AIYIMA A07 TPA3255 Review (Amplifier)

[conuss]

So does it still clap when on-off or is affect finally defeated?..
Haven't come up with a TPA3255 power amplifier yet to forget about the problems of this lame attenuator? What an exorbitant problem !! ))

 

[NoClipping1337]

Mine seems fine, no issues with it turning on/off either via the switch or killing the power.

 

[conuss]

Mine seems fine, no issues with it turning on/off either via the switch or killing the power.

From the very start, the A04 was all right with this, but the manufacturer, poor fellow, could not cope with the A07! If now A07 doesn't clap on-off, let's clap our hands for solving a hellish problem! ))

 

[Kalessin]

So does it still clap when on-off or is affect finally defeated?..
Haven't come up with a TPA3255 power amplifier yet to forget about the problems of this lame attenuator? What an exorbitant problem !! ))

I get a tiny turn-on click through my speakers, and the same when turning it off.

 

[jaatre]

@AIYIMA
Since the A07 has earned a recommendation from Amir, there are quite a lot of folks eager to try your product and future products.
It will be good if the customer feedback is taken for future SKUs.

This is what I have seen across several forums:
1. The pop issue during turn-on turn-off on the A07. Has this issue been resolved in the A08?
2. Providing something like A07 with an in-built power supply (something like MEANWELL 48V 8A) and NO Bluetooth/USB input (adding RCA plus XLR outs will be a nice touch)
3. For HT folks, 3 channel amp in a single chassis

If you can meet the above requirements in your product line-up, these can easily be the best bang-for-buck Class D offerings in the market.

 

[Toku]

@AIYIMA
Since the A07 has earned a recommendation from Amir, there are quite a lot of folks eager to try your product and future products.
It will be good if the customer feedback is taken for future SKUs.

This is what I have seen across several forums:
1. The pop issue during turn-on turn-off on the A07. Has this issue been resolved in the A08?
2. Providing something like A07 with an in-built power supply (something like MEANWELL 48V 8A) and NO Bluetooth/USB input (adding RCA plus XLR outs will be a nice touch)
3. For HT folks, 3 channel amp in a single chassis

If you can meet the above requirements in your product line-up, these can easily be the best bang-for-buck Class D offerings in the market.

AIYIMA A07 has no pop noise problem. Because the A07 has a pop noise prevention control chip.
A similar unbranded model, which was the base model for the AIYIMA A07, is on sale, but this model does not have a built-in pop noise prevention circuit.

 

[Raindog123]

NO Bluetooth/USB input (adding RCA plus XLR outs will be a nice touch)

A07 does not have BT/USB. It only has analog in - RCA and 3.5mm jack. No balanced in, though.

(And unfortunately looks like @AIYIMA has not been active since Dec'20)

 

[jaatre]

AIYIMA A07 has no pop noise problem. Because the A07 has a pop noise prevention control chip.
A similar unbranded model, which was the base model for the AIYIMA A07, is on sale, but this model does not have a built-in pop noise prevention circuit.

I read something otherwise in a few places.. maybe I mistook the A04 for the A07, my bad

A07 does not have BT/USB. It only has analog in - RCA and 3.5mm jack. No balanced in, though.

Let me clarify, I meant to say that we need something like the A07 but with a good PSU inside. The A08 will be their answer for that but it has BT and USB. So it'll be A08 minus BT and USB [/QUOTE]

 

[Kalessin]

There is a tiny turn-on pop through the speakers with the A07 that I bought a few weeks ago, but not loud enough that I'd consider it a problem. Because I was in a rush this morning, I did make the mistake this morning of unplugging the 1/8" plug from my laptop with the amp powered on, and got a BIG pop... but that one's on me!

The external power supply is not a problem for me. I put it on the floor and run the low-voltage wire up to the small amplifier case on my desk. I much prefer that to a bigger box with an internal voltage transformer from 120v main to DC 48v.

If you would like to contact Aiyima, send email to [email protected] (their English is a little basic, but they're friendly).

 

[eardiggler]

Just received the Aiyama A08 this morning. This is the unit that's uses a 3255chip and comes with a built in PS. It also includes a cheap DAC w/BT and a volume control. Manufacturers SNR is rated at 111db.

I can confirm It also has a small 'pop' when powered on which is mildly disappointing. The volume knob also scrapes the edges of the chasis when turned. The unit has a cheap look and feel to it but since it was only $117 on Amazon w/free shipping it's almost pointless to complain. I can't hear any background noise or hiss at full power which is refreshing. Subjectively, it sounds no better or worse than my slightly more expensive amplifiers.

Overall I'm happy with it.

 

[maxx264]

wow I just found out I can buy this amplifier in china for about half the price you mentioned.

 

[jaatre]

So it looks like few folks still have the pop issue on the new models.

wow I just found out I can buy this amplifier in china for about half the price you mentioned.

Is there a link that you can provide?

 

[mario_rouge]

I sent it back just for the pop noise. I don't want to risk breaking my speakers.

 

[eardiggler]

wow I just found out I can buy this amplifier in china for about half the price you mentioned.

