First a little context.
Hiroyasu Kondo was an engineer working for Sony in the early 70’s. In the mid 70’s he experimented with using silver as a conductor, formed his own company called Audio Note, and began producing silver interconnect cables. He was also rebuilding the Ortofon SPU cartridges and used some of the silver wire to wind a custom step up transformer for the SPU.
Towards the end of the 70’s he designed and built a moving coil cartridge called the Audio Note Io. Io is the name of one of Jupiter’s moons. The cartridge had a number of interesting features including the use of fine silver wire for winding the coils, a tapered titanium cantilever, Alnico magnets, massively strong brass side cheeks clamping the magnetic circuit in place, hardwood pieces fore and aft, and all internal air cavities filled with epoxy. The magnetic circuit was designed without unnecessary discontinuities in its shape such that lines of flux would run smoothly around it and the pole pieces were in turn shaped to focus that field intensely on the point where the coils were. The coils themselves only had 4 turns on each side of the coil former which kept the weight down but which gave very, very low output. (a tenth of what normally comes from an MC cartridge) Unusually too, the wires from the coils were dressed through the circular neoprene damper behind the coil former rather than flying loose to the cartridge’s output pins. This prevented the wire from influencing the movement of the coils. A custom transformer with a ratio of 1:100 was made to take the low output up to a suitable level. (normal MC transformers only need to be 1:10 or so.)
Weighing in at 18g and with very low compliance the Io needed to be used with the heavier arms of the time.
Later, Audio Note produced a lower cost, simplified version of the Io called the Soara. This shared the silver wiring & some of the key features but with an aluminium cantilever. It was also of a simpler mechanical construction with side panels that were glued on and which often fell off! It was a lovely sounding cartridge though.
Later still (mid 80’s) Audio Note also produced the Io Ltd which shared the same body and generator as the Io but featured a two part electromagnet where silver wire was wound onto the Permendur pieces (each shaped almost like a telephone handset) and taken to an additional pair of pins on the rear of the cartridge. Two extra wires ran from these pins, along the tone arm and away to a battery based power supply which fed the cartridge 1.2v at 500mA. The use of an electromagnet rather than a more normal permanent magnet is a subject in itself. Electromagnets were used in loudspeakers long before permanent magnets became the cheaper, simpler norm. Debates still rage about whether an electromagnet gives a better, more linear, magnetic field than a well designed permanent magnet in a loudspeaker. In a cartridge however, to my mind, there isn’t any doubt having listened to one. Incidentally, there are some ‘active’ pickups made and used in electric guitars. Some guitarists don’t like them as they apparently give too clean and undistorted a sound.
On Permendur.[/b] Sometimes known as Permadure, this alloy first invented in the 1920’s consists of 48% Cobalt 50% iron and sometimes 2% Vanadium. It has an extremely high saturation flux density of 2.4 Tesla which allows it to be used in the creation of very powerful, high performance magnetic circuits. It has had various audio applications usually in older speaker drivers such as the Lowther PM4A which does have a field strength of 2.4T in its magnet gap. More recently, the Japanese driver manufacturer Ale has also produced a range of staggeringly expensive compression drivers with magnets featuring Permendur. It is a very expensive material which by all accounts is difficult to machine as well. However it isn’t just the strength of the field that is important but how it behaves when a coil with a signal passing through it is induced to move by that magnetic field. It’s this characteristic of Permendur that has made it attractive to some audio designers.
Audio Note continued to produce the cartridges, wire and transformers throughout the 1980’s but, having started more serious production of electronics towards the end of that decade, sought to cease cartridge production in Japan. Perhaps it was just awkward. Perhaps the growth of CD had made them think that the demand for analogue products would decline. Peter Qvortrup, the then distributor for Europe, wanted the cartridges to remain available and did a deal with Audio Note Japan to buy the technology and designs and begin production of the cartridges in the UK. A deal was done and a couple of engineers from the UK visited Tokyo in 1988 to learn how to build the cartridges. The long process then began in the UK to find suppliers prepared to do the necessary work while some Japanese parts suppliers (cantilever/coil former assemblies) were retained. Small scale cartridge production began in the UK in the early 90’s. Cartridge production in Japan did cease. Later during the 90’s Audio Note Japan and Audio Note UK fell out in a big way with the Japanese company continuing to make their own electronics & cables under the Kondo brand name while AN UK continued with their own electronics, loudspeakers, digital products and turntables being made here. It wasn’t until 4 or 5 years ago that Kondo started to make the Io again in Japan (called the IoJ) and recently have added a lower cost version called the IoM to their line up. In doing so they made some interesting revisions to the design changing to an Aluminium body and aluminium cantilever and changing the diamond to an elliptical profile. Mr Kondo died early in 2006. A Mr Ashizawa (who worked with him for some 20 years) seems to have undertaken subsequent design duties. There is talk that Kondo may also produce the Ltd again.
I have been using one of the UK made Io1 cartridges for the past few years and have enjoyed it very much. The Io1 was almost the same as the original Io but for the use of an aluminium body. To my ears it sounded strong and organised in the same way as those Japanese made cartridges but it also retained the easy fluidity they all had and the same even handedness in dealing with all frequencies.
