Topping PA5 Review (Amplifier)

[q3cpma]

Very nice! Especially when you consider its target use (where "lack" of power doesn't matter as much and reachable volume control is a must). Now, I just want to see what the generalist version will look like (integrated main, no volume control, moar power).

Kudos to Topping for pushing balanced interconnections into the stone age world of Hi-Fi.

 

[vitalii427]

How about some D30Pro love Topping? XLR and double the output. Double the height if needed to fit in that power supply

@JohnYang1997, thanks for great product!

I agree with @D700 about D30Pro. XLR (4V sensitivity), without volume knob, internal ps and some case to match D30Pro would be great! I’ll take two blindly. This power output is more than enough for my 4367, but for this price I’ll go bi-amp

 

[Georgrig]

The pa3s is keeping the rack warm until pa5 arrives.

Don't want to be rude, but... the pointy feet should touch the desk, no?

 

[Frank Sol]

Should I sell the VTV Purifi Eigentakt ?

 

[Klint]

As you need it. Max. gain is 19.1dB.

Thanks, so i can put the volume at max and from pre amp choose how loud to listen.?

 

[tabby]

Thanks, so i can put the volume at max and from pre amp choose how loud to listen.?

Yes

 

[Eggs Ackley]

Don't want to be rude, but... the pointy feet should touch the desk, no?

More stable this way, doesn't slide.

 

[Gorgonzola]

Should I sell the VTV Purifi Eigentakt ?

The PA5 is a great, class-leading achievement. But I won't be selling my VTV Purifi, (which is stereo with VTV buffers). The PA5's SINAD is great but not as stunningly low as the Purifi (with the Eval-1 buffer anyway). Personally I'd be happier not see the higher-order spike in the PA5, albeit they are likely inaudible.

Probably the PA5 actually has enough power for me, but don't see the extra juice as doing any harm. In my case the money is spent so the price differential is irrelevant.

Topping sees to like the small form factor which might explain the external power supply, (though maybe it reduces noise too). I would like them to do some thing closer standard format, say even 17"/430mm wide, with internal supply.

 

[Vini darko]

Quick question. How long is the power cable on both sides of the power brick? @JohnYang1997

 

[frogmeat69]

More stable this way, doesn't slide.

I have a small leather mouse pad I keep the rack on, protects the glass top on my desk, and the rack doesn't slide.

 

[Walter]

Thanks, so i can put the volume at max and from pre amp choose how loud to listen.?

One technique that is often used is to set the volume on the preamp to max with the amp turned down low, then raise the volume on the amp to slightly more than the loudest you can ever imagine wanting it to go. You then leave the amp volume at that position and adjust from the preamp from then on.

 

[Koeitje]

This is impressive, excellent performance for an excellent price. Hope Topping can push the same tech in higher powered options.

 

[maxxevv]

My wife has been bugging me to get rid of the "ugly" component rack and I keep telling her it is needed.

Now, with CDs and BluRays ripped to hard drives, Roon, and DACs plus the mini components the size of books, I can hide everything behind the chair. Or maybe somebody is making a mini component rack?

They actually do, it has been available for a number of years !

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[antcollinet]

One technique that is often used is to set the volume on the preamp to max with the amp turned down low, then raise the volume on the amp to slightly more than the loudest you can ever imagine wanting it to go. You then leave the amp volume at that position and adjust from the preamp from then on.

Exactly what I do. It avoids any risk of accidentally having the DAC at max and throwing too much at the speakers. Though this is less likely to be an issue with a lower power amp such as this.

Plus - it gives you max SNR in the stages prior to the amp.

 

[Remlab]

Thank you so much Amir for the review. This is a very important project for me and I'm so glad the hard work paid off.

This is definitely an historical moment. There's no looking back. Amazing achievement. Bruno is probably scratching his head right now.

 

[ah-ra]

Exactly what I do. It avoids any risk of accidentally having the DAC at max and throwing too much at the speakers. Though this is less likely to be an issue with a lower power amp such as this.

Plus - it gives you max SNR in the stages prior to the amp.

Sorry, if it's a stupid question, but why does it give you highest SNR in this case? Could not the pre also be clipping if you (as in this case) drive it to it's max...?

 

[abdo123]

Sorry, if it's a stupid question, but why does it give you highest SNR in this case? Could not the pre also be clipping if you (as in this case) drive it to it's max...?

it does not, typically you want whatever part of your chain with the lowest SNR to be the volume control, otherwise you're just amplifying the noise and ending up with the most noise.

 

[antcollinet]

Sorry, if it's a stupid question, but why does it give you highest SNR in this case? Could not the pre also be clipping if you (as in this case) drive it to it's max...?

The components prior to the amp have a noise floor. The higher the signal is from those devices (with fixed noise) the higher the SNR is. (obviously assuming the output is not clipping - which is not noise, but distortion).

Look at it another way. The lower the gain is on the amp (reduced volume) the less the noise on the input to the the amp will be amplified.

 

[ah-ra]

The components prior to the amp have a noise floor. The higher the signal is from those devices (with fixed noise) the higher the SNR is. (obviously assuming the output is not clipping - which is not noise, but distortion).

Look at it another way. The lower the gain is on the amp (reduced volume) the less the noise on the input to the the amp will be amplified.

Okay, got it....! Thanks!

 

[xrk971]

Great design with measured performance that almost knocks the AHB2 off its throne.

My guess is that Topping is using a balanced input opamp or regular multiple opamps to achieve balanced input operation (probably OPA1642) and as driving the TPA32xx with custom optimized PFFB (optimized for extra low gain / higher feedback) as the power amp. Choice of higher Class D carrier oscillation frequency allows smaller inductors and capacitors to be used on the output filter and keeps ultrasonic noise leakage to a minimum in the audible band. The TPA32xx is capable of an extremely low noise floor, currently in the tens of microvolts with PFFB. Increasing level of negative feedback will bring the noise down even lower. TI’s factory designed PFFB white paper specifies 36v power rail, 600kHz carrier frequency, 12.75dB of gain when using TPA3251 and this gives 28.3uV noise. To drop that to 16uV requires modifying the factory PFFB settings for even higher feedback of about 1.75x more. This would make TPA3251 intrinsic PFFB gain close to only 10dB. To get 19.1dB overall gain, Topping is adding about 9dB gain in the input stage opamp, not an unreasonable request. They will probably use dual rail +/-15v supplies for the opamp to provide the high swing needed to drive a 10dB power stage to clipping at max of 68Vpp output. We will see once the insides are revealed…

The factory distortion vs frequency curve has an oddly similar shape to the measured one so this is another clue that we have a TPA32xx core with PFFB, well implemented.