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Thread: Mini-review: Miyajima ETR-Stereo step-up transformer

  1. #1
    Join Date: Feb 2010

    Location: Berkshire, UK

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    I'm Tom.

    Default Mini-review: Miyajima ETR-Stereo step-up transformer



    Well I thought the ETR-Stereo deserved its own thread, so here it is. For readers of the previous thread on the ETR-Mono - I guess this is something of a continuation, at least from the perspective of my train of thought which is to compare the internal SUTs in the EAR 912.

    As I said in my review of the ETR-Mono, the change between it and the internal SUT in the EAR 912 was not, at least at the beginning, a Damascus moment … but as the days progressed (with perhaps a degree of break-in?), I became more and more impressed with its performance, switching back and forth to keep confirming what I was hearing - a clarity and separation of musical threads that I hadn’t heard with my mono cartridges before, a teasing out of elements within that mono wall of sound that nevertheless retained all the musical feel. I was hooked and even quite intoxicated by what I was hearing.

    And by the end of a few weeks, I couldn’t resist ordering its stereo counterpart. It was waiting on me on my return from Italy on Saturday. I had a bit of a play on Sunday, and again last night and tonight .. it’s early days but I think I have a handle on it.

    I was a bit nervous about ordering this … until mine arrived there hadn't been one imported to the UK yet and none was available for demo. There are no write-ups of it in English (or, indeed, in any other language that I could find). So I guess this is a world exclusive for AoS.

    For some six years now I have been really taken by Noriyuki Miyajima’s off-beat take on all things vinyl related, from the cross-ring suspension cartridge design, to his muscular but emotional voicing, to his off-beat use of bamboo, cactus spines and different sorts of wood to manage resonance in various ways. About 5-6 years ago now I sold up an Audio Note Io2 (actually an original vintage Io-J rebuilt by AN-UK to Io2 spec) on hearing a Miyajima Waza, to pursue the Miyajima route, first with a Shilable, followed by a Kansui and latterly a bamboo-cantilevered Madake. I subsequently bought a Takumi - all stereo cartridges, in addition to my mono Miyajima stable of Zero (0.7 mil tip), Premium (1.0 tip) and Kotetu (4.0 tip for 78s). In the meantime, assorted modern and vintage SPUs and other Ortofons, EMT XMT, Koetsu Rosewood, several Denons, have come and gone.

    There are many more links but I've brought a few bits of this story together here and here.

    Finding step-ups to match Miyajima’s stereo cartridges (16 ohm and typically around 0.2-0.23mV) has been harder than you might think given it’s a mainstream-ish sort of spec not much out of line from the 12 ohms typical for many Japanese cartridges. Just something about them that demands a bit more performance than the norm. I had good success with Hashimoto HM-7s despite (in mathematical terms) less than ideal specs, the x30 (high gain) option sounding better than the theoretically better matched x15 (low gain) one. But for some reason I found that nearly ever cartridge sounded better on the Hashimoto’s high gain position.

    I heard Miyajima’s own ETR-KSW with the Shilabe- it was juicy enough, and rather pleasant, but seemed slightly soft and consequently lacking in impact compared to the Hashimoto. I tried altogether (when I count it up) more than a dozen others (see here for part of the story - as above sorry for the holes due to photobucket), from the S&B TX103 - happiest at its high 1:20 setting - to a couple of vintage Ortofon very high gain ones (these being quite wrong of course). Other interesting diversions included an old Audio Innovations S800 (with a ready made 15 ohm ‘low' setting right in the ballpark this was pretty nice if lighter weight presentation than the EAR), a pair of UTC microphone transformers built up for me by Andrew Rothwell - a lovely vintage take on the sound and a decent match on 1:20 setting - as well a including a vintage Carver SUT with some fairly high-end Jensen transformers inside.

    But throughout that time my preferred option has been the 12 ohm setting in the internal SUT of the EAR 912 - equating if I recall correctly to about 145 ohm at the SUT into 47k ohm and a gain of about 1:18. I’ve run this for the best part of two years and been very happy,

    However, the success (for me at any rate) of the ETR-Mono had me intrigued .. I hadn’t been aware of the ETR-Stereo until after the arrival of the mono SUT. What if the ETR-Mono wasn’t only about the synergies and basic common sense of using a mono SUT for a mono cartridge, but also about the quality of the SUT construction in its own right? And the adjustability … so cool especially for a cartridge tart like me that likes to faff around half a dozen times in a night’s listening?

    In the end it was only a few weeks after the arrival of the ETR-Mono that I tool the plunge and it came pretty quickly from Japan, via Hugo at Ammonite.

