AIYIMA A07 TPA3255 Review (Amplifier)

[Sri K P]

- high noise floor
- high mains hum residuals
- high order distortion components in the spectrum
- low BW with roll off at 20kHz

Why is this recommended? Because it is small and Class D? Are there any specifications limits for recommended components? And why not?

I observed Mains and Noise Floor variations 'relative' to power sources and /or other interferences. Isolated , until about 70% volume (2 o'clock pos.), It seems to do just what it's meant to. Clean input = Clean Output. Noisy input = Noisy (amplified Output). 20khz roll-off seems negotiable from an end user listening standpoint (hopefully!). 2.1 makes sense purely with a dedicated Active-sub. Also, volume control won't work!! Limitations? Sure. Worth it? So far .. yes.
Click/ pop : only if the amp is switched on first (before the source). But that's standard for many Great ones too. Not all have a soft-start at this pri. Point!
This amp is a great addition to an Audiophile ensemble, or a great 'starting' point for a sprouting enthusiast. Hope it has a reasonable durability.
Slightly curious with the heat dissipation part. But a few fans seem to help!!
Question: Anyone tried a 3 or 2 ohm load? Also , what's a 4*se config? Thanks folks!! Hope it helps some qs!!

 

[Sri K P]

Not bad for a dinky little amp—and the 77 watts is plenty. Color me impressed.

Happy New Year!

True! Can't quite touch beyond 60-70% mark!

 

[Sri K P]

T.I. chip spec:
View attachment 102801

AIYIMA’s advertisement:
View attachment 102800

While the figures may meet bench tests, I'd suspect more than 70% that in a listening environment (just adding). Personally, I'd rather use dedicated monos instead of mod (cause no two channels even on high end Hifi have 'zero' conflict, and pure addition.
Click & Pop free ? Well, not quite (unless amp is the last thing to be switched on)
Adding (2.1 only if sub has separate dedicated amp). Also, not volume control. Flat signal!!
What's 4

T.I. chip spec:
View attachment 102801

AIYIMA’s advertisement:
View attachment 102800

Absolutely worth the buck, with 'Realistic' expectations. won't take the bench tests at face value (cause in a Live listening environ no one goes that loud all day, unless hard of listening

 

[mlieber507]

I recently acquired my A07 and found it to be some what better than measured by AudioScience who used a 48 volt power3 amp supply. The power supply in the review appears to be rated at 48 volts and 3 amps, or 144 Watts. That is a little less power than provided by the 32 volt, 5 amp supply, which is 160 watts. A more reasonable assessment of 48 volt performance would be provided by using a 48 volt, 10 amp supply. These are available for $40.00 at Amazon.

 

[antcollinet]

I recently acquired my A07 and found it to be some what better than measured by AudioScience who used a 48 volt power3 amp supply. The power supply in the review appears to be rated at 48 volts and 3 amps, or 144 Watts. That is a little less power than provided by the 32 volt, 5 amp supply, which is 160 watts. A more reasonable assessment of 48 volt performance would be provided by using a 48 volt, 10 amp supply. These are available for $40.00 at Amazon.

depends on speaker impedance.

 

[mlieber507]

Hello everyone

I'm considering buying an a07 to solve a problem and I'd really like to have your opinion.
My AVR has a big issue : output voltage is far too high on the left surround channel. It "fried" twice in a row the speaker attached (fortunately just a resistance to replace).
I send it to repair. Did not work. PITA to do it again. Looking for an alternative.
My idea was to use a power amplifier (a07) on the surrounds to bypass my AVR amplification on the faulty channel and use pre-out channels for surrounds.
I cannot be absolutely sure that the problem comes from the amplifier part of the AVR (and not the pre-amp), but as it clearly comes from having too much power out of that channel, that hypothesis seems reasonable to me.an
For now I'm ready to bet on that, given a07 price (<100) vs new AVR price (~1500/2000).

I'm just not sure a07 would be okay with my current surround speakers.
Would you mind giving me your thoughts ?

Here they are :

• 100 watts RMS
• 94 db (1w-1m)
• 8 Ohms
• Bandwidth : 75 Hz - 20 KHzan

I'm using them in a dedicated room (7.1) exclusively for cinema. Action fan. Bass fan.
Most of time I listen at -10. Sometimes -5. even 0 when wife is away

Thanks a lot for your insight !
JM

Are you sure that your channel with the high voltage does not have a substantial DC component being fed to the speaker. If there is DC on the channel, it may be possible to null it out. As far as getting mono out of an A07, you can wire the 2 outputs in parallel using .1 ohm load leveling resistors. You would feed the same signal into both inputs and the results would be a monoblock. If you do this with2 A07's you would have a stereo based on 2 independent monoblocks. Be careful with the volume controls to avoid overloading your speakers. If you just use one channel in each of 2 A07's the configuration will run unusually warm because an idle A07 channel dissipates more heat than an active channel. You should use the same model of amplifier for both channel or they may be an audible difference in tonality between the 2 channels. Also, your AVR probably has an automated set-up procedure that will balance channel volumes automatically.

 

[mlieber507]

depends on speaker impedance.