Of course, it's always cheaper to order direct but you will have to wait a lot longer to receive it. Plus returning is more of a PIA if you don't like it.

 

[eardiggler]

I sent it back just for the pop noise. I don't want to risk breaking my speakers.

What do you think the 'Pop' noise is exactly? Is it current running to the speakers? I do worry about frying or damaging the voice coils on my speakers. I remember my old Pioneer SX 636 made a similar noise when turned on. That was a capacitor coupled receiver and I remember measuring way too much power going to the speakers when turned on due to old leaky capacitors. I imagine this noise is something different than that.

 

[conuss]

What do you think the 'Pop' noise is exactly? .

'Pop' noise is something that is not in AIYIMA A04 TPA3251 !!

 

[eardiggler]

Just to be on the safe side I measured the DC offset of the A08 to see if the 'pop' sound might be related to a spike of some kind. I'm pretty sure I measured this right with the both speakers unplugged and nothing connected into the RCA inputs w/BT off.

Measurements:

Max Mv after turning on: 31Mv
Minimum Mv after turning on: -232Mv (I did measure -416Mv at one point while cycling on and off quickly)
Resting state after turning on: -6.2Mv
Max MV when after turning off: +154.3Mv (Spikes up before draining to 0Mv)

When turning on I can visually see how the voltage drops to -232Mv then works back up to +31Mv then back down again to -6.2Mv where it stays.
When turning off it spikes to +154Mv then drains out in about 15-20 seconds. I'm wondering if the audible thump when turning on is the -232Mv passing through the speakers?

Is that enough voltage to cause damage to a speaker voice coil?

 

[Toku]

Just to be on the safe side I measured the DC offset of the A08 to see if the 'pop' sound might be related to a spike of some kind. I'm pretty sure I measured this right with the both speakers unplugged and nothing connected into the RCA inputs w/BT off.

Measurements:

Max Mv after turning on: 31Mv
Minimum Mv after turning on: -232Mv (I did measure -416Mv at one point while cycling on and off quickly)
Resting state after turning on: -6.2Mv
Max MV when after turning off: +154.3Mv (Spikes up before draining to 0Mv)

When turning on I can visually see how the voltage drops to -232Mv then works back up to +31Mv then back down again to -6.2Mv where it stays.
When turning off it spikes to +154Mv then drains out in about 15-20 seconds. I'm wondering if the audible thump when turning on is the -232Mv passing through the speakers?

Is that enough voltage to cause damage to a speaker voice coil?

The DC offset voltage of the speaker terminal shows a fairly large value. That is causing pop noise.
In AIYIMA A07, SP output is stopped by turning on the MUTE operation of TPA3255 for a certain period of time to prevent pop noise when the power is turned on / off. I checked the A08 board, but I can't find an IC chip to do it.
The maximum DC offset voltage standard for the TPA3255 in a stable state after the power is turned on is 60 mV.

This DC offset voltage actually causes a large amount of current to flow through your speakers.
As you understand, the old Pioneer SX 636 is due to the charging current of an electrolytic capacitor with a large SP output, which was common in old amplifiers.


<<additional information.>>
I asked a Japanese user, but it seems that pop noise does not occur even if the power switch is turned on / off or the AC-plug is inserted or removed.
So I think the product you received is out of order.

 

[eardiggler]

The DC offset voltage of the speaker terminal shows a fairly large value. That is causing pop noise.
In AIYIMA A07, SP output is stopped by turning on the MUTE operation of TPA3255 for a certain period of time to prevent pop noise when the power is turned on / off. I checked the A08 board, but I can't find an IC chip to do it.
The maximum DC offset voltage standard for the TPA3255 in a stable state after the power is turned on is 60 mV.

This DC offset voltage actually causes a large amount of current to flow through your speakers.
As you understand, the old Pioneer SX 636 is due to the charging current of an electrolytic capacitor with a large SP output, which was common in old amplifiers.


<<additional information.>>
I asked a Japanese user, but it seems that pop noise does not occur even if the power switch is turned on / off or the AC-plug is inserted or removed.
So I think the product you received is out of order.

Thanks so much for your response and research.

I'm not going to bother plugging my speakers back in because they are only a few weeks old. They got hit with the spike about 30 times already including an older set of beloved more expensive speakers. I don't think it caused damaged as the DC spike is very fast but I also don't want to risk it.

What's interesting is the A08 came directly from the factory through Amazon as I was in contact with the manufacturer over email when I ordered. It took about 3 weeks to take delivery. I'm surprised they would send units out without QC testing but then again I'm not surprised either.

Here's the unit and my 416Mv reading after powering it on and off before letting the caps completely drain out. Unless I received a defective unit I think you guys may be better off just getting A07 and separate high quality power supply.

 

[JeffGB]

While I can understand people not wanting the turn on/turn off transient, I don't understand why anyone is worried about their speakers. A quick calculation indicates that .416v put through an 8 ohm resistor is only .021 watts of power. I might worry if I was driving a tweeter with no filter but I wouldn't worry about a normal full-range speaker system. My Adcom GFA-5500 has a turn on transient that causes the woofers to move 1/4 inch or more and has never damaged anything, so I wouldn't worry about it.