    Plugging it in it was fairly clear that the SUTs in the EAR were already doing a pretty stellar job with stereo. As with the ETR-Mono, initial impressions weren’t of night and day improvements, of lifted veils and all that, but subtle .. but then again it’s pretty hard to get night and day differences at this level. The character of the two SUTs is similar - like the EAR 912 (and Tim de Paravini’s sound in general), the Miyajima provides a solid, substantial sound, with plenty of emphasis on instrumental timbre - wood sounds like wood, brass like brass. The sound from the ETR-Stereo is weighty and substantial. But then, a few sides in, I started to hear what it was all about. In the first instance, it wasn’t the music that became apparent .. it was .. space. Back to front space, in a left to right setting rather than the mono ‘wall of sound’. Really 3D. Not just 3D but with more information about the acoustic space altogether. This is stuff on the record that the cartridge was picking up, that was not presented quite as cleanly by the EAR 912 SUT section as it might be. Clean - that word had been the main takeaway from the ETR-Mono as well. With that came the perception of more expressive performances - more definition in the percussion, more articulation in the bowing and vocal inflection, just more expression all round. This isn’t ‘detail as such - detail is a two-edged sword and can be distracting and fun-destroying - going round the floods of detail route is has been kiss of death for many a DAC. No, this was about more of the music coming through.

    Quite a lot of listening done now and I’m hearing new things - not new details, but new music - in many recordings, and simply relaxing and enjoying others even more than I did. Did I mention it’s stellar with Lieder? And jazz. And the Bowie I was thrashing for my lad on Sunday night. It seems unfazed no matter what I throw at it. It’s a shade more dynamic than the EAR, something that surprised me as that’s an EAR strong point. (Though I had noticed this with the ETR-Mono as well).

    What’s perhaps been most intriguing is that the improvement over the EAR 912 isn’t at its most obvious with the Miyajima cartridges - actually the EAR 912 12 ohm setting is a bloody good match - but with my recently arrived Ikeda 9TT. This is 2 ohm and 0.2mV so quite a challenge for most SUTs. The ETR-Stereo handled it with aplomb and it sounds significantly better than the 1:40/3ohm setting of the EAR. It also made a superb job of a sleeper cartridge I keep here that is really something rather special - an SAEC C-3 - line contact, boron cantilever, made by Excel Sound Corporation who are responsible for the recent Hana range (though the vintage C-3 is in a bracket somewhat above these). 40 ohm and 0.4mv. So it’s far from a device intended solely for Miyajima’s own cartridges, it’s a real Swiss Army knife for cartridges of all description - a designation I’ve used before about the EAR, but this is like one of the super-fancy ones. Funnily enough I’m without an SPU at the moment so for the first time in ages don't have one I can test it with - though I have a strong suspicion that it would be good match given what I’ve heard from the Ikeda.

    It’s probably worth going into some detail on the settings, which are a bit complicated.

    The knob on the left controls capacitance - something that was quite a thing with older Japanese preamps in the 70s and early 80s - allowing capacitance to be added above the base amount present in the arm cable, with six options from 0.0uF added up to 2.2uF. I can’t hear any difference really with any cartridge I’ve tried, and my sense is it’s intended for principally for use with MM cartridges, which do respond to changes in capacitance which is the appropriate way to deal with rising amplitude at higher frequencies (common for example in the higher-end AT MMs). The 0.0 setting bypasses. [Edited in response to Alan's post below - this requires further investigation].

    The next knob is the input coil. This is set according to the impedance of the cartridge - though Mr Miyajima emphasises in his notes that the settings should be chosen by ear and not by rigid observation of guidelines. Nevertheless, the guidelines say a value of 80 is broadly for 2-5 ohm cartridges, 120 for 5-12 ohm cartridges, 180 for 12-30 ohm cartridges, and 270 for 30-100 ohm. My experimentation bore out that these are appropriate values, settling on 80 for the Ikeda, 180 for the Miyajimas, and 270 for the C-3.

    The next knob - output coil - controls the output coil, an by extension the gain. This for me is where it got interesting, and I think where the interaction with the EAR is at its most curious. The ratios in the EAR feed a very high gain valve LR phono stage. It manages this by having an interchange transformer in between the phono section and the (similarly high gain) output stage which matches the signal by enabling attenuation by -6 and -12db (there is a bypass 0db setting as well). This throws away signal. What I found instead of using this with the ETR-Stereo was the ability to match the gain directly by using the output coil. Different gain combinations are available using 1000, 2000, 4000, and 8000 settings. Miyajima presents a mathematical formula for precisely calculating impedance, which I’m not going to go into - it’s on his web site but as a humble musician I don’t follow it particularly. I have been using trial and error very successfully.

