This is a review and detailed measurements of the Topping PA7 Plus stereo class D amplifier. It was sent to me by the company and costs US $549.
The PA7 Plus is stylish with firm switches that have nice action. You can select power on/off or trigger input. In addition, you have a choice of balanced or RCA inputs:
Yes, there is a monster external power supply. It provides a whopping 52 volts at 6.5 amps! I really like the staggered speaker terminals as it allows even the largest speaker connectors to fit in there without interference. Other derktop amplifiers use much tighter spacing.
The amplifier has large vents on the back, sides and bottom. In use the left side got firmly warm but nothing concerning.
Note that there is a non-Plus version (PA7) that has lower power and lower cost ($449).
Topping PA7 Plus Measurements
Let's start with our usual measurements starting with balanced input:
As you see gain is medium level at max volume at nearly 20 dB. SINAD lands in our excellent category and even sneaks into our top 20 best amplifiers ever measured:
RCA input shows more ground currents and noise but still holds its own:
But note that gain increases substantially to 26 dB.
Noise performance is extremely good:
We are talking about near state of the art DACs at full power!
Multitone shows off the very low distortion:
Excellent channel separation is achieved despite the very small enclosure, beating vast majority of amplifiers I test:
An interesting filter is implemented which sharply reduces load dependency:
I take that 0.7 dB to get load independence.
Let's get into our power measurements:
191 watts with very low distortion into two channels is fantastic for such a small amplifier. Here is the same with 1% THD:
Even at 8 ohm you have lots of power:
Note how the noise floor competes with Purifi reference amplifier and even its distortion! It is just short of its power.
There is more distortion at higher frequencies but below 1 kHz, it is extremely good:
Reactive Amplifier Power Testing
I tested the PA7 Plus using the PowerCube reactive load that simulates both capacitive and inductive loads as to better match behavior of a real speaker. Response at 4 an 8 ohm was excellent:
I could even get it to work with 2 ohm but one out of two times it would go into protection and stay there.
Conclusions
Even though the PA7 Plus is based on a commercial amplifier IC, it is clearly that significant engineering optimizations have gone into the design to produce such a low noise and distortion amplifier. The package is excellent and power supply quite hefty to enable very high power output (nearly 400 watts combined at 4 ohm!). Yes, you have a big brick to hide but the amp itself remains quite small on the desk. You could even use it in a main system if you leave the volume set and use the DAC or a pre-amp with a remote.
I am happy to add Topping PA7 Plus to my recommended list.
Note: amplifiers are some of the least reliable audio gear due to high currents and voltages involved. I short circuited the PA7 Plus and while it created a large spike, it nicely went into protection and recovered. Still, if you are risk averse, you may want to wait a bit to see what the reliability turns out to me.
------------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
The PA7 Plus is stylish with firm switches that have nice action. You can select power on/off or trigger input. In addition, you have a choice of balanced or RCA inputs:
Yes, there is a monster external power supply. It provides a whopping 52 volts at 6.5 amps! I really like the staggered speaker terminals as it allows even the largest speaker connectors to fit in there without interference. Other derktop amplifiers use much tighter spacing.
The amplifier has large vents on the back, sides and bottom. In use the left side got firmly warm but nothing concerning.
Note that there is a non-Plus version (PA7) that has lower power and lower cost ($449).
Topping PA7 Plus Measurements
Let's start with our usual measurements starting with balanced input:
As you see gain is medium level at max volume at nearly 20 dB. SINAD lands in our excellent category and even sneaks into our top 20 best amplifiers ever measured:
RCA input shows more ground currents and noise but still holds its own:
But note that gain increases substantially to 26 dB.
Noise performance is extremely good:
We are talking about near state of the art DACs at full power!
Multitone shows off the very low distortion:
Excellent channel separation is achieved despite the very small enclosure, beating vast majority of amplifiers I test:
An interesting filter is implemented which sharply reduces load dependency:
I take that 0.7 dB to get load independence.
Let's get into our power measurements:
191 watts with very low distortion into two channels is fantastic for such a small amplifier. Here is the same with 1% THD:
Even at 8 ohm you have lots of power:
Note how the noise floor competes with Purifi reference amplifier and even its distortion! It is just short of its power.
There is more distortion at higher frequencies but below 1 kHz, it is extremely good:
Reactive Amplifier Power Testing
I tested the PA7 Plus using the PowerCube reactive load that simulates both capacitive and inductive loads as to better match behavior of a real speaker. Response at 4 an 8 ohm was excellent:
I could even get it to work with 2 ohm but one out of two times it would go into protection and stay there.
Conclusions
Even though the PA7 Plus is based on a commercial amplifier IC, it is clearly that significant engineering optimizations have gone into the design to produce such a low noise and distortion amplifier. The package is excellent and power supply quite hefty to enable very high power output (nearly 400 watts combined at 4 ohm!). Yes, you have a big brick to hide but the amp itself remains quite small on the desk. You could even use it in a main system if you leave the volume set and use the DAC or a pre-amp with a remote.
I am happy to add Topping PA7 Plus to my recommended list.
Note: amplifiers are some of the least reliable audio gear due to high currents and voltages involved. I short circuited the PA7 Plus and while it created a large spike, it nicely went into protection and recovered. Still, if you are risk averse, you may want to wait a bit to see what the reliability turns out to me.
------------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
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