Topping A900 released: insane beast

[JediJoker]

This thing looks awesome, but you only need that much power for the Mod House Tungsten. Looks like a perfect pairing though. Seems like the Tungsten is the source of this recent arms race for headphone amp power.

60Vpp (30V) is certainly enough to drive a Tungsten to beyond listenable levels. 40Vpp (20V) should be plenty for any sane person.

 

[unpluggged]

60Vpp (30V) is certainly enough to drive a Tungsten to beyond listenable levels. 40Vpp (20V)

How do you get these numbers?

The maximum output level of the A900 is about +22 dBu (9.75 VRMS) single-ended and about +28 dBu (19.46 VRMS) balanced. This is plenty, but nothing special; my ADI-2 Pro has same figures for its headphone output. And it has two of them, with independent signal paths.

 

[jkim]

How do you get these numbers?

The maximum output level of the A900 is about +22 dBu (9.75 VRMS) single-ended and about +28 dBu (19.46 VRMS) balanced. This is plenty, but nothing special; my ADI-2 Pro has same figures for its headphone output. And it has two of them, with independent signal paths.

According to Topping's specs (usually accurate) and RME's specs, the maximum phone output numbers of the A900 and the ADI-2 Pro are

• Topping A900: load 32 Ohm or up, +28.7 dBu (21.2 Vrms, 60 Vpp)
• RME ADI-2 Pro: load 150 Ohm or up, +28 dBu (19.5 Vrms, 55 Vpp)

Sure, the A900 is slightly more powerful. But I would say this is a negligible difference in practical use. If the price of the A900 is over $1k, I would definitely take the ADI-2 Pro any day and enjoy its DAC/ADC as well. No brainer, indeed.

Honestly, I hadn't know the ADI-2 Pro's headphone output is this powerful until I saw the above post. Impressive! I would never need that much power, though.

EDIT. There should be a somewhat larger difference for lower impedance loads. So, the A900 as a dedicated amp may be worth a try for someone wanting to drive extremely power-hungry planar magnetic phones. But I still think it's overpriced for its incremental output increase over the A70 Pro.

 

[NTK]

60Vpp (30V) is certainly enough to drive a Tungsten to beyond listenable levels. 40Vpp (20V) should be plenty for any sane person.

How do you get these numbers?

The maximum output level of the A900 is about +22 dBu (9.75 VRMS) single-ended and about +28 dBu (19.46 VRMS) balanced. This is plenty, but nothing special; my ADI-2 Pro has same figures for its headphone output. And it has two of them, with independent signal paths.

For sine waves, Vp (V_peak, amplitude of the sine wave) = √2 × Vrms.
And Vpp (V_peak_to_peak) = 2 Vp

Therefore, for differential output, Vpp = 2 × √2 × 19.46 = 55 V. Thus, close enough (~ -10%) to Topping's claim of Vpp of 60 V.

But I'll say publishing the max output with Vpp is very nonstandard, and IMO, for no other purpose than to mislead the less technically knowledgeable readers by specifying output capability with an unconventional expression (Vpp) that is 2.8× the standard expression (Vrms) everybody else uses.

 

[jkim]

Therefore, for differential output, Vpp = 2 × √2 × 19.46 = 55 V. Thus, close enough (~ -10%) to Topping's claim of Vpp of 60 V.

I'm not sure where the 19.46 Vrms came from. It has not been measured by a 3rd party yet. Topping's specs---750 mW @ 600 Ohm or 1500 mW @ 300 Ohm, THD+N < 0.1%---translates to 21.21 Vrms (60 Vpp), THD+N < 0.1%.

 

[NTK]

I'm not sure where the 19.46 Vrms came from. It has not been measured by a 3rd party yet. Topping's specs---750 mW @ 600 Ohm or 1500 mW @ 300 Ohm, THD+N < 0.1%---translates to 21.21 Vrms (60 Vpp), THD+N < 0.1%.

