Koetsu

This Koetsu Rosewood Signature cartridge (serial no. 065) was manufactured around 1992…

(The white label is a distributor’s label, not from Koetsu.)

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Below… this Koetsu Rosewood (serial no. 11756) was manufactured in the mid-1980s – I purchased this cartridge on the second-hand market in 1987.

The previous owner had a Garrott Brothers ‘Microscanner’ stylus installed onto it.

In 2002, I commissioned Melvin Ang (Koetsu S E Asia) to deliver the cartridge to Koetsu in Japan to have it re-built and upgraded to Rosewood Signature specification.  The original Rosewood body, much valued for its age, was re-used but everything else was replaced.

(The Signatures are samples selected with closer-tolerance, matched coil characteristics.)

The re-built cartridge is shown here, mounted onto a Wand tonearm…

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And below, mounted onto a TransFi Terminator linear tracking tonearm…

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Koetsu cartridges were named in honour of Honami Koetsu, a 16-17th Century Japanese calligrapher and Raku-style ceramic artist.geese_490x344

Yoshiaki Sugano began actively making Koetsu moving coil cartridges during the late 1960s, after retirement from a career mostly at Toyota Motor Co.   Sugano also pursued an interest in painting.

Following publicity from enthusiastic overseas reviewers such as The Absolute Sound magazine, demand grew rapidly, especially from the USA.  Sugano was assisted by his wife and daughter.

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No doubt informed by Sugano’s knowledge of traditional sword-making, the Koetsu moving coil cartridges place emphasis on careful material selection, ‘aging’ and fine adjustment.

For example, I understand that the magnets are Samarium-Cobalt or Platinum-alloy, the magnet-yokes high Cobalt content steel alloy,  the tension wire is Berylium.  Coil wire gauge, 6N copper and silver-clad copper, are carefully specified.  The cantilevers are solid Boron, slotted to receive a highly polished diamond stylus (around the shank of the diamond, there is a rectangular reinforcement plate, similar to a ‘tsuba’  hand-guard of a Japanese sword).   A one-piece Diamond cantilever-stylus is also available.

Every Koetsu cartridge was tested and listened to on Garrard 401 turntables (except for the Blacks which are only sample-tested)… so it would not be surprising if Koetsu cartridges sound very good on idler or rim-drive turntables.

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Sugano’s own music system consisted of a Garrard 401, with his own tonearm and a step-up transformer.  Loudspeakers were 3-way horns, together with an infinite baffle, wall-mounted bass driver, all actively driven by multiple low-wattage amplifiers (made a friend).  He regarded his system as only a ‘modest’ system.

Sugano would enjoy western classical music whilst painting, in a living room-studio with parquet-wood floor.

100_2462aSadly, Yoshiaki Sugano passed away in January 2002 in eastern Japan, at the age of 94.

Koetsu cartridges continue to be manufactured by his sons, Fumihiko Sugano and his brother.

Models

Black Goldline – Rosewood Signature – Urushi Wajima – Onyx Platinum                 ( Images from http://www.koetsusea.com )

There continues to be a range of Koetsu cartridges available… beginning from the lowest cost, metal-bodied Koetsu Black.  Then there are the wood-bodied models… the Rosewood, Rosewood Signature and several Urushi lacquered models.  There are also lower-output, Platinum-alloy magnet versions of the wood Koetsus.  The very best Koetsus are the stone-bodied models, all of which employ the Platinum magnets.

My own humble experience with Koetsu cartridges began with the Rosewood in 1987.  I was using an Audio Research SP8 ‘Mk I’ preamplifier (phono input impedance 49.9k Ohms).

Like many Koetsu users, for many years I thought that the Koetsu did not have very good tracking ability… high level, high frequency passages (eg. female voice) would occasionally distort.

It was only after much experimentation that I learned how to optimally ‘load’ a moving coil cartridge.  With proper loading on the preamp input, the ‘mis-tracking’ disappeared.  Many owners use 100 Ohms loading.  This is a good starting point.  I have found that loadings between 50 – 130 Ohms can work well, depending on your system and preferences.

