Topping B100 Amplifier Review

[Burns]

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.

So many pages in B100 and B200 and other Topping products. So many unknowns. What about reverse engineering? Is it so difficult to work out such devices and their circuits? Many services repair star amplifiers using meters, oscilloscopes and other measuring devices, without having access to the manufacturer's schematics. Recently I saw a nice thread here about E70 Velvet where someone started solving the implementation of AKM chips in this device thanks to AKM circuit schematics

 

[antcollinet]

What about reverse engineering? Is it so difficult to work out such devices and their circuits?

Not really. But who is going to do it, and why? You?

 

[pjug]

and why?

Exactly. Other than for curiosity sake, who cares if they want to call it Class B or AB? It idles at about the same power as some other ABG amps from Benchmark and Outlaw so what difference does it really make?

 

[oleg87]

So many pages in B100 and B200 and other Topping products. So many unknowns. What about reverse engineering? Is it so difficult to work out such devices and their circuits? Many services repair star amplifiers using meters, oscilloscopes and other measuring devices, without having access to the manufacturer's schematics. Recently I saw a nice thread here about E70 Velvet where someone started solving the implementation of AKM chips in this device thanks to AKM circuit schematics

I'm sure Topping's competitors have already done that.
For anyone who doesn't stand to profit from playing the specmanship game, the payoff isn't really there - it's usually not that hard but tedious enough to not offer much intrinsic motivation. If you want to build a quality amp, there's plenty of well-documented designs out there already.

And as far as specmanship goes, for the average audio application you'd probably gain more by sacrificing 20dB of SINAD and getting 10x more power relative to this thing, so is it really that interesting?

 

[KL....]

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.

Yes, classB by definition implys that an output transistor/mosfet turns off then on whereas classAB implys that an output transistor/mosfet does not turn (completely) off then on through using such mechanisms as Type1/2 Emiter Followers, classA bias offset, etc which reduces/eliminates the potential for crossover distortion (such as the B200).

By stating that it is classB (really) could be suggested is not appropriate, reasonable, nor correct, unless they are focused on classB efficiency. The measurements indicate that the B100 is not classB (alone), why? because classB crossover distortion would be visable/showing but it is not, is it?

Perhaps it could be suggested (until we know) that it could be called classBA (with reference to classB efficiency) where A is employed in some manner without the resulting classA bias offset but again, we will not know until it is tested & measured for classA bias offset. Perhaps, someone who has one can do this and perhaps @amirm still has the B100 that he tested & measured and if so, wouldn't mind doing this for us?

 

[Sokel]

I'm sure Topping's competitors have already done that.

I'm not sure a global competitor would be interested in this.
diyaudio has lots of very low THD+N amps over the years but woud they stand in market? History says no.

These days the race is about conformity with standards, efficiency, etc.
They are a lot more interested on how to make a nice story about SMPS's so they could get rid of linears as they are a lot cheaper if they start some big scale production.

 

[Music1969]

They are a lot more interested on how to make a nice story about SMPS's so they could get rid of linears as they are a lot cheaper if they start some big scale production.

EU regulation will push out linear PSU's

 

[KL....]

I'm not sure a global competitor would be interested in this.
diyaudio has lots of very low THD+N amps over the years but would they stand in market? History says no.

These days the race is about conformity with standards, efficiency, etc.
They are a lot more interested on how to make a nice story about SMPS's so they could get rid of linears as they are a lot cheaper if they start some big scale production.

Thank and if you do not mind, have a look at the Daitron RFS/SMPS, and let me know your thoughts....

• RFS50a - Ripple Noise: 1mVp-p .... only about 80% efficient but (good, even very good) ripple output. To ask, would you say PSRR is more import than ripple output? With LPS low/very low ripple output often implys a good/high PSRR level, doesn't it? With SMPS good/high PSRR (although rarely mentioned) appears to be easyly achieved but low ripple output is not easyly achieved, is that correct? With SMPS, would you say PSRR is more important than low/very low ripple output?
• RFS Series Ultra Low Noise AC/DC Power Supply

 

[Sokel]

EU regulation will push out linear PSU's

Not so sure, most of the major companies usually use some short a secondary PSU for stand-by and stuff.
And the upcoming adjustment has no rules about idle, only stricter stand-by (0.2W)

 

[Sokel]

Thank and if you do not mind, have a look at the Daitron RFS/SMPS, and let me know your thoughts....

• RFS50a - Ripple Noise: 1mVp-p .... only about 80% efficient but (good, even very good) LPS ripple output. To ask, would you say PSRR is more import than ripple output? With LPS low/very low ripple output often implys a good/high PSRR level, doesn't it? With SMPS good/high PSRR (although rarely mentioned) appears to be easyly achieved but low ripple output is not easyly achieved, is that correct? With SMPS, would you say PSRR is more important than low/very low ripple output?
• RFS Series Ultra Low Noise AC/DC Power Supply

As everywhere else it's an act of balance.
I do prefer LPS for line-level (it's my own vice, I make some myself too) but these days if someone wants some serious power along with eficiency at amps SMPS is the way.
What's important is the end result, and if Purifi or the new icepower conductor have already solve the better part of rising distortion up-high we're good, no matter the PSU.

