Topping B100 Amplifier Review

[Sokel]

But, this thread will push them in the right direction and we will hopefully see better performing products really soon - this is free education for them but not a cheap way to go about it but Im sure they will prevail and come out in a way that all will benefit.

//

If they want to participate at the continuous power honest race they must state lower numbers.
If they really want it to perform at the numbers they state now they must increase size/heatshink area or include fans.

Can't see some other way around.And that goes for all amps producing some heat or serious power.
Efficiency is often misleading as the charts are cramped but if one pay attention is all there to see.
As for now king for low heat is Purifi but still,at the high power models thermals are also important.

 

[pma]

I have tried to make a "honest" test with respect to specified power parameters, with another amplifier:

A250W amplifier test review

I would like to see the same test with B100 with 1 hour pre-conditioning at 12.5W/4ohm and 5 minute test at 100W/4ohm, in case that the manufacturer still rates this product as 100W/4ohm/THD+N<1%. Unfortunately, it does not reach 100W/4ohm even for a short while. I would always like to see such test with Topping B200.

 

[LKA]

Two New FTC Rules

The US Federal Trade Commission (FTC) has issued two new/newly revised rules relevantor possibly relevantto the hi-fi industry.

www.stereophile.com

"Previously, manufacturers measured power by driving their amplifiers at 1kHz and raising the power until the THD+N reached 1%. Now they must ensure that that standard is met at all frequencies between 20Hz and 20kHz, with THD+N less than or equal to 1%. For most amplifier circuits, the highest THD+N occurs at 20kHz."

The FTC Updates the "Amplifier Rule"

At the end of 2020, the Federal Trade Commission proposed eliminating what had come to be known as the "Amplifier Rule," which had been in effect since 1974. Then-FTC commissioner Christine S. Wilson wrote, "Freeing businesses from unnecessarily prescriptive requirements benefits consumers." To...

www.stereophile.com

"As a practical matter, for most amplifiers, maximum output power will be determined by a 20kHz power measurement instead of a 1kHz measurement."

 

[pma]

For most amplifier circuits, the highest THD+N occurs at 20kHz."

This does not necessarily would be true. Yes it is the case when you are below the distortion clipping knee. But, when you are above the knee and approach to 1% distortion, the scenario may change, as I have shown

https://pmacura.cz/FCT/A250W_FR_thdfreq_241W_4R_BW45kHz.jpg

https://pmacura.cz/FCT/A250W_thdfreq_241W_4R_BW45kHz.jpg

Try it with your amplifiers, go near the maximum power (THD+N<1%) and measure the THD vs. frequency. In my case, distortion rises at low frequencies, because the power supply is very heavily loaded and the ripple becomes enormous, and the PSRR effect is not effective enough. And, the feedback looses effectiveness once the output hits clipping.

At lower power (150W/4R), it is exactly as you have said, THD 20kHz is the highest.

https://pmacura.cz/A250W_thdfreq_150W.jpg

 

[LKA]

Those are not my words, I was just quoting.

 

[pma]

This means that if you hear any distortion, it is somewhere else and not in the power amplifier. I tried to measure power at 1% THD but the protection circuit would not allow it. THD would remain incredibly low and then shut down if I increased input voltage. So 86 watts is what you get for max and peak power. Company spec is 83 watts which is an honest assessment. They do spec 100 watts at < 1% THD which I probably could achieve if I tried harder.

This comment is under your measurement of distortion vs. power into 4ohm load. The amplifier shut down at 86W and you were saying that “company specs is 83 watts which is an honest assessment”. But, 83W is company specs into 8ohm, however they say 100W into 4ohm. Anyone can see it in the specs sheet that was posted as well. So, apples to apples and not to oranges, please.

https://www.audiosciencereview.com/forum/index.php?attachments/img_0793-jpeg.392556/

 

[V.b.]

86W vs 100W is 0.6db louder. You need at least 1 db to notice.

In the meantime, it has 16db SINAD better than Purifi 1ET400 amps.

And it does not have raising distortion with frequency.

Should it be able to output 100w? Yes. Do I care? No. Should it deserve more than one mention in this thread? No.

Half the power in 8ohm is a more reasonable concern.

Also the issue with single ended signal on balanced input is of concern, and thanks to pma to bring it to light. This has real world consequences, as for example using a Wiim Ultra and placing the B100 monoblock next to the speaker with a long run signal cable.

To fix that, B100 would require an extra step to turn single ended to differential and it would add noise and distortion. I can see why they chose not to do that on a 120db SINAD amplifier. As in, it is a feature, not a bug.

 

[totti1965]

As far as I have understood, the problem that @pma has found out, occurs only with Adaptor Cable from RCA (WiiM) out to XLR (B100) in. And hopefully with RCA to RCA there is no issue (only 5 Watts of power etc.), or am I completely wrong???

 

[staticV3]

As far as I have understood, the problem that @pma has found out, occurs only with Adaptor Cable from RCA (WiiM) out to XLR (B100) in. And hopefully with RCA to RCA there is no issue (only 5 Watts of power etc.), or am I completely wrong???

Even with proper differential input signal, pma was still unable to reach Topping's stated power figures using official FTC guidelines, but yes: the issue was gone.