A 144 watt supply will top-out before a 160 watt supply.

 

[dr_mick51]

I recently acquired my A07 and found it to be some what better than measured by AudioScience who used a 48 volt power3 amp supply. The power supply in the review appears to be rated at 48 volts and 3 amps, or 144 Watts. That is a little less power than provided by the 32 volt, 5 amp supply, which is 160 watts. A more reasonable assessment of 48 volt performance would be provided by using a 48 volt, 10 amp supply. These are available for $40.00 at Amazon.

Hi. This sounds nice. But honestly why do you think you need a bigger power supply? Did you max out the pot and still not getting satisfied?. What's your speakers sensitivity?
What is your source output voltage? Maybe you just need to improve your source or use a preamp. I really found hard to believe that 70-75w/ch are not enough for your room. Unless you have very inefficient speakers.
Also, if you want to run this amplifier at its optimum operational point(lower distortion) you need to run it at 5w. Beyond that point distortion starts to increase.
You don't need as much power as you think. 10w RMS will be plenty and provides enough peak music power(PMPO) for whenever that extra power is required(short burst).

 

[mlieber507]

I observed Mains and Noise Floor variations 'relative' to power sources and /or other interferences. Isolated , until about 70% volume (2 o'clock pos.), It seems to do just what it's meant to. Clean input = Clean Output. Noisy input = Noisy (amplified Output). 20khz roll-off seems negotiable from an end user listening standpoint (hopefully!). 2.1 makes sense purely with a dedicated Active-sub. Also, volume control won't work!! Limitations? Sure. Worth it? So far .. yes.
Click/ pop : only if the amp is switched on first (before the source). But that's standard for many Great ones too. Not all have a soft-start at this pri. Point!
This amp is a great addition to an Audiophile ensemble, or a great 'starting' point for a sprouting enthusiast. Hope it has a reasonable durability.
Slightly curious with the heat dissipation part. But a few fans seem to help!!
Question: Anyone tried a 3 or 2 ohm load? Also , what's a 4*se config? Thanks folks!! Hope it helps some qs!!

A TPA3255 consists of 4 single ended amplifiers that can be operated individually or as 2 bridged amplifiers that provide higher output than each single ended amplifier. Further the 2 bridged channels can be combined into a parallel bridged arrangement that provides a mono-channel capable of operating into very low impedances such as 2 or 3 ohms. The parallel configuration can also provide somewhat more power than the bridged configuration into 4 ohms. It does not look as if a stereo-wired A07 is specified to support impedances below 4 ohms.

 

[mlieber507]

Hi. This sounds nice. But honestly why do you think you need a bigger power supply? Did you max out the pot and still not getting satisfied?. What's your speakers sensitivity?
What is your source output voltage? Maybe you just need to improve your source or use a preamp. I really found hard to believe that 70-75w/ch are not enough for your room. Unless you have very inefficient speakers.
Also, if you want to run this amplifier at its optimum operational point(lower distortion) you need to run it at 5w. Beyond that point distortion starts to increase.
You don't need as much power as you think. 10w RMS will be plenty and provides enough peak music power(PMPO) for whenever that extra power is required(short burst).

My concern was the validity of the test procedure which makes it appear that a larger power supply will supply less output. In fact the 48 volt supply used in the test provides less power than the 32 volt supply, so we do not really know if amplifier output power goes down with increasing voltage and current, which would imply a serious design issue.

 

[dr_mick51]

My concern was the validity of the test procedure which makes it appear that a larger power supply will supply less output. In fact the 48 volt supply used in the test provides less power than the 32 volt supply, so we do not really know if amplifier output power goes down with increasing voltage and current, which would imply a serious design issue.

Ok. I get your point. Well, both voltage and current are limiting factors at the moment of determine max power coming from the amplifier into a specific load(speaker).
Voltage will determine how big the amp can swing. For example. If you want to produce 100w at 8ohm you calculate P=VxI. This V is the output swing (AC) , not the DC input voltage. But there is a ratio between R, V and I for a 8ohm speaker, and a different one for a 4Ohm speaker.
P=I^2 x R =Vout x I.
A 8ohm speaker will require more voltage than a 4ohm speaker to reach the same power. And 4ohm speaker will require more current than a 8 ohm speaker to reach the same power.
Basically it all depends on your speakers and the power supply total power=Vdc x I, not only voltage. And there must be an optimum proportion between Voltage and current on the power supply. A 48v and 1A power supply is as useless and a 24v and 2A. But even in that case I would prefer the 48v and 1A power supply. Not because I would get more power, it's because the amp runs cleaner at higher voltages with lower power demand.
If you check the Figure 8 on the datasheet: Output power vs Supply Voltage you can see what is the maximum power at 1% THD +N the amp can produce if provided the required current as well.
Example at 48v and 8ohm the maximum power is 130w. But this also means the power supply needs to provide 260w plus 15% extra power due to efficiency related losses.so let say 300W power supply at 48V means 6.25A.
At 24v and the same 8ohm the max power the amp can produce is only 35W. Again this requires a power supply of 70w plus losses. But at 70w the loss percentage is higher than at 260w. Let's say 20% according to figure 9 on the datasheet. Total power required by power supply is 84W at 24v and 3.5A. So, even if you have a 24v and 10A power supply the maximum power the amp can produce is limited to 35W per channel at 1%THD +N.
The same issue happens if you have a 48V power supply with not enough current. It cannot produce the 130W the amp is capable.