 

[fjc36]

What can a pair of these mono blocks drive in terms of wattage.

B100 is a class B type PA, it is a high efficient PA, but need very good matching for the positive and negative reel, otherwise tone quality will not be good. Does Tipping mensions any of the circuitary matching and fine tunging? How is the crossover distorsion value measured by Amirm? A small bias adjustment to reduce the crossover distorsion and no maintainace is needed in a long run? Is a nice low THD data goog enough ? How about its Intermodulation Distortion performance? I quess it shows in the multi-tone test., right?

 

[Music1969]

but need very good matching for the positive and negative reel, otherwise tone quality will not be good.

what do you mean here?

 

[staticV3]

B100 is a class B type PA, it is a high efficient PA, but need very good matching for the positive and negative reel, otherwise tone quality will not be good. Does Tipping mensions any of the circuitary matching and fine tunging? How is the crossover distorsion value measured by Amirm? A small bias adjustment to reduce the crossover distorsion and no maintainace is needed in a long run? Is a nice low THD data goog enough ?

Measurements as good as what Amir got would be impossible if the B100 had any detectable crossover distortion.

Just like saturation/clipping, that would wreak havoc on all but SNR and frequency response measurements.

Though the B100's amplifier class may still be in limbo, we know for sure that it has no crossover distortion to speak of.

How about its Intermodulation Distortion performance? I quess it shows in the multi-tone test., right?

IMD performance is shown in both the Multitone test and 19+20kHz CCIF test. Both are flawless.

 

[audioje]

My PA5 ii is still working well but this will be my next amp if anything happens to pa5ii. If I have no power issue with pa5ii, I would have no power issue with b100, right?

 

[staticV3]

My PA5 ii is still working well but this will be my next amp if anything happens to pa5ii. If I have no power issue with pa5ii, I would have no power issue with b100, right?

The PA5II and B100 have identical output power, though the B100 has a more aggressive protection circuit.

It's possible that if you're currently at the limit of your PA5II's capabilities, you'll encounter this protection circuit on the B100.

You can use a basic multimeter to measure the output voltage of your PA5II and estimate how much power you're using currently.

 

[KL....]

My PA5 ii is still working well but this will be my next amp if anything happens to pa5ii. If I have no power issue with pa5ii, I would have no power issue with b100, right?

As has been indicated in this thread, that will depend whether your speakers minimum impedance is <4R, especially if they dip to 2R for too much/often through the 20-20K range. Have a read through this thread, you should read many instances about this, through this thread.

Edit: Apologys, I have not checked the PA5ii, the above was in reference to the B100 :=)

 

[Old_School_Brad]

I'm not sure a global competitor would be interested in this.
diyaudio has lots of very low THD+N amps over the years but woud they stand in market? History says no.

These days the race is about conformity with standards, efficiency, etc.
They are a lot more interested on how to make a nice story about SMPS's so they could get rid of linears as they are a lot cheaper if they start some big scale production.

I'm not sure what you mean by conformity with standards, as it doesn't seem like manufacturers of small form factor amplifiers follow any specific ones?

Otherwise, I agree with your other points -I’ve seen some impressive measuring designs on DIYaudio and also believe the efficiency and cost benefits of SMPS transitions are appealing from a manufacturer’s perspective.

The PA5II and B100 have identical output power, though the B100 has a more aggressive protection circuit.

It's possible that if you're currently at the limit of your PA5II's capabilities, you'll encounter this protection circuit on the B100.

You can use a basic multimeter to measure the output voltage of your PA5II and estimate how much power you're using currently.

I'm not sure if this is exactly what you meant. A basic multimeter isn't suitable for measuring an amplifier's output voltage while playing music, nor for determining power requirements. A true RMS, high-bandwidth multimeter would be needed for more accurate readings, but even then, it would only provide an indicative measurement using steady-state signals.

 

[Sokel]

I'm not sure what you mean by conformity with standards, as it doesn't seem like manufacturers of small form factor amplifiers follow any specific ones?

They get around this with this pre-certified (I hope, although I have seen ones stating more than 0.5W just hooked in with no load which is illegal in Europe) external PSUs.
The ones that don't use them probably certify them themselves or don't sell them through official Europe importers. But that will change sooner or later, things are narrowing down fast.

 

[staticV3]

A basic multimeter isn't suitable for measuring an amplifier's output voltage while playing music

It's not, but you can play music, adjust the volume, then play a 60Hz 0dBFS test tone and measure the output voltage.

From that you can infer the output voltage while playing music.

 

[Burns]

the thread about B100 is starting to resemble legends about the creation of pyramids and has an unscientific background. Thanks to the fact that no one knows what it does and how it is built, manufacturers will be able to bend reality. It looks like this device could contain good Harry Potter spells and the only value that is supposed to define them is SINAD