The difference between 19.46 V and 21.21 V is 0.73 dB, right at the edge of JND, which means it is unnoticeable by humans outside of the best controlled lab tests. Not a difference I'd worry about.

 

[jkim]

The difference between 19.46 V and 21.21 V is 0.73 dB, right at the edge of JND, which means it is unnoticeable by humans outside of the best controlled lab tests. Not a difference I'd worry about.

Of course, we know that's not a practically meaningful difference. I was just wondering where that number came from since we were talking about technical aspects of the amp. And because we have no reason to mistake a manufacturer's claimed spec, even 1 dB, without actually testing it.

 

[Mike123]

A current amplifier with a voltage gain of 1 would be a nice addition to this device. As for the fully balanced volume control - I built one DIY for much less money .

 

[Herbert Shooler]

I cant wait for Amir to measure this beauty, we may have a SOTA GOAT objectivists dream on our hands....and if so I will get one as a reference amp. Massive power within sky shattering specs. TOPPING = TOP KING

 

[ab2215]

Doesn't have a digital input? USB? S/PDIF? Toslink? AES/EBU? Ethernet?

well that's a deal breaker. I am out!

 

[ObjectiveSubjectivist]

well that's a deal breaker. I am out!

Its just an amplifier

 

[Roland68]

well that's a deal breaker. I am out!

Its just an amplifier

If a pure and puristic headphone amplifier had these digital inputs, I would be out too

 

[unpluggged]

For sine waves, Vp (V_peak, amplitude of the sine wave) = √2 × Vrms.
And Vpp (V_peak_to_peak) = 2 Vp

Yes. That's why I asked how they came to 60 VPP = 30 VRMS

I'm not sure where the 19.46 Vrms came from

By converting +28 dBu to volts. And the +28 dBu figure was obtained by adding specified gain to specified input sensitivity (and, perhaps, rounding it a bit to the nearest integer, I don't remember now precisely). It's all in the specs.

 

[kemmler3D]

Finally a headphone amp worthy of driving my Truthear Gate IEMs.

 

[Roland68]

Finally a headphone amp worthy of driving my Truthear Gate IEMs.

Do you mean 30 pieces in rows or parallel ;o) ?

 

[Chagall]

EDIT. There should be a somewhat larger difference for lower impedance loads. So, the A900 as a dedicated amp may be worth a try for someone wanting to drive extremely power-hungry planar magnetic phones.

That's the rub. Tungsten, Susvara, DCA Stealth, E3 and Truthear Gate apparently

But I still think it's overpriced for its incremental output increase over the A70 Pro.

Who knows, maybe this one will work for a couple of years without issues, making it infinitely better. Let's see how this comment ages...

 

[The_Fall]

Looks amazing, but missing some usability for me. There is no RCA support so it is limited as a pre-amp. And only one pre out. I do like the RCA and XLR pre out selectivity on the Pre90 -- I send one to the poser amp and one to the sub...

Does it come in black?

 

[staticV3]

Does it come in black?

Silver only

 

[majingotan]

It drove my Susvara totally fine with plenty of headroom to spare

 

[welwynnick]

Topping flexing their muscles - this is completely gratuitous and completely unnecessary, and I completely love it. I must have one .... one day....
It makes no rational sense with the L70 and A70Pro already in the range, and with noise figures that are just as good, but the extra headroom seals it.
Topping must have felt the need to make a preamp that could drive the B100 at low gain (into 4 ohms at least).
It would also be able to drive all those low-gain, low-input-impedance Hypex and Purifi amps directly, without a buffer.
The A900 generates 21.2 Vrms at 600Ω and holds it all the way down to 32Ω, and only drops 11% to 18.8V into 16Ω, which is even better load tolerance to the A70Pro (18%).
I wonder what the input impedance is? The Pre90 was anomalous at just 2kΩ , but the A70Pro was better at 20kΩ.
I agree about quoting Vpp figures instead of Vrms. Very annoying. Who does that?