 watts is a lot with loudspeakers of any reasonable level of sensitivity (and non-sadistic impedance and phase curves).

Time for math. I need to just keep this post in my clipboard for every time these claims are made. The claims are made in good faith, and sound reasonable, but don't stand up to scrutiny. That said, I will concede this state is accurate perhaps during 80% of listening time. That said, these amps would start clipping on my roughly 87dB floor standers at around 96dB at the listening position. That's not exactly a lot. Y'all need to keep in mind the 6dB/m decay from the speakers, and that you do NOT get to use doubling for stereo sources, as you do for monophonic bass. If something is mixed full left, you need to play it all with one speaker.

Maths: 87dB/1W/1M --> 2M=80dB. 3M=77(ish)dB. Let's start there, then, for what we really get out of a watt.

That watt is also all I get for average volume with these amps on some material. At a 77dB average, they're spent. According to one study, that's roughly the background noise in an average "modern" restaurant. But why are they done? Ideally, I would have 20dB of headroom in reserve for various symphonic tracks. That drains the amp entirely, since that's 100W into 4R. On music with less dynamics, I might be able to squeeze out an 87dB average. Still, this is not sufficient to reproduce a piano playing full tilt. With inefficient (or, perhaps, normal efficiency these days) speakers, the amps cannot put any instrument "in the room" at "real" level short of a violin. They might get you a bass drum, but there's nothing left for the rest of the band. They can't even do the singing in a church service on that speaker. According to the journal Noise Health, Catholics apparently average around 90dB and Pentecostals will crank it up to 95dB. In a choir performance, the pews near the chorus were hit with 104dB peaks. The conductor got 110. The organist got 105. That might get compressed a bit when put to tape, but not enough to avoid clipping if you want "front row" seats (or you want to re-live singing Carmina Burana).

With small amps, you either need much more efficient speakers, or need to be one of the many audiophiles who listens at chamber music levels. Many of you apparently do fall into one of these categories, but for those who do not do so all the time, flea amps are not appropriate. (In the 86dB 4 ohm speaker era, 100W/4R is a flea amp, since it is the equivalent of a roughly 10W/8R amp in the 96dB, 8 ohm era.) All of this is why, at least in my view, 400W into 4 ohms is not at all unreasonable. That's another 6dB for the average level, which is still only 4 watts.

Moreover, many people will use the B100 for bookshelf speakers. With a couple of exceptions (e.g., KEF Reference One), most bookshelf speakers will be exhibiting high levels of distortion and high compression by the time the power limit of the B100 amplifier is reached, and should not be played that loud.

Untrue. Many bookshelf speakers will happily handle momentary peaks of well over 100W. Revel M106, March Sointuva, Polk R200... Recommended amps are often 200W or more, and speakers will take way more, particular with subs and a crossover, since the limit is almost always woofer bottoming and /or voicecoil heating from bass. And with with sensitivities often well down in the 83dB to 86dB range, bookshelf speakers can easily be power starved at high volume with 100W. Don't think for a minute just because you have bookshelf speakers that a small amp can drive them to full output. It can't, unless they've very cheap or very efficient. Power compression is just barely setting in at 103dB on the Sointuva, at which point a 100W amp is clipping.

Again, small amps are not for the "bookshelf" crowd. They're for the "never turn it up to 11" and "horn speaker" crowd, regardless of speaker type. And that may well be a lot of people. Great amp, but not for everyone.

 

[pablolie]

Another thing to keep in mind - it's been proven over and over again that -at lower listening levels- our hearing benefits from slight boosts in lows and highs. So super-linearity may not always be the audio nirvana we sometimes make it out to be. I also have a long history of stating that the extreme power numbers that now seem standard with Purifi and Ncore designs just make me shrug my shoulders, it's a very 1980s thing to go "Duuuuude you can really FEEL this!" and be impressed by that. I want finesse at everyday listening levels. A refined 50W is plenty, especially as we can now optimally set up subs easily.

 

[oleg87]

I've heard massive amounts of feedback (often used to get these kind of low numbers in AB amplifiers) can flatten the sound or narrow the soundstage width ... but I've never heard this or tried, has anyone compared an amp with heavy feedback to a low feedback, but good measuring a/b amps?

