Allo Volt+ D Amplifier Review

[phoenixdogfan]

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

Just find an unwanted and unused and obsolete laptop you haven't thrown away yet.

 

[sir_frigorifero]

This was my amplifier. Very pleasantly surprised by the results, which I expect will build hype for the TPA325*-based amplifier that is supposedly coming out of Allo later this year. I would also like to see a dashboard with the "stock" 19V power supply if possible, but I don't remember if I sent Amir the power supply along with the amp.

Two "complaints" I have are with the physical size and the attenuator knob. The amplifier is definitely bigger than it looks, IIRC about a foot wide. The knob is quite stiff, small, and blocked on three sides by the case. I've never used a stepped attenuator before so maybe the stiffness is normal, but a bigger and longer knob would be a big usability win.

Another thing is the lack of a power button. I use an on/off electric plug but it gives a little buzz to the sound

 

[tomtoo]

This was my amplifier. Very pleasantly surprised by the results, which I expect will build hype for the TPA325*-based amplifier that is supposedly coming out of Allo later this year. I would also like to see a dashboard with the "stock" 19V power supply if possible, but I don't remember if I sent Amir the power supply along with the amp.

Two "complaints" I have are with the physical size and the attenuator knob. The amplifier is definitely bigger than it looks, IIRC about a foot wide. The knob is quite stiff, small, and blocked on three sides by the case. I've never used a stepped attenuator before so maybe the stiffness is normal, but a bigger and longer knob would be a big usability win.

I think most people will have some 19V supplies from old laptops lying around. Allo even list a 19V supply as an add-on. That said, the difference in power output performance will be stark.

Just for fun, you could consider running a power output test on say a 19V 60-90W typical laptop brick to give people a real world idea.

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.

 

[DSJR]

First , I would like to say a big thx you , to Amir , for the free work hs is putting into this great community.

The component you are discussing about is a ..."simple" common mode choke , used a lot on analog devices they are slowly disappearing as part of the "cost cutting drive".

Next (with blue pots) is a very smart design called a "capacitance multipler". It drops the DC voltage about 1.5V and it removes noise by up to 50db (0-20Khz) (PSRR) on your DC power. Yes you can use up to 31V on Volt+D

The output filter on Amp is NOT a datasheet copy(not TI design). We spent a lot of time finding optimal values and fine tuning the output filter, we have much , much more filtering the normal datasheet .

I think that one of the reason why people find Volt+D to sound good...is the noise reduction on the output filter. I am fully aware that it should not matter, and yet it is my opinion that it does. I have no hard data to explain it but this output goes direct to speakers. Very good speakers have zobel networks and such that remove the HF noise (attenuate it) but most speakers have substandard (or none at al ) filters and somehow some of the hi frequency finds the way to your ears. (again no hard data but its what I think and design to remove it)

Note that I do design using a AP machine but I do not get guided by only THD+N at 1Khz. I pay attention to other (measurable) data and try to attenuate.

I REALLY don't need another power amp, but this one shows just how far we're moving forward these days.

To answer the question regarding bypassing the volume attenuator, I'd just set the control to maximum myself... I'm assuming the attenuator is made up of separate 'L pads' for each step, meaning the max volume setting is basically straight through...

 

[Vasr]

I would be very cautious about using any laptop power adapter for a power amp especially if you have it on for hours for daily use. Most of them aren't really designed for or good at sustained use at or close to max rated power and can get uncomfortably hot if not burn out. Especially the more recent ones that are designed to be as small in form factor as possible. The problem is you never know which ones are good or bad for this purpose just by looking at it or reading its numbers.

Use a minimum 90w adapter and to be safe get an adapter used for a gaming laptop, rather than a portable ultralight laptop.

 

[Robbo99999]

These types of products, related to passive powered stuff I know very little about, but this amp has obviously done very well for it's budget then.....is the market for "passives" decreasing & being replaced by "actives", because I think we review a lot more active gear, which is why I know a lot more about the active side (in terms of owning it too)? I get the impression that active sound systems are more bang for the buck in terms of sound quality, etc, with greater flexibility for some cheap room DSP via miniDSP for instance? This don't have to be a big discussion as it's not the topic of this review, but I wanted to make this short comment. Are passives on the way out with the exception of AVR sound systems?

 

[tomtoo]

I would be very cautious about using any laptop power adapter for a power amp especially if you have it on for hours for daily use. Most of them aren't really designed for or good at sustained use at or close to max rated power and can get uncomfortably hot if not burn out. Especially the more recent ones that are designed to be as small in form factor as possible. The problem is you never know which ones are good or bad for this purpose just by looking at it or reading its numbers.

Use a minimum 90w adapter and to be safe get an adapter used for a gaming laptop, rather than a portable ultralight laptop.

Did anyone doed a long time test with this amp?
I dont think that much more than 2*40w long time is realy realistic. Nice little amp for desktop use. A good 24v 120w adapter should bring it nearly max. realystic usebility.

