Topping PA3s Review (Desktop Amplifier)

[Toku]

Does anyone have a channel misbalance under 1/4 volume. It seems that right channel is very slow to come up to the match volume of the left channel.

I worked around it by lowering the volume of the DAC but i was wondering if there is a way to fix this permanently?

Another thing i noticed with this amp is even when the volume knob is set to Min I can still hear the music through my speakers albeit at a very low volume. is this normal as well?

The volume pot used for Chinese products is very small, about 10mm square. It is inevitable that such a small product will have large gang errors.
I think the volume pot used in the PA3s is the same as the PA5 and LA90, but the size of the gang error is up to luck.
If it really bothers you, you have no choice but to lower the input signal and use it in an area where the gang error is small, or replace the volume pot yourself.
I bought PA3/PA3s/PA5 and they didn't have the big gang error like yours.
If it's been a while since you bought it and it's still possible to return it, there is also a way to return it as a defective product and then buy a new one.

 

[The Masked Onion]

Thanks for the reply Toku.

I think I'll hit up the local reseller in the new year since I have 2 months left on the warranty.

What would be a better way to 100% confirm this issue? Connect a multimeter to each speaker terminal and play a test tone at 1/8th volume and compare the voltages?

 

[antcollinet]

Thanks for the reply Toku.

I think I'll hit up the local reseller in the new year since I have 2 months left on the warranty.

What would be a better way to 100% confirm this issue? Connect a multimeter to each speaker terminal and play a test tone at 1/8th volume and compare the voltages?

That should do it. Make sure your test tone is at a low enough frequency for your multimeter to be able to measure it though.

Also - depending on your meter, the high frequency components from the class D switching might cause erratic results.

 

[deadwood83]

I have nothing kind to say about the quality of the pots chosen. Unknown brand (CTR?) 4-gang, 9.6x11.15mm size, 5k value. Each gang handles one side of a differential signal pair. SE is converted to differential by an OPA1656 in front of the input selection relays. Measuring one I removed-

Full Closed:
Gang 1: 4800
Gang 2: 5028
Gang 3: 4910
Gang 4: 4848

Half Open:
Gang 1: 771
Gang 2: 756
Gang 3: 749
Gang 4: 781

1/3rd Open:
Gang 1: 167
Gang 2: 155
Gang 3: 198
Gang 4: 204


They are cheap and a bit unsuited for purpose; especially near either end of the range. That full +/- 20% is on display.... but between channels.

DAC most likely controls volume in the 32-bit or 40-bit range. Since it does not function as a gain control, I would wager the pot imbalance is worse than just decreasing DAC volume at most levels. The MA12070 also likes to make a nice hiss when the signal doesn't have a ground tie before the chip. I replaced my volume pots with a 10k/1k divider made of thin film chip resistors of proper tolerance (<1%, I used 0.5%).

It's a mostly fine amp but again; assembly quality and component quality (mostly the pot) are well... not incredibly price competitive compared to 2x $35 eval boards which actually follow Infineon's EMI/EMR benchmarks on the output side. Again, the entire output filter of this device is 4x 0402 SMD diodes. Infineon recommends less than 60cm of cable length with ferrite beads as output filters. With zero filtering that is surely less but Topping will never warn you. Best measured performance was with murata beads on the filters (what the eval boards have).

Infineon is based in EU so that 0.86 USD cost per unit is likely lower with assembly in-region for all component sources (APAC / Asia PACific). The cost mention from Infineon is because an assembled module has a BOM of about $2.3USD (10k+ quantities). I will not hazard a guess at Topping's production cost because they are relatively small in the mass-market scale.

Two first-party Infineon reference modules are cheaper from Mouser but even more cost effective would be two of the Shenzhen Pillor boards available on Ali. THey are basically Infineon eval boards but with a larger form factor and larger copper pours. They use LC filtering (an L-only version is available for short wire runs). The Topping is probably the best pre-assembled MA12070 but you give up performance (likely), cost, and build quality.

All that said, the price/perf for other assembled amplifiers is also quite poor. The MA12070 just lets Infineon carry the majority of the design burden with an easy low-cost implementation using clever stuff to make up the difference. It's a very neat chip with an incredibly simple and basic layout requirement. This amp could have been much more solid with some attention to assembly/QC, 1-3 better components, and maybe a barebones output filter.

