WolfX700 Measurement of Topping A90 Headphone Amp

[Veri]

Sorry I did not apply for permission to disassemble the device and publish internal photos ... I think the basic confidentiality of the prototype is reasonable ... so I did not try to do that at all.

Makes perfect sense!

 

[Yuno]

Just wondering, but isn't the fact that you need to turn the device off and on each time you switch between HP and Pre-amp a bit problematic? General idea that I have about electronics is that turning things on and off is not healthy for the device. Obviously this is not a factor normally, but if you switch between hp/pre frequently through the day, you could be turning your device on and off dozens of times a day.

Or maybe it's not really off, but more of a "mute". That would makes sense since there is a dedicated power on/off switch on the back anyways.

 

[WolfX-700]

Makes perfect sense!

I will definitely take it apart when I get the retail version

 

[Veri]

I will definitely take it apart when I get the retail version

Thanks! PS sorry to bother you, Wolf. but if you do any more measurements will you do multi-tone of A90?
I just want to compare it to

 

[WolfX-700]

Thanks! PS sorry to bother you, Wolf. but if you do any more measurements will you do multi-tone of A90?
I just want to compare it to

 

[Veri]

View attachment 53806

Looks very similar lol. As expected. Thank you very much for bearing with me, @WolfX-700 You're the man!

 

[WolfX-700]

Looks very similar lol. As expected. Thank you very much for bearing with me, @WolfX-700 You're the man!

It should be noted that Multitone performance is likely to be affected by the AP signal source

 

[JohnYang1997]

It should be noted that Multitone performance is likely to be affected by the AP signal source

The AP's dac is limiting the multitone performance. Try with some other DACs like D90, dx7pro etc. The best DAC so far for multitone is Matrix Element X as far as I know.

 

[JohnYang1997]

Oh and Bruno's Mola Mola DAC.

Also dx7pro for comparison

 

[WolfX-700]

Oh and Bruno's Mola Mola DAC.

 

[JohnYang1997]

Don't forget Soncoz/LA-QXD1/Khadas/March, all performing similarly here:

Okto Stereo DAC will probably be the best multi-tone result to date if the prototype was any indicator. Don't you think?

The top ain't 0db. The soncoz is limited by 9038q2m. Okto is also just better than -120db.

 

[Veri]

The top ain't 0db. The soncoz is limited by 9038q2m. Okto is also just better than -120db.

Ohh wow I never realised the top was not at 0db, that changes things !!
Thanks

 

[Rigel]

I was waiting for this test WolfX-700.. Thank you

Congratulations JohnYang1997 on your contribution to the design.

A question if you don't mind. Whether the headphone output is balanced or not, I would be interested to know if the processing of the two channels is totally independent in this output.
I currently have an SP200, but maybe I cheer up with the A90 to combine it with the D90 that I already have. It would be your perfect partner.

Just as a comment. I have seen so many times in good level equipment "the need" for the power supplies to be external or separated / isolated from the rest of the electronics, transformer vibrations, radiated field etc. I was struck by the excellent technical characteristics of the D90 with an internal power supply included in such a small space, transformer welded to the same motherboard, near the electronics, etc. With the A90 I am even more surprised by being SMPS. I guess the new generations of low noise voltage regulators must have a good responsibility in that.

¿To what extent does it limit or not, having an internal power supply? That is, could you have any advantage in benefits if these power supplies were outsourced?

Thank you.

 

[Veri]

A question if you don't mind. Whether the headphone output is balanced or not, I would be interested to know if the processing of the two channels is totally independent in this output.

If you mean that unlike the SP200, that the balanced is "truly" balanced instead of using the single ended output. Then yes, absolutely. it's balanced.

To what extent does it limit or not, having an internal power supply? That is, could you have any advantage in benefits if these power supplies were outsourced?

I believe the measurements speak for themselves.. @JohnYang1997 has been developing this amp and its low-noise output for a long time!!

 

[LTig]

Opamps

Of course. It's very difficult to get such a performance without opamps.

I guess maybe a brute force approach: lots of ultra low THD opamps in parallel; shares the load and decreases noise.

 

[Martin]

Thanks to @Peib for posting this photo:

Now that's a SOTA stack; it looks nice in silver.

Martin

 

[Johan Liebert]

Less power yes.

I think a small high performance desktop amp like a successor to the Topping PA3 would be interesting to a lot of people who have passive monitors for a desktop setup.

Sorta surprised that the PA3 was never measured here.

Will the A90 have a 2.5 or 4.4 mm balanced output?

 

[JohnYang1997]

I think a small high performance desktop amp like a successor to the Topping PA3 would be interesting to a lot of people who have passive monitors for a desktop setup.

Sorta surprised that the PA3 was never measured here.

Will the A90 have a 2.5 or 4.4 mm balanced output?

Plan will have 3 models of power amps. Two in the near future one in the far future. The first model is exactly what you described, a desktop amp with extremely good 5W performance.

A90 has a 4.4mm balanced out as shown in the photo. This unit is less of a prototype but a pre-production unit. Everything is essentially locked in, only few resistors or capacitors may change. What you see here is pretty much what you will get.

 

[VeerK]

Plan will have 3 models of power amps. Two in the near future one in the far future. The first model is exactly what you described, a desktop amp with extremely good 5W performance.

now this is the information I’m interested in, can you tell us anything about the other two? We definitely need lower power alternatives to the ahb2

 

[Feilong4]

Not sure if this has been asked yet, but will there be some sort of indicator for the volume knob in the production units?