Aiyima A70 Mono [PFFB, Full-range/subwoofer amplifier] - User Impressions | Owner's Thread

[Guddu]

Dear FMs, << Note: Check out Amir's review/measurement post >>

This thread is dedicated to A70 Mono - Aiyima's TPA3255 monoblock amplifier with PFFB, switchable to full range or subwoofer amplifier.
I intend to share my impressions using this amplifier, testing and evaluating features along with observating any gliches/issues if noticed.

*** I hope other A70 Mono owners may also sum up their feedback and some work arounds here to help other potential owners or interested ones ***

Here, I mean to summarize:
> what I get as a buyer or user of Aiyima A70 Mono amplifier
> aspects other than measurements that you might be interested in
> testing features & functions to see if there are any issues and how could get around those, if any
> I also hope that this thread could provide some information as to "what to expect" while you look to buy one for yourself

I bought A70 mono pair on Amazon soon after it became available. and it got delivered on 3rd Oct 2024. I have been using A70 mono pair from day 1 and posting this after about 3 weeks of continuous use.

Look & Feel:
> Amplifier case work is solid & a bit heavier, bigger (than other similar amplifiers) with side vents and decent bottom feet providing some clearance.
> Front panel uses toggle switches for power operation and RCA/XLR input switching, I see it be more stable than other methods used in other amplifiers for these operations.
> Front panel has dual big golden knobs for main volume control and SW-FREQ (low pass filter), it did look a bit unusual in the begining but did not take much time to get used to.

*Note: The powe switch has ON/Auto position - Auto here is TRIGGED IN operation. There is no auto signal sense here.
*Note: Left Knob SW FREQ comes in play when amplifier is set to "SUB" mode using switch on the bottom plate of the amplifier.
> Back panel has enough space and clearance between different connectors because of bigger case, and connectors/binding posts used seem better than others.
> 12v triggered input works fine, tested with Denon AVR as well as Emotiva processor 12v triggered out.

> A switch on the bottom plate is used to switch the amplifier to full range or sub-woofer amplifier.

Power Supply:
> It came with 48v 5a GAN PSU, I guess this one has become standard PSU with Aiyima amplifiers for now.

12v Triggered Input
> worked fine, tested many many times with Denon AVR and Emotiva Processor's triggered out

Idle Power Consumption
> Measured on 20a smart plug
> When Powered ON/AUTO but No audio playing: approx. 6W (A70 mono, one amplfier)

> When toggle set to OFF, no power drawn captured

Amplifier Case Temperature
> Playing amplifiers for long duration, about 80dB average, I never found the amplifier case even warm enough.
> Note that its begining of winter here, and room temp. is around 20 C.
> For me, A70 Mono has better thermal performance than any other amplifier I have had.

Background noise, hiss or pop on Power ON/OFF
> Nothing at all..... Yes, nothing at all
> On full volume, no hiss from speakers..... SILENT

Pop sound on Power ON/OFF
> Nothing at all..... Yes, nothing at all
> I have tested it every possible way - power toggle switch ON/OFF, smaer plug ON/OFF, wall plug ON/OFF... result is always same - NO POP
> This has been a concerning issue for me, specially with Fosi & Topping amplifiers...... can not say about anyone else but it always scared me for my speakers

My Setup, Connectivity and Pairing devices:
PC & nVidia Shield Pro (source) >>>> Topping E50 >>>>balanced out>>>> A70 Mono pair >>>> Sierra-LX / ELAC DBR62 Speakers
TV ARC >>>> Denon x3200w Front Pre-Out >>>> RCA >>>> A70 Mono pair >>>> Sierra-LX / ELAC DBR62 Speakers

> LED on the right goes BLUE for RCA and RED for XLR/TRS input

Subjective:
> Clean and powerful sound with excellent stereo separation, absolutely non-fatiguing for me....... like Topping PA7
> My Sierra-LX paired very well with A70 Mono, no shorness of low end punch for these low sensitivity speakers
> I just could not differentiate between Topping PA7 and these A70 mono amplifiers, other than A70 mono cound go louder than Topping PA7
> Overall, full marks performance for me.... no complaints

* While I plan to add on more details later as I observe, capture or measure something that could be useful for someone, I am wrapping it up here with a note that several issues which I was seeing as a user with other similar amplifiers, those seems to have resolved here with A70 Mono.

 

[Graham849]

Thanks Guddu, are you able to connect a passive subwoofer and report some impressions in that use case?

