Topping B100 Amplifier Review

[MAB]

"Clipping behavior will be cleaner, as the clipped peaks of the output waveform are not modulated by the ripple on the supply rails. Having said that, if your amplifier is clipping regularly you might consider turning it down a bit."

Agree with Douglas Self, for sure.

 

[pablolie]

Personally, I shall never ever again waste a minute of my life trying to hear differences between amps that measure "well enough", which I'd define as load-independent with a SINAD of 90ish+ and good characteristics at lower volumes. And anything over 100W is wasted on me, because I am now a firm believer in the superiority of 2.1 or 2.2 systems in the majority of real world environments.

 

[Ismapics]

Blows the Cambridge CXA81 MKII integrated out of the water and you have $ left for better sources.

 

[Ismapics]

Class B amps are only used in RF due to crossover distortion. So the common version is a hybrid Class AB, not class B. Here, feedback is used so much as to nullify crossover distortion in class B. Much like the way Hypex amps use a lot of feedback to deal with all sorts of non-linearities in class D.

This may have been answered before, but: Why can't AMPS power output and distortion be measured using pink noise?

 

[ryanmh1]

This may have been answered before, but: Why can't AMPS power output and distortion be measured using pink noise?

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

 

[Esprit]

Here:

If the product has a CE certification, it is not up to the seller to verify whether the product meets all the required parameters and characteristics. He is not even equipped to do so (see also for example the regulation against electromagnetic interference).

 

[rongon]

EddNog said:
...the B100’s triple nested feedback design.

oooh. Do you know something about that? How did you find out it's a triple-nested feedback design? (I hadn't seen that info anywhere else.) Two stages, each with a local NFB loop around them, and all of it with a global NFB loop wrapped around it? Or something different from that?

That could be NFB applied along the lines of the old RCA 50-Watt High Fidelity Amplifier from the later RCA Receiving Tube manuals. That's a four-stage design with a push-pull output stage having feedback from plate to grid of output tubes, then output tubes plates to preceding stage cathodes, and a global loop from speaker output to first stage voltage amplifier. It would be pretty cool if Topping was doing stuff like that with the B100. Or is that old news in contemporary solid state amp design?

 

[Deleted member 72219]

oooh. Do you know something about that? How did you find out it's a triple-nested feedback design? (I hadn't seen that info anywhere else.) Two stages, each with a local NFB loop around them, and all of it with a global NFB loop wrapped around it? Or something different from that?

That could be NFB applied along the lines of the old RCA 50-Watt High Fidelity Amplifier from the later RCA Receiving Tube manuals. That's a four-stage design with a push-pull output stage having feedback from plate to grid of output tubes, then output tubes plates to preceding stage cathodes, and a global loop from speaker output to first stage voltage amplifier. It would be pretty cool if Topping was doing stuff like that with the B100. Or is that old news in contemporary solid state amp design?

It’s how they describe this, “T’ang-ku-la,” amplification module. I know nothing beyond that, it’s basically just marketing lingo as far as I am aware.

-Ed

 

[oleg87]

oooh. Do you know something about that? How did you find out it's a triple-nested feedback design? Two stages, each with a local NFB loop around them, and all of it with a global NFB loop wrapped around it? That would be NFB applied along the lines of the old RCA 50-Watt High Fidelity Amplifier from the later RCA Receiving Tube manuals. That's a four-stage design with an output stage having feedback from plate to grid of output tubes, then plate to preceding stage cathodes, and a global loop from speaker output to first stage voltage amplifier. It would be pretty cool if Topping was doing stuff like that with the B100. Or is that old news in contemporary solid state amp design?

I don't follow this stuff closely because frankly I'm quite happy with 0.01% distortion levels, but I know high-order loops are standard in the Hypex/Purifi class D amps because the designer has talked about it. Applying such techniques to linear amplification should be easier.

 

[rongon]

It’s how they describe this, “T’ang-ku-la,” amplification module. I know nothing beyond that, it’s basically just marketing lingo as far as I am aware.

