Topping B100 Amplifier Review

[totti1965]

W

What is the measurement unit for relaxed-ness of sound?

dB!



Examples of use of 80 Hz Highpass:

 

[antcollinet]

Hi everyone!

I am looking at this amp, but I want to use it in 0db mode. Crazy, I know, but that got me thinking: do I actually need a amp for that? Or could a simpler circuit do the same? I mean, would it be enough with a very low impedance buffer at the output of the DAC?

By zero db mode - you mean Vin = Vout yes?

But here is your problem - lets assume your DAC puts out up to 2V with normal program material - 2V into 4 ohm speakers needs 500mA. So your low impedance buffer needs to deliver more than 500mA *without distorting* - perhaps as much as 1A if the speaker curve dips as low as two ohms. If by buffer you mean op amp, then that is not going to hack it.

In fact a power amp is exactly the low impedance buffer you need.

 

[Julf]

dB!

So really what you are talking about is distortion - and most people are more familiar with % rather than dB in that context.

 

[Roland68]

Hello,

Sharing my experience with a set of B100's driving KEF R5's (not meta): when played just a tad louder than my normal listening level, these little devils went into protection mode. For the data: I measured around 70 dB on my listening spot with an app when they blew, in a room of about 6,00m x 5,00m, opening at the back to stairs.

Just a reset revived them. It happesn everytime with a passage asking some more bass control (Tool, Chocolate Chip Trip, when the bassdrum kicks in for example, around 2:20).

Tried to see if it made a difference if I changed input gain setting (H/M/L) and also line output from my Wiim Ultra, to no avail. Also changed wiring: tried RCA>TRS first, also went from Wiim Ultra>USB>SMSL SU8.XLR>B100.TRS to get a balanced connection but same happened. So this is probably the <4ohm "trip"?

Performance when they were working was excellent, compared to a stereo PA5IIplus it seems cleaner on all fronts, a less stressed feel on my ears (yeah. I know. I was going to type "more black" here...oh now I did anyway) . ABX testing is hard, but I can switch the speaker cables pretty fast and repeat the same track again and every time I heard the same difference...but no science here. Som maybe it's just my ears & mind here playing tricks.

Anyway, I will return them and thought I'd share if any R5 owner wants to go the same way, here is a warning

Best alternative around same pricerange I can find is Audiophonics AS300-s250nc (https://www.audiophonics.fr/en/powe...ifier-ncore-nc252mp-2x250w-4-ohm-p-18419.html).
Would this be a better combination?

The impedance curve is quite steep for an 8-ohm speaker.

If you noticed a significant difference between the B100 and the PA5 II/Plus, you probably won't be happy with an amplifier based on the Hypex Ncore NC252MP.
Alternatively, you could use the B100 to drive the midrange and treble of the R5 and an additional amplifier for the bass. The 3E Audio A7 would be a good choice for this due to its 2-ohm capability.

 

[staticV3]

I just tested with RCA>RCA connection, and I can play louder for longer, almost cancelled the return...until it happened again! Wiim Ultra on 800mV out, B100 gain on highest, playing Celestial Echo by Yello & Malia (

) on Tidal. Not at once, but somewhere during the first 1 or 2 minutes of the track the B100 "crashed". Luckily they don't ever crash with a big bang but gracefully, so no danger to the speakers. Return not cancelled...

Have you tried enabling the WiiM's Sub output? (even if no sub is connected)

Set the crossover frequency as low as it goes, then increase it step by step as you listen to music, until you first hear a drop in bass output from your speakers, then go back down one step.

By doing this, you reduce distortion in your speakers and reduce the output power from your B100, without losing volume or quality.

This may also prevent the B100 from triggering protection. It's a win-win

 

[NoFuzz]

I do use the sub out, kept it at 80Hz. I also use Wiim's Roomfit functionality to optimise the sub and in-room response. For testing I also tried without Roomfit and sub and want to have that freedom without worrying the amp would crash.

