Allo Volt+ D Amplifier Review

[Poultrygeist]

I am currently using a regulated linear PSU with the Volt+D because it has something the +D doesn't have and that's an on/off switch. Can't tell any sonic differences. I have a more powerful Meanwell switching mode ps which I intend to try once I build an enclosure for it with an on/off switch.

 

[MacCali]

I am currently using a regulated linear PSU with the Volt+D because it has something the +D doesn't have and that's an on/off switch. Can't tell any sonic differences. I have a more powerful Meanwell switching mode ps which I intend to try once I build an enclosure for it with an on/off switch.

I thought the whole point of class D is maximum efficiency. Not an audio expert here, but it’s getting the most from the least. So not sure what more juice would do but would be interested on your input after trying. Just something to consider if that sounds reasonable

 

[Poultrygeist]

I thought the whole point of class D is maximum efficiency. Not an audio expert here, but it’s getting the most from the least. So not sure what more juice would do but would be interested on your input after trying. Just something to consider if that sounds reasonable

My Volt+D sounds very good with just a 12V 5 amp regulated power supply. Allo.com recommends their 19V 5 amp brick which I also have and enjoy. The Meanwell at 24V 15 amp which I formerly used with this TPA3116 Yuanjing would be a slight power increase over the other two.

 

[NoSnakeOil2]

It does. If you don't need full power though, one of those laptop power supplies could do the job.

How much power might one lose if you tried to power it with a laptop external power bank?

 

[Vaejoviscarolinanus]

I am confused by the voltage you are supplying to this amplifier @amirm "I used my lab power supply at its max setting of 31 volts and 3 amps." The dashboard says "13.5V Lab Supply", then we are back to 31V on the power v distortion graphs ? Inconsistency like that drives me crazy are there some typos here ? Also, as someone else mentioned, is 31V above the input for this TI chip, because in any case Allo states 19V-26V for the power supply. *edit wrote this during your reply above.

Some additional tests run at 19V would be extremely useful as well, since that is the power supply voltage Allo has as a bundle, and is also a very common laptop power supply voltage.

I am using a 24v 5amp power supply and I have a wonderfully clean and musical sound coming from this little science project looking amp. It is driving a pr of monitor audio bronze bx2 with a sub $200 streamer. I have $167 invested including shipping and taxes for the amp. I can’t remember getting this type of value from a amp since I was a young student and I purchased a Nad 3020 ( still working).

 

[JeremyFife]

Sry is "stark" the english word, the same as in german "stark"?? Strong,hefty? Did not now that in english the word “stark" is used?

At least my english teacher never used it.

Stark (in English) = an obvious difference between objects; Hi contrast. Also empty or bare.

 

[MacCali]

I am using a 24v 5amp power supply and I have a wonderfully clean and musical sound coming from this little science project looking amp. It is driving a pr of monitor audio bronze bx2 with a sub $200 streamer. I have $167 invested including shipping and taxes for the amp. I can’t remember getting this type of value from a amp since I was a young student and I purchased a Nad 3020 ( still working).

Curious to see what the PA5 has to offer.

However, with the volt I understand the limitations of a class D and the benefits. All my other amps are A/B and A/B with high bias in A. I really do prefer class A sound.

Yet they are pretty pricey and heaters

 

[Poultrygeist]

Every class D amp I own ( and I've got 7 or 8 ) improved with a tube preamp. A tube preamp's warmth overcomes the sterile dryness that is a common complaint of class D.

 

[MacCali]

Every class D amp I own ( and I've got 7 or 8 ) improved with a tube preamp. A tube preamp's warmth overcomes the sterile dryness that is a common complaint of class D.

Wouldn’t doubt it for a second. I know Thomas & Stereo was saying he wanted to make a unit with tubes and purifi modules.

Think one company has already done this, he mentioned.

Honestly got no bad vibes from the Volt, I like the little guy. Have no plans on selling it.

I got too many amps rights now and I’m literally floating in a sea of audio equipment. Only reason why I’m hesitant on getting the PA5.

Think my next big purchase will be my first 4K UHD player

 

[HansHolland]

Every class D amp I own ( and I've got 7 or 8 ) improved with a tube preamp. A tube preamp's warmth overcomes the sterile dryness that is a common complaint of class D.

