Topping PA5 Review (Amplifier)

[Serg]

... where do we go from here?

More power... much more!

 

[F1308]

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.

Why there is no volume then on AHB2 ?

 

[Robbo99999]

This is not my area of knowledge, as I don't own or use any passive speakers, but that's one impressive showing from such a small and reasonably priced solution!

 

[pma]

driving the TPA32xx with custom optimized PFFB (optimized for extra low gain / higher feedback

Highly unlikely, TPA32XX has much higher distortion - check the datasheet and application notes. PFFB does not help much to this IC.

 

[abdo123]

Highly unlikely, TPA32XX has much higher distortion - check the datasheet and application notes. PFFB does not help much to this IC.

Specially with the operating voltage, i would be very tempted to run a 3255 with a higher voltage.

 

[xrk971]

Why there is no volume then on AHB2 ?

There is an image perception that a serious “power amp” does not have volume control because one uses a preamp to drive it and the preamp provides the volume control function. In the case of the AHB2 the gain is quite low and typical use would indeed require a preamp to get the levels needed to hit clipping. We are used to overall amp gains of circa 26dB to 29dB. When amps are in the teens of dB gain, they will sound “soft” unless driven be a preamp with sufficient swing and added circa 6dB to 15dB of gain.

 

[Lambda]

So what is it Gain at Max. and at what volume setting was it measured?
Also what is the output impedance vs frequency?

I don't like the design but it performs amazing.

Wonder how performance would change if measured in with bursts and not continuous sine signals.

 

[andrewjohn007]

I wonder what the atmosphere is like over at Allo right now?

 

[Sheriff1972]

Would be keen for a higher powered version. Something in a similar chassis to the 90SE DAC

 

[w1000i]

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.

Any plan for bigger one

 

[F1308]

There is an image perception that a serious “power amp” does not have volume control because one uses a preamp to drive it and the preamp provides the volume control function. In the case of the AHB2 the gain is quite low and typical use would indeed require a preamp to get the levels needed to hit clipping. We are used to overall amp gains of circa 26dB to 29dB. When amps are in the teens of dB gain, they will sound “soft” unless driven be a preamp with sufficient swing and added circa 6dB to 15dB of gain.

Thank you.

 

[JohnYang1997]

Any plan for bigger one

In the work.

 

[Deleted member 23424]

Would be keen for a higher powered version. Something in a similar chassis to the 90SE DAC

Precisely what I've been looking for for quite some time.

 

[F1308]

Any plan for bigger one

He already answered a question like yours with something like (@4 Ohms) "A 200W+ one is also going to happen not too far into the future."

 

[F1308]

In the work.

Lovely, and standing by to surely congratulate you once more.

 

[xrk971]

Highly unlikely, TPA32XX has much higher distortion - check the datasheet and application notes. PFFB does not help much to this IC.

I was able to achieve 0.00074% THD on TPA3255 at 1W using standard factory recommendations for PFFB. I would imagine that with some more optimizations, one can achieve 0.000524% at 5W. The distortion vs frequency plot measured here is a fingerprint that matches the TPA32XX with PFFB. Look at Fig 70 in the PFFB white paper from TI. 0.0015% THD spec from Topping is consistent with this plot.

 

[Labjr]

Wow! Can't wait to see what's next. More power, multi channel.

 

[Rottmannash]

Excuse my curiosity, but why so many of you refer to Amirm as Amir...?

That's his real name.

 

[xaviescacs]

Impressive. We are close to the end of this story.

 

[Sheriff1972]

In the work.

Excellent. Count me in!