 

[antcollinet]

A 144 watt supply will top-out before a 160 watt supply.

Depends if it hits a voltage limit, or a current limit first.

EDIT: - take your 32V psu - that can deliver (less than) 22.6V RMS. Into an 8 ohm speaker, it will voltage limit at 64W per channel = 128W. Lower than the total output possible from the PSU

With the same speaker, the 48V PSU will voltage limit at 144W per channel - Total 288W - much more power than the PSU can deliver with it's 3A, so that PSU will current limit at it's rated power of 144W. Actually for short term peaks, it will be higher than this since typically these PSU's can deliver higher than rated current for a short time.

So with 8Ohm speakers, the 48V 3A PSU can deliver more power continuously, and much more for short term peaks.

For a 4ohm speaker it will be different. The lower voltage higher current PSU will deliver more power.

 

[linuxfan]

Can these be modified to run bridged mono?

In stereo mode the chip is already configured as bridge-tied load.
For mono the TPA3255 chip can be configured in parallelled BTL (PBTL) ... and yes, it's feasible you could modify an existing BTL board to make it PBTL. But this would involve delicate soldering, and you would risk damaging the board.
It's far more sensible to just buy the mono version of the A07, which AIYIMA already provides as model A3001 -
https://www.aiyima.com/products/subwoofer-amplifier-aiyima-a3001

Do a forum search for "A3001". This has been discussed before.

 

[tonimccloud]

what cable do i need to connect the aiyima to a power supply like this one? I see some v+ v- N L...

lianshi 36V 10A 360w fuente alimentacion transformador de conversión Con protección contra cortocircuito y sobrecarga Para de lámpara LED de automatización industrial AC220V a DC36V https://amzn.eu/d/fiBamNn

 

[sarumbear]

- high noise floor
- high mains hum residuals
- high order distortion components in the spectrum
- low BW with roll off at 20kHz

Why is this recommended? Because it is small and Class D? Are there any specifications limits for recommended components? And why not?

For the nth time for you to understand: at it ranks in the middle of all the amps @amirm measured and it is cheaper than most. That’s why!

Read it again!

Handling a complex load by power amplifiers

I think we have to draw a Price vs Tolerance chart (PriTo™),it will be surely a steep slope one but hopefully will eliminate most of the debate. Or stop having double standards regardless the price as any technical nerd would do. Either would work.

www.audiosciencereview.com

 

[sarumbear]

Indeed!

I doubt it. These are amplifiers using TI application note, which is a decent amplifier.

 

[linuxfan]

what cable do i need to connect the aiyima to a power supply like this one? I see some v+ v- N L...
lianshi 36V 10A 360w

There is a YouTube video here -

... but if you need to ask, it means you are not familiar with this type of product, and I worry for your safety. And I hope you intend to mount that power supply inside some form of enclosure? Otherwise you will have exposed AC contacts.

Also that particular power supply is not particularly good quality, and on the Amazon-UK reviews it's claimed that it draws 10W at idle!
In my opinion a better option would be the Meanwell LRS-350-36. Or for those who are unfamiliar with wiring, the Meanwell GST360B36 - with a full plastic enclosure.

 

[Gsrchrisu1]

​

https://www.amazon.ca/dp/B0B4WYGSPL?psc=1&ref=ppx_yo2ov_dt_b_product_details

I used one of these with a meanwell LRS-350-48 adjusted down to 42 volts. Just got a pair of OPA1656 off ebay this afternoon and its sounding great. Also replaced all the caps with Nichicon uKw, coil craft inductors, wima caps. Basically copied Trungmc.

 

[HappyMetalGuy]

The AIYIMA DC 48V 5A power adapter arrivel,Now it is upgraded http://amz.do/NxsfMn

I cannot pass the 1/4 volume in my office.
SETUP:

Aiyima A07 45€ (Used)
SMSL SU-1 80€
CD Transport 35€ (Used)
Mission LX2 MKII 200€.
Speaker Cables 9€
RCA 5€
Coaxial 12€

Total 386€

Budget was 400€ so now I can buy 2xLM4562 Opamps to roll on A07 "just for fun".
Also tried with Acoustic Energy AE100 MK2 and Dali Oberon 1 with same results. Cannot understand why the need for all that power maybe it's even bad for the life of A07?

 

[Hiten]

just for studying purpose have been reading TPA3255 datasheet. LINK. With various implementations and varying power supply voltages and amps, am finding it little confusing. Though at 51V it achieves (~100W, 8 ohms approx. 0.1% thd) It seems those voltages can be lowered to be on safe side and for longetivity of the chip as 51v is maximum.
So what would be ideal power supply requirement (volts and amps) to have 0.1 % distortion(Standard i suppose) and what maximum watts (in to 8 ohms and 4 ohms) one would get with those safe side voltages ?
thanks.