 

[somebodyelse]

As far as I have understood, the problem that @pma has found out, occurs only with Adaptor Cable from RCA (WiiM) out to XLR (B100) in. And hopefully with RCA to RCA there is no issue (only 5 Watts of power etc.), or am I completely wrong???

It will also occur with 'impedance balanced' outputs as only one leg is driven - like the example preamp from 'The G Word'. Transformer balanced outputs that don't have a centre tap will also have a problem as their output isn't ground referenced.

 

[pma]

Correct. There is a question how it would work when driven from a true transformer based floating balanced output, I would guess that poorly, because the XLR input of the B100 is balanced only by name, it has no CMR abilities (common mode voltage drives both outputs up even if there is no difference voltage).

BTW, I got no reply from Topping support to my technical questions (10 days left at least).

 

[restorer-john]

There is a question how it would work when driven from a true transformer based floating balanced output

I have a number of vintage CD players and even a D/A converter with transformer based balanced outputs in addition to RCA.

 

[Ziofrenko]

Ed, we've already established that there are two key factors significantly lowering your power requirements:

1. You use a subwoofer.
2. You typically listen at low volumes (as you mentioned in a previous post).

The numbers are clear, but to make a fair comparison, we need to consider equivalent scenarios, and your setup doesn’t align with the example above.

It doesn't seem to me that you read carefully: the space is large and does not high-pass filter its frequencies, so the amp works even on the minimum impedance peaks.

 

[Sokel]

It doesn't seem to me that you read carefully: the space is large and does not high-pass filter its frequencies, so the amp works even on the minimum impedance peaks.

Classical "couldn't wait to comment" ?

Topping B100 Amplifier Review

Do we know the output voltage of that outboard supply? Jan Jan, you will find the info in the 1st post of the thread. And output is a BTL, so 38V is enough. However, 4A is not enough. It may lead to those 4ohm stepped sine shut downs.

www.audiosciencereview.com

(don't worry,has happened to all of us)

 

[EddNog]

It doesn't seem to me that you read carefully: the space is large and does not high-pass filter its frequencies, so the amp works even on the minimum impedance peaks.

High-pass filtering has not provided as much of a benefit as expected. I’m only able to play like 2-5dB higher before amp cuts out despite high-pass filtering (4th order) at 100Hz.

Generally speaking, it’s mostly the fact that I like my music at what is likely a lower than average volume level by several dB. Seems I’m more concerned about preserving my hearing than other people. ¯\_(ツ)_/¯

-Ed

 

[Sokel]

High-pass filtering has not provided as much of a benefit as expected. I’m only able to play like 2-5dB higher before amp cuts out despite high-pass filtering (4th order) at 100Hz.

Generally speaking, it’s mostly the fact that I like my music at what is likely a lower than average volume level by several dB. Seems I’m more concerned about preserving my hearing than other people. ¯\_(ツ)_/¯

-Ed

Is that with RCA>RCA from DAC to B100?
100Hz is not high enough to relieve the satelites but to go higher you'll need two subs directly under the mains able to go to 500Hz or so so you can cut them at 250-300Hz (bass-bins effectively,at the W371A fashion) .

(it's a good thing preserving your hearing,REW has a really nice meter about it reporting exposing time)

 

[EddNog]

Is that with RCA>RCA from DAC to B100?

(it's a good thing preserving your hearing,REW has a really nice meter about it reporting exposing time)

What is RCA? ;-)

No, I am using XLR from E70 Velvet (set to 5V) at the moment to the B100s.

Tomorrow my Geshelli JNOG3 arrives, which still has XLR outputs.

-Ed

 

[Sokel]

No, I am using XLR from E70 Velvet (set to 5V) at the moment to the B100s.



-Ed

So no limitation by the known issue,ok.

 

[Old_School_Brad]

It doesn't seem to me that you read carefully: the space is large and does not high-pass filter its frequencies, so the amp works even on the minimum impedance peaks.

Actually, he does. However, I admit I assumed it when I wrote my post, as Edd only later confirmed in a comment that he had high-passed them.

And I do believe I read carefully. I try, at least. For instance, I recall Edd mentioning in another thread that he enjoys listening at low volumes (around 65-70 dB at the listening position), which is indeed a relatively low SPL. It’s no surprise, then, that he’s satisfied with the amplifier's performance.

We all have unique setups, listening habits, and musical tastes. That’s why it’s important to approach others' shared experiences with caution -neither dismissing nor blindly accepting them outright. Details need to be provided, and questions need to be asked.

 

[EddNog]

Actually, he does. However, I admit I assumed it when I wrote my post, as Edd only later confirmed in a comment that he had high-passed them.

And I do believe I read carefully. I try, at least. For instance, I recall Edd mentioning in another thread that he enjoys listening at low volumes (around 65-70 dB at the listening position), which is indeed a relatively low SPL. It’s no surprise, then, that he’s satisfied with the amplifier's performance.

We all have unique setups, listening habits, and musical tastes. That’s why it’s important to approach others' shared experiences with caution -neither dismissing nor blindly accepting them outright. Details need to be provided, and questions need to be asked.

The high-pass filtering is a recent development since I bought the WiiM Ultra. I’ve spent the longest part of my B100 ownership pushing full-range.

And when I finally did high-pass the speakers, it didn’t add a whole lot of headroom.

-Ed