    But altogether there are gain options (according to the specs) from about 1:3.7 to about 1:100 which is about as wide as most people would need, with the options to trim the impedance to match a 47k MM input: the final knob adjusts impedance between the output coil and the phono stage - presumably with resistor loading. With the mono SUT I found it quite valuable to have the ability to trim the output into the EAR at different settings. But I haven’t quite got a handle on it yet on the ETR-Stereo. It allows further adjustment of the sound mainly to reduce peakiness or excessive treble - I haven’t found it necessary with any of my cartridges into the EAR but I will continue to experiment.

    So to summarise: a blind purchase (or perhaps not so blind given my experience with its mono counterpart) that seems to have worked out very well indeed. I guess on the one hand I’m quite relieved. In general I’m not one for buying brand new kit if I can avoid it and buying new + unheard is something I almost never do. But I found I’m also a bit sad in a way as I haven’t in the least felt short-changed by the EAR 912 - in fact much of the write-up I did of the ETR-Mono was singing the praises of the EAR. Going back to it as I have been doing for comparison is far from shabby. But after a few days I’m sold. I will not be going back to the EAR internals. Even at it's £2.5k retail price I think the ETR-Stereo is pretty good value.

    Of course the classic thing that happens when you start to pull at the material of a stable setup is that things start to unravel. What lies beyond the EAR 912 - a preamp I always thought would be a family heirloom? Could I be on the verge of another transformation?

    Well perhaps I could be because I’m already pondering Miyajima’s own preamp, specifically designed to work with these SUTs .. another risk though. I guess we’ll see where that one ends up.



    Last edited by montesquieu; 12-09-2018 at 10:20. Reason: Edited capacitance section based on input from Firebottle
    Main: Speakers 'RFC' Tannoy Canterburys / custom crossovers with Tannoy ST50 supertweeters; Amp - Silvercore 833C monoblocks; preamp TBA watch this space; Vinyl: Schopper'd Thorens TD124 MkII + Ikeda IT345-CR1 9 inch and Ikeda IT-407 12 inch tonearms; Cartridges Stereo - Miyajima Madake, Miyajima Takumi, Ikeda 9TT, vintage Ortofon SPU GE; Mono - Miyajimas - Zero 0.7, Premium 1.0, Miyajima/Edison '78' 4.0 conical, and Shure M44 strapped for mono with several Expert Stylus conicals for different eras of 78s; Phono stage Allnic H7000V used with Miyajima ETR-Mono and ETR-Stereo SUTs; Digital: Audio Note CDT2/II transport, heavily enhanced AN DAC based on kit but aspiring to DAC5 spec.

    Study: Speakers - Tannoy DC6; Amp: Marantz PM-4; Digital: CDP Sony CDP-X3000ES & Arcam rBlink; Vinyl: Garrard 401 with AT 1503 MkI broadcast arm, Ortofon SPU Classic GM, Ortofon 2-15k SUT and Puresound Tenuto platter mat

  2. #2
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    Loved reading that Tom, a very detailed and thorough read.

    Congratulations on what looks to be a stunning buy and good on you for getting off the beaten path.




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  3. #3
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    Wow, fantastic write up Tom, thanks for taking the time.
    'Cartridge tart'

    The capacitance switching you erroneously described as adding pF (picoFarad) values. I was expecting the values to be nF (nanoFarad), but looking on the web site the values are quoted as uF (microFarad).
    From my experience these are very high values, not that I have ever added such high values, so it comes as a little surprise to hear that they make no difference to the sound.
    Perhaps the uF is an error on the web site?

  4. #4
    Join Date: Feb 2010

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    Quote Originally Posted by Firebottle View Post
    Wow, fantastic write up Tom, thanks for taking the time.
    'Cartridge tart'

    The capacitance switching you erroneously described as adding pF (picoFarad) values. I was expecting the values to be nF (nanoFarad), but looking on the web site the values are quoted as uF (microFarad).
    From my experience these are very high values, not that I have ever added such high values, so it comes as a little surprise to hear that they make no difference to the sound.
    Perhaps the uF is an error on the web site?
    Really interesting Alan, I suspect you are correct about these being uF rather than pF - not being particularly up on the impact of capacitance, I was typing from cursory reading rather than detailed knowledge.

    Perhaps also a bit of expectation bias going on as I've fiddled with capacitance before on old Japanese amplifiers using MC cartridges and not heard much if any change.

