Poll for Topping PA5 owners only please.

[Roland68]

This is misinformation and messing around with replacing perfectly good capacitors is not going to solve anything.

The capacitors will not be the problem and capacitors do not fail after 2000-3000hrs at 85 degrees celscius.

View attachment 236856

see here:

Estimated Life Calculator for Capacitors | NICHICON CORPORATION

You will find information about Nichicon's estimated life calculator for capacitors here.

www.nichicon.co.jp

As said, it is an easy to check possibility of the error cause. Of course it doesn't have to be because of that.
After 30 years of experience with such problems in industry and high-availability IT technology, I can assure you that exactly such problems occur, especially when companies are not familiar with such problems.

Is Nichicon's data wrong?

Of course, the following must still be taken into account:
- Smaller capacitances have a shorter service life at high temperatures
- The low load on these capacitors (only in the signal path, very low voltage) further reduces the service life at high temperatures, since the chemical process in the electrolyte is not sufficiently activated. In addition, there is at least 80-90% idle time without any load on the capacitor at a possibly high temperature.
This is also not conducive to the service life.
All the points listed above together could reduce the service life significantly, even at lower temperatures.

And again, it doesn't have to be because of that, but if...

My first intention was the D-01 Black Box. Does anyone know if the circuit is just encapsulated or encapsulated?

 

[WileeCoyote]

12th June 2022 most likely.

A simple approach to a possible problem with the PA5.
The description of the error by almost all owners of a defective PA5 is striking.
- Noise, hiss or crackling on one or both channels
- Complete failure on one or both channels
- Failure or error occurs after 1500 to 3000 hours, especially when the PA5 is continuously powered on.

I know the first two phenomena from old amplifiers where the coupling capacitors (small electrolytes) have dried out. Something like this happens after 20-30 years, sometimes even after 10.

If I see that correctly, there are 4 pieces of Nichicon (U)FW 10uF/50v as coupling capacitors in front of the potentiometer and after the Topping D-01 Black Box.
Anyone who is familiar with heat dissipation in devices, components and heat sinks will quickly recognize that the 4 Nichicon (U)FW 10uF/50v are in a hot spot between the D-01 Black Box and the heat sink.
This will not be a problem in the first 1-3 hours after switching on (slight air circulation due to rising heat). But after a few hours, when all the components, board and case have reached their final temperature, these 4 capacitors should be the warmest spot in the device (apart from the TPA3251).
- Average lifetime of the Nichicon (U)FW approx. 2000 hours at 85°
- Smaller capacitances have a shorter service life at high temperatures
- With a range of 2.2 - 33,000uF, the 10uF is at the lower end of the service life
- The low load on these capacitors (only in the signal path, very low voltage) further reduces the service life at high temperatures
Under certain circumstances, these 4 coupling capacitors could then fail exactly after 1500 - 3000 hours of continuous operation.

If you have a defective PA5 and the corresponding possibilities, you could even measure it with a multimeter. 1,000 KHz tone at the input and measure this at the potentiometer and output coupling capacitor on the underside of the board.
Alternatively, 4 new capacitors could simply be soldered in parallel on the underside. if the PA5 then works again... However, then the guarantee is probably gone.

As I said, only one possibility or approach.
Another would reside in the D-01 Black Box.

How hot do these units get? 85 is really getting up there and it would be ouch to touch… correct me if I’m wrong but I haven’t read that these units are hot like that

 

[tiago.trindade]

220612

Do you know what the number scheme means?

Since all of them end with “12”, I also assume the first two are the year and the next two are the month of production

 

[restorer-john]

After 30 years of experience with such problems in industry and high-availability IT technology, I can assure you that exactly such problems occur, especially when companies are not familiar with such problems.

Don't make the mistake of extrapolating your experience with high frequency buck/smps capacitors on computer cards/motherboards to low level coupling in audio circuits.

You are barking up the wrong tree.

 

[iLoveCats]

I guess, at this case cables do work as antenna as far as DAC low output impedance doesn't shunt cables. Have you tried to detect noise hiss changing with PA5 volume reducing?

When I got home from work the channel was completely dead. Also I had some connections backwards so it was in fact the left channel. I also noticed the amp was cool to the touch when it's been warm since I bought it in February.

