The Best All-in-One DAC, Preamp and Headphone Amps

“All-in-one” is doing three separate jobs, and only one of them is hard to get wrong. Every box on this page converts digital to analog well past the point of audibility. What actually varies — enormously — is whether it can act as the volume control for the rest of your system, and whether anything other than a computer can plug into it.

If what you want is a headphone amplifier that happens to have a converter in it, you are on the wrong page and we would rather say so now: our DAC and amp combos page ranks the same category on published milliwatts into 32 and 300 ohms, which is the right axis for that question. This page ranks on the preamp job, because the queries that brought most people here — “all in one DAC preamp headphone amp”, “DAC with preamp and headphone amp” — are asking whether one chassis can replace three.

The three-job test, and where boxes fail it

A preamplifier does two things a DAC does not. It selects between sources, and it sets the level going to a power amplifier or a pair of active speakers. A DAC with a socket on the back is not a preamp; a DAC whose output level you can change is.

So the test we applied, in order:

1. Can anything besides a computer plug into it? A box with one USB input is a sound card in a nice case. A preamp needs sources.
2. Is the line output level under your control, and does the manufacturer say so in writing? Not “it has a knob” — many of these knobs only affect the headphone jack.
3. How many volts does that output make? This is the number nobody compares and it varies by nearly a factor of two across this page.
4. Is headphone power published at more than one impedance, with a distortion condition? One figure at 32 ohms tells you almost nothing.

Notice what is not on that list: the DAC chip. Two boxes here use ESS converters, one uses AKM, one uses a discrete resistor ladder, and one uses a converter whose maker will not name the part. On published distortion figures, four of the six are already an order of magnitude beyond what a room and a pair of ears can resolve. The chip is a specification, not a decision.

Criterion one: what can actually plug into it

This is where the field separates immediately, and it separates on a feature that costs almost nothing to include: an analog input.

Three of the six cannot take an analog source at all. That is fine if every source you own is digital, and disqualifying the moment you own a turntable, a cassette deck or a CD player with only analog outputs. It is the single most common way people buy the wrong box in this category: the product is called a preamp, and then the phono stage they already own has nowhere to go.

The WiiM Ultra is the outlier in the other direction — it has a phono input built in, so a turntable connects without a separate stage at all. We rank it fourth anyway, and the reason is in its own write-up below: WiiM publishes no gain figure, no RIAA accuracy and no input capacitance for that phono stage, so there is no way to judge it. Our phono preamp guide explains what those numbers do.

Criterion two: is the output actually variable?

A volume knob on the front does not mean the sockets on the back are variable. On several desktop DACs the knob controls the headphone output only, and the line output stays at a fixed level — which is correct behavior when you are feeding an integrated amplifier, and useless when you are feeding a power amplifier that has no volume control of its own.

Here is what each maker publishes, in their own words:

• Cambridge DacMagic 200M— the specification lists max output level as “2.1V rms (fixed or variable – user selectable)” unbalanced and “4.2V rms (fixed or variable – user selectable)” balanced. Both output pairs, stated in the spec table itself. That is the clearest published answer on this page.
• FiiO K9 Pro ESS— an OUTPUT switch selects HP or PRE. FiiO’s own support article states that in PRE the output moves to the rear panel and the volume knob adjusts it, and that in HP the front panel is live instead. The two are exclusive: in PRE mode the headphone sockets are silent.
• FiiO K11 R2R — PO, PRE and LO modes, switched by double-pressing the knob, each remembering its own volume. LO is the fixed line output, PRE is the variable one.
• FiiO K7 — headphone, speaker (preamp) and pure DAC modes. Pure DAC takes the volume control out of the path entirely, which is what an integrated amplifier wants.
• iFi ZEN DAC 3 — a variable/fixed switch on the rear, covering the RCA and 4.4 mm line outputs.
• WiiM Ultra — the line output level is set from the touchscreen or the app, and there is a fixed mode for feeding an amplifier with its own volume control.

All six pass this criterion, which is worth saying plainly rather than implying a failure that is not there. The differences are in how: a physical switch you can find in the dark, versus a menu, versus a phone.