No Io’s ever had the lush (to my ears overblown) qualities of the more expensive examples of the Koetsu cartridges and the bass always seemed far more powerful and accurate than that you could find elsewhere. However, this year I decided that it was probably time to get the cartridge rebuilt and spoke to ANUK about it & what the options were. There was some delay as they were waiting for a new supply of cantilevers (with diamonds fitted) from Japan, but these finally arrived and their cartridge builder began working through his backlog of orders.
On Diamonds.[/b] Qvortrup used to buy diamonds from van den Hul and send them out to Japan to have them fitted to cantilevers there before Audio Note Japan received and used those assemblies. Most of the Io’s sold in Europe in the 80’s were therefore equipped with the vdH stylus. At some point Mr vdH fell out with Gyger (who made the diamonds to his spec) and that source of diamonds, I think, dried up. Gyger does still produce something similar to the vdH profile and they are used by Goldring & Ortofon amongst others. I believe the current diamonds ANUK use are sourced in Japan & are apparently more expensive & better cut/polished than the older Gyger made ones were. I don’t know much about the elliptical diamonds used on current Japanese cartridges. I imagine they too are sourced in Japan.
Of the current ANUK models the Io1 is the most accessible. Above that is something called the Io2 which has largely the same internals but a significantly heavier body made from plated gunmetal. Above that there is a model called the Io Gold which keeps the heavy body but replaces the soft iron pieces in the magnetic circuit with Permendur ones.
And finally, some way above that, there is the UK version of the Ltd. I had the option to try an Io Gold but Peter Q had been telling me about experiments they were doing with different metals for the cartridge bodies and eventually supplied the copper bodied ‘Gold’ pictured here.
The aluminium bodied Io1 I had been using was fairly heavy at 11-12g but the copper bodied one was significantly heavier at 18g and was beyond the range that my SME arm will cater for. SME do make a heavier counterweight for such situations & I shall have to order one of these but in the meantime I used the bridge part of the arm (removed some time ago) as an additional counterweight which allowed me to set a tracking force of around 2g.
The solid silver pins on the back of the new cartridge also gave a slight problem. They are made from 1mm diameter silver so all of the headshell tags needed to be carefully crimped down to give a snug fit on these pins. ANUK did look at obtaining some larger diameter silver for the purpose but would have had to buy 25Kg worth which might have kept them in cartridge pins for the next 100 years or so!
The arm is wired with AN silver wire internally & externally and connects to a pair of the old Audio Note Japan S6 transformers in a separate box. ANV cable then connects this to the home made phono stage I use.
All of the Io cartridges will need a step up transformer. It is nigh on impossible to make a good sounding and quiet enough active stage to take 0.05mV and boost it to MM level (5mV). Kondo make a transformer called the SFz which is suitable and extremely good. ANUK also makes a number of different transformers which can be used with the Io. These vary in ambition both in terms of the wire, core materials used and price. At the top of the range there is a model called the S8 which I’d like to hear but haven’t yet.
Describing the sound of an Io is not easy. The cartridges are extremely dynamic, they capture timbre and tone like nothing else and somehow allow the emotion in the music to be communicated more effectively than any other cartridge I’ve listened to. The bass performance is also immensely powerful & well resolved. I’m sure the mechanical integrity of the design plays a large part in this. There is nothing that can rattle, buzz or vibrate that shouldn’t. There are no air pockets or flimsy body panels. What you get seems to be what is on the record, in full, with nothing added or lost. Their other strength is a subjective reduction in distortion in comparison with other cartridges. There’s less sense of a mechanical process taking place. The music can swell and decay effortlessly in the way that it does when heard live. Complex recordings don’t become congested or muddled.
As I said earlier I had been using the Io1 for several years (itself a testament to the quality of the diamond used) The new cartridge retains all of these qualities but adds to the refinement quite considerably. Dynamic sweeps become still more effortless, low level detail is more readily apparent, distortion is reduced further. This is the shortcoming of describing the sound of something with reference to something else. My own personal reference with regard to cartridges is the Io Ltd. I haven’t heard one properly for a number of years but I have a very strong mental impression of its performance. The new cartridge triggered some very pleasant and almost forgotten reminders of how the Ltd sounds. The Io1 never did that. I suspect that the Permendur used plays a big part here and has a very definite effect on the behaviour of the magnetic circuit. I feel the Io Gold is a fair way along the road towards that ultimate level if still someway short. Having said that, this is still the best cartridge I’ve listened to at home bar an Io ltd. It is a very significant step up from an Io 1. Its difficult to say how it compares with the Japanese made cartridges. I think those too are some way advanced from the original Japanese made Io’s in terms of refinement. They too can sound fabulous. Hopefully at some point I’ll get the chance to compare this British made take on the design with a current Japanese one although, for me, it’s rather immaterial as I could never justify the cost of going Japanese! I believe you can listen to the UK made Io’s at Noteworthy Audio (in England) or at Kevin Galloway’s place (in Scotland) the Japanese made cartridges can be heard at Definitive in Nottingham.
There it is. If you have a good quality turntable, a sizeable record collection and can justify the outlay you owe it to yourself to consider an Io. The UK made Io1 is a fine place to start while the UK made Io Gold and the Japanese cartridges are pretty much as good as it gets imho.
Then there is the Ltd. Still on another level altogether. Maybe next time!