Topping PA5 Review (Amplifier)

[Rottmannash]

You get higher amplitude.
Tests dont need to be "real world like" they need to be reviling. and we need to have the knowlage to kow how to translate re results to real world.
SINAD a 1Khz is also not real world at al but it tells a lot.
You might not get a lot of >10 kHz periodic high amplitude signals but you sure get a lot of fast rise time signal wit high amplitude.


I have lot of old gear that came with schematics.
a portable TV from the 90s with the schematics in the normal user manual including waveform diagrams at test points.
also that modern Sony camera in the video.
And if buy super expensive test gear i also get a lot of this documentation.


Not the coil but the material in it is the interesting part.

Off topic but what type of inductors do the Purifi modules use?

 

[Lambda]

Off topic but what type of inductors do the Purifi modules use?

This Thing We Have About Hysteresis Distortion - PURIFI

Read any Purifi interview and someone is sure to mention hysteresis distortion (or iron distortion, same thing). What is it about and how serious is it? Hysteresis happens in any coil that has a magnetic core. For instance the iron yoke in a speaker driver. It sits inside the voice coil. Or...

purifi-audio.com

it is less proprietary component so it is harder to tell from pictures.
https://www.tdk-electronics.tdk.com/inf/80/db/fer/rm_8.pdf
Something like this.

 

[HammerSandwich]

Would you give a Car Dealer the benefit of the doubt if they try to sell you a care with the Engine serial number Grid off?

Dealer != OEM.

If Amazon/Apos/etc. opened your new PA5 to grind off the part numbers, would you criticize Topping? And Ford/VW/etc. definitely use proprietary part numbers & huge markups on commodity components from outside suppliers.

 

[sarumbear]

This thread went of the rails.

 

[rebbiputzmaker]

You open the case and you look at the PCB from below and you count the number of pins ... and we should guess the chip)
In my opinion one or more smart people should be able to guess soon ....

 

[Walter]

Nevertheless, 65$ for this
or 110$ for this
or 85$ for this
Let's just imagine the last two with upgraded engeneering & parts : ? $

If you go back a few pages, you'll see that @xrk971 already went into detail on that exact scenario.

 

[bsas]

This thread made me learn something important: the $101-$499 price threshold is full of crazy people. If an amp is $1000, $2000 or $3000, whatever no one comments on price per part. If an amp is $99 or less, also. But, if you are specifically in the middle people goes bat shit crazy about the brand of an inductor???

Guys, it is very simple: this is an amp from a known company that measured very well on Amir's test suite. If you like the company or you don't, it matters just to yourself. If you care where the amp was built, it matters just to yourself. If you like the price or you don't, it matters just to yourself.

If you like the amp, buy it. If you don't, don't buy it. If think it is too expensive, wait for a deal or a sale or just don't buy it. Done.

Can we now discuss more interesting things: like for example why the 18-19kHz should be important and other more technical and scientific facts. I joined this forum for the science, not for the cheap stake babbling ... If price was a science, the stock market would be 100% predictable...

 

[Heesung]

I was thinking of using 2 PA5s for my AV receiver preouts (front/center).
I wonder if it is OK if I use only 1 channel of PA5 for my center speaker.
Is PA5 (or any other stereo power amp) going to be fine if only one channel is used?

 

[restorer-john]

It's a good job I didn't loose sleep over not knowing the brand and value of every component in the AHB2 before I bought it.

Though with the cost of those components it should sell for only $ 2500, in my opinion......

Benchmark should really update those photographs. It must have been an early prototype they photographed.

The screw on the rear plate?
And the two pictures have different speaker terminal cables:

One picture short cables straight to the PCB with end entry blue booted spade terminals and the other shot showing side entry spade terminals, longer cables going up and over, running against the rear panel. And that strange screw...

 

[0bs3rv3r]

I was thinking of using 2 PA5s for my AV receiver preouts (front/center).
I wonder if it is OK if I use only 1 channel of PA5 for my center speaker.
Is PA5 (or any other stereo power amp) going to be fine if only one channel is used?

Ground the unused input and put an 8 ohm resistor on the output to be sure.

 

[Heesung]

Ground the unused input and put an 8 ohm resistor on the output to be sure.

Thanks but could you be more specific? How can I ground the unused input?

For the output, the following is correct?
PA5 left out ----- speaker cable ----- 8 ohm resister ----- speaker cable ---- PA5 right out

Something just came up to my mind...
Using RCA splitter adapter for my AV receiver's center channel preout and using both channels of PA5 to bi-amp my center speaker....
Is this gonna work?

 

[Sharpi31]

If you can solder, get a spare RCA plug and solder the pin to the shield. Then sit the plug on the input connector of the unused channel.

 

[Lambda]

How can I ground the unused input?

Can we now discuss more interesting things: like for example why the 18-19kHz should be important and other more technical and scientific facts. I joined this forum for the science, not for the cheap stake babbling ... If price was a science, the stock market would be 100% predictable...

It is more like Audio engineer review anyways

Cost breakdown analysis - Wikipedia

en.wikipedia.org

 

[Heesung]

It is more like Audio engineer review anyways

View attachment 170949

Cost breakdown analysis - Wikipedia

en.wikipedia.org

Where can I get this thing???

 

[0bs3rv3r]

For the output, the following is correct?
PA5 left out ----- speaker cable ----- 8 ohm resister ----- speaker cable ---- PA5 right out

No. No cable. Just a resistor between the two speaker terminals of the channel not being used.

 

[Heesung]

No. No cable. Just a resistor between the two speaker terminals of the channel not being used.

So, just put both legs of a resistor into each speaker terminal of the unused channel of PA5, right? Correct me if I'm wrong.

 

[0bs3rv3r]

So, just put both legs of a resistor into each speaker terminal of the unused channel of PA5, right? Correct me if I'm wrong.

Basically yes. Are they screw-down terminals that you can put the resistor leads under? If not you could also solder the resistor between two banana plugs and plug them into the terminals.

And make sure the shorting plug is on the input - otherwise you might cook the resistor if the PA5 dumps 10's of watts of noise into it.

 

[Lambda]

Where can I get this thing???

"rca shorting plug" or "RCA short" "rca cover"
on aliexpress,ebay,amazon

So, just put both legs of a resistor into each speaker terminal of the unused channel of PA5, right? Correct me if I'm wrong.

Yes
You can get them ready made with wires cheap on amazon

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[amirm]

I was thinking of using 2 PA5s for my AV receiver preouts (front/center).
I wonder if it is OK if I use only 1 channel of PA5 for my center speaker.
Is PA5 (or any other stereo power amp) going to be fine if only one channel is used?

It is going to be fine. In the extreme you may need to ground its input as stated but I would not worry about it.

 

[0bs3rv3r]

"rca shorting plug" or "RCA short" "rca cover"
on aliexpress,ebay,amazon

Yes
You can get them ready made with wires cheap on amazon
View attachment 170951

Don't need high power resistors if you keep the input shorted.