This is a review and detailed measurements of the Allo Volt+ D class D amplifier. It was kindly sent to me by a member and costs US $129 in this "dual mono" configuration with stepped attenuator.
I am not a big fan of these clear cases but in this case, pun intended, it works!
Hard to take a picture of it though without heavily accentuating dust and such that normally is not visible:
Dual TI TPA2116 class D amplifiers are used plus a front-end switching power supplies to generate the required plus and minus supplies.
Not that no power supply comes with this amplifier. You have a choice of what you put in there. I used my lab power supply at its max setting of 31 volts and 3 amps. It could use more than 3 amps with 4 ohm load as the power supply current limited near max power sweeps. It was fine with 8 ohm load though as that doesn't need as much current.
There is no remote control so this is really a desktop amplifier.
There is a gain switch below that switches between 19 and 26 dB. I used the default 19 dB which works well with desktop DACs that have no trouble producing near 2 volts you need for max power.
Overall the Volt+ D makes a very positive impression with respect to looks and build quality.
Amplifier Audio Measurements
As usual we start with our dashboard:
This is nice! Budget class D amps routinely produce SINAD in 55 to 65 dB and here we are well above that at 84 dB:
I was also impressed with how low the noise floor was at 5 watt playback:
Many amplifiers fail to achieve 96 dB which is my target for this level of playback.
Crosstalk is superb, better than just about any amp I have tested recently:
Frequency response has a tiny bit of roll off at 20 kHz:
As I noted in the introduction, with 4 ohm load my power supply lacks enough current so I also tested with one channel driven:
So it seems that getting the 60 watt advertised power level is possible.
Taking advantage of onboard capacitors, I ran my burst test:
So even in stereo you have over 60 watts, going to nearly 90 watts with one channel.
Power into 8 ohm load is naturally lower:
Notice that noise floor is very low contributing to very good response at lower power levels.
Varying the frequency gives us the following power levels and distortion:
At or below 1 kHz response is excellent and frequency independent. Above that it varies which is typical of many class D amps.
Finally, I ran a spectrum analysis without my usual class D amp filter in the path:
Wow, TI put some clever filtering/design in there. Usually the switching frequency is down just 10 to 2 dB from our main tone. Here, nothing rises above -88 dB or so! TI advertises that the amp will not interfere with AM radio and it definitely won't.
Conclusions
The Allo Volt+ D amplifier is a delightful surprise. Careful design has elevated the performance of these switching "chip amplifiers" to that of mass market hifi/class AB designs. Yet, it runs cool and costs very little. Yes, you need an external power supply and that is the only flaw I see with going with this solution.
Overall, I am happy to recommend the Allo Volt+ D for its nice and elegant design and performance especially at this price.
------------
As always, questions, comments, recommendations, etc. are welcome.
Good news: my garden helper text me that he is available to come and pull the weeds. Hooray! I don't have to break my back doing that. Alas, he doesn't work for free so I need money by end of tomorrow to pay him. He makes much more than me per hour so please donate toward this good cause using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
I am not a big fan of these clear cases but in this case, pun intended, it works!
Hard to take a picture of it though without heavily accentuating dust and such that normally is not visible:
Dual TI TPA2116 class D amplifiers are used plus a front-end switching power supplies to generate the required plus and minus supplies.
Not that no power supply comes with this amplifier. You have a choice of what you put in there. I used my lab power supply at its max setting of 31 volts and 3 amps. It could use more than 3 amps with 4 ohm load as the power supply current limited near max power sweeps. It was fine with 8 ohm load though as that doesn't need as much current.
There is no remote control so this is really a desktop amplifier.
There is a gain switch below that switches between 19 and 26 dB. I used the default 19 dB which works well with desktop DACs that have no trouble producing near 2 volts you need for max power.
Overall the Volt+ D makes a very positive impression with respect to looks and build quality.
Amplifier Audio Measurements
As usual we start with our dashboard:
This is nice! Budget class D amps routinely produce SINAD in 55 to 65 dB and here we are well above that at 84 dB:
I was also impressed with how low the noise floor was at 5 watt playback:
Many amplifiers fail to achieve 96 dB which is my target for this level of playback.
Crosstalk is superb, better than just about any amp I have tested recently:
Frequency response has a tiny bit of roll off at 20 kHz:
As I noted in the introduction, with 4 ohm load my power supply lacks enough current so I also tested with one channel driven:
So it seems that getting the 60 watt advertised power level is possible.
Taking advantage of onboard capacitors, I ran my burst test:
So even in stereo you have over 60 watts, going to nearly 90 watts with one channel.
Power into 8 ohm load is naturally lower:
Notice that noise floor is very low contributing to very good response at lower power levels.
Varying the frequency gives us the following power levels and distortion:
At or below 1 kHz response is excellent and frequency independent. Above that it varies which is typical of many class D amps.
Finally, I ran a spectrum analysis without my usual class D amp filter in the path:
Wow, TI put some clever filtering/design in there. Usually the switching frequency is down just 10 to 2 dB from our main tone. Here, nothing rises above -88 dB or so! TI advertises that the amp will not interfere with AM radio and it definitely won't.
Conclusions
The Allo Volt+ D amplifier is a delightful surprise. Careful design has elevated the performance of these switching "chip amplifiers" to that of mass market hifi/class AB designs. Yet, it runs cool and costs very little. Yes, you need an external power supply and that is the only flaw I see with going with this solution.
Overall, I am happy to recommend the Allo Volt+ D for its nice and elegant design and performance especially at this price.
------------
As always, questions, comments, recommendations, etc. are welcome.
Good news: my garden helper text me that he is available to come and pull the weeds. Hooray! I don't have to break my back doing that. Alas, he doesn't work for free so I need money by end of tomorrow to pay him. He makes much more than me per hour so please donate toward this good cause using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
