Topping PA5 Review (Amplifier)

[bravomail]

Just received and test it. I connected with SU-9 via XLR(female) to TRS cable and speaker JBL Stage A130, amplifier power more than enough for listen loud 80dBA(measured with UNIT-T UT353 sound level meter) at middle range (3m).

I'm not report subjective review as some may not want to hear it. But I promised to buy the next class AB amp that @JohnYang1997 will release soon. I respected your R&D result.

Anyway, the build of speaker binding post connector very loosen. I need to open cover to fix it from inside. Thank @genfreeciv for internal picture ,it made easier to find how to open it. It need to be more qc for this price level.

u can express ur feelings as in "the amp isn't broken" do u feel any improvement? compared to?

 

[bravomail]

Would you mind explaining why maxing the volume on the dac and turning down the amp makes a difference, and why this is more important for unbalanced interconnects? I always found this confusing. Do I turn the volume down on the dac, the amp, the preamp (if there even is one in the system), or digitally.

ok. DAC will produce some noise, no matter what level u set it to. Theory is that DAC noise will remain constant, or at least u can increase DAC output faster than DAC noise will increase. Then, next in chain, amp with huge gain, will amplify less incoming noise.
KSTR also is correct about cables liking higher signal. With any cable connection u want higher signal in the cable.

 

[shal]

@anphex,
close, but no cigar ;-)

Behringer ?

 

[pma]

Would you mind explaining why maxing the volume on the dac and turning down the amp makes a difference, and why this is more important for unbalanced interconnects?

Improving S/N, as already stated. Also improving ratio between useful signal and hum/buzz voltage, that is created by leakage ac currents (capacitive or ground loop) as a voltage drop across SE cable shield and this unwanted voltage is independent of useful signal. The bigger the ratio useful signal/shield interference voltage drop, the better.

 

[pma]

search utub for "binaural". they use special dual microphone setup with "human-like" ears. it works. u-tub usess 88kBit AAC - but it still works!

Yes but he speaks about 300kHz BW. This is a nonsense in any kind of recording. I do not need to search, I know how high do B&K special mikes go. Still below 100kHz. And how is it going to be reproduced?? This 300kHz / flat phase request is an utter nonsense.

 

[xrk971]

300kHz bandwidth is not the same as asking the 44.1kHz bandwidth audio signal to not have a 2usec phase shift within a certain window.

The audio content that gives us the spatial clues is actually in the 1kHz to 8kHz range. It’s not even the tweeter. Even a full range driver limited to 10kHz bandwidth can give sound localization. This localization is encoded in the minute phase shifts of the limited bandwidth sound. We need to remember that as the research and science shows, the human auditory system is capable of detecting microsecond phase information. Not frequency bandwidth.

 

[BadAudioAdvice]

My PA5 just arrived in the mail.

Sadly the speaker output jacks are loose and flopping around as others have mentioned - and the manual makes it very clear that the warranty is "instantly" voided if you open it.

@JohnYang1997 Is it OK to open it up ourselves to repair this issue without voiding the warranty?

 

[pma]

Quality control poor or missing, I have already mentioned it (when inspecting the teardown photos).

 

[ModDIY]

Quality control poor or missing, I have already mentioned it (when inspecting the teardown photos).

Indeed it is a little disappointing considering the price.

User experience is quite low. )-:

Edit: I was considering purchasing this amplifier when I see pictures with better solders, cleaner and cleaned PCBs, solid post binding.

Topping have an interest in correcting these assembly faults.

 

[Frank Sol]

Probably rushed to make the holidays wish list

 

[BadAudioAdvice]

To be honest, I don't mind it - it is a simple fix - I just want to confirm that I won't void the warranty.

For this level of performance, at this price - I have set my expectations accordingly.

Since I haven't connected it yet, my first impressions are:
- Decent weight, feels substantial.
- Case is nice and solid
- Well packed

I am looking forward to getting it hooked up.

 

[Frank Sol]

To be honest, I don't mind it - it is a simple fix - I just want to confirm that I won't void the warranty.

I hope you get that Confirmation... I would be worried too

 

[Lambda]

and the manual makes it very clear that the warranty is "instantly" voided if you open it.

This is not legal.

We’re Afraid of Warranty Stickers, but Really, Manufacturers Should Be | iFixit News

According to a survey published today by consumer group U.S. PIRG, 45 out of 50 appliance manufacturers automatically void the warranty of a device if it has…

www.ifixit.com

'Warranty Void If Removed'? As It Turns Out, Feds Say Those Warnings Are Illegal

The Federal Trade Commission says tying warranties to the use of specific parts or services is prohibited. And the agency has told six companies they have 30 days to fix their ways or face penalties.

www.npr.org

Please take some picture from the inside for us if you open it

 

[BoredErica]

License the DSP from Dirac and call it a day. Get rid of MQA altogether. Improve the volume knob to something large, tactile and iconic that would generate envy from non-audiophiles and you'll have an international hit on your hands.

Sounds great, though I wonder which good options for volume knobs there are which are large and tactile.
Bit off topic on my part though. (Can't be worse than another 5 pages of subjectivist vs objectivist arguments...)

 

[ModDIY]

Sounds great, though I wonder which good options for volume knobs there are which are large and tactile.
Bit off topic on my part though. (Can't be worse than another 5 pages of subjectivist vs objectivist arguments...)

5 pages plus the dozen earlier. It reminds me of a cockfight, it's who's right, also where he works or has worked, on the types of products and so on. To be fun it is, however moderation is lacking on this forum.

 

[jlesterp]

By the way, I could be wrong and the PFFB is passive (PPFFB) but perhaps higher order than 2nd. As long as the input (into the PPFFB) can be driven high enough (say 10Vrms with frontend OpAmps running from +-15V) the feedback factor can be increased significantly but limited of course by the 21dB "open loop" gain of the chip.

Here's a TPA3255 module with passive PFFB, I increased the negative feedback from 6.9dB to 11.4dB. Gained some 4dB on 1kHz THD+N.
My funky spectrum analyzer might be a limiting factor though.

 

[douede]

Some SMT rework to remove the dead TPA3255 and replace it worked well but it is not a job for every DIY’er.

...and it becomes even more tricky if some traces blew up with the firework

 

[Redheart]

PA5 Amp is ordered with E50 Dac. Really looking forward to it, should be a nice upgrade from A07.
but the SINAD graph, while having a nice crisp definition now, has the decibel ratings written upside down when you read it as intended with the name of the amps!

 

[xrk971]

Here's a TPA3255 module with passive PFFB, I increased the negative feedback from 6.9dB to 11.4dB. Gained some 4dB on 1kHz THD+N.
My funky spectrum analyzer might be a limiting factor though.

View attachment 171330
View attachment 171331

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View attachment 171333

Thanks for sharing this. As expected, 4dB more feedback (7dB to 11dB) reduces distortion by an equal amount. This will lower the gain as well, probably down to circa 11dB now. So preamp gain will need to increase by 4dB to keep amp output the same.

 

[xrk971]

...and it becomes even more tricky if some traces blew up with the firework

Yep. I have seen craters left behind when a GaN FET goes ballistic.