Speaker Asylum: REVIEW: ICW Capacitors ICW Polypropylene Capacitors Accessory by andy evans General speaker questions for audio and home theater.

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Model:	ICW Polypropylene Capacitors
Category:	Accessory
Suggested Retail Price:	$Varies
Description:	Ranges PW, PX, SA and COAX
Manufacturer URL:	ICW Capacitors
Manufacturer URL:	ICW Capacitors

Review by andy evans ( A ) on February 18, 2002 at 05:29:53 IP Address: 152.163.205.51

Add Your Review for the ICW Polypropylene Capacitors

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REVIEW - ICW Capacitors – PW,PX,SA and COAX series polypropylenes

ICW are a UK company based in Wrexham, and what makes their capacitors particularly interesting is their no-compromise approach to design. As long as their high end customers like B&W and Tannoy need the best possible sound for their class-leading products, ICW are more than willing to oblige by pushing frontiers just a little bit further. So as we go up their range of polypropylene capacitors, the construction becomes more and more radical.

The entry level PW range uses 4 micron film rated at a true160v, and comes with spot welded copper clad steel lead-outs. The advantage here is small size, though the thinner film inevitably means slightly looser windings and more potential for self-resonance within the capacitor. In comparison to the competition in this price range, though, this is still a very good product.

The next in the range, the PX, increases the film thickness to 6 micron's with a tighter and more controlled winding tension and hand soldered insulated copper lead-outs. The voltage rating is a comfortable 250v, but the size more than doubles in comparison to the PW.

The flagship of this range is the SA, rated at 630v. Again, the lead-outs are insulated copper, hand soldered, but the film's thickness increases to 10 microns and the foil is hand wound and subjected to extended heat treatment to optimise tightness. Together with a flatter and wide construction to keep the width of the film as thin as possible, these techniques result in improved ESR, a substantial decrease in self resonance and a reduced susceptibility to drift over time. Power handling is improved and this capacitor sounds particularly clean in hi-fi or PA applications at higher volumes. The size is large - think of a squat coffee mug for 47uF – and this in itself improves its damping qualities.

So how do these radical design departures translate into sound? Well, each design advance seems to produce the expected results. The 47uF review capacitors were tested in the first order series crossover of the Magneplanar SMGa. The PX sounded slightly better than the PW, though both have the same sonic signature – detailed, clear and clean. In the same set-up an Ansar polypropylene of the same value sounded softer and warmer with a pleasant and non-tiring sonic signature. Perhaps a good alternative? Well, the single most important parameter that starts to emerge from the ICW range is the audible advantage of a more controlled, damped construction. The slightly veiled softness in the Ansar is arguably an acceptable trade-off at the PW level. But the PX starts to cut through the fog and brings a worthwhile increase in clarity – a step up in quality.

Moving up to the SA brings more clarity again. Critical listening to voices (Der Meistersinger, Chicago SO Solti, track 9) with the SA in the system revealed a welcome absence of ‘spread’ - voices were point sources in the soundstage, smaller in size and with more air in between. This was the single most obvious difference, and once audible it became persuasive. The soundstage was more focussed – a collection of individual instruments rather than an ensemble. Another gain was a more distinct timbre to voices, so they were more easily distinguishable one from another. Also, bass was more damped and thus easier to differentiate. Once the ear became used to this more precise soundstage it became harder to return to the slightly fuzzier images of the other caps.

There is a fourth variation – the same winding with a coaxial termination option, some of which are used in the top B&W speakers. Essentially similar to the SA (the size is identical) it has two leadout wires on the bottom rather than one on each side making it handy for chassis mounting. This is the most damped capacitor in the range, and all the gains of the SA series – point source imaging, focus to voices, air between the instruments – are taken just a little further.

Blind testing with an audio designer colleague confirmed these listening impressions but added something of a paradox. He rated the SA highest as ‘clean’ and more lively than the coaxially terminated device. While admitting that this option was smoother, detailed and more laid back, he found it a touch lifeless. He also liked the lively dynamic of the PX, commenting on the ‘open midband’, ‘attack’, ‘fast bass’ and reverberant acoustic. He found the Ansar ‘smooth, somewhat soggy with looser bass’ but liked its ‘good instrumental tone’ and rated it about equal to the PW which he found ‘open, detailed but again with looser bass’. So listener taste is not an absolute, and those who like a richer more reverberant sound might be happiest with SA or even the PX. Those searching for clarity and precise focus will favour the coaxial component, and be happy with its drier acoustic.

All these caps have a family resemblance, and none are prohibitively expensive. When it comes to the SA and Coaxial level of clarity, inserting these caps into an existing product can take it a level up in quality. In crossovers, capacitors really can make that much difference, and a little money spent here brings real dividends. The difference in price (the SA is around double the 5 to 6 GBP of the PW/PX series for a 47uF value) would do absolutely nothing to worry the DIY constructor. At this price, the SA range is tremendous value – a real audio bargain.

In the lower capacitor values there is the even more radical ASMF (Audio Stud-Mounted Flatpack) range. Here we are not talking just a bit flatter and wider, we are talking FLAT – think Frisbee or discus. Designed without compromise, it delivers even less resistance due to the decreased film width - the ESR improves by as much as a factor of 10 – has less resonance due to the winding technique and large mass, and has chunky captive M8 bushes designed to be bolted onto a base or onto the lead-outs chosen. This is true industrial construction – design parameters taken to their logical conclusion. The values in this range don’t go up to 47uF so this will be the subject of a further test of coupling caps.

I’ve been very impressed with ICW caps, and look forward to using them in future projects. I’d confidently recommend trying these out – they aren’t faddish or designer items, they have all the solid virtues of intelligent design, good engineering and careful construction, and in addition the company is friendly, helpful and welcomes user feedback. What more can I say?

Andy Evans andy@artsandmedia.com

Note - I am a freelance media consultant and author and have no business connection with anybody in the HiFi industry.

http://www.icwltd.co.uk

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Product Weakness:	Manufactured in the UK and would benefit from a wider distribution network and more 'audio credibility'.
Product Strengths:	One of the market leaders, excellent sound, industrial construction, keen prices.

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Associated Equipment for this Review:
Amplifier:	Leak Stereo 20 (modified circuit)
Preamplifier (or None if Integrated):	DACT type stepped attenuator
Sources (CDP/Turntable):	CD-ROM + Chris Found V-DAC 2.5
Speakers:	Magneplanar SMGa
Cables/Interconnects:	Silver plated copper/Teflon wrap
Music Used (Genre/Selections):	Classical, Jazz, Soul
Room Size (LxWxH):	18ft x 16ft x 8ft
Room Comments/Treatments:	Usual soft furnishings
Time Period/Length of Audition:	Two months
Type of Audition/Review:	Home Audition

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