Topping Mini 300 Amplifier Review

[whazzup]

To close the loop (for no one) for my earlier post about the temperature of components in the mini 300:

Topping Mini 300 Amplifier Review

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...

www.audiosciencereview.com

Texas Instruments does rate the TPA3255 up to 70°C operating range. I'm not refuting all the other comments about everything being in spec.
Just that in my case, I have it on easily more than 12 hours almost daily until I shut down for the day, and it's at my desktop pc with its own fans (so 1 more fan isn't too noticeable). And as have been mentioned already, decreasing the operating temperature of electrical and electronic components by 10°C typically doubles their expected lifespan and reliability, so if it doesn't cost me much to run the amp at lower temps, why not?

To get an estimate of the heatsink temp in the chassis, I let the amp stay powered in the chassis and go about my business for some time, then powered off and pull out the board to check the temp. I got 57°C (note that it had cooled about 2 degrees by the time I finished fiddling around with the camera and the room sensor, about a minute later). Chassis temp was 41°C.

Then I added an cheap external usb fan (supposed to be 18db) that came with its own rubber feet, because that's the easiest way I could think of to add some active cooling. And added some silicon feet under the amp as well to allow some airflow between amp and fan.

Let the amp run again in the chassis with the external fan beneath, then powered off, pulled out the board and checked the temp again. With some airflow, the heatsink temp dropped to 46°C (again, a short pause before I could take the photo). Chassis temp was at 32°C.

To summarize what I could measure (with room temp at 29-30°C, 84-86°F):

Heatsink temp in chassis: 57°C / 134°F
Heatsink temp in chassis with external bottom fan: 46°C / 115°F
Heatsink temp in the open: 50°C / 122°F
Heatsink temp in open with fan (pointed at heatsink): 34°C / 93°F


Yes, there's likely going to be greater dust buildup over time. And 18db fan noise (in my case). Pros and cons. Please use the data and make your own decisions.

 

[OldTimer]

To summarize what I could measure (with room temp at 29-30°C, 84-86°F):

Heatsink temp in chassis: 57°C / 134°F
Heatsink temp in chassis with external bottom fan: 46°C / 115°F
Heatsink temp in the open: 50°C / 122°F
Heatsink temp in open with fan (pointed at heatsink): 34°C / 93°F


Yes, there's likely going to be greater dust buildup over time. And 18db fan noise (in my case). Pros and cons. Please use the data and make your own decisions.

What Speakers do you use? Could be low speakers’ impedance. Spec mentioned is 4-8 ohm. It’s different from Fosi V3 that can handle 2 ohm. It’s from the spec: 2-8 ohm.

 

[whazzup]

At the moment

What Speakers do you use? Could be low speakers’ impedance. Spec mentioned is 4-8 ohm. It’s different from Fosi V3 that can handle 2 ohm. It’s from the spec: 2-8 ohm.

Currently Monitor Audio Bronze 1s. Supposed to be 8 ohms. Don't think I have super low impedance speakers, all are around 4-8 ohms.

 

[tb2025]

To close the loop (for no one) for my earlier post about the temperature of components in the mini 300:

Topping Mini 300 Amplifier Review

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...

www.audiosciencereview.com

Texas Instruments does rate the TPA3255 up to 70°C operating range. I'm not refuting all the other comments about everything being in spec.
Just that in my case, I have it on easily more than 12 hours almost daily until I shut down for the day, and it's at my desktop pc with its own fans. And as have been mentioned already, decreasing the operating temperature of electrical and electronic components by 10°C typically doubles their expected lifespan and reliability, so if it doesn't cost me much to run the amp at lower temps, why not?

