Topping PA5 II Stereo Amplifier Review

[VVR]

Nice study, MAB!

I used to own minidsp 2x4hd some time ago and was surprised to hear a lot of hiss in my then active system. I didn't measure, but calculated based on S/N data what the noise was at the output of my power amps and how this translated in SPL from my 86db/2.83V speakers. It's really not difficult. I found that -90db S/N of the 2x4hd is insufficient in active system with high gain amplifiers without volume control.
Taking into account the output noise voltage and comparing it to the SPL at 2.83V of my speakers, then compensating for 2 speakers and the listening distance I came to something about 35db acoustic noise. According to Google that knows everything, this corresponds to the level of "whisper". Whisper is exactly what I was hearing. Quite annoying! I sold the 2x4hd.
My conclusion from all that was that if the volume control is at the front end its minimum S/N should be -110db. Anything else might be audible in not all but some configurations.
Of course, my current E50 + PA5II, having much better S/N than my old system, are dead silent at any volume level. With my ear in the tweeter I couldn't tell if the amp is on or not.

 

[Julf]

We need to set our sights higher, not lower.

We need ti set our sights on real, not imagined, issues.

 

[Yorkshire Mouth]

My own twopence worth.

It’s not binary.

We can decide if it’s possible to hear a difference. If the answer is no, then that’s it, job done. In that case it is indeed binary.

If the answer is yes, that’s not the end of the debate. We surely need to ask:

- Can we hear the difference in normal listening situations?
- Can we hear it with all types of material?
- This difference we hear, is it apparent all the time, often, occasionally, or very rarely?
- Is it a large difference, especially when compared to other compromises in our systems?
- How much would it cost to ‘fix’, and how does that compare with the use we could put the money to elsewhere?

So, to take one extreme, I might face a choice between two amps, which are priced at £400 and £450. The difference would be noticeable on almost everything I play, and enough to spoil my enjoyment. And I’m more than happy with the rest of my kit.

At the other extreme, the two amp are priced at £1,000 and £150, the different can only be heard on pipe organ recitals (which I never listen to), only when notes below 18hz are played (which is a tiny fraction of recordings), and is only small anyway. Meanwhile, with the difference in price I could upgrade my speakers, which I’ve auditioned and love compared to my old ones.

I’ve used extremes to demonstrate the point, but the general ethos remains. As ever, get as much performance as possible for your money from your whole set up.

 

[zxcvbnm]

Just bought a PA5II for 2 days. My yamaha rn303 died recently after 2.5 years of abuse.

So far the impression is neutral. It has no hissing or main noise and sounds so clean but the gain was insufficient with correction EQ on. So if you are planning to abuse it to arena level of loudness, it wont let you

For lightly compressed materials with DR15-19 dynamic range you might be very disappointed. For music with DR12 dynamic range and below it is loud enough to enjoy.

My setup:
DAC: Aune x1s (2Vrms RCA output)
Preamp: Topping A50 at +0dB gain
Speakers: JBL A130 (high passed from sub)
Sub: SVS SB1000 pro (my sub at -12db volume and PA5II at full volume)
Sitting distance: ~1.2m
Room volume: 30m3

Musics I used for testing:
DR15-19:
- Sibelius symphony no2 (DR15). Climatic moments in the 4th movements are way to quiet.
- Rachmaninoff symphonic dances - LSO 2012 recording (DR19). It is like you listen from the outside of the concert hall.
- Eliane Elias - Cross current (DR19). Surprisingly ok. If it has around +6dB more gain then the snare transients will get enough bite.

DR12-14:
- Rachmaninoff variation on theme of Paganini. Quiet passage volume is very close to sitting 2/3 distance in the back of a small concert hall.
- Dvorak symphony no9: same as above.
- Fleetwood Mac Rumours and Norah Jones: enough volume to happily vibing to

DR11:
Opeth - Blackwater park album (DVDA version): enough for head banging but not moshpit level.

DR9 - Pop: averaging at 75dBA in the verses, 80dBA in the chorus. I really dont need it to be any louder.