 

[hanzo1001]

thanks Guddu , glad to hear a70 mono is a good mono power amp
i have fosi za3 and very happy with it , so when the v3 mono come out i don't eager to upgrade because of x2 price of za3 .
last week i saw 50 % off early bird deal , so i got a pair of a70 mono today . can't wait for a test tonight

 

[lobe67]

hello and thanks for your input
I was almost pulling the trigger to get 2 Fosi V3 mono blocks but i was a bit concerned by the high temperature it would get to. The Aiyima A70 mono is intresting me because it seems better cooled and also because I have an open baffle project and i imagine i could use the subout instead of a passive cross over for my woofer ?

 

[Bruce Morgen]

Does PFFB even makes sense for a subwoofer application? It seems to me that the load impedance dependency of Class D chips manifests only at very high frequencies at which subwoofers don't even function.

 

[lobe67]

Does PFFB even makes sense for a subwoofer application? It seems to me that the load impedance dependency of Class D chips manifests only at very high frequencies at which subwoofers don't even function.

Well i guess one wouldn’t use only the sub out but also the main output where PFFB seems to be more effective

 

[hanzo1001]

upgrade to sparkoss ss3603 today , sound so sweet

 

[Vlvvv]

Hello! Dear owners of this device, do you have any pop when turning on/off this device? Thank you)

 

[Guddu]

Hello! Dear owners of this device, do you have any pop when turning on/off this device? Thank you)

No pop, as mentioned in the first post.

 

[Iainohyeah]

Although the speaker protection is first class in these, as mentioned above, it's worth showing due care to the power sockets/jacks.
We (I) should know better but it's easy to become blasé about these things.

DO NOT plug or unplug these when connected to the mains as there is a real risk of shorting or electric shock. Looks cool in a dark room but also requires the application of new underwear.

Again, not something anyone here should be doing anyway but there is a correlation in electrical items becoming safer (and smaller!) and the care we (I) feel has to be taken with them.


And be careful you don't take his eye out with that fork!

 

[Settembrini]

Dear FMs, << Note: Check out Amir's review/measurement post >>

This thread is dedicated to A70 Mono - Aiyima's TPA3255 monoblock amplifier with PFFB, switchable to full range or subwoofer amplifier.
I intend to share my impressions using this amplifier, testing and evaluating features along with observating any gliches/issues if noticed.

*** I hope other A70 Mono owners may also sum up their feedback and some work arounds here to help other potential owners or interested ones ***

Here, I mean to summarize:
> what I get as a buyer or user of Aiyima A70 Mono amplifier
> aspects other than measurements that you might be interested in
> testing features & functions to see if there are any issues and how could get around those, if any
> I also hope that this thread could provide some information as to "what to expect" while you look to buy one for yourself

I bought A70 mono pair on Amazon soon after it became available. and it got delivered on 3rd Oct 2024. I have been using A70 mono pair from day 1 and posting this after about 3 weeks of continuous use.

Look & Feel:
> Amplifier case work is solid & a bit heavier, bigger (than other similar amplifiers) with side vents and decent bottom feet providing some clearance.
> Front panel uses toggle switches for power operation and RCA/XLR input switching, I see it be more stable than other methods used in other amplifiers for these operations.
> Front panel has dual big golden knobs for main volume control and SW-FREQ (low pass filter), it did look a bit unusual in the begining but did not take much time to get used to.
View attachment 399881
*Note: The powe switch has ON/Auto position - Auto here is TRIGGED IN operation. There is no auto signal sense here.
*Note: Left Knob SW FREQ comes in play when amplifier is set to "SUB" mode using switch on the bottom plate of the amplifier.
> Back panel has enough space and clearance between different connectors because of bigger case, and connectors/binding posts used seem better than others.
> 12v triggered input works fine, tested with Denon AVR as well as Emotiva processor 12v triggered out.
View attachment 399878
View attachment 399876
View attachment 399877
> A switch on the bottom plate is used to switch the amplifier to full range or sub-woofer amplifier.
View attachment 399879

Power Supply:
> It came with 48v 5a GAN PSU, I guess this one has become standard PSU with Aiyima amplifiers for now.
View attachment 399880

12v Triggered Input
> worked fine, tested many many times with Denon AVR and Emotiva Processor's triggered out

Idle Power Consumption
> Measured on 20a smart plug
> When Powered ON/AUTO but No audio playing: approx. 6W (A70 mono, one amplfier)
View attachment 399882
> When toggle set to OFF, no power drawn captured

Amplifier Case Temperature
> Playing amplifiers for long duration, about 80dB average, I never found the amplifier case even warm enough.
> Note that its begining of winter here, and room temp. is around 20 C.
> For me, A70 Mono has better thermal performance than any other amplifier I have had.