Concerning the 3E-Audio A5/A7:
I am using the amp also for HT to play the fronts with my Denon nX4500. Therefore, I need two inputs and be able to switch. I tried using the Ultra as it has a RCA input, but it has a high latency. I did not try yet to fix that with the distance settings in the Denon, if that is at all possible, gonna try that later this week.

Sound character
Would the Hypex NC252mp be different in sound compared to TP3155 or the B100? Damping factor of the Hypex is more than enough (>1000) from what I've read at Archimago's site, though the PA5iiplus I currently have seems to be enough too (around 200?). Or could the wattage also be a factor and be safe with the NC252MP?
Difference between B100 and the PA5II+ is not day and night. I'll try this weekend to do some blind testing (which is when someone else changes the amp and doesnt'let me know or see what has changed, if anything) and maybe end up with the PA5ii+, but I'm a bit worried about durability.

Bi amping
I don't know about bi-amping, increasing the cable salad, and wouldn't I need 2 stereo outputs from the Wiim, which only has one?

Status at this moment: I'll by the Audiophonics AS300 NC252MP, which has a 10% discount even now since we ar ehaving black fridays here too (though no turkeys in ovens as much yet today). Though that 3E-audio amp is a bargain now at Ali's...

 

[Jazigo]

By zero db mode - you mean Vin = Vout yes?

But here is your problem - lets assume your DAC puts out up to 2V with normal program material - 2V into 4 ohm speakers needs 500mA. So your low impedance buffer needs to deliver more than 500mA *without distorting* - perhaps as much as 1A if the speaker curve dips as low as two ohms. If by buffer you mean op amp, then that is not going to hack it.

In fact a power amp is exactly the low impedance buffer you need.

Yes, Vin = Vout, with 4V on 4ohm speakers.

I thought a emitter follower configuration with an opamp was just the thing for this? From my understanding, this is exactly the configuration that is used for a output buffer stage since it only gains on ampere and has low impedance (?).

 

[HakanC]

I just tested with RCA>RCA connection, and I can play louder for longer, almost cancelled the return...until it happened again! Wiim Ultra on 800mV out, B100 gain on highest, playing Celestial Echo by Yello & Maliaon Tidal.

That is also one of my favorite songs, and i have played dozens of times the last three months without any problems
But I have my Ultra output set to 2V and the B100 gain to medium.
Connection between Ultra => B100 are RCA-cables and my speakers are ~5 Ω with a sensitivity of ~87 dB

Status at this moment: I'll by the Audiophonics AS300 NC252MP, which has a 10% discount even now since we ar ehaving black fridays here too (though no turkeys in ovens as much yet today).

I hope that it works fine for You

I have found one review here of a NC252MP-amp but that amp didn't like the 2 Ω load test

Buckeye NC252MP Stereo Amplifier Review

This is a review and detailed measurements of the Buckeye NC252MP balanced stereo class D amplifier. It was kindly drop shipped to me by a member and costs US $575. The amp is almost the size of a loaf of bread and literally weighs nearly as much! Amazing how far amplification technology has...

www.audiosciencereview.com

Hopefully that will not be a problem with the Audiophonics-amp and Your speakers.

I bought my Ultra and my B100s in lat jan/early feb this year(-25) but today I would have bought the WiiM Amp Ultra.

 

[antcollinet]

Yes, Vin = Vout, with 4V on 4ohm speakers.

I thought a emitter follower configuration with an opamp was just the thing for this? From my understanding, this is exactly the configuration that is used for a output buffer stage since it only gains on ampere and has low impedance (?).

Op amps don't have the output current capacity for 1A - unless you are talking about adding a power transistor stage as the output buffer from the op amp, with the feedback taken at the output of the transistor stage. But it would need to be a push pull output stage - or you would be putting DC on the speaker and break it. And what you have now built is - a power amp - albeit with low power capability. If you were going this way you'd be better thinking about using a dedicated low power linear amp chip.


