AIYIMA A70 Mono Amplifier Review

[pma]

Voted poor, mostly for the multitone behavior.

 

[restorer-john]

The unit has diagnostics for the Com port and it says that is fine.

I know you are probably all over this, but is it a proper hardware com port or a USB-to serial "com" port on the PC? You must have many hundreds of USB enumeration/descriptors from all your DAC testing. Is there a limit before the OS goes AWOL?

Com ports have never been the same since windows took over and blocked direct port access from W98 onwards.

 

[NirreFirre]

My guess on the sw functionality is a half hearted try on a plate amp replacement. They live in a harsh environment, are seldom of the best quality and often belly up before the high value driver or box does.
I've had 2 SVS branded amps (~500W) give up (output stage issue in both, probably a single $1 component that I failed to locate and replace) with a unreasonably replacement cost and if I didn't have the miniDSP+miniDigi already in the chain, this could have been useful.

Having 150W may not be enough though and a used Crown amp with some (hard to setup) DSP/PEQ functions is a better buy imho.

 

[amirm]

I know you are probably all over this, but is it a proper hardware com port or a USB-to serial "com" port on the PC?

It is the usual USB to serial emulator. Tried finding a new driver but none exists as the silicon is pretty old. Company only provided the software in private so maybe there is an update. Will find out when work week starts.

 

[Sokel]

I went straight for the multitone test as soon as I saw x-over ability and yep,it's bad.
Like any other (including the one in many subs) almost copy-paste bad implementation with the same trend: going worst as going lower.

I think is time for a good look at these stuff,I have seen it over and over both in analog and digital x-overs down there.
Even some pro-gear are just as horrible but it also took some good time for others to even acknowledge the problems and apply fixes.
I guess it's ok for subs down there where distortion is not a decisive factor as much but it's a pity when some of the low distortion drivers (like Purifi) are canceled by that.

I guess is ok otherwise.

Thanks Amir!

 

[JeremyFife]

Thanks for another timely review Amirm. I was really hoping that your review would clear up my confusion about the features of this Amp ... It hasn't

Decent performance at a low price. I keep reading now that electronics should be a solved problem, and we should focus on features (assuming that the design is not b%$§#cked up).

I still don't understand the feature set of this Amp: lots of knobs and switches that I just wouldn't use. Perhaps others would. Not for me.

Occam needs to sharpen his razor.

 

[WOLFAGRAM]

Hello Folks.

It really is amazing what a hundred bucks will buy in the amplifier world. These little amps must really make the big brand product managers lose sleep at night thinking how they can compete.

Investors behind those big brands spent decades clandestinely lobbying for strict environmental laws in the west (while pretending they are against them on the basis of costing them money in short term). They wanted to put western decently payed workers out of production work and increase their investment returns by producing cheaply elsewhere. That seemed as a long-term lucrative strategy, and it was for a few decades. At the same time, they got to blame environmentalists, and not their own greed. Now that is starting to backfire.

Cheers.

 

[totti1965]

As is, measurements showed that neither made a difference in frequency response of the speaker output. If you however toggle a switch underneath, the front control at least becomes active, setting the high frequency roll off. I could not figure out what the back control did. Reading the instructions didn't help but my conclusion was that the switch turns the amplifier into one that drives passive subwoofer (woofer and no amp). Passive subs have fallen out of favor in US at least for more than two decades. You can get ultra low cost subs that are active. AIYIMA has seemed to gone to great lengths to implement such a functionality with dedicated front and back controls. It is quite puzzling to me. Hopefully you all didn't talk them into this!

No!!!!! As a self builder I like extra power from an Amp for the bass region (one device less!). The Aiyima is a step in the right direction, even I would prefer to have 1.000 Watts for each of my Linkwitz Dipole Subwoofers (Hobby HiFi).

 

[diaolodoro]

I could not figure out what the back control did. Reading the instructions didn't help but my conclusion was that the switch turns the amplifier into one that drives passive subwoofer (woofer and no amp). Passive subs have fallen out of favor in US at least for more than two decades. You can get ultra low cost subs that are active. AIYIMA has seemed to gone to great lengths to implement such a functionality with dedicated front and back controls. It is quite puzzling to me. Hopefully you all didn't talk them into this!