-Ed

Yes, I saw that, replied to a post about it. It's marketing stuff. No real details in it.

 

[rongon]

Something else just popped into my head.
What's the problem with a unity gain speaker level amplifier module if you have a line stage that can drive it?
You're going to need what used to be called a 'control amplifier' anyway. You need input selection, volume control, you might want tone controls, and so on. You might even want something with room correction and gain.
If that 'control amplifier' had +24dB of gain, and the power amplifier has unity gain, the gain apparent to you the listener would be as expected (maybe about 1V rms signal to full power, or something like that).
That would work, wouldn't it?
So this B100 with just a little gain isn't so horrible. Of course, putting another little amplifier stage in front of it is going to increase distortion and noise by at least a tiny bit. I think it's nice to have the flexibility to choose where that 24dB of gain will come in your system. Maybe...

 

[terryforsythe]

Of course, putting another little amplifier stage in front of it is going to increase distortion and noise by at least a tiny bit.

No need for another amplifier stage. The B100 has three gain settings:

Balanced: 0, 10.4dB and 19.9dB

Single Ended: 6dB, 16.4dB and 25.9dB

 

[rongon]

Yes, I know, but increasing the gain on the B100 also increases noise and distortion, but by such an infinitesimal amount that it's not going to be audible, or even worth mentioning.

If you want all those other features then you could pick the low gain option on the B100 and add a 'control amplifier'. I like the flexibility for system building.
I think that's a nice feature, or it could be for me.

 

[tomchris]

It is great to see a new addition to Topping's product line of amplifiers.

Measurements look impressive.

Personally, I prefer the ability to handle very low ohm loads over hunting for lower THD at this order of magnitude. Perhaps, one day in the future, Topping will add a monoblock with low Ohm handling and high current capability. One can only hope.

I can't wait to see what the future holds.

 

[sarieri]

Some of us are getting all cynical and trying to find faults...

Topping is known for its unreliable QC on amps, so there might be a reason for all the critics here. Topping may very well deserve it.

Just some personal experience with Topping here. I have about 5 Topping amps, 2DACs, and few other preamps. Two LA90d dead after one month of use, one ClassD RA3 dead one day after delivery, one Pre90 preamp with popping noise. And guess what does the cooker from Topping say? JohnYoung said “you should avoid Topping since you have no good luck.” lol, hell I will, there are gears out there measures better.

 

[Doodski]

The problem is that NFB destroys the sound, hence why the THX AAA Benchmark AHB2 and the likes sound dead and closed in, a cold sterile tool with no enjoyment.

You apparently do not know how feedback works. It is an algebraic summing process and has nothing to do with deadness, closed in and sterile.

 

[ryanmh1]

It’s how they describe this, “T’ang-ku-la,” amplification module. I know nothing beyond that, it’s basically just marketing lingo as far as I am aware.

It's gobbledygook. There is no such defined term as triple nested feedback. Could mean 1 global loop with three local loops inside that, or something else, like a loop in a loop in a loop. Doesn't matter either, since feedback is feedback, and they've applied it spades, implying potentially more than 2 poles and a complex feedback design. Hard to stabilize. Hopefully the protection engineering is good, too!

 

[rongon]

Right.
Stability is the question.
Put a 10kHz square wave through it and see what comes out.
That would tell us how well the circuit's been stabilized.
Right?

 

[mhardy6647]

These amps' behavior into a particularly reactive load (e.g., a Quad ESL-57 loudspeaker --or connection to most any loudspeaker via a Polk Audio "Cobra Cable", both well documented killers of marginally stable amplifiers) might be interesting to study.

 

[therobin]

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.

I don't understand this assessment. You say you could not get above 86W@4ohm due to protection and also state it is rated for 83W. But the spec sheet you posted below it clearly states it is rated at 100W into 4ohn and 83W is into 8ohm (and is only a <10%THD) rating. However, your 8ohn test shows it clipped at 50W. In either case, your bench shows it failed to achieve its rated power out on the spec sheet.