Or just go for one of the really cheap little class D amp modules - because if you are not an amp designer, and just cobbling something together yourself, you won't get better performance.

 

[NoFuzz]

That is also one of my favorite songs, and i have played dozens of times the last three months without any problems
But I have my Ultra output set to 2V and the B100 gain to medium.
Connection between Ultra => B100 are RCA-cables and my speakers are ~5 Ω with a sensitivity of ~87 dB


I hope that it works fine for You

I have found one review here of a NC252MP-amp but that amp didn't like the 2 Ω load test

Buckeye NC252MP Stereo Amplifier Review

This is a review and detailed measurements of the Buckeye NC252MP balanced stereo class D amplifier. It was kindly drop shipped to me by a member and costs US $575. The amp is almost the size of a loaf of bread and literally weighs nearly as much! Amazing how far amplification technology has...

www.audiosciencereview.com

Hopefully that will not be a problem with the Audiophonics-amp and Your speakers.

I bought my Ultra and my B100s in lat jan/early feb this year(-25) but today I would have bought the WiiM Amp Ultra.

That is a problem indeed in the nc25wmp! Found another nc2525mp test here in this very knowledgeable forum showing the same. It was even an Audiophonics but the smaller version MPA-S250NC (https://www.audiosciencereview.com/forum/index.php?threads/audiophonics-mpa-s250nc-amp-review.45306/)

Well, that leaves me to the e3 audio, though I'm expecting it to sound similar to the PA5ii+.

I did try the "mid" setting, but not on RCA>RCA. This testing is a daytime job

I had the Wim Amp Ultra here and could not find anything wrong with the sound but if I remember correctly, there was no option to also input the Denon fronts (not without the long delay). I thought the flawless sound was because of the Roomfit so I switched it for the Ultra, having more input options and also Roomfit

That E3audio (the brand name is confusing) A7 is over half the price of the Audiophonics AS300...very tempting to just try and see (hear) what it would do!

 

[Jazigo]

Op amps don't have the output current capacity for 1A - unless you are talking about adding a power transistor stage as the output buffer from the op amp, with the feedback taken at the output of the transistor stage. But it would need to be a push pull output stage - or you would be putting DC on the speaker and break it. And what you have now built is - a power amp - albeit with low power capability. If you were going this way you'd be better thinking about using a dedicated low power linear amp chip.


Or just go for one of the really cheap little class D amp modules - because if you are not an amp designer, and just cobbling something together yourself, you won't get better performance.

You seem to be correct that the problem is the current. The way of using a 'emitter follower'/'buffer amplifier' is very commonly used in pre-amplifier.

 

[totti1965]

Perhaps an important information for @NoFuzz:

Stabilty wise you would need e.g. the 3e audio A5 (with 2x TPA 3251 - the original version that @amirm has testet) and NOT the A5 se!
So it will be a bit more expensive than the aliexpress commercial!

Look at the table:

 

[antcollinet]

You seem to be correct that the problem is the current. The way of using a 'emitter follower'/'buffer amplifier' is very commonly used in pre-amplifier.

Because line level signals only need very low current - typically much less less than 1mA. Preamps all deal with line level signals.

OP amps are only low output impedance when compared with line level loads - typically >10Kohm, though some might be as low as 2K.

Speakers - at 4 and 8 ohm are a different beast.

 

[NoFuzz]

I just experimented with the gain, RCA connection etc and with B100 gain on Mid, Wiim Ultra on 2.00 mv, connected through RCA (as advised by @totti1965 and @HakanC) I did not have the crashes when playing same tracks loud (70 dB average, peaks of 83.7...this was for me the max I would play and the B100's held up...so this works! Maybe keeping them, but have be able to integrate them with the Denon X4500 surround setup (Denon front out>Ultra line in > B100 RCA in)

Last night I (accidentily) did a blind test in that I came home late and didn't remember what amp was connected. Started out sounding good, but after a few tracks it felt it somehow sounded stressing, as if playing on its limits. Absolutely the wrong words here I guess, but that's how i heard it. Could be the late night listening of course, had dinner and drinks so who knows ;-) But it turned out to be the Topping PA5mkiiplus playing.
I'm gonna try the real blind test probably this weekend: somebody else changing amps without showing/telling what is connected. Suggestions on approach are welcome of course!