I think in the future, I should collect another old headphone amp (like the topping a50) to add the missing gain after subwoofer highpass for the PA5II. And yes, only if the PA5II could live to that time

 

[john11]

Dual mono amps may be the way to go if your system is not loud enough. there are quite a few china amps that can be run in mono, at good prices and good sound quality, perhaps buy 2 of these.
Or the ever popular hypex as an alternative, you can get the HYPEX NC252MP 250 watts output for £200 if you want to build the amp yourself, or ready built for £350

 

[bobcat11]

Dual mono amps may be the way to go if your system is not loud enough. there are quite a few china amps that can be run in mono, at good prices and good sound quality, perhaps buy 2 of these.
Or the ever popular hypex as an alternative, you can get the HYPEX NC252MP 250 watts output for £200 if you want to build the amp yourself, or ready built for £350

I just heard about Hypex amps. Ilooked for pre-built models but they are very high in Canada.

 

[grogi.giant]

I just heard about Hypex amps. Ilooked for pre-built models but they are very high in Canada.

NAD amps are also based on Hypex modules. But they aren't cheap either...

 

[john11]

If price is a problem you can very easily build your own amps using ready made circuit boards, that is a great way of getting the price down if there are worrying budget constraints.
There are loads of good quality boards on ebay, aliexpress etc I have built a ton of them and the price to performance ratio is worth considering.
There are quite a few testimonials and tutorials on this site and diyaudio concerning ready made class-d boards you can look into
My latest project is the quad 405-2 clone, sounds better than my PA5 II, the quad boards are £35 a pair and are simple to install into any enclosure
May be an option for you to consider

 

[antcollinet]

but the gain was insufficient with correction EQ on. So if you are planning to abuse it to arena level of loudness, it wont let you

Well you are driving it from a source that can't reach the voltage the amp needs for full power. So this is not a surprise.


Source it from a balanced output capable of 4V, and there will be much less of a problem.

 

[villason]

Can anyone tell me if this is connected to mains ground? I have terrible noise if the ground is connected to -V as in many amps.

 

[grogi.giant]

Can anyone tell me if this is connected to mains ground? I have terrible noise if the ground is connected to -V as in many amps.

View attachment 352644

This should be completely isolated from the mains and not grounded.

 

[TheLastGerman]

The fully insulated power supply unit has a two-pole euro plug, so there is no mains ground connection.

 

[howard416]

Can anyone tell me if this is connected to mains ground? I have terrible noise if the ground is connected to -V as in many amps.

View attachment 352644

Even with balanced connection? Or you plan to use it with SE cables?

 

[epierre]

Hello,

I've changed my amps to Topping PA5 II to remove the noise. This works but that has raised some "plok" sound while playing on both of the tweeters.

I use the speakers in direct mode and I protect both tweeters with UDYN Cap QS4 47.00µF Condensateur MKP 400Vdc that I installed end of 2016. Source is a minidsp 2x4HD.

I also have the disconnection noise on the speakers I didn't have better though shenzenaudio says I shouldn't (and I didn't have before).

 

[john11]

Here's a good upgrade. Solder a 4700uf 50v nichicon kw capacitor onto the power cable as close to the amp as possible, then sit back relax and enjoy the immediate improvment in sound quality. Tested and works. Quick easy upgrade costing you pennies

 

[antcollinet]

Tested and works

Tested - wow - can we see the measurement results showing the improvements from the output of the amp?

And any measurements you've taken to verify the increased capacitance doesn't destabilise the power supply?

Thanks.

 

[Sokel]

Tested - wow - can we see the measurement results showing the improvements from the output of the amp?

And any measurements you've taken to verify the increased capacitance doesn't destabilise the power supply?

Thanks.

Destabilizing the amp is the least of the worries,I would worry destabilizing the house by fire

 

[john11]

Did this a month ago and works very well, for a quick easy cheap mod it is well worth it, and i doubt adding a little extra capacitance is going to burn the house down

 

[Julf]

Did this a month ago and works very well, for a quick easy cheap mod it is well worth it, and i doubt adding a little extra capacitance is going to burn the house down

Your doubt is noted, but I assume you haven't made any calculations to verify the effects of the capacitance? What does "works very well" mean?

 

[antcollinet]

Your doubt is noted, but I assume you haven't made any calculations to verify the effects of the capacitance? What does "works very well" mean?

Or a risk assessment on the possibility of capacitor failure and ejection of flammable electrolyte - and how that is contained by whatever enclosure the capacitor isn't in.