COLIN WONFOR: Q-20-P preamp and Q-20 power amp test review

Neil McCauley writes:

First, here’s how the makers describe their units:


The Q-20-P complements the Q-20 power amplifier, it features MC, MM and one line input, a line-level output and a headphone output.

The Q20P is designed to be as simple as possible in order to maintain signal integrity. It is ideal for the office and student room being small and compact; whilst it is designed to match the Q20 Power Amplifier it can be used as a stand-alone headphone amplifier.

The PCB tracking is designed to shield all signals and to keep the track mass identical between the channels, this will reduce timing and phase errors providing the listener with the best musical image possible.

The Phono (Vinyl) inputs provided are for Moving Coil and Moving Magnet cartridges. Allowing both types to be connected at the same time provides the user with the ability to select which cartridge / turntable combination is best suited to play the audio source.

The Q20P uses Colin’s hallmark work for the SECA headphone amplifiers, these, like all the SECA circuits Colin has designed, use a FET driver with constant current sources for bias. There are no transformers to limit the frequency response or change the very important phase angle.

All inputs are selected using low-impedance / low-noise relays.

The Q20P has a single pre-amp output stage; this output stage use a mix of standard NFBK and FFFBK this compensates for poor cable loading and helps to provide a much more accurate reproduction of your choice of listening. This together with EWA Interconnect Cables will give a very realistic and enjoyable listening session. £960 including UK vat @ 20%

The Q-20

The Q-20 amplifier may be a lowly 20-watts however do not let that deceive you, paired with the right speakers it will surprise you. Two versions are available, one with a Volume Control (Q-20-V) and one without (Q-20).

  • The input impedance is 22KΩ.
  • Input sensitivity for full power is 1V providing 25W into 8 Ω both channels driven
  • Power Rating 25W/8Ω both channel 40W/4Ω both channels
  • Frequency Bandwidth 5Hz – 60KHz ±1dB
  • Damping factor > 100
  • Idle power less than 10W
  • The main PSU consists of a 120VA transformer and total bulk capacitance of 20,000µF @ 50V
  • £960 including UK vat @ 20%

Power amp design philosophy

Push-Pull Class A Power Amplifiers. These power amplifiers have been designed to produce the superb acoustics of a SECA (Single Ended Class A) design without the associated heat dissipation. They are Push-Pull Class A amplifiers of differing output power and ability to drive loads but they all use the same basic circuit.

Each amplifier uses a set of high-power complementary output transistors each of which is driven by its own pre-driver stage. This along with a unique current sharing technique ensures a true balanced performance.

The Q-20 Stereo has four output transistors, the M-50 Stereo has 16 and each HB-100 Mono-block has 16.

Each pre-drive section is set to run in SECA mode with all of them driven by a single SECA stage this being the only voltage gain stage. This allows us to use minimum feedback and thus reduce the sometimes drastic effect feedback can have on the music. The main reason for having any feedback is to keep the DC offset very low, which in turn reduces the forced positioning of the voice coils in the speaker leading to less distortion.

The drive stage is biased as a SECA with a constant current load in the same way as the SECA designs in the EW Audio range. However this stage is running only at 1W thus the heat dissipation is minimal, this works so well the amplifier runs cool or just warm under normal use.

The damping factor is unusual in that it increases as the load is increased. This is due to the unique bias technology where the output impedance decreases as the current demand is increased.


A warning

These are small units. Not Toshiba Aurex small, but small nonetheless. One might initially be forgiven for, on first having sight of them, think these are designed for a bedroom / second system. This would be wrong. Make no mistake; in combination these are an audiophile iron fist in a velvet glove. Bruce Lee rather than Sylvester Stallone.

Frankly, impossible

As you can see from what the makers say, and is typical of EWA, no bombastic statements and no hype. They prefer self-effacing objectivity. We like that.