Thank you all for helping out here!

 

[Julf]

I'm gonna try the real blind test probably this weekend: somebody else changing amps without showing/telling what is connected. Suggestions on approach are welcome of course!

Make sure gains are matched.

 

[NoFuzz]

Make sure gains are matched.

Thanks, yes that is an important thing! I Did that using a (stereo) sine tone and measuring dB at speakers. One amp left using left output of Ultra, one amp right using right output of Ultra, phone mic at each speaker driver and comparing results. Going to check that again before the test, to confirm

 

[Panelhead]

My system is very different than yours. Speakers are an easy load, much higher efficiency and higher impedance.
But I have a pair of B100 and a PA 5 II. The PA 5 II sounds “louder” when playing the same tracks. I was using the mid gain position on the B100’s when I compared.
No explanation, this is listening a levels below 1 watt for peaks. I used dac output to try and match sound pressure levels.
I justified this to myself after looking at the Topping measurements. The B100 are more linear at very low output levels.
But from my days building diy Class AB solid state amplifiers, in your case the Plus is not the model. For low impedance loads I used lower supply rails. Same power rated transformer, lower voltage and higher current outputs. That stressed the output devices less during high current use.
Assume you have the standard power brick, try it again.

 

[Julf]

I used dac output to try and match sound pressure levels.

How did you do that? Matched by ear, or by meter?

 

[Panelhead]

By ear of course. But did try adjusting level with the 0.5dB steps from a RAW MDA to “normalize” the levels.
Used to have gear to do it and later used a computer to do this. Spent too much time measuring and not enough listening.
Think the levels used while listening plays into what I hear. Or think I hear. Speakers are playing 20dB below the 1 watt rated output level. Milliwatt levels.
Think I could hear longer note decay using an E70 Velvet compared to the RAW MDA1. Someone posted the 32 tone plots and the”grass” height differences. But that is 40dB below accepted audibility.
My solution was to stop connecting the RAW MDA1 and PA 5 II. Using low gain setting in B100 and having the trigger to turn amps on and off were bigger pluses than my perceived small audio differences. Plus sorting which is”correct”.
At these performance levels features are more important. At least to me.

 

[totti1965]

Last night I (accidentily) did a blind test in that I came home late and didn't remember what amp was connected. Started out sounding good, but after a few tracks it felt it somehow sounded stressing, as if playing on its limits. Absolutely the wrong words here I guess, but that's how i heard it. Could be the late night listening of course, had dinner and drinks so who knows ;-) But it turned out to be the Topping PA5mkiiplus playing.
I'm gonna try the real blind test probably this weekend: somebody else changing amps without showing/telling what is connected. Suggestions on approach are welcome of course!

Thank you all for helping out here!

Ha ha ha! I also was nearly killed in this forum because of telling the folks, that I can clearly hear a difference between my Fosi V3 and the Topping B100.
Alcohol makes things clearer sometimes…. LOL.

But the PA 5II…. that is another ballpark than the Fosi V3. I am pretty shure, that my 60-years old ears would not be able to detect any differences between them and the B100.

I admit I'm 10% subjective, which is why I treated myself to €150 worth of RCA cables for Christmas, which I had custom-made by the seller to a magical 1.44 meters – the length at which they supposedly sound the most harmonious.

Needless to say, I can clearly hear a difference compared to my previous €5 cables, but supposedly only if it is not blinded:
https://www.ebay.de/itm/324332118998