 

[JakeK]

Having done it yourself would you recommend the average person with a basic soldering iron does a DIY replacement of the volume pot in their PA3s?

 

[The Masked Onion]

Just wondering if you could just remove the pot all together and bridge each pot gang connections and turn it in to a power amp?

 

[JakeK]

Reading that again the pots don't measure well at all for an amp that measure so well otherwise. 1/3 volume with the most variance is right where I'm using it and I'm sure many others use it about there as well!

 

[deadwood83]

Yeah it's really mediocre.

That's why the first thing I did to both my PA3s amps after some metering was fixed attenuation on the input. Infineon recommends 1.8Vpp (not Vrms, but Vpp) for input signal.

The consumer will need to know if primary use will be RCA or XLR.
If RCA, then the bypass can look like:

(.447 Vrms = 1.2634Vpp).

If XLR (+4dBu = 4.910Vpp) then the voltage divider (really an impedance divider but a rough ratio is fine) needs to have a ratio of about 1:2.78 so it could look like:

But the chip can take up to 6Vpp input without issue so you can realistically just bridge In/Out and put a 10k to ground from the output if your gear never goes above 6Vpp. But a lot of stuff will happily output 6+Vpp via XLR so I just settled for 1k/10k as a middle ground and handle volume at the DAC (also I had those values on hand so.... cheap).

The PCB is a little fragile so I would only recommend removal if you have a beefyish iron, and I would just bridge all the pins with massive solder blobs and slowly work it out. A $40 USD 858D hot air clone from Amazon/Ali/Banggood will also make short work of it with less risk. HAving a hot air will also allow you to sloooooooooooooooooowly and carefully re-align the rear I/O which is most likely soldered together completely off-horizontal and likely stressing the solder joints and PCBs (both of mine were soldered off-axis). Just make sure to keep the PCB facing upright so the tiny SMD diodes don't fall off.

But you also need a looong 2mm super slim allen key to reinstall the front bezel (can be seen here).

 

[antcollinet]

Yeah it's really mediocre.

That's why the first thing I did to both my PA3s amps after some metering was fixed attenuation on the input. Infineon recommends 1.8Vpp (not Vrms, but Vpp) for input signal.

View attachment 250821

The consumer will need to know if primary use will be RCA or XLR.
If RCA, then the bypass can look like:

(.447 Vrms = 1.2634Vpp).
View attachment 250827



If XLR (+4dBu = 4.910Vpp) then the voltage divider (really an impedance divider but a rough ratio is fine) needs to have a ratio of about 1:2.78 so it could look like:
View attachment 250826


But the chip can take up to 6Vpp input without issue so you can realistically just bridge In/Out and put a 10k to ground from the output if your gear never goes above 6Vpp. But a lot of stuff will happily output 6+Vpp via XLR so I just settled for 1k/10k as a middle ground and handle volume at the DAC (also I had those values on hand so.... cheap).

The PCB is a little fragile so I would only recommend removal if you have a beefyish iron, and I would just bridge all the pins with massive solder blobs and slowly work it out. A $40 USD 858D hot air clone from Amazon/Ali/Banggood will also make short work of it with less risk. HAving a hot air will also allow you to sloooooooooooooooooowly and carefully re-align the rear I/O which is most likely soldered together completely off-horizontal and likely stressing the solder joints and PCBs (both of mine were soldered off-axis). Just make sure to keep the PCB facing upright so the tiny SMD diodes don't fall off.

View attachment 250828
But you also need a looong 2mm super slim allen key to reinstall the front bezel (can be seen here).

Surely much much easier** to put some fixed attenuation externally to the input?

** not to mention - non voiding of warranty

 

[deadwood83]

Surely much much easier** to put some fixed attenuation externally to the input?

** not to mention - non voiding of warranty

That leaves the channel imbalance of the cheap pot in place. I also wanted to see how they were assembled and if I could force them to a specific input so I wanted to open them up for some other reasons. I also wanted to see if the microcontroller was doing anything with I2C to put it in a better (for application) power mode profile since the MA12070 has 3 modes and 3 profiles which impact THD. IMO it is not expensive enough to make the hassle of chasing on warranty much of a concern for me.

 

[JakeK]

Surely much much easier** to put some fixed attenuation externally to the input?

