Topping Mini 300 Amplifier Review

[Luvchampagne]

I'm going to be using the mini300 as part of my spk16 active speaker project. Based on my preliminary analysis they should be an excellent fit for the tweeters.

 

[Michael Zenkl]

I own one, and besides feeling that it sounds rather "lean", I have measured a gain of 25.5 dB at maximum volume setting, so one has to consider that when pairing with other amplifiers with higher gain in an active multi amp setting

 

[Angst92]

I own one, and besides feeling that it sounds rather "lean", I have measured a gain of 25.5 dB at maximum volume setting, so one has to consider that when pairing with other amplifiers with higher gain in an active multi amp setting

I've just had one turn up, and my immediate first impression was also that it sounds rather lean compared to the Fosi V3 it was supposed to be replacing, cant really explain it. It also seems to be fairly heavily biased to the right channel throughout the entire range of the volume pot.

 

[oldloder]

I've just had one turn up, and my immediate first impression was also that it sounds rather lean compared to the Fosi V3 it was supposed to be replacing, cant really explain it. It also seems to be fairly heavily biased to the right channel throughout the entire range of the volume pot.

This sounds like the polarity is reversed on one of your speakers ... you might want to double check that as a rule out.

 

[Angst92]

This sounds like the polarity is reversed on one of your speakers ... you might want to double check that as a rule out.

It's not, it's wired up correctly.

 

[90sNintendoKid]

Imho your weak link is the Minidsp 2x4hd by lots, not a little. In all likelihood the noise is from the Minidsp not the mini 300. Have you swapped out the Minidsp to verify that?

What objective data are you using to state that the Minidsp 2x4HD is causing the noise?

 

[Tell]

What objective data are you using to state that the Minidsp 2x4HD is causing the noise?

In this case it seems like it, the MiniDSP 2x4HD clocks in at 100dB, while the PCM5102 that is noticeable quieter have a noisefloor around -112dB if I remeber correctly. But again it's not like the 2x4HD is audible noisy, I need to have my ear a decimeter from the tweeter to hear anything.

 

[90sNintendoKid]

In this case it seems like it, the MiniDSP 2x4HD clocks in at 100dB, while the PCM5102 that is noticeable quieter have a noisefloor around -112dB if I remeber correctly. But again it's not like the 2x4HD is audible noisy, I need to have my ear a decimeter from the tweeter to hear anything.

Thanks, I hear hiss when I have a Minidsp 2x4 HD and t.racks DSP mini pro and I have to have my ear a few centimetres from the speaker which sounds like a similar experience to you. Otherwise I hear no hiss.

 

[Angst92]

I've just had one turn up, and my immediate first impression was also that it sounds rather lean compared to the Fosi V3 it was supposed to be replacing, cant really explain it. It also seems to be fairly heavily biased to the right channel throughout the entire range of the volume pot.

I'll retract the comment about the channel balance, after repairing the fosi the balance is the same so clearly the issue is something else. What I will say though is that it runs a lot hotter than the fosi and I think this is purely down to bad design.
The fosi has vents top and bottom and uses the chassis as a heatsink whereas the topping has a separate internal heatsink with no top vents to the chassis so heat seems to just build up in it.

 

[Petrushka]

Im so old I remember when a 70 Wpc amp was called a Brute.

Now you can buy a better, more powerful amp for the price a family meal at McDonald’s.

 

[terminus12]

Does the E50 II have any advantage over the DX1 II when paired with the Mini 300? Using a CCA as a transport via Toslink.

 

[ATTI]

@terminus12
more convient connection with TRS-TRS without 4.4mm adapter cable, additional external power connector, new AK4497S chip, bluetooth, the same case appearance and size with Mini 300.

 

[Roland68]

I'll retract the comment about the channel balance, after repairing the fosi the balance is the same so clearly the issue is something else. What I will say though is that it runs a lot hotter than the fosi and I think this is purely down to bad design.
The fosi has vents top and bottom and uses the chassis as a heatsink whereas the topping has a separate internal heatsink with no top vents to the chassis so heat seems to just build up in it.

Without a specific figure for the actual temperature, such statements are completely useless and meaningless.
Most users are unaware that amplifiers, in particular, should maintain a certain minimum operating temperature—and that this temperature should remain as constant as possible.
Furthermore, humans are completely unreliable at interpreting perceived temperatures; while one person might consider 30°C hot, another might view 35°C as merely lukewarm. As long as you can keep your hand on the amplifier for 10 seconds without burning yourself, the temperature is below 40°C—well within the safe range.

