Ferrum Audio ERCO Review

Ferrum ERCO



The treble section is transparent as well as dynamic and it extends well. It at the same time isn’t overly present or focused. The Hypsos and OOR combo offers a more spacious presentation and better extension.

The clarity here is good and there is enough body, detail and energy to keep things exciting. All-in-all the treble tuning is pretty safe. I don’t see anyone finding this “too hot” or “too aggressive”. If you like the more energetic and super extended (Beyer) kind of treble however, you better look elsewhere.


A balanced, transparent, clean and very musical tuning.

Sound Inputs

Very often DACs and DAC/AMP combos sound different depending the input used. For this test we’re using the Hifiman HE6SE in balanced mode and we check out the optical and coaxial input from the xDuoo X10Tii.

The optical input, compared to the USBC input, has an even higher level of clarity and transparency but the amount of overall body in the presentation is lighter. The presentation is detailed and super clear with slightly more forward vocals. The note extension with this input is very good as well. The optical input is balanced, lighter and more neutral but the timbre, extension and energy levels are increased. The mids also sound very spacious and have excellent separation. Technically this input is very high performing

The coaxial input shares the same characteristics but the big difference for me here is that you get a tad more body and impact, a slightly smoother presentation (vocals) but with a much more open, airy and wider presentation. For me personally this doesn’t always sound right, so for me it’s the USB-C input which carries my preference.

Ferrum ERCO

Sound – Headphones

For this section I used the ERCO with the USB input from my laptop with Roon. The balanced output is the one being used unless specifically mentioned.

Let’s first start with some dynamic headphones. First up is the 250Ohm Beyerdynamic DT1990 PRO which is my favourite Beyer headphone. For this headphone we’re of course using the single ended 6.35mm output. Great bass which reaches down very low. The sub rumble is lighter but it’s definitely there. The ERCO is always perfectly in control of the bass, keeping it tight with a good punch. The vocals here are a bit more to the front but they have a very natural and smooth feel to it. I really like the synergy with the ERC. The DT1990PRO makes up for the top end presence, and note extension which the ERCO somewhat is shy in. The result is a very dynamic and engaging sound with impressive layering and stereo imaging. Sure it’s a more V-shaped presentations but the combo works great together.

The Ferrum ERCO has no issue driving the 300Ohm Sennheiser HD 800 S to loud volumes but that’s not everything. The HD 800 S sounds fast and precise but it’s not the fullest in body and presence as the HD 800 S can sound with a good OTL tube amp or the Violectric DHA V590 in example. The HD 800 S here is lighter but it has excellent extension. The depth and layering are there but they’re not very present. The bass, mids end top end is very clear and transparent, but I am missing a bit of dynamism, musicality and engagement with this combo. It just doesn’t work well for me, and that mostly regarding fulness and body.

The Meze Audio Empyrean is a fuller, darker and (bass) heavier sounding headphone on its own, and as such it in theory should be a better match with the clear, transparent, and fast sounding ERCO. In reality you get a very full bass presentation which in balanced mode even might be a bit overly present for some of you. The delivery from top to bass is full, smooth, and warmer but that’s all on the Empyrean. If you like to clear/clean up and speed up the Empyrean, the ERCO is an excellent amplifier to do it with. It’s a very musical combo but it’s also very full and bass heavier, with a very soft top end. I am sure many love this typical signature, but for me it’s a bit soft, missing clarity and balance.

The TOTL Audeze LCD-5 is completely different from the Empyrean and it has a super precise, lighter and very transparent character. With the ERCO there actually is a good, neutral, amount of body and the clarity and precision is super high. The spaciousness and airiness here are exemplary and the overall energy level is high. Bass has a good punch and kick, mids are spacious and super transparent and the highs are extended and energetic. With this combo you get the most “outside of your head experience”. I’m a fan of the combo.

The Hifiman Susvara is one of the best headphones on the market but the DAC and AMP used to drive it are super important to get it right. The ERCO and Susvara combo’s performance is acceptable, but it’s not at the same level of say the Headonia 2A3 and Feliks Envy. What is mostly missing for me here is extension and precision as well as energy. The combo for my ears sounds a bit dull and there’s nothing really standing out that wins me over. So this combo is not for me. At the same time, I really like the ERCO and Hifiman HE6SE combo.

It really is about trying different combos and discovering what works for you. I found the pairings with OOR easier than with the ERCO, so it does look like the unit is a bit more complicated or “picky” in regard to headphone synergy.

