Sure Electronics AA-AB32313 2x400

[ravels]

I make measurements Sure Electronics AA-AB32313.
All measurements are made at 10 watts of power and a load of 3.9 ohm.
The right channel (bottom) - loopback soundcard.

Thanks!

The fifth harmonic distortion appears to be a little on the high side, can you see anything else that is not as expected based on the specs?

Is there any way you can repeat the measurements with a 8-ohm load?

 

[ravels]

They all looks similar (tripath + STA516B(E)). I ordered 2 AA-AB31321 monoblocks, and I think it has parallel BTL output. There are few things I don't understand. AA-AB31321 is rated 800W@1.5 ohm, so it's 400W@3ohm ,200W@8 ohm...etc. However, there is AA-AB31315 which also rated 400W@3ohm. If they are all STA-516BE based, what would be the difference? The 2nd thing is the supply voltage. The customer support told me over voltage will burn the amp., e.g 40V->50V. The STA-516BE has maximum voltage of 65V and up to 60V is recommended. I can't see why 50V will burn the amp, and they refused to answer more technical questions I asked. Weird...

If you look at the PCB pictures below the thermal images, AA-AB31321 appears to be a configuration with two output ICs (STA516BE?) whereas AA-AB31315 appears to have a single output IC. In order to be able to drive 800W into 1.5-ohms, you would probably need 2 STA516BEs in parallel. Not sure about the output driver IC in the second configuration, since STA516BE data sheet states 400w into 2-ohms at 52V whereas the Sure AA-AB31315data sheet states 400W into 3-ohms at 44V. I don't know of any updates to STA516BE, does another vendor make a similar device with higher output power capability?

AA-AB31321: http://store3.sure-electronics.com/media/wysiwyg/AA-AB31321_5.jpg
AA-AB31315: http://store3.sure-electronics.com/media/wysiwyg/AA-AB31315_5.jpg

 

[ppy]

have you checked maybe your chips under the heatsink?
are they STA516BE / TC2001?

Yes, 2xSTA516BE and TC2001.

 

[ppy]

The fifth harmonic distortion appears to be a little on the high side, can you see anything else that is not as expected based on the specs?

Is there any way you can repeat the measurements with a 8-ohm load?

I think I made a mistake in the measurement.
For measuring amplifier in BTL mode I used this divider.
Do you think this schematic is correct?

 

[canvas]

If you look at the PCB pictures below the thermal images, AA-AB31321 appears to be a configuration with two output ICs (STA516BE?)

Thanks. I see the difference now. AA-AB31321 does have 2 STA-516BEs working in parallel. Now I wonder the difference between this AA-AB31321 (800W) and AA-AB31392 (1000W). It seems they just increase the recommended supply voltage which I think the AA-AB31321 should also work on 50V VCC.

 

[ravels]

I think I made a mistake in the measurement.
For measuring amplifier in BTL mode I used this divider.
Do you think this schematic is correct?

That should divide the amplifier output voltage by a factor of 23, though it depends on the tolerance of the resistors. 3.9 ohm is a power resistor, right?

 

[ppy]

3.9 ohm is a power resistor, right?

Yes, of course.

I remake the divider, and made the following measurements.

 

[ppy]

It is evident the predominance of even harmonics.
This is typical of Tripath Technology. The sound is similar to the "tube sound".

 

[ravels]

Yes, of course.

I remake the divider, and made the following measurements.

That looks pretty good!

 

[ppy]

That looks pretty good!

And it sound not too bad.

 

[Groucho2004]

Linear power supply for this amplifier is not recommend to use.

Can you elaborate on that statement?

 

[29285]

It is evident the predominance of even harmonics.
This is typical of Tripath Technology. The sound is similar to the "tube sound".

Interesting. Did you ever measure any tube amp with similar THD-performance?

 

[ravels]

On a totally unrelated topic, does anyone know if it is possible to change the fan trip temperature for this board (AA-AB32313)

 

[pblossom]

Fan...

I built this with the Meanwell 36v 8.9a power supply. Even at idle, the fan comes on every 5 minutes. Anyone else have this happen?

 

[denbret]

You are lucky, mine the fan works all the time. I wrote 5-6 times to Sure, I twice sent a video as they had requested. Ultimately no response.

 

[ppy]

Can you elaborate on that statement?

High-frequency power supplies better cope with the problem of "power-supply pumping" when working with Class D amplifiers.
But this is not true for the bridge amplifier mode. AA-AB32313 runs in PBTL mode.

I take my words back. This amplifier can try with a linear power supply.

 

[ppy]

Interesting. Did you ever measure any tube amp with similar THD-performance?

I can only compare with the tube amplifier. It is interesting to you?
On this page there are measurements that show the predominance of even harmonics in the signal.

 

[Groucho2004]

High-frequency power supplies better cope with the problem of "power-supply pumping" when working with Class D amplifiers.
But this is not true for the bridge amplifier mode. AA-AB32313 runs in PBTL mode.

I take my words back. This amplifier can try with a linear power supply.

What was the supply voltage for your last set of measurements?

 

[ppy]

What was the supply voltage for your last set of measurements?

I made measurements at 10 watts. The dependence on the power supply type is minimal. Recent measurements are made with a linear power supply of 45V from the amplifier NAD 326bee.

 

[Groucho2004]

I made measurements at 10 watts. The dependence on the power supply type is minimal. Recent measurements are made with a linear power supply of 45V from the amplifier NAD 326bee.

I was just wondering how much the supply voltage matters. The allowed range in the data sheet is quite large but I read somewhere that it "sounds" better with the voltage at the upper end.