Before getting to the crucial how-does-it-sound section (in a word, outstanding) I should explain some of my own preferences and how to be entirely and consistently objective – by which I mean remain completely and consistently uninfluenced by the nature and personality of the designer, their publically stated philosophies and past exposure to their other designs – is, frankly, impossible.

People that tell you otherwise probably lie about other things too.

For example, you’ll find other of my reviews of EWA products. They were all positive and, consequently, I had high expectations that this all new pre/power – their entry level – would, at the very least, be satisfactory. That said, I have never met Colin. So no direct influence there.

Our reviews are based on what we and our guests hear. Or put differently, we focus on the musical ability of the items being reviewed and specifications are only of marginal interest.

HP knows Colin rather well and here’s what he has to say on the matter.

Colin is disarmingly and, sometimes, alarmingly honest. Possibly too honest for this (behind the scenes) occasionally vicious industry. Yet despite all the health and commercial setbacks he remains upbeat, humorous, charming, inventive and remains one of the industry’s true gentlemen.’

Preferring British amplification to, well, almost anything – in most cases

In addition to EWA designs and Colin Wonfor’s solo design fingerprints for > 30 years I must confess to a liking for the sonic outcomes from quite a few other British designers.

The designers listed below produce musical sounds that HP and I very much like. These two lists are illustrative rather than exhaustive.

These include bass agility, bass definition and tautness, transparent midrange, the ability to sound detailed at low volumes, a feeling of unrestricted dynamic range, sweet treble and so on. I have no observations to make regarding their perceived technical competences because I don’t have the type of knowledge necessary to do so meaningfully.

My list includes in no particular order:

  • Time de Paravachini
  • John Edward Sugden
  • Some of the Rega amplification designs
  • Occasionally Naim designs
  • Mike Creek
  • Harold Leak
  • Colin of course and others.

HP’s list includes in no particular order

  • Chris Bryant (XTC and Orelle)
  • Richard Dunn (NVA)
  • Stan Curtis
  • Bob Stuart ( the older Meridian stuff)
  • Dr. Richard Bews + Prof. MJ Hawksford of LFD Audio.
  • Colin Wonfor.

All different to each other in personality, route-to-market and so on - yet seemingly - all pointing generally in the same direction.

I share with HP the need for sonic characteristics that keep me engaged rather than impressed. By and large, he and I agree that all of the above designers are producing products which historically and currently keep us engaged ….. which, we hope you'll agree is a reasonable start.

Anyway, I was already – to some extent – positively prejudiced towards a Colin Wonfor design. Better for you to know this upfront. To date no paper magazine seems even remotely interested in giving editorial space to EWA.

So, how about the US ‘house sound’ – if indeed there is one?

I asked HP about this. He said ….. “It’s not that I don’t admire the outcomes of some US designers. John Curl (Mr. Mark Levinson’s senior designer in the early days and, arguably, the designer’s designer) James Bongiorno (SAE, Sumo and much more) and others. I admire the sounds they produce greatly. But …. and it’s a big but, my perception is that in the main I’m impressed with their designs’ sheer heft, effortless dynamics, grunt, slam and all the other terms which are difficult to explain.”

“So my perception is that in the main, UK designs are agile and don’t need to be driven hard in order to engage and excite whereas the reverse is true for many but by no means all US designs.

Okay, okay – these are broad-brush exceptions but forgive me inasmuch as I’m trying to make a point here. Yes, of course there are ‘lumbering’ UK designs and highly, highly competent agile US ones. That’s it.” And, so, back to you Neil

Straight out of the packaging

Stage one was to connect these via a cheap pair of Black Rhodium interconnects (all I had immediately to hand at the time), a cheap set of LFD Audio speakers cables and my trusty XTZ CD player into a much loved and rather battered pair of JPW Minims

I just pressed ‘play’ with no idea what was in the player. Immediately and as if on steroids The Beatles ‘Drive My Car’ catapulted into life. Not sprang, but catapulted. It was like an audible slingshot – if that makes sense. It was similar, albeit to varying degrees, with every other disk played.

