Topping PA5 Review (Amplifier)

[wjp007]

View attachment 180045

I hear you but look at the block diagram. That doesn't show any kind of differential input stage.

 

[NTK]

I hear you but look at the block diagram. That doesn't show any kind of differential input stage.

Differential means that the signal is not ground referenced. To quote Bruno Putzeys ...

 

[Katji]

It's Wilsonite Madagascar laminate.

wow. It sounds like Formica, high pressure paper laminate but I suppose it's more like vinyl wrap?
Did you make the stands too?

 

[antcollinet]

I hear you but look at the block diagram. That doesn't show any kind of differential input stage.

Block diagrams are not circuit diagrams.

For example, they don't show how the circuits are reconfigured based on the mode input pins for 4xse, 2xbtl differential, or 1x differential pbtl


EDIT - it is even possible the differential summing is done in the PWM domain.

EDIT some more - also the 3255 is not the only device in this amp. It is highly likely (especially based on circuits I've seen on post filter feedback) that Topping have implemented an external differential input stage for the amp.

 

[anotherhobby]

wow. It sounds like Formica, high pressure paper laminate but I suppose it's more like vinyl wrap?
Did you make the stands too?

Thanks! Yes, Wilsonite is basically exactly like Formica (not like vinyl wrap). Most patterns would look a lot better on a counter top than on some speakers, but this one happens to look pretty damn good on my subs.

The stands are just a set of legs I got here and bolted to the cabinets. I made this thread about the build.

 

[tvrgeek]

I don't think there is any roll-off in the highs when driving it single-ended. If all this speculation is correct, it would be similar to the linked Magnius review in that the distortion would be much higher because the distortion cancellation of the balanced circuit would not occur. Perhaps John Yang may comment on this at some point.

All this cancelation is ONLY if there is common mode noise to be rejected. ONLY. Balancing a differential input is actually very hard. I might refer you to the Self and Cordell books on the subject as well as the Jensen transformer site for facts, not assumptions. BTY, using balanced connectors does not prevent a ground loop in all cases.

Roll-off is usually caused by insufficient current to the next stage.

Oh yea, all consumer gear is not floating ground. Bad assumption on Hypex's part.

 

[bartgign]

Hello guys

Any advices for a good DAC with this power amp ?

With :

Bluetooth
Balanced
Good ASR Review

Thanks !

 

[daftcombo]

All this cancelation is ONLY if there is common mode noise to be rejected. ONLY. Balancing a differential input is actually very hard. I might refer you to the Self and Cordell books on the subject as well as the Jensen transformer site for facts, not assumptions. BTY, using balanced connectors does not prevent a ground loop in all cases.

Roll-off is usually caused by insufficient current to the next stage.

Oh yea, all consumer gear is not floating ground. Bad assumption on Hypex's part.

What could explain the (subjective?) difference he hears between the MOTU & the Audient then? Impedance output differ perhaps?

 

[Drengur]

Any advices for a good DAC with this power amp ?

With :

Bluetooth
Balanced

Depends on the price you would like to pay. SMSL SU-9 would be a good candidate if you'd like to spend a bit. If I'd need Bluetooth I would probably go for the Topping E50 + BC3.

 

[AudioArchitech]

I would look at the SMSL DO200 DAC

 

[Jukka]

Tweeters only use a few watts so it going to work fine.

The dashboard SINAD for 10 kHz for this amp would be around 95 dB. Better than average, but not as good as for mid range.

 

[Matias]

The dashboard SINAD for 10 kHz for this amp would be around 95 dB. Better than average, but not as good as for mid range.

2nd harmonic at 20 kHz would be inaudible because of Fletcher-Munson curves.
That is why 1kHz main tone and its harmonics is more used: it is right where our perception is more sensitive.

 

[pma]

And again you do not consider intermodulations.

 

[Matias]

And again you do not consider intermodulations.

And again you don't consider that musical content is -40 dB at 20kHz and somewhat higher at 10 kHz. Let's see those IMD charts with those levels and then we can conclude something practical.

 

[Kalupaw2]

Is this amp suitable for 2x bookshelf speakers and 1 sub?

 

[tvrgeek]

It depends. Live in an apartment and are reasonable about levels. Probably. I just modeled my current Seas speakers, and the SB and CSS I may use for my next build, determined what power would exceed X-Max, and yea, it should handle what I do most of the time. I ran a 40W Creek for a week while I was refurbing my 60W MOSFET and it did OK. Now, if you expect to do live full symphony or just have to crank up AC-DC, then no unless the mains were Klipshorns. If your mains are reasonably efficient, they it just might.

 

[tvrgeek]

And again you don't consider that musical content is -40 dB at 20kHz and somewhat higher at 10 kHz. Let's see those IMD charts with those levels and then we can conclude something practical.

What is so often missed is the IM caused by harmonics exciting the tweeter breakup. It does not take much. Won't see that in am amp test into a fixed load, but we can HEAR it.

We also forget, we are not all 30 year old men in England 60 years ago.

 

[antcollinet]

And again you do not consider intermodulations.

I think the multi tone shows us everything we need for intermodulation.

 

[restorer-john]

I think the multi tone shows us everything we need for intermodulation.

It shows how the amplifier performs at 5W, with 31 tones.

 

[antcollinet]

It shows how the amplifier performs at 5W, with 31 tones.

True - but that 5W multi-tone is the equivalent of 100+W of actual music to get a 20kHz freqeuncy that high (assuming 20kHz is typically 40dB down)