Depending on the ambient temperature, a range of 35–50°C is perfectly normal for an amplifier and is no cause for concern. Conventional amplifiers have been operating in this temperature range for 40 to 50 years without issues; why should that suddenly change?

The cooling design of the Mini 300 has been proven effective for five years; even with room temperatures exceeding 35°C and under heavy load, I haven't measured any unusual temperatures—not even after 10 hours of operation.

Various measuring devices are available starting at €2–3; semi-professional infrared thermometers start at €6–10; and professional-grade temperature probes (digital K-type) with displays—accurate to within 0.1°C—can be purchased for just €5–20.

 

[Angst92]

Without a specific figure for the actual temperature, such statements are completely useless and meaningless.
Most users are unaware that amplifiers, in particular, should maintain a certain minimum operating temperature—and that this temperature should remain as constant as possible.
Furthermore, humans are completely unreliable at interpreting perceived temperatures; while one person might consider 30°C hot, another might view 35°C as merely lukewarm. As long as you can keep your hand on the amplifier for 10 seconds without burning yourself, the temperature is below 40°C—well within the safe range.

Depending on the ambient temperature, a range of 35–50°C is perfectly normal for an amplifier and is no cause for concern. Conventional amplifiers have been operating in this temperature range for 40 to 50 years without issues; why should that suddenly change?

The cooling design of the Mini 300 has been proven effective for five years; even with room temperatures exceeding 35°C and under heavy load, I haven't measured any unusual temperatures—not even after 10 hours of operation.

Various measuring devices are available starting at €2–3; semi-professional infrared thermometers start at €6–10; and professional-grade temperature probes (digital K-type) with displays—accurate to within 0.1°C—can be purchased for just €5–20.

I could purchase a device to measure the temp for exact readings however I was merely commenting on the relative difference on observed heat build up between the two devices.
Is the topping probably perfectly safe and within spec, yes. But that doesn't mean that it's design isnt suboptimal, the fosi is clearly much more effective at moving heat away via convection.
It doesn't make sense to me that on the topping you would have an internal heatsink but no vents directly above it if you aren't directly coupling it to the chassis.

 

[Roland68]

I could purchase a device to measure the temp for exact readings however I was merely commenting on the relative difference on observed heat build up between the two devices.
Is the topping probably perfectly safe and within spec, yes. But that doesn't mean that it's design isnt suboptimal, the fosi is clearly much more effective at moving heat away via convection.
It doesn't make sense to me that on the topping you would have an internal heatsink but no vents directly above it if you aren't directly coupling it to the chassis.

That is precisely the point most people fail to grasp. With an amplifier, you don't want maximum convection—that would be very easy to achieve.
The goal is a constant temperature without rapid fluctuations, the kind that can easily occur with direct convection. Topping has consistently demonstrated that they understand this; that is why none of their amplifiers feature heatsinks exposed to direct airflow. Users unfamiliar with these principles often accuse Topping of incorrect heatsink orientation (e.g., horizontal instead of vertical), but such claims stem simply from ignorance and a lack of understanding.

Furthermore, you are comparing apples and oranges.
The Mini 300 and the Fosi are different amplifiers using different amplifier ICs. The Fosi delivers twice the power and must dissipate significantly more heat when under load. The downside is that the temperature can fluctuate much more drastically depending on the load—something that is highly undesirable, especially in amplifiers. Think of the "temperature-dependent (stable) operating point of semiconductors/electronic components."

The 3E Audio A5/A7 models offer another excellent example of a well-executed cooling design utilizing indirect convection—without any cooling fins at all.
These amplifiers also maintain a very stable temperature, hovering around 10–12°C above ambient room temperature.
With the A5/A7, as well as the Mini 300/PA5(II), cooling efficiency increases slightly as the temperature rises.
There is a specific reason why the ventilation slots on the 300/PA5(II) are located at the rear rather than right next to the heatsink.
Perhaps these manufacturers know far more about this subject than you might imagine.

 

[terminus12]

@terminus12
more convient connection with TRS-TRS without 4.4mm adapter cable, additional external power connector, new AK4497S chip, bluetooth, the same case appearance and size with Mini 300.

So I bought the E50 II on sale for $170 from a European store with a 2-year store warranty. I’ve also ordered the DX1 II, but that one will be for the HE400SE.

