Topping PA5 Review (Amplifier)

[maty]

20hz power graph and crosstalk measurements showed otherwise. Adding more doesn't do any better especially at 38V.

Topping PA5 (TPA325X) : Is a modification worth it? ?

Hi amigos, Now that the Topping PA5 has been revealed to the public and its chip is known. I was wondering if we could start to study the amp and modify it, like the Sabaj A20A and other amp we went through) The amplifier has been reviewed and measured here : Topping PA5 Review (Amplifier) |...

www.diyaudio.com

What do you think about other cap (same uF or something more) with better Rated Ripple and less ESR? Is it a good idea a cap with less ESR with your PA5 or other class D amps?

 

[KSTR]

The lower the ESR the higher the chances a tank circuit is formed with the ceramic bybass cap right at the chip (ESL of the e-cap + C of the ceramic). Low ESR isn't always a good choice.

 

[Paco De Lucia]

Changing the caps in this product won't have any positive effect.

 

[maty]

Changing the caps in this product won't have any positive effect.

In class D amplifiers I have no idea. In class A and AB there is a difference.

 

[xrk971]

Would this difference be noticeable if playing speakers to around 60Hz and Subwoofer handling the rest?

It all depends on how loud you play, speaker sensitivity, type of speaker (reflex, sealed, TL, etc). 60Hz is needed to reach 55Hz kickdrums- where typically deepest bass reach is for most music. But having more reserves for headroom is always nice vs the amp hitting a limit. You can calculate how much charge is stored by multiplying rail voltage by capacitance. 38v x 2200uF = 84mC of charge.

On my amp with 51v rail x 4700uF x 2 = 480mC.

That’s quite a difference in how much charge can be delivered from a woofer on a hard kick drum “punch”.

Edited to fix unit error from mJ to mC. Energy stored in a capacitor is 1/2 x Charge x Voltage^2 (in Joules).

 

[Kevinfc]

I’m setting my sights on the next, higher powered version of this amp, which John alluded to earlier. I can’t wait to hear more about it in the future.

As far as the pricing discussion, I think we’re splitting hairs a bit too much around here. By all evidence it seems to be a very good offering at $349 for a 50wpc plus amp.

My only criticism (from afar, as I do not own it), is the name. PA5 sounds like a crude amplifier which would be used for addressing the public, i.e. public address, not a fine piece of equipment used for music. But I’m probably just being silly.

 

[TNT]

I’m setting my sights on the next, higher powered version of this amp, which John alluded to earlier. I can’t wait to hear more about it in the future.

As far as the pricing discussion, I think we’re splitting hairs a bit too much around here. By all evidence it seems to be a very good offering at $349 for a 50wpc plus amp.

My only criticism (from afar, as I do not own it), is the name. PA5 sounds like a crude amplifier which would be used for addressing the public, i.e. public address, not a fine piece of equipment used for music. But I’m probably just being silly.

probably -> certainly

//

 

[TheTalbotHound]

@amirm @JohnYang1997 Could either of you measure the Phase shift for the PA5, like in this graph for the Hypex NC400?

 

[pma]

On my amp with 51v rail x 4700uF x 2 = 480mJ.

480mC, not 480mJ. That’s quite a difference.

 

[maty]

Phase shift in class D amplifiers. How it affects the sound?

Two days ago I was reviewing, again, the manual of the new IcePower 1200AS2 class D module and I was struck by this graph, where the phase shift is almost 70º at 20 kHz! Hypex NC500 only says: Output coil inductance: 10 uH Effective output inductance ithis number divided by loop gain. Is it...

www.diyaudio.com

 

[Vini darko]

480mC, not 480mJ. That’s quite a difference.

What's mC ?

 

[sarumbear]

The PA5 has only a single shared 2200uF of bulk rail capacitance between the PSU and the TPA3255 chip. The value recommended by the TI reference design is two 4700uF (one on each channel). This would dramatically increase the charge reserves for deep bass transients and also improve stereo channel separation.

You say crosstalk will suffer. Why doesn’t show it in the measurements then?

 

[pma]

What's mC ?

milliCoulomb, charge unit. He confused energy with charge. His charge is 480mC, his energy is 12.2J (Joule). It is good to understand basics, it gives a potential to understand more sophisticated circuit rules.

 

[pma]

You say crosstalk will suffer. Why doesn’t show it in the measurements then?

The only quantity that might "suffer" would be power supply rail modulation by amplifier supply current. This current depends on output swing and load and the supply rail modulation will also depend on signal frequency and capacitor bank Xc impedance at the signal frequency. So the modulation ripple will be higher with smaller capacitance. Now it is about the PSRR, if it is high enough, there should be no considerable worsening of the crosstalk. This (capacitor value) is definitely not the most important design point.

 

[sarumbear]

The only quantity that might "suffer" would be power supply rail modulation by amplifier supply current. This current depends on output swing and load and the supply rail modulation will also depend on signal frequency and capacitor bank Xc impedance at the signal frequency. So the modulation ripple will be higher with smaller capacitance. Now it is about the PSRR, if it is high enough, there should be no considerable worsening of the crosstalk. This (capacitor value) is definitely not the most important design point.

Agreed. However, I’m disappointed with the posters who were striking this amplifier after reading a post presuming there’s a fault in the design. Haven’t they learned at least to be objective? Look at the figures that are disputed.

Also, the poster who thinks who found an error should show his credentials instead of just saying “in my design”.

 

[xrk971]

480mC, not 480mJ. That’s quite a difference.

Yes. My bad. Charge Q in Coulombs. Joules would be = 1/2 Q V^2.

Thanks.

 

[Vini darko]

milliCoulomb, charge unit. He confused energy with charge. His charge is 480mC, his energy is 12.2J (Joule). It is good to understand basics, it gives a potential to understand more sophisticated circuit rules.

Thanks I have some reading to do.

 

[Laserjock]

Physics is phun

 

[Holmz]

Is MFor uF not a reference to this?

 

[laudio]

I’m setting my sights on the next, higher powered version of this amp, which John alluded to earlier. I can’t wait to hear more about it in the future.

As far as the pricing discussion, I think we’re splitting hairs a bit too much around here. By all evidence it seems to be a very good offering at $349 for a 50wpc plus amp.

My only criticism (from afar, as I do not own it), is the name. PA5 sounds like a crude amplifier which would be used for addressing the public, i.e. public address, not a fine piece of equipment used for music. But I’m probably just being silly.

Ever hear of nakamichi power amps? Pa5 pa7.