To get an estimate of the heatsink temp in the chassis, I let the amp stay powered in the chassis and go about my business for some time, then powered off and pull out the board to check the temp. I got 57°C (note that it had cooled about 2 degrees by the time I finished fiddling around with the camera and the room sensor, about a minute later). Chassis temp was 41°C.
View attachment 545884


Then I added an cheap external usb fan (supposed to be 18db) that came with its own rubber feet, because that's the easiest way I could think of to add some active cooling. And added some silicon feet under the amp as well to allow some airflow between amp and fan.
View attachment 545887


Let the amp run again in the chassis with the external fan, then powered off, pulled out the board and checked the temp again. With some airflow, the heatsink temp dropped to 46°C (again, a short pause before I could take the photo). Chassis temp was at 32°C.
View attachment 545892


To summarize what I could measure (with room temp at 29-30°C, 84-86°F):

Heatsink temp in chassis: 57°C / 134°F
Heatsink temp in chassis with external bottom fan: 46°C / 115°F
Heatsink temp in the open: 50°C / 122°F
Heatsink temp in open with fan (pointed at heatsink): 34°C / 93°F


Yes, there's likely going to be greater dust buildup over time. And 18db fan noise (in my case). Pros and cons. Please use the data and make your own decisions.

Hi, I also use a case fan to blow at the bottom, but the sound quality fluctuates randomly, sometimes good and sometimes bad. Sometimes the bass is punchy, and sometimes it lacks impact, without any pattern. Even the volume is noticeably different, while the knob hasn't been moved at all. This issue has been bothering me for a long time, and I just can't find the cause.

Have you tested its performance at different temperatures? Does temperature affect the sound?

 

[OldTimer]

Based on this, speakers’ impedance can change. The amp will be damaged by your speakers.

Speaker impedance, measured in ohms (Ω), is the total resistance a speaker presents to an amplifier when an audio signal is applied. It is not a fixed value; instead, it varies with frequency due to the speaker's electrical properties, including resistance and reactance.

Key Factors Influencing Impedance Changes

1. Frequency Response:
Impedance Variation: The impedance of a speaker fluctuates across different frequencies. For instance, at lower frequencies, the impedance may be lower due to the voice coil's inductance, while at higher frequencies, it can increase due to capacitive effects. This means that the nominal impedance rating (like 4, 6, or 8 ohms) is often just an average value, and the actual impedance can dip below this rating during certain frequencies

2. Power Levels:
Current Draw: Lower impedance speakers draw more current from the amplifier, which can lead to higher power output. However, this can also strain the amplifier if it is not designed to handle the increased load. Conversely, higher impedance speakers draw less current, which can reduce the risk of overloading the amplifier but may require more voltage to achieve the same power output

3. Speaker Design:
Voice Coil and Crossover Effects: The design of the speaker, including the voice coil and crossover components, can influence how impedance changes with frequency. The inductance of the voice coil and the reactance from the crossover network can cause the impedance to vary dynamically as audio signals are played

 

[whazzup]

Hi, I also use a case fan to blow at the bottom, but the sound quality fluctuates randomly, sometimes good and sometimes bad. Sometimes the bass is punchy, and sometimes it lacks impact, without any pattern. Even the volume is noticeably different, while the knob hasn't been moved at all. This issue has been bothering me for a long time, and I just can't find the cause.

Have you tested its performance at different temperatures? Does temperature affect the sound?

I have had the fan under the amp for only half a day, will let you know if I encountered any weird issues. Also, my speakers are high passed at 100hz, so they're not really required to play the low frequencies. I do adjust the volume quite often (louder in the day, lower at night), so will be hard to tell if there're any subtle differences. Technically my fan will be always on whenever the amp is on. I'm just bringing the close to 60°C temp to maybe the 40s? Which should help not harm the amp's components.

There are tpa3255 designs with fans on them, so I don't think adding a fan will cause such problems.

Dual Tpa3255 300W RMS per channel Wondom AAM8 amplifier with 117db SNR 36uVrms noise floor and XLR balanced input

Hello everyone,in this video: I’ve got a pretty interesting amplifier to review. The AAM8 model boasts highly impressive specifications. Single board houses two TPA3255 chips, each operating in PBTL mode, which allows it to deliver 300W RMS of output power per channel. The board is very...

www.audiosciencereview.com

 

[whazzup]

Based on this, speakers’ impedance can change. The amp will be damaged by your speakers.

Speaker impedance, measured in ohms (Ω), is the total resistance a speaker presents to an amplifier when an audio signal is applied. It is not a fixed value; instead, it varies with frequency due to the speaker's electrical properties, including resistance and reactance.