** not to mention - non voiding of warranty

That only works if the pot will be balanced at max and you devise your attenuation to only use the amp with the volume knob at max. What sort of fixed attenuator would you use?

 

[antcollinet]

That only works if the pot will be balanced at max and you devise your attenuation to only use the amp with the volume knob at max. What sort of fixed attenuator would you use?

Sure - but most pots tend to be OK in the higher end of the range. The intent of the external attenuation to allow you to keep it there.

I'd make an attenuator out of a few resistors. I belive they can be purchase relatively inexpensively though.

 

[ilya_sy]

Guys, I'm thinking to upgrade my system with mission qx2 mk2 speakers. These are 4 ohm impedance speakers with minimal impedance 3,6 ohm. Will topping pa3s be a good matching amp in terms of technical issues or there can be some problems. Need your opinion.

 

[ModDIY]

Guys, I'm thinking to upgrade my system with mission qx2 mk2 speakers. These are 4 om impedance speakers with minimal impedance 3,6 om. Will topping pa3s be a good matching amp in terms of technical issues or there can be some problems. Need your opinion.

No problem. I have a friend who has the PA3s for almost 2 years, these speakers are 4 ohms with a minimum of 3.4 ohms. For my part, I have the Sabaj A20a 2019 ver (Infineon MA12070) and the same speakers.

 

[armaster]

I received the PA3s and have been testing it for 36 hours in a row, but I can't hear any hiss noise when I put my ears on the speakers.
SMSL AO200, DA-9, SA300, SAbaj A20a, AIYMA A07 also have a low level but can be heard clearly.
But with PA3s, I can't really hear hiss noise no matter how many times I check it.

Some posts mention that the pa3s has noise, others mention that there is no noise. With my pa3s, I can detect noise up to 50cm from the speaker if the volume level is 3/4 or more. Noise occurs if RCA input is selected. It also appears if balanced input is selected, but only if there is a cable connected to the input. if cable is not connected to balanced input, then there is no noise.

 

[Elgrosso]

I just replaced 2 hypex amps with 2xPA3s on my active system, on high mids & tweeters.
The idea was to get rid of the noise, and I didn't need much power anyway.
It works great, much less noise, and more a white noise while before it was like a hiss. I can hear it at 20/30cm but nothing once seated.

Now I need to find a solution for the low mids, that need at least 60w.
I understood it's not possible to bridge them, but I don't get why.

 

[Elgrosso]

Coming back to my post, I got rid of them. They worked fine, but they had some kind of protection (well I assume) that would lock them every power cycle.
Since I used them as power amp the volume was at max, and I believe they didn't like seeing max volume on startup so directly went into protection.
I just had to lower it, power off/on again but it was just too burdensome every time.

 

[Toku]

this is an icepower that retails $99 (classicaudioparts now sell them for $50} it outputs slightly less power than pa3s yet the whole board is like half the size of the external psu alone.
not impressed.

The model name is ICEpower 50ASX2.
TEAC in Japan still uses that module in their expensive NR-7CD and other products.

 

[Solveit]

I couldn't resist to buy one after messed with those cheap China boards wich are very good with mods but to little power.
2xMA12070 is what I needed so this was perfect and pretty cheap.
But it need proper grounding, there SMPS didn't work out for me so I took my Mean Well LRS-350-24 upped to 26V and
it went quiet with the RCA input.
I have an unbalanced to balanced board also but strangelyI have some very low "chirping" in one channel with longer speaker cable, 2,3m vs 1m to the other channel.
I have this for try out because I know the hard way it's sensitive to RF/EMI and as I understand Topping don't have any LF filters at ouput?
Anyway it sounds very good with the power I needed!

 

[ReisDaddy]

Hello, i'm new here, sorry if im in the wrong forum.
I bought used Wharfedale floor speaker and plan to buy this PA3s (Marked the image with red circle).

I read somewhere that minimum we need to power the speaker is 50%, so i think Topping PA3s is enough?
I'm just listening to music, no movie, no game, no tv. And the db is around 70-75db, not more. If more than that, my wife will sound more than 75db.

Right now im using Fozi ZK-002. Just for survival (temporary), better than nothing. While im still saving for the right amplifier.
Anybody have same situation? Thank you in advance.