Please stop listening to audiophile fairy tales.

 

[mlsstl]

I suspect that the vast majority of people commenting that 86W/ch is not enough power have never measured the SPL of their system when listening to music, and have no idea of how much power they actually are using.

That's something I've recommended for years -- "loud" and "medium", etc., mean nothing since those are subjective terms. A moderate volume for a heavy-metal headbanger fan would likely be intolerably loud for many others. One can buy a hand-held sound level meter for under $20 on Amazon. Or, there are many free sound level meter apps one can download for your phone. Either method will give you a reasonably good idea of how loud you like to listen with an actual dB number - a much more valid reference than just "loud."

Another interesting thing to do is hook up an inexpensive digital AC voltmeter to your speaker terminals This will give you a good idea of how much average power it takes to get to your preferred listening level. Sure, you want to leave headroom for peaks, but given that many recordings, especially pop, rock and the like, are already dynamically limited and compressed, many people think they need a lot more headroom than they really do.

Of course, loudness and power are logarithmically, not linearly, related, so there is still an argument for lots of extra power, but even then, for many people, the case is way overstated.

 

[SMen]

THIS! Typically when listening to music with a vocalist, I set the volume at a level that makes sense (to me, being a vocalist myself). If it's too loud, that experience in and of itself just feels unnatural.

I do turn the volume way up on big orchestral recordings because if you're in a concert hall with a 30-piece orchestra, it's going to get LOUD.

-Ed

I suspect that the vast majority of people commenting that 86W/ch is not enough power have never measured the SPL of their system when listening to music, and have no idea of how much power they actually are using.

Well, yes, but I suspect headroom comes in handy ... I often think the debate should include the implementation of compression at the recording and mixing stage ...
I find different recordings have a volume level that suits them - and I can dial it in. I have confess I am a V3 mono user ... so I'm quite glad not to feel the need for these, regardless of SINAD etc.

 

[SMen]

Another thing to keep in mind - it's been proven over and over again that -at lower listening levels- our hearing benefits from slight boosts in lows and highs. So super-linearity may not always be the audio nirvana we sometimes make it out to be. I also have a long history of stating that the extreme power numbers that now seem standard with Purifi and Ncore designs just make me shrug my shoulders, it's a very 1980s thing to go "Duuuuude you can really FEEL this!" and be impressed by that. I want finesse at everyday listening levels. A refined 50W is plenty, especially as we can now optimally set up subs easily.

Well yes, in a way. Bring back dial in loudness controls for low level listening. I do find myself enjoying my V3 mono watts though ... even the small amount of them I am using!

I wonder if we might finally be going to leave the 'audiophile' 80s behind ... that is when things like balance controls, and loudness and tone controls were dropped from so much 'audiophile' gear.

 

[mhardy6647]

Then you can combine a speaker with normal sensitivity with a nice Single Ended Triode (3 Watt) and have good headroom anyway. Happy You!

I wasn't gonna go there...

3.5 watts per channel here.
and, yes, tubes.
Worse than that -- direct heated triodes.

 

[Ismapics]

You want to measure distortion using noise? In the terrible analogies department, that's like measuring optical clarity using a lens covered in dirt.

Please don't be condescending. Music is not a 40hz or a 1K tome either. So the questions comes from the ability of the amp to amplify music (made from multiple frequencies) not just a single tone. Also, Pink noise is not distortion, is just all frequencies played at the same time and same amplitude. Hence in cases used to tune and equalize (car audio).

 

[oleg87]

Please don't be condescending. Music is not a 40hz or a 1K tome either. So the questions comes from the ability of the amp to amplify music (made from multiple frequencies) not just a single tone. Also, Pink noise is not distortion, is just all frequencies played at the same time and same amplitude. Hence in cases used to tune and equalize (car audio).

 

[Sokel]

There are db's and realism to consider ...

A standard drum set ranges between 90 decibels to 130 decibels.
I would not want a drum kit in my room.

75 decibels might be an acoustic guitar played to the max ... so I could max out happily listening to an acoustic guitar maxing out at 75dbs ... but 50 db's would not be particularly realistic representing said guitar ...

