This is a review of the Neohipo-BP10 - classD stereo amplifier. I got it really cheap of an action site and I didn't have an intended use for it but I thought it's really cool as small amplifier. I could use it for a small system or even to measure the speakers I make. It's incredibly small and versatile. It has Bluetooth input and analog input in the form of an 3.mm stereo jack. It is based on TI's TPA3116 class D chip. Looking at TI's datasheet, we should expect around 10W in 8ohm with the included 12V/5A adapter at 1% THD+N. Expected THD+N is around 0.03% (-70dB) at 5W in 8ohm. It might be a bit higher with the 12V adapter. The amplifier can use a supply voltage as high as 26Vdc, so I will repeat these measurements when I have a power supply with a higher voltage.
Here are some pictures of the amplifier:
Initially, for these measurements I used my trusty QA401 analyzer as it's easier to use than the Cosmos combination and for a power amplifier the QA401 has enough performance. But a few days after performing the measurements, I realized that the QA401 has a common ground between all inputs and outputs and that the BP10 has differential outputs, hence the negative connector for the output is not connected to the ground used by the input circuitry.
I then decided to use my Cosmos ADC + Scaler combo, together with the Topping D50s as a generator.
Here is the 1kHZ at 1W into 8ohm with the amp in stereo mode:
This is actually decent. Much better than I initially measured. Not stellar but it's decent performance for the cost. I would have liked to see it above 80dB SINAD but that is not the case.
WOW!!! This is amazingly bad. I have to say I was not expecting this. We have a SINAD of -45dB at 1W into 8ohm. It did not matter if I went up or down with the power. Going up to 5W got the SINAD around -20dB so I decided not to post this. What is strange is that the harmonics content changes depending on volume. Changing the volume from the large knob on the top, also changes the harmonics content. SINAD remains the same but you see odd harmonics disappearing and even ones increasing. It looks like the input circuitry is the limiting factor but I can't say for sure.
The input circuitry does saturate fairly quick but it's not that bad actually. I was able to go as high as 8W until THD jumped.
Here is the 1kHZ at 5W into 8ohm with the amp in stereo mode:
Identical SINAD as for 1W but a bit worse THD. This is definitely noise limited.
Here is a 1kHz test tone over Bluetooth. I used my phone connected to the amp and I played a YouTube video with a 1kHz test tone. I know this is not ideal but all clips showed the same performance.
Well THD is a bit better than using the analog input and I can go as high as 6W.
Here is the multitone:
We have 80dB of noise free signal up to around 10kHz. Again, this is decent performance.
Again, this is incredibly bad. I will say it's unusable.
IMD:
This is around -30dB, again, very very poor performance.
Performance is decent here as well.
I also looked at the frequency response:
It is pretty flat up to 20kHz, so this looks OK. There is about 1dB attenuation on low frequencies.
Well, this is rather disappointing. I was hoping for some decent performance, maybe at least a SINAD of -70 to -80dB but we are far from that. I did not measure in bridge mode. I will do this today and update the post. I will also post an update when I find a power supply with a higher voltage.
Listening to the amp was OK. I could tell the high distortion when playing louder but on most parts it was OK. The Bluetooth sounded OK.
As a conclusion, if you need a small amp that performs like a tube amp, this little amp is for you. Not sure if the sample I have is defective or not.
The conclusion is that this is a decent amp that can definitely be used if you do not have high expectations. Looking at the measurements we see decent performance that is close to good tube amps
. For the price, around 30EUR, this is an interesting device. With the included adapter that outputs 12Vdc, it can deliver around 2 x 10W and if you do not push it above 5W, it performs OK. I'm curious if increasing the supply voltage to 24Vdc will improve THD and SINAD. Max output power will definitely increase but not sure about THD. It does seem to have rather high noise that limits the SINAD. I also like the Bluetooth input that performed OK and that give you a lot of flexibility.
I also have to apologies for posting wrong measurements initially.
Here are some pictures of the amplifier:
Initially, for these measurements I used my trusty QA401 analyzer as it's easier to use than the Cosmos combination and for a power amplifier the QA401 has enough performance. But a few days after performing the measurements, I realized that the QA401 has a common ground between all inputs and outputs and that the BP10 has differential outputs, hence the negative connector for the output is not connected to the ground used by the input circuitry.
I then decided to use my Cosmos ADC + Scaler combo, together with the Topping D50s as a generator.
Here is the 1kHZ at 1W into 8ohm with the amp in stereo mode:
This is actually decent. Much better than I initially measured. Not stellar but it's decent performance for the cost. I would have liked to see it above 80dB SINAD but that is not the case.
The input circuitry does saturate fairly quick but it's not that bad actually. I was able to go as high as 8W until THD jumped.
Here is the 1kHZ at 5W into 8ohm with the amp in stereo mode:
Identical SINAD as for 1W but a bit worse THD. This is definitely noise limited.
Here is a 1kHz test tone over Bluetooth. I used my phone connected to the amp and I played a YouTube video with a 1kHz test tone. I know this is not ideal but all clips showed the same performance.
Here is the multitone:
We have 80dB of noise free signal up to around 10kHz. Again, this is decent performance.
IMD:
Performance is decent here as well.
I also looked at the frequency response:
It is pretty flat up to 20kHz, so this looks OK. There is about 1dB attenuation on low frequencies.
Listening to the amp was OK. I could tell the high distortion when playing louder but on most parts it was OK. The Bluetooth sounded OK.
As a conclusion, if you need a small amp that performs like a tube amp, this little amp is for you. Not sure if the sample I have is defective or not.
The conclusion is that this is a decent amp that can definitely be used if you do not have high expectations. Looking at the measurements we see decent performance that is close to good tube amps
. For the price, around 30EUR, this is an interesting device. With the included adapter that outputs 12Vdc, it can deliver around 2 x 10W and if you do not push it above 5W, it performs OK. I'm curious if increasing the supply voltage to 24Vdc will improve THD and SINAD. Max output power will definitely increase but not sure about THD. It does seem to have rather high noise that limits the SINAD. I also like the Bluetooth input that performed OK and that give you a lot of flexibility.I also have to apologies for posting wrong measurements initially.
Last edited:
