AIYIMA A07 TPA3255 Tear Down

[gasolin75]

30V .5 A would seem way to small but don't forget the 10:1 peak to average ratio of music

That's one reason i wanna have something bigger, i don't think just because i have an 10a power adapter that i would use more than currrent if my power adapter was 32v 6a

 

[carlmart]

to get a tube sound from this amplifier use an unregulated 32V adapter 30V .5 A would seem way to small but don't forget the 10:1 peak to average ratio of music I use a Jameco clarity can be improved by replacing the 6V reference for the opamps with a 5.6V low noise zener and using OPA32 TI opamps

Unregulated 32v from a switching supply?

What I wonder is how no one has tried using a linear DC supply, as 32v 5A wouldn't be that large or expensive.

 

[carlmart]

Has anyone modified the A07 following the TI datasheet, that seems to show how to bridge the TPA3255?

 

[wonderfulaudio]

I hope somebody can answer the below questions for the Aiyima A07 model which is still in production now. I just got two of them for subwoofer duty.

1) I see that the caps on the supply are 50V but recommended supply voltage is 48Volts, isn't it dangerously close to the caps exploding.
2) What components determine the low frequency cutoff of this amplifier, there is NE5532 pre-amp before TP3255, does it have any kind of HPF to block DC? I want that HPF to be at 5Hz as I have DSP which does EQ at 25Hz, the printed user manual that came with the amp mentions -3dB at 20Hz which is too high for me.
3) What is this unnamed chip part number and its role, pls see the red circled (ok, its oval) IC on the left

Also, for subwoofer duty, I will use a bigger enclosure with a fan on the heatsink and route the power supply directly to the caps because the DC jack on the PCB cant carry current needed for 250W+250W for my stereo subs
Warm Regards,
WA

 

[Wolf11Man]

If an electonic part is rated for 50V DC it is not dangerous to run it at 50V DC. Otherwise it would be rated lower. In fact it will not explode even with some overvoltage, maybe 10%. 50V is simply the voltage it will meet it's documented specs as you can read in the data sheet.
Marketing and sales talk have put some kind of "it has to be overdimensioned to be good" in many audiophiles heads. This it complete nonsense, a technical device has to be made to meet it's specified performance and life expectancy.
There are some parameters in electonic components that can influence sound, the voltage rating of electolytics is none of them.

 

[Bruce Morgen]

I hope somebody can answer the below questions for the Aiyima A07 model which is still in production now. I just got two of them for subwoofer duty.

1) I see that the caps on the supply are 50V but recommended supply voltage is 48Volts, isn't it dangerously close to the caps exploding.
2) What components determine the low frequency cutoff of this amplifier, there is NE5532 pre-amp before TP3255, does it have any kind of HPF to block DC? I want that HPF to be at 5Hz as I have DSP which does EQ at 25Hz, the printed user manual that came with the amp mentions -3dB at 20Hz which is too high for me.
3) What is this unnamed chip part number and its role, pls see the red circled (ok, its oval) IC on the left
View attachment 502803
Also, for subwoofer duty, I will use a bigger enclosure with a fan on the heatsink and route the power supply directly to the caps because the DC jack on the PCB cant carry current needed for 250W+250W for my stereo subs
Warm Regards,
WA

FWIW, I've been running a stacked pair of A07s with 50WVDC Nichicon caps at 48VDC virtually 24/7/365 since 2020 with no additional cooling measures -- and not a single problem of any kind. BTW, it's not realistic to expect "250W+250W" at suitably low distortion from an A07 -- at 48V with a nominal 4 ohm load, the available WPC will barely make it into three digits before distortion becomes audible. IOW and IMO don't worry about that power jack -- I've never read about even one of those ever failing. IIRC (and again FWIW), Aiyima themselves offers a 7+ amp 48V SMPS with that sort of barrel connector for their TPA3255 amplifiers, which implies that the mating jack has more than enough current capacity to safely run an A07 at "full throttle". Even the cheapest 5.5x2.5mm "barrel" connectors are rated for at least 5 amps, so offhand I'd say "stand down from red alert" on that issue -- but of course it would do no harm to bypass the A07's power jack if you still want to do that.

 

[wonderfulaudio]

I once put a 2200uF/16V cap on 12V trafo and it exploded near my face, the cap barrel flew past me quite far, had it hit me it would have been serious. That was two decades ago. May be caps got better now.

Also a power supply of 48V@7Amps is not utilizing the chip to its max potential with just a little over 150W+150W RMS

 

[Joe Smith]

I once put a 2200uF/16V cap on 12V trafo and it exploded near my face, the cap barrel flew past me quite far, had it hit me it would have been serious. That was two decades ago. May be caps got better now.

Also a power supply of 48V@7Amps is not utilizing the chip to its max potential with just a little over 150W+150W RMS

The A07 amp is better suited to a 36v/5-10a supply brick in my experience. The original specs published for these small amps are misleading.

 

[Wolf11Man]

I once put a 2200uF/16V cap on 12V trafo and it exploded near my face, the cap barrel flew past me quite far, had it hit me it would have been serious. That was two decades ago. May be caps got better now.

If you connect a 16V capacitor to some 12V transformer, it has to explode- Even at 6 Volt AC this would happen. Electolytics are polar and instandly start to cook with AC.
Even with a rectifier the capacitor would have seen more than 17 Volt DC, because idle is up to 50% higher than the nominal voltage at load.
If you got a 12 V transformer, idle voltage should be 12V x 1.41 + 10%

 

[wonderfulaudio]

If you connect a 16V capacitor to some 12V transformer, it has to explode- Even at 6 Volt AC this would happen.

I meant after bridge rectifier