On reflection, this is not surprising, as Sugano used a step-up transformer…. and assuming say 26 – 28dB transformer Gain, connected to a 47k Ohms preamp input, then the load impedance presented to the cartridge would be 117 – 75 Ohms.

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IMG_2985I currently use a vintage Fidelity Research FRT-4 Step-Up Transformer, which has switchable Gain – 31dB – 26.3dB – 25.2db – 20dB. (Shown here with loading resistors changed to Caddock TF020 – these now removed completely.)

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Another option, these above are modern Stevens and Billington Step-Up Transformers, 20dB Gain (installed into metal boxes).

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The sound:

The sound of the Koetsu Rosewood or Rosewood Signature is warm-toned, with plentiful low level, harmonic information and ‘decay’.  High frequencies, when optimally loaded, are not ‘forward’ and record surface noise is not emphasised (like many high-end cartridges tend to do).  Sound presentation is ‘big’ and ‘spacious’.  On a belt-drive turntable, the Rosewood can sound very ‘resonant’.

(More recent Rosewoods seem to have slightly more high frequency presence, a slightly more ‘neutral’ tonal balance.)

On a rim-drive turntable, the Rosewood gains some ‘leading edge’  definition to everything.  Bass is stronger but not unnaturally ‘tight’.  There is increased energy & scale, more ’empty space’ within the ‘soundstage’ and more clarity, more ‘solid’ ‘images’.

Notes:

  1. I prefer to use my Koetsu Rosewood/Signature cartridge with the alloy bottom plate removed.  This may be sacrilegious but the sound has more dynamic freedom and ‘openness’, greatly improved ‘separation’ and retrieval of information.  (There seems to be some effect on magnetic fields and/or eddy currents.)  The bottom plate seems to soft-glued in place and can be removed with (great) care, without damage.
  2. Brass mounting screws – compared to stainless steel, brass screws and nuts provide weightier bass, smoother treble extension, more ‘solid’ tone and overall more ‘sustain’.  Stainless steel sounds more ‘clean’ and ‘tight’, with a smaller, less expansive presentation.
  3. Tracking Force 1.95gm (to 1.97gm).  Melvin’s advice is spot-on here.
  4. Vertical Tracking Angle (VTA) – set by ear, together with Tracking Force, usually cartridge top-plate is near-parallel to record.

 Further reading:

  • Koetsu – Warwick Mickell, Australian Hi-Fi.
  • Koetsunami – Alvin Gold, Hi-Fi News & Record Review, Sept 1984.
  • Remembering Yoshiaki Sugano – Stig I. Bjorge, Stereophile, 27 Jan 2002.

All comments welcome!…

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18 thoughts on “Koetsu

  1. I really enjoyed your comments about Koetsu cartridges. I have just purchased a Koetsu Black goldline and I am using it with great success (I think) with an Ortofon ST80 SUT. I have been so impressed at how every record I have played so far – including many that I thought were too difficult when played with my Ortofon Kontapunkt b – now sound so alive and without (tracking) distortion. I am a British expatriate living in Jakarta and I have just returned to the UK to see friends and family and to bring back a number of records that I’d previously believed too difficult to track or disappointing. I am hoping that these will now be given a new lease of life with my Koetsu and SUT. The rest of my system is Michell Gyro SE + Techno arm a, Unison Primo amplifier and Quad 21L loudspeakers. Cheers, Simon.

    • Thank you & greetings Simon!
      The Ortofon 27dB SUT sounds ideal for your Koetsu, IMO – giving around 100 ohms cartr load.
      Nice system too – the Unison looks smart & a classic TT.
      Would be keen to hear how the cartr ‘runs in’ down the track.
      Cheers, Owen

      • Thanks Owen and lovely to hear from you. I was initially diappointed with the new SUT/cartridge because they sounded wonderful in the shop but when I got home I found I had a hum problem. Many emails later, the shop sent me a VPI RCA with earth cable and this helped considerbaly to reduce the hum when attached between SUT and amp. The VPI cable is on loan and so I’m looking for an alternative while on holiday in the UK. Cheers, Simon.