I started at a low volume. I was transfixed. I increased the volume. Everything, every individual nuance stayed in line with every other one. I had to remember that this is ‘merely’ a 20w power amp (8 ohms doubling into 4 ohms) .

But then again, Wonfor-watts aren’t quite like anyone else’s watts it seems.

Suffice to say I tried many other music genres through this basic set up at differing volumes BUT I remained attentive and surprised rather than 100% engaged.

And so I experimented

The cheap Black Rhodium interconnects were replaced by increasingly sophisticated / expensive LFD Audio ones. The cheaper LFD Audio speaker cables replace by their Hybrid ribbons and then latterly EWA speaker cable – these being subject to a review in the next few months.

Each change was an improvement (not always the case with less sophisticated amplification) being both audible and repeatable.

I had to keep a datum somewhere and so the XTZ cd player was a constant throughout. And then the Minim’s were replaced by HP’s beloved Vandersteen 2c Signatures. And ….. then ….. I became fully engaged.

There’s little value for you my reader in itemizing all the different tracks, characteristics at different SPLs, my room acoustics and so on. You won’t be able to replicate all these variables because, of course, you have your own variables to content with.

So far, so good in that I was and remain amazed that these modest looking, low power entry level EWA units can pack such a wallop. Apparently the power amp can deliver peaks of > 100 RMS per channel.

We subsequently found out that the pre can drive a pair of these power amps without any modification. We really, really hope to get around o this one day soon, very soon in fact.

Intrigued, HP asked Colin a few questions. You might find his answers as interesting as we do.

Q: Our readers know you pay strict attention to power supply design and construction in all your electronics. In the range of three preamps, is the PSU design common to all or are they refined in the two more sophisticated units?

A: The Q20P (small pre) we use large value reservoir capacitors of 10,000uF to reduce the ripple voltage down to a very low level, this is done because the Head Phone Amp section is a low power SECA design, to produce the best sound for your headphones. This DC voltage from the twin 10,000uF is then regulated to reduce the noise even more for the Phono and line level stages, a third and isolated PSU is also provided the control the relays this insures no click ON or OFF noise sneaks back into the audio circuits.

The M50P uses and more costly but better system with 4 4700uF Capacitors and 6 regulated power supplies for the audio sections and again a isolated relay power supply. This has a much more powerful SECA deigned head phone amp,

Q: On the entry level items you captive mains leads rather IEC plugs. What has driven this decision?

A: The M50P uses our own power cord and it is a captive type, then we can provide the best connection to the mains. The Q20P again a captive mains cord of a good design by because of cost restrictions is not our design.

Q: When developing your designs, in the lab and final voicing outside the lab, do you rely on standard mains purity or do you use mains regeneration (your design or third party) and/or mains filtering of any description?

A: This is a very interesting subject, there are many types of filter and mains regens, but since the cost of these are far to costly for most users I design and test audition without the benefits of reconstituted mains, as that would make the PSU a simply task and most likely cost less but would sound crap without the frills of a pure input source. So my argument is design it right to work if possible in every day homes and offices and not to be relied on a design that purifies the mains.

Driving other power amps

Tight schedules meant I had to hand this section over to HP. Here’s what he had to say.

LFD Audio designs have been a personal favourite for over 10 years. I owned lots. That said, being involved is a less than simple affair. Items come to the end of their limited production run without warning. The product line is frustrating. Currently the entry-level linestage (their term for a preamp) is £8,000 and no entry level power amps either other than the NLE (“A PA0 SE on steroids” says Dr. Bews) at £1,750 but a series of state-of-the-art integrateds at far less money.

The original LS1, LS2 and near legendary LS3 linestages are all long gone and very rare on the auction sites. So what is available for owners like me of the NLE, PA2M (SE) and PA3 mono power amps if we seek a comparable preamp at ‘reasonable’ money?

