Topping PA5 Review (Amplifier)

[pma]

Normally, one would place an kind of volume pot after the input diff-amp (the "dereferencer") so that it never compromises CMRR.

I think we know this, however then 4 gang pot is not used. If there is a 4 gang pot it indicates to 2 independent signal paths for + and - branches through the whole amp or that the pot is before the input stage. Anyway the use of 4 gang pot compromises the CMRR.

 

[Dynky]

Can someone please check and confirm whether a pair of Neutrik NA3FP adapters will fit on the inputs?

 

[KSTR]

I think we know this, however then 4 gang pot is not used. If there is a 4 gang pot it indicates to 2 independent signal paths for + and - branches through the whole amp or that the pot is before the input stage. Anyway the use of 4 gang pot compromises the CMRR.

You got me wrong it seems. What I mean is the typical re-balancer circuit at the input which has balanced output signal with CM=0 (and some DM gain, perhaps), and after that you need a 2-gang pot per channel to control volume for the output paths in most any pot configuration, be it simple voltage divider + buffer/gain cell (with log pot) or inverting feedback divider of the output amp itself (linear).

 

[nhs]

I think we know this, however then 4 gang pot is not used. If there is a 4 gang pot it indicates to 2 independent signal paths for + and - branches through the whole amp or that the pot is before the input stage. Anyway the use of 4 gang pot compromises the CMRR.

As your previous post, I am also very interested in a measurement at another position of the volume knob, at about 9db gain would be fine. I personally have to attenuate the gain to match the level of other surround amp's. Hope, @amirm would do it.

 

[0bs3rv3r]

Would it be worth to put a beefier PSU ? (Like 36V 6A or more for example ?)

Run it on 3 batteries?

What is absolute maximum on the DC inlet?

Why do these things? Which measurement do you hope to improve? It already measures spectacularly.

 

[Papaya_X]

Why do these things? Which measurement do you hope to improve? It already measures spectacularly.

I hope to give more power output ?? I don't know that's why I am asking what would be the improvement if there is any

 

[Calleberg]

I hope to give more power output ?? I don't know that's why I am asking what would be the improvement if there is any

Well to start, the standard PSU is 38V, which is also the maximum rating of the TPA3251, if thats whats inside... So a 36V PSU is not going to help things.

You will have to wait until they release the 260Wx2@4Ohm TPA3255 Version with 52V 16A PSU

 

[DS23MAN]

The powerbrick is rated at 4 amps continues and can supply more for short periods.

 

[Papaya_X]

Well to start, the standard PSU is 38V, which is also the maximum rating of the TPA3251, if thats whats inside... So a 36V PSU is not going to help things

Yes it was a mistake, would there be any benefits in terms of power (not measurements) to run a 38V 6A/8A PSU with this amp ?

 

[TNT]

Why do these things? Which measurement do you hope to improve? It already measures spectacularly.

Maybe it will improve its impulse/dynamic behaviour thanks to a battery based PSU low impedance and current capability. All the measurements was steady state so this aspects isn't covered as I see it. To make a car analogy which we all love som much; ASR is testing highway crusing comfort but no acceleration or off-road tests are performed

//

 

[Toku]

I examined the pin arrangement based on the close-up photograph of this IC chip. As a result, I was convinced that it was TPA3251 or TPA3255. Furthermore, considering that the power supply voltage of PA5 is 38V, it can be said that it is TPA3255. Probably no doubt.

 

[F1308]

Topping PA5 appears as P50...

 

[Lambda]

All the true hole solder joints and the hand Solder inductors look bad and inconsistent.
And i hate that they did not clean up the flux

 

[Toku]

All the true hole solder joints and the hand Solder inductors look bad and inconsistent.
And i hate that they did not clean up the flux

When I look at the posted photos, I get a lot of doubts.

1. As a product version, the PC board is dirty. There are many scratches on the parts used. Isn't this PA5 a prototype for testing?
2. The information printed on the board is blacked out to hide it. I don't think this kind of treatment is necessary for the product version. Maybe it was a photo taken before the product was announced?

 

[pma]

1. As a product version, the PC board is dirty. There are many scratches on the parts used. Isn't this PA5 a prototype for testing?

To me, it looks like just a functional sample. If it was a serial production piece, then the factory quality standards would be very, very low.

 

[nhs]

To me, it looks like just a functional sample. If it was a serial production piece, then the factory quality standards would be very, very low.

Afaik, the pics are taken from the device of @genfreeciv. It must be also a piece from the serial production.

 

[Matias]

A little dusty from the factory but no big deal. I also do product photography, and close up pictures tend to magnify the dust.

 

[genfreeciv]

Hi all,
The product that I took teardown photos was delivered through amazon.co.jp.
I used a flash when I took those photos to clearly record the text printed on the circuit elements , so I think the dust and scraches stood out.
It's true that it's not as clean as the inside of the MOTU M2 I once opened, but I think it's cleaner than that of a BA100 of Breeze audio from China.

 

[Lambda]

Also it is kind of stupid to put a heat sink like this in a case like this.
Airflow trough fines is sub optimal to say the least.
a proper Thermal interface to the cases would be a better solution for sure but i guess also a more expensive and complicated solution

genfreeciv​

Wat kind of Processing HDR, tone mapping, Clarity, local contrast, dynamic range compression. or how ever the manufacture calling it are you using?

Maybe back of on this slider... like a lot

 

[pma]

Also it is kind of stupid to put a heat sink like this in a case like this.
Airflow trough fines is sub optimal to say the least.
a proper Thermal interface to the cases would be a better solution for sure but i guess also a more expensive and complicated solution

It is the same issue as with AIYIMA A07 that I bought for testing and posted a lot of results. But this one is too expensive to me to buy it just from a simple curiosity reason. I am afraid that no one else here would be willing to perform a continuous power test.