Criterion three: volts, and the +6 dB trap

Output voltage is the specification that decides whether a preamp can drive a power amplifier to full output, and it is almost never compared. The published figures on this page run from 2.1 V rms to 5 V rms — and both boxes that have balanced outputs publish exactly double their unbalanced figure.

The practical consequence: if your power amplifier or your active speakers need a strong signal, the K9 Pro ESS’s 5 V and the DacMagic’s 4.2 V give you room the 2.1 V boxes do not. If they do not, extra voltage is not a feature — it just means you will run the volume control lower, which is its own problem when the volume control is in the digital domain. Our DAC versus preamp page covers that trade-off in more detail than this page has room for.

Criterion four: the headphone half, honestly

You are buying a headphone amplifier whether you use it or not, so it should at least be specified. Four of the six publish power at three impedances with a distortion condition attached. The other two do not, and that shows up in the ranking.

The DacMagic’s two published points are more informative than they look, because they are both the same voltage.

If headphones are the main event rather than a bonus, our impedance and power guide walks through what your own pair actually needs. The short version: an amplifier’s power into 32 ohms tells you very little about how it drives a 300 ohm pair, and more power is not automatically safer — a sensitive in-ear on a two-watt output lives in the first few degrees of the volume control, where channel balance and noise are at their worst.

The R2R exception, and why it is ranked fifth

The FiiO K11 R2R uses a discrete resistor ladder rather than a delta-sigma chip: four channels, 192 thin-film resistors at 0.1% tolerance. It is an unusual thing to find at this price and it is genuinely interesting engineering.

It also measures far worse, and FiiO says so. The published line-out distortion is “About 0.025%” — the word “About” is FiiO’s, not ours — against < 0.00025% for the K9 Pro ESS balanced output. That is roughly a hundredfold difference in published THD+N.

We are not going to tell you that makes it sound worse, because we have not measured or listened to either and we do not publish verdicts we have not earned. What we will say is that if the reason you are buying a converter is measured transparency, this is the one product here that trades it away deliberately, and you should know that before you buy rather than after. It stays on the page because its PRE mode, its 2.7 V line output and its published headphone power at three impedances all clear our criteria — and because a maker that publishes an unflattering number is telling you something useful about itself.

What nobody on this page publishes

Three gaps are worth naming, because they are the questions we could not answer from manufacturer documents and would not answer from anywhere else:

• Volume control implementation. Only FiiO names the part on the K9 Pro ESS (NJU72315 volume ICs). Whether the others attenuate in the digital domain — and therefore lose resolution at low settings — is not stated by anyone.
• Output impedance, on five of six.Cambridge publishes < 50 Ω unbalanced and < 100 Ω balanced. Nobody else publishes a line output impedance at all, which is the figure that decides whether a long interconnect into a low-impedance amplifier input will roll off the treble.
• The WiiM Ultra’s headphone output, in watts. WiiM publishes the amplifier chip, an SNR of 119 dB and a THD+N that degrades from −99 dB into 300 Ω to −92 dB into 32 Ω — everything except the one number a headphone buyer needs.

How we would choose

If it has to replace a preamp and you own anything analog, the FiiO K9 Pro ESS. It is the only box here that takes an analog source, publishes 5 V from a balanced pre-out, gives the volume knob to the rear panel with a physical switch, and specifies headphone power at three impedances. It is also the largest and most expensive, and that is the trade.

If it lives in a hi-fi rackand every source is digital, the DacMagic 200M. Cambridge’s specification is the most explicit about the thing that matters — both output pairs are user-selectable fixed or variable — and the build is a component rather than a desk accessory. Just do not buy it as a headphone amplifier first.

If it lives on a desk, the FiiO K7. It has the analog input the cheaper boxes lack, the pure DAC mode for feeding an integrated amplifier, and the most headphone power per dollar on the page.

If it also has to stream, the WiiM Ultra — with both caveats intact: no published headphone power, and no published specification for the phono stage that is the main reason to choose it over a cheaper streamer.

If the budget is tight, the K11 R2R for the feature set and the ladder DAC, or the ZEN DAC 3 if a single USB cable is the entire installation and you will never need a second input.