Believe me when I tell you I have through the years experimented with many different preamps driving legacy LFD Audio power amps - with varying degrees of success. Inevitably, given the opportunity, I had to try the diminutive and comparatively inexpensive EWA Q-20-P

I’m here as a guest of Neil’s review and so it would be impolite to hijack it so I'll keep the summary brief. The Q-20-P was very reminiscent of the LS2 albeit with on-board phono stages and at far less money too. LFD Audio linestages never have onboard phono stages! In short, with legacy and, for all I know, new LFD Audio power amps this preamp really should be on your shortlist. Neil and I am awaiting review samples of the EWA M-50-P and the HB-100-P to continue this facet of the experiment.

Appearance / casework

EWA is, I think they will agree, not boutique design when it comes to casework. Everything is tough, rigid, no loose bits and a bit agricultural. The ‘feel’ is reassuringly solid. To paraphrase their own words – the beauty is on the inside. Okay, I can accept this – mainly. Lads, a tad more wife acceptance factor might prove handy. Just a thought.

Why I only used CD

Due to a planning cock-up (entirely my fault) I was for the review period without a working turntable of sufficient quality. HP’s trusty Pink Triangle is going to Arthur at Funk Firm for an overhaul, upgrades and one of his latest arms and he’s still undecided about which Dynavector to buy.

However, Colin (via HP) has offered us a rematch of the same preamp plus a pair of these power amps in 2018 to be used for bi-amping. HP will have his deck up and running and so an addendum will be added to this review of experiences via the built-in phonostages.

HP’s two-penneth

Permit me please to use a few automotive analogies here. All the usual phrases and terms to describe home reproduced sound have devolved to clichés. I recognise that not all of you are as car-inclined as me but under the tight time frame, it might be a useful shortcut without too many compromises.

On paper, the ‘best’ car I ever owned was a BMW E31. It was mighty. 550 Nm (406 lb-ft) of torque. You could start in 4th gear and it would still surge away. 0-62mph < 5.8 seconds which is pretty good for a car > 2 tons. Beautiful looks too. But somehow I was never fully engaged. The point being though that while I respected and admired the engineering prowess there was always an air of disappointment. And it handled like a boat. So off it went. In audiophile terms, based on listening to a £0.25m system, the convenient equivalent might well be recent designs from Dan D’Agostino in terms of non-engagement. Okay so far?

Eventually I ended up with an Audi A3 1.8t sport. Nippy, tight, beautifully built, very strong in collisions and very satisfying for 12 years. However, it still didn’t quite delight. An amplifier analogy that strikes me as appropriate in the context being Accuphase. What I really wanted though was …

The visceral thrill of the original Peugeot 1.9 GTI. Now that car was truly ‘something else’. Poorly built compared to both the E31 and the Audi, yet it really didn’t matter. It was like a go-kart for roads. I never failed to step into and out of it with a big silly grin on my face. I miss it dearly. So what’s the point I’m laboring to make here?

Let’s forget just for a moment the inbuilt ambiguities underlying the concept of value. Let’s put to one side the obvious pleasure for many of us in owning a piece of equipment with the fit and finish that would make a horologist proud. The pre/power combination being reviewed here never, ever, failed to produce a grin. I felt a sense of regret when I wasn't listening via it.

To me - it is in every positive respect - the audio equivalent of the original Peugeot 1.9Gti

Neil’s conclusion

I’m tempted to say “what he says above” but that wouldn’t be adding much now would it? This entry-level combination punches so far above it’s weight as to be astonishing. I love it. I’d probably hide it away in a cupboard but that’s just a personal affectation.

If you are in the market for a pre-power combo under £3k > £4k (possibly higher, but I cannot be certain) then these must be on your shortlist.

Congratulations to everyone concerned.



EDITORIAL NOTE: The opinions expressed in the above post do not necessarily reflect those of our editorial team – just in case you wondered. Neil McCauley


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