 

[Angst92]

That is precisely the point most people fail to grasp. With an amplifier, you don't want maximum convection—that would be very easy to achieve.
The goal is a constant temperature without rapid fluctuations, the kind that can easily occur with direct convection. Topping has consistently demonstrated that they understand this; that is why none of their amplifiers feature heatsinks exposed to direct airflow. Users unfamiliar with these principles often accuse Topping of incorrect heatsink orientation (e.g., horizontal instead of vertical), but such claims stem simply from ignorance and a lack of understanding.

Furthermore, you are comparing apples and oranges.
The Mini 300 and the Fosi are different amplifiers using different amplifier ICs. The Fosi delivers twice the power and must dissipate significantly more heat when under load. The downside is that the temperature can fluctuate much more drastically depending on the load—something that is highly undesirable, especially in amplifiers. Think of the "temperature-dependent (stable) operating point of semiconductors/electronic components."

The 3E Audio A5/A7 models offer another excellent example of a well-executed cooling design utilizing indirect convection—without any cooling fins at all.
These amplifiers also maintain a very stable temperature, hovering around 10–12°C above ambient room temperature.
With the A5/A7, as well as the Mini 300/PA5(II), cooling efficiency increases slightly as the temperature rises.
There is a specific reason why the ventilation slots on the 300/PA5(II) are located at the rear rather than right next to the heatsink.
Perhaps these manufacturers know far more about this subject than you might imagine.

As far as I can see, the A5/A7 use a thick block of metal that is coupled to the chassis with thermal compound as a heatsink? That makes sense that it is stable and works without top vents as it's a large thermal mass and directly radiates heat externally. It is a very different design from the topping method of a small finned heatsink inside which will rely on airflow through the body to move the heat away properly. There's a reason av receivers and stereo amps are generally fully ventilated on the top, bottom and all sides when they use finned heatsinks to cool internal components.

 

[Roland68]

As far as I can see, the A5/A7 use a thick block of metal that is coupled to the chassis with thermal compound as a heatsink? That makes sense that it is stable and works without top vents as it's a large thermal mass and directly radiates heat externally. It is a very different design from the topping method of a small finned heatsink inside which will rely on airflow through the body to move the heat away properly. There's a reason av receivers and stereo amps are generally fully ventilated on the top, bottom and all sides when they use finned heatsinks to cool internal components.

And AV receivers, in particular, often reach internal and heatsink temperatures exceeding 45–50°C even when idling (significantly higher than the Mini 300); the exterior casing is naturally much cooler, as it isn't used for cooling in these devices.

But feel free to ignore this information.
It is also intended to inform any interested users who are worrying—quite unnecessarily—about the heat generated by their devices.

 

[Angst92]

And AV receivers, in particular, often reach internal and heatsink temperatures exceeding 45–50°C even when idling (significantly higher than the Mini 300); the exterior casing is naturally much cooler, as it isn't used for cooling in these devices.

But feel free to ignore this information.
It is also intended to inform any interested users who are worrying—quite unnecessarily—about the heat generated by their devices.

I'm not ignoring that information, my only point was that it doesn't seem like an optimal design. Both the fosi and your example the A5/A7 use the chassis directly connected as part of the heatsink to increase the thermal mass and move the heat outside. The topping does not, it uses a small finned heatsink that will require airflow through the case to move the heat away but then has sub optimal ventilation. Other devices that use those types of heatsinks on components are well ventilated for optimum airflow.

 

[Roland68]

I'm not ignoring that information, my only point was that it doesn't seem like an optimal design. Both the fosi and your example the A5/A7 use the chassis directly connected as part of the heatsink to increase the thermal mass and move the heat outside. The topping does not, it uses a small finned heatsink that will require airflow through the case to move the heat away but then has sub optimal ventilation. Other devices that use those types of heatsinks on components are well ventilated for optimum airflow.

Sorry, that doesn't make sense. You're overlooking why Topping chose this cooling design and why it is so optimal, especially for this specific amplifier.
Of course, it is incredibly easy and cheap to implement cooling based on direct convection using a finned heatsink. However, the "more is better" approach is actually counterproductive to the amplifier electronics' performance.
There is a vast difference between maximum convection—often found in cheap amplifiers simply because it is a low-cost, simple solution—and indirect convection precisely tailored to the specific use case. The latter is significantly more expensive to develop and test until it is optimized.
There are many small pieces of the puzzle that enable the Mini 300, PA5(II), and 3E Audio A5/A7 to achieve the best measurement results and performance among TPA3251/55-based amplifiers.