 

[restorer-john]

When I got home from work the channel was completely dead. Also I had some connections backwards so it was in fact the left channel. I also noticed the amp was cool to the touch when it's been warm since I bought it in February.

Another one, oh dear.

Push for a refund as it's only eight months old.

 

[xenvre]

Just joined the party. Bought it May 30th and after few months today I started hearing pops and wind-like sound from the left channel. It is independent of the volume knob. Still working nicely when playing music though, but it's there - on the other hand the right channel is totally silent when not playing music.

I have two years warranty from my local dealer PlayStereo. Hope they will help me sort out the problem.

 

[gamerpaddy]

Mine just got hit,
loud pop on right channel after playing for a hour, and now its noticeably quieter.
serialnumber# 2111126187
bought 9th of march, but used on ebay.
since i dont have any warranty, its gotta be a troubleshooting session yay

so, first measurements..
where as the left channel has a Vpp of 15.8VAC @ 440hz (L- 7.9V, L+, 7.9V roughly)
right channel is way quieter at 2Vpp where as R+ has 2V, R- has 0V.
first guess: tpa35xx dead, gonna investigate further. maybe even a depotting of the myterious module.

see pa5 thread for teardown of the potted module.

 

[iLoveCats]

Mine just got hit,
loud pop on right channel after playing for a hour, and now its noticeably quieter.
serialnumber# 2111126187
bought 9th of march, but used on ebay.

Funny enough I plugged mine back in and it now turns on/off with a loud pop and on input 1 the left channel works again but is quiet and distorted. If I swap the cables over to input two its the right channel that's quiet and distorted. . Either way it's still broken, just behavior I wasn't expecting after it had been unplugged for a couple days.

 

[Roland68]

Funny enough I plugged mine back in and it now turns on/off with a loud pop and on input 1 the left channel works again but is quiet and distorted. If I swap the cables over to input two its the right channel that's quiet and distorted. . Either way it's still broken, just behavior I wasn't expecting after it had been unplugged for a couple days.

This is a very uncommon error.
Could you please test whether the two inputs match the loudspeaker outputs?
Just plug in the right channel alternately on both inputs. Then the right speaker should be loud and clear on one input and quiet and distorted on the other input.

 

[Peter Chuang]

Hello, I have my failure PA5 fixed and returned from TOPPING. It works fine now and I found the enclosure is cooler than where it was. Does anyone know how TOPPING repaired the failure? is switching frequency reduced to mitigate thermal issue?

 

[wlgreg]

Hello, I have my failure PA5 fixed and returned from TOPPING. It works fine now and I found the enclosure is cooler than where it was. Does anyone know how TOPPING repaired the failure? is switching frequency reduced to mitigate thermal issue?

I would be very curious to know if a “fixed” PA5 tests differently from the one which forms the basis of Amir’s glowing review. Does the “fix” change/reduce any of the stellar scores that encouraged so many people to buy the unit in the first place?

It’s like the ship of Theseus thought experiment…how many pieces can you change/swap before it’s not the original PA5 anymore?

 

[norcalscott]

I would be very curious to know if a “fixed” PA5 tests differently from the one which forms the basis of Amir’s glowing review. Does the “fix” change/reduce any of the stellar scores that encouraged so many people to buy the unit in the first place?

It’s like the ship of Theseus thought experiment…how many pieces can you change/swap before it’s not the original PA5 anymore?

I am highly interested in this myself. In my opinion, it would be high priority to re-do these tests on a "repaired" unit to see how it is impacted. No doubt, new units will also eventually have (or maybe already have) this fix, so this could be a deciding factor to many folks' decision to purchase one based on the initial review here.

 

[restorer-john]

see pa5 thread for teardown of the potted module.

where is that?

 

[MAB]

where is that?

Topping PA5 Review (Amplifier)

how loud will pa5 drive the hifiman susvara, the actual sensitivity is 79 db/ unknown 1 vrms or not Here is the Susvara's sensitivity and efficiency as claimed by Hifiman and measured by 3rd parties: The PA5 can output at least 26Vrms into 60Ω. That's 92dB + 20*log10(26) = 120.3dB SPL , which...

www.audiosciencereview.com

 

[restorer-john]

You know, potted modules have always been a source of unreliability since forever. Silly manufacturers are still trying it in 2022 at the expense of their customers.