Just to put things right,in not only about SPL.
A kick drum can go to 125dB,yes,with the pedal far enough (18-20cm) from the drumhead but the important thing here is its dynamic range which can go up to a staggering 80dB.
And,acoustic guitar is not at 75dB,is more closer to 90dB.
(you don't even want to know what a sax can do)

 

[Roland68]

Just to put things right,in not only about SPL.
A kick drum can go to 125dB,yes,with the pedal far enough (18-20cm) from the drumhead but the important thing here is its dynamic range which can go up to a staggering 80dB.
And,acoustic guitar is not at 75dB,is more closer to 90dB.
(you don't even want to know what a sax can do)

A good saxophonist gets just over 95 dB out of a saxophone. I once measured it in the studio when there were a few problems with a recording.

 

[Sokel]

I suspect that the vast majority of people commenting that 86W/ch is not enough power have never measured the SPL of their system when listening to music, and have no idea of how much power they actually are using.

Here's a capture of 12 minutes of sheer beauty:
Can someone please state at what level I listen too?
Bedřich Smetana's - Má Vlast: Vltava :

To make it easy,average,min and max are (A) weighted,peak is (Z) weighted (as always) .

 

[Sokel]

A good saxophonist gets just over 95 dB out of a saxophone. I once measured it in the studio when there were a few problems with a recording.

(close to 120,yes,a hundred-and-twenty dB at the center of the bell for extreme forte for an alto)

 

[terryforsythe]

Please don't be condescending. Music is not a 40hz or a 1K tome either. So the questions comes from the ability of the amp to amplify music (made from multiple frequencies) not just a single tone. Also, Pink noise is not distortion, is just all frequencies played at the same time and same amplitude. Hence in cases used to tune and equalize (car audio).

The issue with trying to use Pink noise for harmonic distortion is that it is just that, noise, but noise that is generated over the entire audio spectrum at a constant level. The noise masks the harmonics. For example, say you want to measure the harmonics of 1kHz. Those harmonics will be at 2kHz, 3kHz, 4kHz, etc. and, hopefully, be at least -30dB down from the 1kHz signal. But, with Pink noise, there already are signals present at those frequencies, and at the same reference level (assuming a system with a flat frequency response). Thus, you will not be able to get an accurate measurement of the distortion. The harmonics will be buried in the noise.

 

[Sokel]

The issue with trying to use Pink noise for harmonic distortion is that it is just that, noise, but noise that is generated over the entire audio spectrum at a constant level. The noise masks the harmonics. For example, say you want to measure the harmonics of 1kHz. Those harmonics will be at 2kHz, 3kHz, 4kHz, etc. and, hopefully, be at least -30dB down from the 1kHz signal. But, with Pink noise, there already are signals present at those frequencies, and at the same reference level (assuming a system with a flat frequency response). Thus, you will not be able to get an accurate measurement of the distortion. The harmonics will be buried in the noise.

REW can now use Fast Subband Adaptive Filtering for measuring THD+N using pink,white,brown noise or even music.
It's a killer feature.

 

[terryforsythe]

Here's a capture of 12 minutes of sheer beauty:
Can someone please state at what level I listen too?
Bedřich Smetana's - Má Vlast: Vltava :

To make it easy,average,min and max are (A) weighted,peak is (Z) weighted (as always) .

What settings did you use to show the LA and LZ measurements?

Using the RTA in REW, I measured RMS and Peak, sampling 3 songs. This about as loud as I typically listen, measured at about 2m:

 

[Sokel]

What settings did you use to show the LA and LZ measurements?

Using the RTA in REW, I measured RMS and Peak, sampling 3 songs. This about as loud as I typically listen, measured at about 2m:

View attachment 393444

Open REW,choose the "SPL meter" tab and then choose SPL,choose weighting,fast or slow and Logger.
At the window which will open press the upper right red dot,same as the RTA window.

 

[Sokel]

What settings did you use to show the LA and LZ measurements?

Using the RTA in REW, I measured RMS and Peak, sampling 3 songs. This about as loud as I typically listen, measured at about 2m:

View attachment 393444

Also,as a test use a bass-heavy song and first measure it with (A) weighting and then with (C) weighting WITHOUT changing level and observe the big difference as the later captures lows too.