    I've only had the ETR-Stereo for a few days and have focused on the input and output coils mainly with a bit of a play with impedance. I haven't really had a proper listen to the capacitance settings so perhaps there is something to be had there.

    I'll change the original post to be correct for the Miyajima web site, and report back findings once I've had a longer play.



    Quote Originally Posted by Mike Adams View Post
    Nice review Tom.
    Obviously with the wide range of cartridges the versatility of this is really helpful, and I guess this has more options than the settings of the EAR 912?
    Whilst the products from Miyajima are certainly good I don't think the KSW was a good match for any of the stereo cartridges, are you finding the versatility of the settings is allowing a more suitable match or do you suppose the Tx are potentially better?
    Any thoughts on how it would compare with the HM7s on the equivalent settings?
    Re pre amps there are a couple of models though from memory the interesting one didnt have CE certification (from memory)
    Yes it does have more options than the EAR - the EAR has four:

    x 30 step-up, giving a cartridge loading of 52 ohms into a 47k ohm phono stage (labelled 3 ohms, for low impedance cartridges)
    x 24 step-up, cartridge loading 82 ohms @47k (labelled 6 ohms)
    x 18 step-up, cartridge loading 145 ohms @47k (labelled 12 ohms)
    x 10 step-up, cartridge loading 470 ohms @47k (labelled 40 ohms)

    This is complemented by the attenuation option, which isn't really a setting, so much as a way of making sure the phono stage doesn't overload given the potential for massive gain.

    The ETR-Stereo (and the ETR-Mono, though with different values) by contrast has 4 input options and four output options giving a total of 16 possible combinations, that's before you add the trimming available from adjustable impedance and capacitance.

    I think the improvement I'm hearing is a combination of being able to tweak to find the 'perfect' match, and the fact that these dedicated SUTs are very high quality.

    As for the Hashimoto question, I'm hoping Adam (who bought my HM7s) will bring his over at some stage for a shootout.

    The preamp I'm looking at is the EC5 which has three phono inputs, two with trimmable input impedance - yet more options to play with ....
    Main: Speakers 'RFC' Tannoy Canterburys / custom crossovers with Tannoy ST50 supertweeters; Amp - Silvercore 833C monoblocks; preamp TBA watch this space; Vinyl: Schopper'd Thorens TD124 MkII + Ikeda IT345-CR1 9 inch and Ikeda IT-407 12 inch tonearms; Cartridges Stereo - Miyajima Madake, Miyajima Takumi, Ikeda 9TT, vintage Ortofon SPU GE; Mono - Miyajimas - Zero 0.7, Premium 1.0, Miyajima/Edison '78' 4.0 conical, and Shure M44 strapped for mono with several Expert Stylus conicals for different eras of 78s; Phono stage Allnic H7000V used with Miyajima ETR-Mono and ETR-Stereo SUTs; Digital: Audio Note CDT2/II transport, heavily enhanced AN DAC based on kit but aspiring to DAC5 spec.

    Study: Speakers - Tannoy DC6; Amp: Marantz PM-4; Digital: CDP Sony CDP-X3000ES & Arcam rBlink; Vinyl: Garrard 401 with AT 1503 MkI broadcast arm, Ortofon SPU Classic GM, Ortofon 2-15k SUT and Puresound Tenuto platter mat

  5. #5
    Join Date: Jan 2009

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    Superb write up Tom, as usual.

    You've whetted my appetite, and like you I'm a bit of a "cartridge tart"; though I don't go changing quite so many cartridges around in an evening's listening session!

    Apropos the capacitance values, it doesn't surprise me they are in uF: for most MCs the extra capacitance will make little or no difference, but for some it can make a huge difference (in particular, the Fidelity Research MC202 needed loading with 2.2uF to tame the top end).
    Barry

  6. #6
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    Quote Originally Posted by montesquieu View Post
    As for the Hashimoto question, I'm hoping Adam (who bought my HM7s) will bring his over at some stage for a shootout.
    Yes, for sure the Hashimoto will be with me on my imminent next visit to Montesquieu Château.
    "lack of passion is fatal"


    Vinyl: Tenuto gun metal mat / Thorens TD-124mk2 / SME 3009 unimproved /SME-3012r ikeda rewire / audio-technica ATP-12T - phonomac modified / STEREO: Jan Allaerts MC1 Boron/Shure M3D / Ortofon SPU A95 / Cartridge Man Music Master / Shure - SC35C (US) / SAEC C3 MC MONO: Miyajima Zero B 0.7mil mono / Miyajima Premium 1.0 / Amps & SUTs: Radford STA25 mk3 / AD Audio 'Satchmo' pre & phono / Hashimoto HM-7 SUT / ETR-MONO SUT Digital: SW1X Audio Design DAC 1 signature / Roon / Tidal Speakers: Tannoy 12" MGs' in RFC custom 'Rutland' Cabinets with RFC crossovers / Tannoy ST-100 Super Tweeters Cables: Duelund DCA16GA tinned copper / Kimber 12TC / SW1X Audio Design USB-SPdif / Duelund DCA20GA interconnects / SW1X Audio SPDIF Aero 6 / Mains Power Conditioner / Box Furniture rack / Audiodesk Systeme Vinyl Cleaner / a very beautiful & understanding Wife!