As a user of a DIY passive subwoofer, I feel responsible and happy at the same time
Subwoofer plate amplifiers are very expensive (almost 1$ per Watt) to the point that there's no reason to build a mid-range DIY subwoofer and not buy an off-the-shelf one However this is not the case for the multiple high-end or super budget DIY subwoofers, which DIY starts to be a viable solution.

Currently I'm using a $15 "100w" Tpa3116d2 Subwoofer amp with my custom passive subwoofer. Using some EQ it's enough to shake my 15-sqare-meter room and dig down to 23Hz.
However I wanted to upgrade the amplifier and I was waiting for new mono amplifiers JUST like this one. However the low frequency distortion didn't seem that great, so I'll wait for something else.

 

[billou5767]

It really is amazing what a hundred bucks will buy in the amplifier world. These little amps must really make the big brand product managers lose sleep at night thinking how they can compete.

price of product 1/3 1/3 1/3 in general a 20000 e car its 6000 e to make it 50% of 6000 its electronic

an oled tv panel its 80/150 e depending size

no publicity and catalog : win 1/3

make produc 50% cheap : 8kg / 1 kg 50% of 1/3

margin tva

logic

 

[Joe Smith]

I don't use subwoofers, but even if I did, I think the way it is implemented on this model would keep me away, waiting for something better. The decision to make the massive SW control on the front just baffles me. If they wanted to provide control for both passive and active SWs, both should be on the rear IMO.

 

[Halbknapp]

I don't use subwoofers, but even if I did, I think the way it is implemented on this model would keep me away, waiting for something better. The decision to make the massive SW control on the front just baffles me. If they wanted to provide control for both passive and active SWs, both should be on the rear IMO.

I do use passive Subwoofers but would still (very sadly) not see any benefit of this unit over something else as the implementation is poor.

 

[Ismapics]

Any comment on what chip it uses. It's a great value, still think a little stretch to Outlaw Audio may be better.

 

[Guddu]

Any comment on what chip it uses.

TPA3255

 

[CedarX]

From Aiyima description, the switch on the bottom sets the amp to ‘Full Range’ or ‘Sub’. If set to ‘Sub’, the front rotary control is to adjust the cutout freq.
The rear ‘Sub Out’ and corresponding freq. adjustment appear independent (that part is not very clear) from the main amp ‘Full Range’/ ‘Sub’ setting…

 

[early rejecter]

The rear ‘Sub Out’ and corresponding freq. adjustment appear independent (that part is not very clear) from the main amp ‘Full Range’/ ‘Sub’ setting…

The front frequency adjustment is for passive subs, using the speaker output with the amp in subwoofer mode. The rear frequency adjustment is for active subs, using the sub out connection next to the adjuster with the amp in full range mode.

 

[musicforcities]

Seems “fine”. But I too am confounded by the subwoofer controls. As Amir said, what one would want vis a vis subwoofer capability is a full frequency range line level sub out (for powered subwoofer) WITH a HIGH PASS filter for the signal passed to the amp and speaker out. So that power is not wasted on power hungry lower frequencies we intend to send to the sub instead of the main speakers. And to lower distortion when using smaller main speakers when playing 80hz-60hz and under at high levels.

Is that what some posters are saying?: that the rear knob is a high pass filter for the speaker out?

Much larger than the Fosi V3 mono. But perhaps that helps with heat dissipation as the V3 reportedly get quite warm.

The shift to improved power supply technology is also welcome.

However, overall the V3 mono seems to be the better option in terms of performance and tidier if one uses the shared power supply — assuming the revisions have ironed out the issues with that shared supply.

 

[EJ3]

"Early Rejecter": I resemble that statement, too! That is great, wish I had thought of "Early Rejecter".

 

[Bob101]

I really don't understand the reason for the sub frequency knob on the front.

Nobody does.

 

[Bob101]

I know you are probably all over this, but is it a proper hardware com port or a USB-to serial "com" port on the PC? You must have many hundreds of USB enumeration/descriptors from all your DAC testing. Is there a limit before the OS goes AWOL?

Com ports have never been the same since windows took over and blocked direct port access from W98 onwards.

XP was peak Windows.