You (and some others) simply don't like the music/recording/mix/master that you are listening to.

There is no such a thing like too correct!

 

[Marcos Mazur]

Just noticed a strange thing with my Volt+ D. When the stepped attenuator is set to anything other than the max, there is a faint buzz from the speakers (decreasing as you step the volume down until it's inaudible, but it's a bit noticeable toward the upper end, where I tend to have it). But, at the very last step, the max, the noise disappears! The last stop definitely works too, it's not like it's disconnected.

Any ideas why this is happening? Does max volume on the attenuator bypass something that may be picking up noise?

Given that I usually have to have the amp turned up near the max, I guess I could just leave it at max all the time, and adjust volume in earlier stages...

So, did you get any solution for the noise? on my Allo Volt +D the same happens, sometimes it stops, but it comes back, regardless of the power supply I use.

 

[Poultrygeist]

You (and some others) simply don't like the music/recording/mix/master that you are listening to.

There is no such a thing like too correct!

Not that it matters but I have no idea what you are saying.

 

[Poultrygeist]

So, did you get any solution for the noise? on my Allo Volt +D the same happens, sometimes it stops, but it comes back, regardless of the power supply I use.

I would try isolating the Volt+D from other components. TPA 31** amps can be subject to RF.

 

[Marcos Mazur]

I would try isolating the Volt+D from other components. TPA 31** amps can be subject to RF.

By what method do you suggest I could isolate Volt +D from the other components? I've tried using an extension cord and plugging it into another room's outlet and it didn't make a difference.
I also intend to do a grounding in my outlet and see if that solves it; actually my outlet is not 3 pin.

 

[Poultrygeist]

By what method do you suggest I could isolate Volt +D from the other components? I've tried using an extension cord and plugging it into another room's outlet and it didn't make a difference.
I also intend to do a grounding in my outlet and see if that solves it; actually my outlet is not 3 pin.

I had a tube preamp that caused interference with one of TPA3116 amps. Once I relocated the preamp on another rack shelf the noise stopped.

 

[Vaejoviscarolinanus]

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!

View attachment 79640

Hard to take a picture of it though without heavily accentuating dust and such that normally is not visible:

View attachment 79641

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:

View attachment 79642

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:

View attachment 79643

I was also impressed with how low the noise floor was at 5 watt playback:

View attachment 79644

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:

View attachment 79645

Frequency response has a tiny bit of roll off at 20 kHz:

View attachment 79646

As I noted in the introduction, with 4 ohm load my power supply lacks enough current so I also tested with one channel driven:

View attachment 79647

So it seems that getting the 60 watt advertised power level is possible.

Taking advantage of onboard capacitors, I ran my burst test:

View attachment 79648

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:

View attachment 79649

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:

View attachment 79650

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:

View attachment 79651

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.

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As always, questions, comments, recommendations, etc. are welcome.

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I am just playing with my Allo volt d + and I noticed that it had a different chipset than is mentioned here and the switchs on the bottom of the unit is 20 or 26 . If my eyes are not failing me then it has a pr of TI 3118 instead of the ones mentioned above. I noticed that it is ver 1.3 and it has a low serial number. I am wondering if it is Worth another look?

 

[HansHolland]

In front of me:

HW Ver 1.3
SL NO: 160
chip: TPA3118 x 2

 

[Poultrygeist]

The +D amps are dual mono and have always used the TPA3118 chipsets from Texas Instruments. I have one of the first ones sold by allo.com which shipped directly from India. Having bought some of their other products allo chose to reward me with an extra capacitance multiplier.

 

[Walter]

I am just playing with my Allo volt d + and I noticed that it had a different chipset than is mentioned here and the switchs on the bottom of the unit is 20 or 26 . If my eyes are not failing me then it has a pr of TI 3118 instead of the ones mentioned above. I noticed that it is ver 1.3 and it has a low serial number. I am wondering if it is Worth another look?

If you read all the posts, you'll see that Amir got the chip number wrong as it was hard to read. His had the TPA3118, also.

 

[Vaejoviscarolinanus]

I missed it, thanks for the clarification. I have removed the ( volume) control and tied the end wires together. It now has a input impedance @60 and the bass definition is greatly improved. I have also been using the 24 volt power supply.