 

[Timbo2]

So the question is how well it handles ripple from a switching power supply? For example Mean Well makes some nice industrial power supplies. If you can back the voltage on the 36V one down enough you might be able to squeak by. Otherwise you could go for one of their 24V models.

Mind you the fan on these aren't exactly quiet when they kick on...

https://www.amazon.com/NES-350-36-S...+36v+power+supply+600w&qid=1598293162&sr=8-13

 

[amirm]

As requested, here is the performance with a 19 volt, 3.15 amp switching laptop supply the owner had sent me but I had not seen.

Here is power into 4 ohm:

The amp went into protection mode with LED flashing. It recovered nicely without intervention.

And power into 8 ohm:

It seems performance is actually improved as the humps in the low wattage range are gone! So much for superiority of my Agilent/Keysight lab supply .

I am going to UPS to drop off a bunch of stuff and like to send this as well. Shout in the next 1 minute if you need something else but otherwise, we are done!

 

[amirm]

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.

It is. More like shocking or drastic.

 

[amirm]

Did anyone doed a long time test with this amp?

My last test is quite stressful as it swept the frequencies into clipping power. It did not at all bother the amp. These chip amps have numerous protection mechanisms internally so much harder to damage.

 

[daftcombo]

As requested, here is the performance with a 19 volt, 3.15 amp switching laptop supply the owner had sent me but I had not seen.

View attachment 79739

Here is power into 4 ohm:

View attachment 79740

The amp went into protection mode with LED flashing. It recovered nicely without intervention.

And power into 8 ohm:

View attachment 79742

It seems performance is actually improved as the humps in the low wattage range are gone! So much for superiority of my Agilent/Keysight lab supply .

I am going to UPS to drop off a bunch of stuff and like to send this as well. Shout in the next 1 minute if you need something else but otherwise, we are done!

Thanks Amir. Disappointing power with such a power supply.
We need to find something better to feed this baby.

 

[tomtoo]

My last test is quite stressful as it swept the frequencies into clipping power. It did not at all bother the amp. These chip amps have numerous protection mechanisms internally so much harder to damage.

I just wonder when it would go into thermal protection. Not say it would get hurt. But running this amp with 120w over hours. I dont know, just a little sceptical. Sry you know iam maybe to old. But a 120W amp without heat sinks fits not into.my brain,

 

[Soniclife]

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.

It's similar but different, it is from German origin. It's a common English word, and John's usage is quite normal.

 

[tomtoo]

It's similar but different, it is from German origin. It's a common English word, and John's usage is quite normal.

Thanks! I learn every day on ASR.

 

[sir_frigorifero]

What are the dimensions of this? They don’t seem to be listed on the manufacturer’s site, and I’ve been fooled by the panther twice now (he’s much bigger than I initially thought).

the dimensions are: 244x171x68 mm

 

[Tatteredmidnight]

the dimensions are: 244x171x68 mm

Not unreasonably large, but not petite for sure.

This was my amplifier. Very pleasantly surprised by the results, which I expect will build hype for the TPA325*-based amplifier that is supposedly coming out of Allo later this year. I would also like to see a dashboard with the "stock" 19V power supply if possible, but I don't remember if I sent Amir the power supply along with the amp.

Two "complaints" I have are with the physical size and the attenuator knob. The amplifier is definitely bigger than it looks, IIRC about a foot wide. The knob is quite stiff, small, and blocked on three sides by the case. I've never used a stepped attenuator before so maybe the stiffness is normal, but a bigger and longer knob would be a big usability win.

While I appreciate designers adding a bit of visual flair, I think the shape of the top and bottom panels are very unfortunate. This doesn’t come through in Amir’s photos, but there are substantial curves on both panels that seem as though they would unnecessarily exasperate this issue.

 

[peanuts]

well you get a box and volume control, but needs a big ass external power supply also. rather buy this
https://www.ebay.com/itm/ICE-Power-...542405?hash=item2ab4899705:g:XU4AAOxye5BREwLv

 

[PeteL]

Dual TI TPA2116 class D amplifiers are used plus a front-end switching power supplies to generate the required plus and minus supplies.

As far as I know there is no such thing as TPA2116. It should be TPA3116, unless I'm wrong, and it's an older model, and all referenced to it would have been wiped from the web... This looks great but amazon is loaded of amps that uses the chip (in a single chip config tough) for 20$ I'm wondering how much performance you gain at 6 times that.

 

[wwenze]

This looks great but amazon is loaded of amps that uses the chip (in a single chip config tough) for 20$ I'm wondering how much performance you gain at 6 times that.

You can look at this for one example. It's a Tripath but at these prices the performance of the chip is bottlenecked by the rest of the product.

https://www.audiosciencereview.com/...-lp-2020a-stereo-audio-amplifier-reivew.9806/