Audia Flight FLS10 integrated amplifier Measurements

Sidebar 3: Measurements

Based on the company's earlier FLS4 power amplifier, the genes of Audia Flight's FLS10 can be traced right back to the inaugural Flight 100 model, launched in 1997. In this current model, eight pairs of power transistors are deployed in bridged mode (per channel) across substantial heatsinks, supported by a huge 2kVA toroidal transformer and 144,000µF of supply capacitance. Regulation is impressively stiff, so the FLS10 not only exceeds its 200W/8 ohm rating by delivering 245Wpc into 8 ohms (23.9dBW) but then offers a +2.5dB uplift to 440Wpc into 4 ohms (23.4dBW).


Fig.1 Distortion versus time at 1kHz/10W/8 ohms for 30 minutes (1800 seconds) after initial switch on. Left channel, black trace; right channel, red trace.


Fig.2 Dynamic power output versus distortion into 8 ohms (black infill), 4 ohms (red), 2 ohms (blue), and 1 ohm (green) speaker loads, all ref. 1kHz/10ms. Maximum current is 37.2A at <1% THD.

Moreover, there's sufficient capacity in that huge PSU to sustain 265W, 500W, 885W, and a full 1385W (37.2A) into 8, 4, 2, and 1 ohm, respectively, under dynamic conditions (see fig.2). Having established its credentials as "no ordinary 200-watter," it's also worth remembering that this bridged/floating output stage should never be connected to a grounded "black" speaker terminal (Quad 'statics and some older Tannoy models spring to mind).

A passing reference is made by the brand for a limited "class-A" operation and, indeed, the FLS10 is fairly power hungry, drawing 170W from the wall at idle and consuming 700W at the rated output. The thick alloy chassis does warm up to around 100.4°F (38°C) and the black heatsinks to 113°F (45°C) after several hours, but the amplifier is sufficiently well compensated that there's barely any drift in distortion over this time (see fig.1). In practice, the right channel had some marginal advantage in all distortion versus level and frequency measurements, but the differences are not especially significant.


Fig.3 Distortion versus power output from 1W to Audia Flight's rated 200W into 8 ohms at 1kHz (left, black; right, red).


Fig.4 Distortion versus frequency at 10W into 8 ohms from 5Hz–40kHz (left infill, black; right infill, red).

Distortion is low, although typically lower at moderate 10–100W outputs (<0.001%) than at 1W into 8 ohms (0.0035%) and 200W (0.002%). Again, these are not large variations (see fig.3). There's arguably greater change in distortion versus frequency (see fig.4) from the lowest bass frequencies, where distortion is just 0.0004%/20Hz rising to 0.009% at 20kHz and 0.03% at an ultrasonic 40kHz (all at 10W into 8 ohms). This is primarily second harmonic distortion, I might add.

Other advantages of Audia Flight's circuit topology, as discussed in Rogier's review, are also realized in the usefully low 0.007 ohm output impedance (20Hz–10kHz, rising to 0.02 ohm at 20kHz and 0.19 ohm at 100kHz) and a very extended frequency response that stretches from 1Hz-100kHz with a mere –0.6dB rolloff (–0.035dB a 20kHz, all ref. 10W into 8 ohms). Any further treble loss into lower impedances, amounting to just –0.08dB at 20kHz into 2 ohm, is of academic interest only. Meanwhile, the amplifier's (near) dual-mono construction leads to a fine ~100dB channel separation through the midrange, falling to a perfectly acceptable 75dB/20kHz.

However, overall gain is a high 46.2dB (via the balanced XLR inputs)—unnecessarily so for use with contemporary 2V line sources—requiring just 196mV to raise the rated 200W into 8 ohms. So, while few users will not from the full range of the digitally governed volume control, it offers a fine 0.03dB channel balance over the top 60dB of its dynamic range. If there is a small fly in the FLS10's otherwise exceptionally load-tolerant ointment, it's that this manifests as a moderate –63dBV hum—possibly caused by switching (rectification) pulses from that huge PSU in close proximity to the audio stages.

As a result, while the A-weighted S/N ratio remains a below-average 73dB (ref. 0dBW), its spectral content is more likely to inject a subjectively pleasing warmth than an annoying hiss or buzz. In use, the grip exercised by the FLS10's low source impedance/high current output will doubtless prove its dominant feature. This Italian flagship is no shrinking violet.—Paul Miller

COMPANY INFO
Audia Flight
Via Alfio Flores 7
00053 Civitavecchia (RM)
Italy
info@fidelityimports.com
(609) 369-9240
ARTICLE CONTENTS

COMMENTS
Glotz's picture

I want this for every reason elucidated in the review, but the 63hz hum gives me pause and the fascia/design for the casework isn't my style. But whatever, everything else about it is exemplary!

The price point is lofty, but one I think meets its performance envelope communicated from the review. For it to challenge a long held reference via the Krell's proves it's pedigree for RVB (and in kind is an insightful observation for the reader).

I will have to hear this again at this year's show!

