Vinyl's continuing demise means sustained interest in passive pre-amps, as more and more of you move over to line-level-only systems. I've got nothing against passives, other than that I tire of reminding people that they are not substitutes for 'active' pre-amps unless you're using a system with short cable runs between pre-amp and power amp.
Only then can you consider this hi-fi oddity which does away with power supplies (bye-bye, noise) and whole metres of wiring and circuitry (hello, transparency). It cannot amplify; it can only attenuate what's fed into it. Passive pre-amps, therefore, are as restrictive as a learner's permit on the M25. But if you fit the bill – line-level sources and short cable runs – passives can transform your system.
The best passive pre-amps appear to have nothing inside, with even an electronics dolt like myself being able to follow the signal's path. What distinguishes the good from the bad is – almost entirely – the quality of the parts.
It explains why such stellar passives as the First Sound and the Mod Quad Line Drive cost as much as high-end active pre-amps despite the cost savings which occurs when you chuck out all the other bits. Cost-no-object sockets, source selectors and volume controls, exotic materials, expensive shielding techniques – these combine to make a shell filled with passive components something of a bargain even when the prices exceed #1000.
The biggest expenditure, the money needed to turn what is basically a stand-alone volume control into the key to the highway, is the volume control itself. This is the junction which can butcher or bless that fragile signal, and there's a world of difference between a #5 potentiometer and a stepped attenuator of the Ben Duncan variety with its #200 sticker price.
What Rothwell Electronics is attempting to do with the Rothwell Passive Pre-Amp is to offer not just a British-made passive at a sensible price, but one which does the impossible: it contains a true stepped attenuator despite a price of #199. Suspicious? So was I, because – unlike the retail prices of petrol or CDs in the USA or Japanese goods around the world – UK-made specialist hi-fi is not subsidized.
The Rothwell is tiny, a 65x220x130mm (HWD) box, nicely finished, sporting four rotary controls. It takes up little space, sits on a wooden plinth, weighs only 850g and would go unnoticed in a shop filled with Levinsons, Krells and the like. The back sports pukka gold-plated sockets for all inputs and outputs, so nothing here suggests 'cheap'. The controls deal with choosing between six inputs (one labelled phono to accept an outboard RIAA pre-amp) and choosing tape or source, with two rotaries controlling volume.
Why two? Because one stepped attenuator capable of dealing with volume control in fine enough steps would be too expensive (and probably too large) to fit in under the price ceiling. So Rothwell used a bit of lateral thinking by fitting two stepped attenuators, one dealing with coarse adjustment and the other for fine adjustment. The former offers 12 steps, the latter six, and the company's maths say that this is equivalent to a 67-way switch-plus-full-mute.
Read more about the Rothwell preamp on Page 2.
And the Rothwell does have that sonic precision and transparency
which distinguishes true attenuators from cheap pots, something I first
heard during my DIY phase a few years back. The Rothwell is
'near-invisible', truly a poor man's Line Drive and probably the best
budget pre-amp this side of the Croft Micro. But they're not directly
compatible, the Croft offering less transparency but infinitely more
practicality (and a phono section...).
As with the Audio Research LS2 reviewed elsewhere in this issue, the
'sound' is hard to describe as the Rothwell virtually disappears. Using
a by-pass from a CD player with an output control and the same make and
model of cables all 'round, I could barely detect a difference. It's
this aspect of passive pre-amps which make many users forego the luxury
of buffered tape loops and genuine gain and all sorts of other
non-essential but eminently useful extras.
But the Rothwell fails, and fails miserably on one count: in
attempting to do the impossible – a stepped attenuator passive pre at
cheapo prices – it failed to acknowledge perceived value, ergonomics
and just about every other non-sonic parameter. It's the difference
between respecting or even liking a piece of equipment and actually
being willing to live with it.
In practice, the Rothwell feels like a kit, like a poorly made toy
with its imprecise action, vague steps, audible 'clunks' when
switching, ringing metalwork and a general
this-must've-been-made-in-Poland presence which seems pathetic next to
a #99 anything from Japan or Korea. So overwhelming is the nastiness
that it undermines what is genuinely superb performance, sound so good
that you'd willingly learn to accommodate the crude level setting
I don't want to suggest that many of you will be put off by this.
British audiophiles are notorious for buying junk which is all but
unsaleable in the rest of the world because of sheer ugliness, naff
construction or whatever. In this respect the Rothwell is your basic
piece of Britkit. Its ace-in-the-whole is that it does, sonically,
everything that you'd expect of a passive pre-amp with a price tag five
What I'd suggest to Rothwell is that they write this off as a noble
experiment and admit that you can't get a stepped attenuator worth
twirling for mere pennies. Find a better attenuator – same
specification but built by people who understand fit and finish – and
relaunch the Rothwell in the exact same package but with the new
attenuator. And if the price tag says '#500' and the sound is as good
as that of the unit before me, I'd still give it five stars.