Ferrum ERCO

Sound – Comparisons

Hypsos + OOR + Musician Pegasus

This exact combo is on our Recommended Buy list and that means it performs exceptionally. The OOR/Hypsos combo is technically better than the ERCO as you will have read in the article up to now.

You get a more out of your head experience, a wider and deeper soundstage with better layering and more air, as well as better note extension and precision (from bass to highs). Speed and presence wise these units perform on the same level but the OOR sounds even more organic. OOR simply is a higher end amplifier and with the Pegasus R2R DAC it really shines.

The ERCO is a very good DAC/AMP unit, but if you have the funds and don’t need an all-in-one unit or DAC, the OOR still is the one to go for as it has the best pure performance.

Burson Conductor 3XP

We’re powering the Burson Conductor 3XP with the Ferrum Hypos and the 3XP is used as DAC/AMP, with the Hifiman HE6SE as headphone in balanced mode. The 3XP is quite a bit cheaper than the ERCO.

In balanced mode there is a rather similar sound signature in regard to body and naturalism, but for me the Burson partially performs at a higher technical level. That translates in a wider and deeper sound stage, better layering and an improved sense of spaciousness. The sub rumble here is also “better” and that bass depth does give it another dimension (even if it makes the overall signature less neutral). The ERCO is more neutrally tuned, more clean and clear sounding and it has the better pace & rhythm. The Burson Conductor 3XP is softer and warmer sounding and less neutral in that regard. For what precision and detail retrieval is concerned, the ERCO performs just a bit better than the Burson.

So 3XP and ERCO are the same and yet they are different. Both units sound good and it here will depend on the sound signature you prefer. I do feel the Burson 3XP doesn’t get the market recognition it deserves.

Ferrum ERCO

Violectric DHA V590

The Violectric DHA V590 is going for the exact same price, but there’s no MQA rendering here.

I actually feel both units are very similar in balanced mode with USB as input. You from highs to lows get a good amount of body with nice impact. Bass is present but not overly so. Sound stage and spaciousness-wise I also find these units to be comparable. The big difference for me is in the presentation. Where the ERCO is faster and more neutral, the Violectric is softer, slower and warmer. The ERCO is tighter, the Vio is softer on the ears.

Again, 2 great units, very comparable in price and functions but the V590 of course has an elaborate pre amp function, a remote and 3 headphone outputs

End Words

The ERCO is a complete DAC/AMP unit. It isn’t the cheapest, but it will get you to the higher end range right away.

ERCO has a more neutral tuning, a good amount of body and presence and a very high level of musicality. At the same time, if you already have a DAC, the OOR – as an amp only – will give you an even higher/better experience in regard to technicalities.

The ERCO is easy to use, looks great and is well-built. It has all the connections you will ever need and on top of that it also “does” MQA for those who are in favor of that. The ERCO is a pretty safe choice but I do suggest to try out your favorite headphones with the unit first as it’s rather picky device.

I do wonder what Ferrum will come up with next. Maybe a DAC only to be used with their excellent, award winning OOR?

Ferrum ERCO

Page 1: Ferrum, ERCO, Design & Build Quality, Lay-out

Page 2: Specifications, Sound Intro, Sound General, Sound Balanced vs Single Ended, Sound Classics Pt1

Page 3: Sound Classics Pt2, Sound inputs, Sound headphones, Sound comparisons, Conclusion


4.2/5 - (133 votes)

Lieven is living in Europe and he's the leader of the gang. He's running Headfonia as a side project next to his full time day job in Digital Marketing & Consultancy. He's a big fan of tube amps and custom inear monitors and has published hundreds of product reviews over the years.


  • Reply April 4, 2022


    Thanks for this nice review.
    I’m highly interested, how close the ERCO will come to Oor/Hypsos, if you combine it with the Hypsos as well.

    • Reply April 6, 2022


      If Hypsos + OOR + PEgasus R2R DAC = 100, I would say Hypsos + ERCO is about 80

  • Reply April 10, 2022


    How does it compare to similar small desktop dac/amps like the Chord Hugo 2, the Mytek Brooklyn DAC+ or the transportable Fiio M17?

    • Reply April 11, 2022


      I don’t have the Mytek, sorry. Fiio M17 review is coming up soon. I’ll see if I find some time to compare it to the H2!

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