John Atkinson's picture
Glotz wrote:
I want this for every reason elucidated in the review, but the 63hz hum gives me pause . . .

It's not hum at 63Hz but hum at –63dBV, ie, 0.07% ref. 1V into 8 ohms.

John Atkinson
Technical Editor, Stereophile

Glotz's picture

I was thinking 63dB down but was distracted at work. ;)

The 3rd photo made me pause earlier as there is another smaller logic transformer over the really huge transformer underneath. That thing is monstrous! As mentioned, but what can you do with a large integrated?

It was awesome when I heard it, but a few minutes isn't really enough time. I'll hold off on strong opinions. I'm sure I'll be smiling at AXPONA...

Glotz's picture

It does remind of Calatrava's Milwaukee Art Museum, but not enough! Lol. I would have loved even more sculpting! I think for $15k a little more artistic expression is important.

georgehifi's picture

Paul:"Moreover, there's sufficient capacity in that huge PSU to sustain 265W, 500W, 885W, and a full 1385W (37.2A) into 8, 4, 2, and 1 ohm, respectively, under dynamic conditions"

(37.2A)? Peak or continuous.
The use of the word "sustain" to me says (continuous) wattage, but after that you say it's just "under dynamic conditions"(peak)???

Cheers George

kai's picture

You wouldn’t want 37 A continuously run through your speakers.
It would make them shine bright - literally.

georgehifi's picture

"You wouldn’t want 37A continuously run through your speakers.It would make them shine bright - literally."

If it's 37a peak, old NAD 3020 will do something like that

All about running out of breath into very low impedance load, + it's a bridged amp which makes it even more less tolerant of low or low epdr loads, like Class-D's can also.
Amps like Gryphon and D'Agostino won't do that as they can go to 100+ amps.

Cheers George

kai's picture

At “a full 1385W (37.2A) into … 1 ohm” there’s not much to worry about this thing running out of steam.
I have yet to see a speaker that can handle this without going into overload one way or the other.

georgehifi's picture

When Gryphon's Krell's and Dagostino's etc etc can do 100A with less 8ohm wattage, we all know know which will be the one running out of breath first.
As for the 1385w, I can get a 6000w Crown amp for just $1000!!! but it won't drive high end speakers with nasty loads like the ones above can.
Cheers George

kai's picture

There might be a little misconception:

The 37 A, or 100 A or whatever Ampere are only drawn if an amp is driving a very complex load that goes down to 1 Ohm, at full power.

37 A into 1 Ohm equals 1,369 W.
100 A into 1 Ohm equals 10,000 W.

In reality both of these powers are way high enough to melt every existing speaker’s voice coil.
But at home use the quality of the first one Watt is what counts, most speakers need less than this for normal listening.

Like having a car that can go 250 mph, then asking for one that can go 500.
In reality driving at a max. of 55 mph.

High power semiconductors BTW are slower, it’s easier to build a quality smaller amp.

georgehifi's picture

Ah that's quite a big no!
Into speakers like the the Wilson Alexia a 150w 100A Gryphon/Krell/D'Agostino etc will sound more powerful with better drive/control and dynamics into that load than a Crown that has 6000w!!! and only <30a peak.

Cheers George

Cheers George

kai's picture

The 6,000 W Crown is made to power PA systems at live music events in big halls.
It‘s intended to be used in it‘s upper power range.

Typically those amps are not suited for home use, where their fan‘s noise might blow louder than the music sounds people want to listen to.

Reducing an amp to it‘s current capabilities falls very short anyway.
Tube amps e.g. don‘t have any current capability above their nominal power.
Does this make them sound weak?

The strongest Class D Crown amp I found on a quick glance was the Crown Xti 6002.
6,000 W into 4 Ohm, mono bridged.
At a price point around 2K take 2 and you got enough power to blow the roof from your house.
Current capability BTW at least 39 A RMS, for the nominal continuous power.

Is it this one you heard?

kai's picture

If you look at the densely stuffed internals, interconnected with a dish of spaghetti (wires), you know where the advantage of a separated pre-/power-amp design lies:
This thing is close to unrepairable once any of it‘s cramped parts breaks.

Ortofan's picture

... either the E-4000 or E-5000 (along with the optional analog disc and DAC boards) from Accuphase.

https://www.accuphase.com/model/e-4000.html

https://www.accuphase.com/model/e-5000.html

If the reviewer is going to be making a comparison to a Krell class-A amp, then he should be reviewing the Pass Labs INT-250 (along with the XP-17 phono stage and one's choice of DAC).

https://www.passlabs.com/products/int-250/

https://www.theabsolutesound.com/articles/pass-labs-int-250-integrated-amplifier/

https://www.passlabs.com/products/xp-17/

https://www.theabsolutesound.com/articles/pass-laboratories-xp-17-phonostage/

unitygain's picture

I had similar concerns during the time I owned mine, but it’s a great amp. Sonically, it was exceptionally vivid and controlled while I had it – with remarkable leading edge precision, a humongous soundstage, and unflappable control (at the aruguable expense of slam) when delineating even the lowest bass registers.

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