Key Factors Influencing Impedance Changes

1. Frequency Response:
Impedance Variation: The impedance of a speaker fluctuates across different frequencies. For instance, at lower frequencies, the impedance may be lower due to the voice coil's inductance, while at higher frequencies, it can increase due to capacitive effects. This means that the nominal impedance rating (like 4, 6, or 8 ohms) is often just an average value, and the actual impedance can dip below this rating during certain frequencies

2. Power Levels:
Current Draw: Lower impedance speakers draw more current from the amplifier, which can lead to higher power output. However, this can also strain the amplifier if it is not designed to handle the increased load. Conversely, higher impedance speakers draw less current, which can reduce the risk of overloading the amplifier but may require more voltage to achieve the same power output

3. Speaker Design:
Voice Coil and Crossover Effects: The design of the speaker, including the voice coil and crossover components, can influence how impedance changes with frequency. The inductance of the voice coil and the reactance from the crossover network can cause the impedance to vary dynamically as audio signals are played

Not sure what you're saying. Yes, almost all speakers have varying impedance over FR (see the speakers review charts at ASR!). But I fail to see how that relates to your statement 'The amp will be damaged by your speakers.' ???

 

[OldTimer]

Not sure what you're saying. Yes, almost all speakers have varying impedance over FR (see the speakers review charts at ASR!). But I fail to see how that relates to your statement 'The amp will be damaged by your speakers.' ???

As it’s always running hotter.

 

[whazzup]

As it’s always running hotter.

Noted. Amir's charts at 4 and 8 ohms didn't reveal any problems, so for my speakers I don't think will be an issue.

 

[tb2025]

I have had the fan under the amp for only half a day, will let you know if I encountered any weird issues. Also, my speakers are high passed at 100hz, so they're not really required to play the low frequencies. I do adjust the volume quite often (louder in the day, lower at night), so will be hard to tell if there're any subtle differences. Technically my fan will be always on whenever the amp is on. I'm just bringing the close to 60°C temp to maybe the 40s? Which should help not harm the amp's components.

There are tpa3255 designs with fans on them, so I don't think adding a fan will cause such problems.

Dual Tpa3255 300W RMS per channel Wondom AAM8 amplifier with 117db SNR 36uVrms noise floor and XLR balanced input

Hello everyone,in this video: I’ve got a pretty interesting amplifier to review. The AAM8 model boasts highly impressive specifications. Single board houses two TPA3255 chips, each operating in PBTL mode, which allows it to deliver 300W RMS of output power per channel. The board is very...

www.audiosciencereview.com

Thanks! I noticed this variation happens even without the fan.

I've tried many TPA3255 amps, including the AIYIMA A70 and O-NOORUS D1, and without exception, they all have this issue, although their PFFB implementation is not perfect.

This makes me suspect it might be a characteristic of Class D amplifiers, perhaps related to the LC filter. This has been really troubling me.

 

[OldTimer]

Thanks! I noticed this variation happens even without the fan.

I've tried many TPA3255 amps, including the AIYIMA A70 and O-NOORUS D1, and without exception, they all have this issue, although their PFFB implementation is not perfect.

This makes me suspect it might be a characteristic of Class D amplifiers, perhaps related to the LC filter. This has been really troubling me.

I have no problem for Class D amp ($60 Fosi V3). Has been using for 5 years with same old speakers that have destroyed 2 Japanese Class A/B amps (Yamaha and Onkyo) after 20 years.

 

[whazzup]

Thanks! I noticed this variation happens even without the fan.

I've tried many TPA3255 amps, including the AIYIMA A70 and O-NOORUS D1, and without exception, they all have this issue, although their PFFB implementation is not perfect.

This makes me suspect it might be a characteristic of Class D amplifiers, perhaps related to the LC filter. This has been really troubling me.

How drastic are the volume changes and for how long?
Measurable (can you take out your mobile phone with a SPL app and start measuring)?
How often do they happen?
Are you seated at the same position when it happens?

 

[tb2025]

How drastic are the volume changes and for how long?
Measurable (can you take out your mobile phone with a SPL app and start measuring)?
How often do they happen?
Are you seated at the same position when it happens?

I haven't measured it yet. It happens every day. I sit in front of my computer daily, and my listening position is fixed.