Background noise, hiss or pop on Power ON/OFF
> Nothing at all..... Yes, nothing at all
> On full volume, no hiss from speakers..... SILENT

Pop sound on Power ON/OFF
> Nothing at all..... Yes, nothing at all
> I have tested it every possible way - power toggle switch ON/OFF, smaer plug ON/OFF, wall plug ON/OFF... result is always same - NO POP
> This has been a concerning issue for me, specially with Fosi & Topping amplifiers...... can not say about anyone else but it always scared me for my speakers

My Setup, Connectivity and Pairing devices:
PC & nVidia Shield Pro (source) >>>> Topping E50 >>>>balanced out>>>> A70 Mono pair >>>> Sierra-LX / ELAC DBR62 Speakers
TV ARC >>>> Denon x3200w Front Pre-Out >>>> RCA >>>> A70 Mono pair >>>> Sierra-LX / ELAC DBR62 Speakers

View attachment 399883
> LED on the right goes BLUE for RCA and RED for XLR/TRS input

Subjective:
> Clean and powerful sound with excellent stereo separation, absolutely non-fatiguing for me....... like Topping PA7
> My Sierra-LX paired very well with A70 Mono, no shorness of low end punch for these low sensitivity speakers
> I just could not differentiate between Topping PA7 and these A70 mono amplifiers, other than A70 mono cound go louder than Topping PA7
> Overall, full marks performance for me.... no complaints

* While I plan to add on more details later as I observe, capture or measure something that could be useful for someone, I am wrapping it up here with a note that several issues which I was seeing as a user with other similar amplifiers, those seems to have resolved here with A70 Mono.

Thanks a lot, this is really useful information

 

[robertospeed]

 

[Mark185]

The A70 mono is on sale right now on Amazon for $118.99 and possibly lower between now and Black Friday. I bought one to use with a 12" passive subwoofer I built years ago. It uses a NHT 12" 4 ohm driver that was very highly regarded 15 years ago. It is still a good driver today. I am using the A70 mono in SW mode. When set for SW mode, the front panel left knob adjusts the low pass frequency. Amir criticized that but I like it. It allows me to play with it as I try this amp with different subwoofer designs I am building. I believe this is a superior choice to drive DIY passive subwoofers compared to the similarly priced plate amps out there.

The only real negative so far is that I tried it with a small Kicker car stereo subwoofer that has a 6.5" driver and 6.5" passive radiator. It is not very efficient and takes more power than the A70 can manage to produce decent bass. Not a problem for me. I only used the Kicker for a quick test. The A70 works much better with the 12" sub. I am also building a smaller ported sub with 2 Dayton Audio 6.5" drivers tuned to 40 Hz. I expect this A70 will also drive that 2 ohm load well.

I have not measured the low pass filter slope yet but I suspect it is 12 dB/octave from how it sounds.

 

[Mark185]

A small update to post above. I spent more time playing around with settings using the A70 mono to drive the Kicker car audio subwoofer because my other two designs are not finished yet. I am modifying the enclosure for the 12" NHT driver because I no longer need the plate amp taking up volume inside.

My preamp is a Fosi Audio ZD3 DAC. I am using the RCA outputs into the A20 amplifier. What I am about to describe may be improved by using the XLR connections for left and right channels. Using the RCA connections, there is barely enough gain from the Aiyima A20 subwoofer output to adequately drive the A70 mono amplifier and get enough volume using the inefficient Kicker sub. I can get it sounding decent for a desktop system with the small sub on the floor but this would never work in a larger room.

Just for grins and giggles, I hooked up a mobile audio subwoofer amp rated at 500 watts into 4 or 2 ohms. I powered that with a switching power supply that can do up to 80 amps at 12 volts DC. Huge difference as one might expect. The mobile sub amp is a Down4Sound JP3 and is not a high end amp in any way but it does a much better job with the inefficient sub than the Aiyima A70 mono. That is because I can adjust the input gain on the JP3 amp in addition to adjusting the low pass frequency. That and the fact that it can put out much higher current and voltage. Not a fair comparison but to me it confirms my thoughts about what speaker works well with what amp.

Long story short, if you are going to use the A70 mono in a system with the A20 amplifier, make sure your passive subwoofer has an efficiency rating of at least 90 dB at 1 watt. Higher is better but in my experience that usually means a larger enclosure that is ported. Small sealed subwoofers are not that efficient. I am currently building a smallish ported sub with two 6.5" Parts Express drivers. It is about 24" x 15" x 10". Tuning freq is 40 Hz and I expect this will work very well with the Aiyima A70 mono.

All of this to say the A70 mono is a great little amplifier if you understand its limitations and what to pair it with. For ~$120 this is still a lot of value and performance for the money.