  2. Simon – hum can be a issue with SUTs & phono setups..
    Not sure if the VPI cable simply has an addit. outboard Gnd wire but…
    Try Gnding the tonearm at the preamp chassis (instead of at the SUT) – may eliminate a Gnd loop.
    Check that your tonearm cable, if screened, that the screen is connected at one plug end only (low imped/source end usually, to the -ve shell).
    Cheers, Owen

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  6. Hi Owen,

    You write a great blog. I can’t build speakers like you but I love horn speakers. Got myself a Klipsch Cornwall.

    Please share with me what are the resistive input loading (100ohms), capacitive input loading (100pf), gain settings (0.4mv) you use for your Koetsu Rosewood cartridge for optimum playback? Mine are the ones in bracket () Though I find the sound satisfactory I wonder whether it is optimised.

    I have a DACT CT100 phonostage which allows me detailed tweaking of cartridge settings.

    Appreciate your sharing.

    Cheers!

    Jeremy

    • Hi Jeremy – nice to hear from you….those Cornwalls should produce a nice big sound.
      – For MC carts, capacitive loading is relatively unimportant – see Hagtech, http://www.hagtech.com/loading.html (I would tend to switch to Off on your CT100.)
      – Impedance (AC resistance) loading for MC carts – the common consensus 100 ohms is a good starting point for most MC carts, which is around 10-20x coil impedance, This is what I use presently. But experiment to suit your ear & set-up. As said, I was using 50-70 ohms happily for a while – a softer, sweeter, less sharp/taut sound, which could suit some setups.
      – If using a Step Up Transformer, then a 26-28dB SUT into a 47-50k input gets you close. (Reportedly, Sugano used such a setup.)
      – With your CT100, once you have determined your preferred ohms loading, you could even solder-in resistors (see manual) in parallel with the 47k setting.
      – Gain – this is system-dependent. I like to have plenty of gain in reserve (vol settings below 11-12 o’clk). If using a wiper vol pot, then between 10-1 o’clock usually avoids any channel imbalance problems. If using say a DACT resistor attenuator, then use whatever suits/sounds best!
      – The CT100 looks like a very versalile phono stage. The extra time constants, 3.18us will give you a brightness lift, the 7950us is like a LF rumble filter.

      And keep us posted on progress!
      PS. What Koetsu do you have? Owen

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  8. Hi, I was lucky enough to find your blog when Googling for info on people who might be able to rebuild the suspension on an old Supex SD900 Super E Plus. Many years ago I had a bad experience of having a Kiseki rebuilt and have not found anyone better since. You clearly have huge knowledge in the field so I was wondering if you have any suggestions? Naturally I dont want to be spending ridiculous amounts on the rebuild as there is a limit beyond which such work is uneconomic but also I need a sensitive repairer who will seek to preserve the fundamental sound of the cartridge. I believe the stylus is still in good shape so the work would just be on the suspension. Finally I am based in the UK. Thanks in advance, Enrico

    • Hello Enrico – thanks for visiting. I’m not sure if I can advise, as I have only had a Koetsu rebuilt in Japan. Over your way of course, is Expert Stylus Co. And a new name (to me) is Northwest Analogue up in Lancashire, who may be worth talking to. Let me know how things pan out, I’m interested too, in who can restore these classic cartridges. Cheers, Owen.

      • Thanks for your thoughts Owen. Lets just say I haven’t had great experience of one of those companies but I will be sure to feedback my hopefully good experiences once I have identified a suitable repairer. Cheers, Enrico

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  10. Question: I can’t tell your location but, for the Rosewood rebuild you went through Koetsu S.E. Asia versus a local distributor….? Any reason or thoughts you could share?

    Thanks!

    • Hi Joseph – thanks for visiting.
      I am in New Zealand & at the time I was able to hand-deliver my cartridge & payment to Melvin in Singapore. (As I recall, the cartridge came back directly by post from Koetsu.)
      I can email you in order to discuss anything further, if you wish.
      Cheers, Owen

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