Topping B100 Amplifier Review

[Deleted member 72219]

You must’ve meant class AB? Class B is not suitable for audio.

Topping specifically clarified that the B100 is Class B and not Class AB. The B200 is Class AB.

-Ed

 

[somebodyelse]

But the total lack of ventilation holes in the amplifier case does not.

Aren't there some in the sides? Ideal for combining with a 'foot' to stand it on its edge, especially given the internal heatsink orientation. If they'd just rotate the front panel labels to match...

 

[BeeKay]

But the total lack of ventilation holes in the amplifier case does not.

Well …

 

[Old_School_Brad]

It does have side ventilation slots, but Topping seems to have overlooked the fundamentals of convection, leaving much to be desired.
That said, they did win the SINAD race, which I believe was their main objective with this project.

 

[NTK]

Well …

View attachment 437181

Well, still the same kind of sub-optimal thermal designs as having horizontal fins. You want the natural convection air flow to rise from bottom to top.

 

[MAB]

At least a vertical arrangement of the cooling fins should be noted. This alone should be a real reassurance for some.

You seem to keep this going. I think the heatsink orientation thing has gone a bit off the rails. And people seem to have no idea how odd a large heatsink in a small case is, or how inefficient horizonal fins in a passive design are.

Heatsinks do have specific orientation, and it matters if there is heat to be dissipated.
Topping has had significant reliability issues in the past, some regarding poor thermal design.
In the mean time we still have people in the PA5 and PA5II threads with fans blowing on their high SINAD amps out of paranoia. That alone is fail.

We have no idea if this amp is reliable.
We have no idea if Topping has taken past failures seriously, done a full failure mode effects analysis, and ironed out their issues across all reasonable use conditions.
We do know Topping are making very odd choices with heatsink and thermal design on their recent amps, as if they produce negligible heat in all use conditions. I don't find this very likely.

None of this is reassuring. It is odd thermal design on both the B100 and B200.

 

[solderdude]

I'm afraid that this is a bimetal switch we see here, these are notoriously inaccurate and quite sharp (like instant sharp)

Looks like an NTC to me.

You must’ve meant class AB? Class B is not suitable for audio.

Technically it is more like an AB but with an almost non existent idle current basically turning it into a class-B but without the cross-over distortion as that is compensated for in some way.

 

[Old_School_Brad]

Looks like an NTC to me.


Technically it is more like an AB but with an almost non existent idle current basically turning it into a class-B but without the cross-over distortion as that is compensated for in some way.

Yeah, that definitely looks like an NTC tucked into the spade lug.

Also, crossover distortion has to be pretty severe to be audible. A tiny quiescent current combined with a lot of feedback is likely the solution.

 

[solderdude]

A true class-B would have severe crossover. One would need an incredibly fast input stage to remove that.
I reckon this isn't truly class-B but rather very near the transistors not conducting almost acting like class-B.
Thermal conditions would be the difficult part to get right as Vbe is temperature dependent.

 

[mermayer]

12V trigger to only one time 12V current pulse. There is a 12V pulse that can be turned on. When something sends another 12V pulse, the device turns off.

That is not correct. In the source on state, the trigger goes permanently to 12V and back to 0V in the off state.

 

[Deleted member 72219]

That is not correct. In the source on state, the trigger goes permanently to 12V and back to 0V in the off state.

This is what I thought as well!

-Ed

 

[Burns]

That is not correct. In the source on state, the trigger goes permanently to 12V and back to 0V in the off state.

I return the honor. I checked. It is as you wrote!

 

[Sokel]

Yeah, that definitely looks like an NTC tucked into the spade lug.

That would make sense too, I have never try them though.
I hope they are not so abrupt and sharp as the bimetal ones.

 

[Old_School_Brad]

That would make sense too, I have never try them though.
I hope they are not so abrupt and sharp as the bimetal ones.

Well, the NTC itself is linear, but how Topping processes its value determines its actual behavior.

It appears that the unit can shut down while playing music, as shown earlier in this thread. I can't recall if that's due to thermal issues or insufficient power. There's also a discussion on DIY where the Topping hype isn't as strong as on ASR.

 

[Julf]

There's also a discussion on DIY where the Topping hype isn't as strong as on ASR.

On the other hand, there is also a lot more voodoo and misinformation on DIY.

 

[fjc36]

Excellent little amp, I am impressed. Bravo, Topping!

For 2 x 300 = 600 USD for the mono pair, personally I would spend a little more for an NC502MP based amp (less sinad, much more power) or even more for an NCx500 based amp (slightly less sinad, highest power). But for a small desktop system the lowest noise of the B100 would be more adequate.

Perhaps B-100 can be used after a high pass and combined with B-200 for the low pass (4-th order electronic crossover). The thing worries me should be the sonic difference in the jointing. Class B combine with class AB? Wish Toppings has an answer or try out..

 

[staticV3]

The thing worries me should be the sonic difference in the jointing. Class B combine with class AB? Wish Toppings has an answer or try out..

There are no inherent sonic differences between Amplifier classes.

A competently designed Class A/AB/B/D/X Amp will sound like a competently designed Amp of any other class.

All perceived differences can be traced back to lack of control procedures, personal biases, or design defects.

 

[Gringoaudio1]

There are no inherent sonic differences between Amplifier classes.

A competently designed Class A/AB/B/D/X Amp will sound like a competently designed Amp of any other class.

All perceived differences can be traced back to lack of control procedures, personal biases, or design defects.

Maybe with state of the art current design it might be useful for something like subwoofers but the traditional view of Class B is that it suffers from crossover distortion and that only tricks can improve it a bit.
Do you have any citations I could review about recent improvements to Class B.

 

[staticV3]

The traditional view of Class B is that it suffers from crossover distortion and that only tricks can improve it a bit.
Do you have any citations I could review about recent improvements to Class B.

Amir's measurements of the B100 prove that Topping have managed to solve the crossover problem, but they don't seem interested in publishing their research, so no papers on how they did it.

 

[antcollinet]

Amir's measurements of the B100 prove that Topping have managed to solve the crossover problem, but they don't seem interested in publishing their research, so no papers on how they did it.

Nor verifiable confirmation that it is class B - or how "pure" class B it is.

Unless someone has gone in there and measured the conduction in the output transistors. Not seen it if they have.