I've basically ruled out all other factors; the only thing left to try is changing the speakers. For reference, my current speakers are the JBL Stage A130.

 

[tb2025]

I have no problem for Class D amp ($60 Fosi V3). Has been using for 5 years with same old speakers that have destroyed 2 Japanese Class A/B amps (Yamaha and Onkyo) after 20 years.

I also have a TDA7294 amplifier, and it doesn't have this issue at all. However, I wonder if it's simply because its SINAD is too low, making it not transparent enough to reveal the changes?

 

[tb2025]

I have no problem for Class D amp ($60 Fosi V3). Has been using for 5 years with same old speakers that have destroyed 2 Japanese Class A/B amps (Yamaha and Onkyo) after 20 years.

I've also tried the Fosi V3, and it was no exception. It shouldn't be related to the power output.

 

[lunaria]

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.

That's utter nonsense. That's not how cooling physics work.
Increased thermal mass reduces thermal spikes. Sub-par airflow doesn't do anything positive. The ignorance and lack of understanding is on your side.
The 300 mini cooling design is good enough for most people (who will only use 1W or less most of the time), but far from from great.
(I'm an engineer, who has evaluated/supervised a lot of thermal designs. There is a 99.99999% chance that you have used internet/mobile phone infrastructure that I've been involved in developing.)

 

[Chr1]

Surely if all of the amps mentioned are running this hot there could be a problem with the speakers. Or cables.
They should be a relatively benign load.
(Either that or they are all being played very loud.)

 

[lunaria]

I have refurbished many of these old amplifiers, and in most cases, the problem is the age of the capacitors, not the heat.
In reality, more capacitors in these units fail due to age—for example, through electrolyte drying out or loss, or the breakdown of the oxide layer caused by infrequent use. Turning a unit on for 3–4 hours every 1–4 weeks is just as damaging as running it for 8 hours a day (or 24/7). Rising resistance and decreasing capacitance over time are other factors leading to age-related failure.

Citation/professional study needed. I have quite a few devices with 50-60 year old electrolytic caps that are within their original specs.
IME, high temperature and ripple currents are what kill capacitors (along with subpar manufacturing quality - e.g. capacitor plaque). Age is not major factor for quality caps.
Capacitors reform the oxide layer, if the electrolyte isn't significantly degraded.

 

[whazzup]

I haven't measured it yet. It happens every day. I sit in front of my computer daily, and my listening position is fixed.

I've basically ruled out all other factors; the only thing left to try is changing the speakers. For reference, my current speakers are the JBL Stage A130.

I have the A130 as well. I can turn off my sub and run the speakers full range and see if I can detect any sudden loss of volume / bass at any time. But you will have to try to describe some concrete cases, or particular tracks on youtube / spotify etc, of the bass being punchy and suddenly not punchy anymore. How do you determine that? Do you listen to the same track over and over? If the bass is lost, how long before it comes back? If it's always random then that'll be hard for me to help in any meaningful way.

 

[tb2025]

I have the A130 as well. I can turn off my sub and run the speakers full range and see if I can detect any sudden loss of volume / bass at any time. But you will have to try to describe some concrete cases, or particular tracks on youtube / spotify etc, of the bass being punchy and suddenly not punchy anymore. How do you determine that? Do you listen to the same track over and over? If the bass is lost, how long before it comes back? If it's always random then that'll be hard for me to help in any meaningful way.

Yes, I would even pause for ten minutes and then rewind to listen to the same track again. You only need to repeatedly listen to a few tracks you are familiar with to spot the issue. I have thousands of songs in my PC music library and regularly listen to a specific set of familiar tracks every day.

Based on my observations over the past six months, the sound quality starts to change most of the time after playing a few songs, or at most within an hour. The difference is something you can absolutely hear. It usually degrades, but sometimes it can also get better. The sound fluctuates across the entire frequency range, especially the drum hits; it is very easy to notice on tracks with low frequencies.

I can hear a few distinct levels of sound quality, and the amp randomly toggles between them. To this day, I still don't know the true potential of this amp, or which level represents its actual performance.

Please forgive my somewhat vague description, but this is honestly so bizarre. I know this is not a placebo effect.