 

[Roland68]

You know, potted modules have always been a source of unreliability since forever. Silly manufacturers are still trying it in 2022 at the expense of their customers.

Only if you can't.
In industry, encapsulated electronics modules (to protect against environmental conditions, oil, dust, fine metal and graphite dust, ozone, underwater, marine use, etc.) run for many years and decades, even at high power.
However, you need a lot of experience for this, or you have to buy them.

But since the above reasons do not apply, the encapsulation is pointless.

 

[restorer-john]

Only if you can't.
In industry, encapsulated electronics modules (to protect against environmental conditions, oil, dust, fine metal and graphite dust, ozone, underwater, marine use, etc.) run for many years and decades, even at high power.
However, you need a lot of experience for this, or you have to buy them.

But since the above reasons do not apply, the encapsulation is pointless.

In the case of Topping, it was clearly done to slow down their compratiots cloning whatever 'breakthrough' they think they made.

Pretty much all the troublesome potted modules in HiFi were created for the same reason. Audio Research did it and caused a ton of trouble. Sony did it, as did Yamaha and some UK manufacturers. A lot of TOTL gear went to landfill due to potted bespoke and unavailable modules. Even smaller Japanese brands made hybrid potted modules in their amplifiers in the 1970s which failed en masse.

 

[Doodski]

In the case of Topping, it was clearly done to slow down their compratiots cloning whatever 'breakthrough' they think they made.

Pretty much all the troublesome potted modules in HiFi were created for the same reason. Audio Research did it and caused a ton of trouble. Sony did it, as did Yamaha and some UK manufacturers. A lot of TOTL gear went to landfill due to potted bespoke and unavailable modules. Even smaller Japanese brands made hybrid potted modules in their amplifiers in the 1970s which failed en masse.

I've been there too. Lots of proprietary potting going on for some. A repair shop just doesn't have the time to break-down a potted or encapsulated module. Sometimes only to result in parts with scraped off identification. Those AR modules where a pain in the butt and there was a huge risk of damaging one when powering up a not exactly 100% repaired amp. I replaced dozens of the Clarion volume-pre circuitry potted homebrew ICs. It was a pain because they where slow on parts and customers where calling and consuming time. Before that it was satellite TV reception electronics that was poured over with stuff that covered the PCB and hardened. It's a near replace the unit situation due to module replacement expense too.

 

[Roland68]

In the case of Topping, it was clearly done to slow down their compratiots cloning whatever 'breakthrough' they think they made.

Pretty much all the troublesome potted modules in HiFi were created for the same reason. Audio Research did it and caused a ton of trouble. Sony did it, as did Yamaha and some UK manufacturers. A lot of TOTL gear went to landfill due to potted bespoke and unavailable modules. Even smaller Japanese brands made hybrid potted modules in their amplifiers in the 1970s which failed en masse.

I've been there too. Lots of proprietary potting going on for some. A repair shop just doesn't have the time to break-down a potted or encapsulated module. Sometimes only to result in parts with scraped off identification. Those AR modules where a pain in the butt and there was a huge risk of damaging one when powering up a not exactly 100% repaired amp. I replaced dozens of the Clarion volume-pre circuitry potted homebrew ICs. It was a pain because they where slow on parts and customers where calling and consuming time. Before that it was satellite TV reception electronics that was poured over with stuff that covered the PCB and hardened. It's a near replace the unit situation due to module replacement expense too.

I wrote something about this in the other thread.
https://www.audiosciencereview.com/...pping-pa5-review-amplifier.28512/post-1354044

But you are doing yourself absolutely no favours.

1. Do you have the next complaint disaster that generates high costs on both sides (shipping, replacement, repair, etc.) and leads to a considerable loss of use for the customer.
2. They further weaken brand reputation and trust. Mainly because of their current behavior.
3. It also doesn't protect the circuit design. Your competitors can get to it without any problems.
4. Your interested fans, who have often provided you with technical support, alienate you.

Unfortunately, I used to have several times with these devices, it was just crap. All of these companies have lost customers as a result and many workshops have refused to accept such devices.
But all the good circuits were copied anyway.