  7. #7
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    Quote Originally Posted by RothwellAudio View Post
    Yes, I spotted that too. 2.2pF would be the capacitance of just a few inches of cable, so that can't be right. Up to 2.2nF would make more sense, though the lower values (0.47nF) would still be a bit too small to do much with most LOMC cartridges. Maybe the values are uF as the manufacturer says. Up to 2.2uF does sound like a lot though.

    As above, the capacitance is probably uF, not pF.

    The numbers for this knob are actually the number of active turns used in the primary coil. The number of turns used determines the primary inductance which does relate to the cartridge coil impedance, in a way. Say for instance that the target for the LF cut-off of the transformer is 10Hz and the cartridge impedance is 5 ohms, a certain primary inductance (and therefore a certain number of turns) will be required to achieve that. If the cartridge impedance was only 2 ohms you wouldn't need so much primary inductance and could use fewer turns on the primary. If the cartridge impedance was 12 ohms you would need more primary inductance and therefore more turns.
    However, that all relates to a certain LF cut-off, arbitrarily chosen at 10Hz. If you chose the LF cut-off point to be some other figure, the turns requirements would be different. But why not simply use the maximum number of turns and get the lowest possible LF cut-off? That would be the best option if the winding wire had zero resistance and there was zero coupling capacitance between windings, but wire like that doesn't exist. In practice it's best to use just enough turns of wire on the primary to keep winding resistance and capacitance down to a minimum.
    The concept of a "correct" setting for any given cartridge impedance is a bit vague and subject to caveats, so I agree with Miyajima - "that the settings should be chosen by ear and not by rigid observation of guidelines".

    That isn't really correct - it's the combination of input coil and output coil which determine the step-up ratio.
    This knob, similar to the previous knob, selects the number of turns used in the secondary coil. The numbers are the number of turns used. Therefore both the "input knob" and the "output knob" are used to calculate the voltage gain. For example, selecting 120 for the input and 4000 for the output gives a turns ratio of 120:4000, or 1:33. Changing the input knob to 180 and leaving the output knob at 4000 would give you a turns ratio of 180:4000, or 1:22.

    The last knob selects a value of resistance load which appears across the secondary coil and is in parallel with the 47k load of the following MM phonostage. Its effect will be mainly to damp ringing in the transformer.

    Yes, the knobs aren't particularly easy to understand and using them is far from intuitive.
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    Vinyl: Tenuto gun metal mat / Thorens TD-124mk2 / SME 3009 unimproved /SME-3012r ikeda rewire / audio-technica ATP-12T - phonomac modified / STEREO: Jan Allaerts MC1 Boron/Shure M3D / Ortofon SPU A95 / Cartridge Man Music Master / Shure - SC35C (US) / SAEC C3 MC MONO: Miyajima Zero B 0.7mil mono / Miyajima Premium 1.0 / Amps & SUTs: Radford STA25 mk3 / AD Audio 'Satchmo' pre & phono / Hashimoto HM-7 SUT / ETR-MONO SUT Digital: SW1X Audio Design DAC 1 signature / Roon / Tidal Speakers: Tannoy 12" MGs' in RFC custom 'Rutland' Cabinets with RFC crossovers / Tannoy ST-100 Super Tweeters Cables: Duelund DCA16GA tinned copper / Kimber 12TC / SW1X Audio Design USB-SPdif / Duelund DCA20GA interconnects / SW1X Audio SPDIF Aero 6 / Mains Power Conditioner / Box Furniture rack / Audiodesk Systeme Vinyl Cleaner / a very beautiful & understanding Wife!

  8. #8
    Join Date: Jan 2009

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    Quote Originally Posted by RothwellAudio View Post
    Yes, I spotted that too. 2.2pF would be the capacitance of just a few inches of cable, so that can't be right. Up to 2.2nF would make more sense, though the lower values (0.47nF) would still be a bit too small to do much with most LOMC cartridges. Maybe the values are uF as the manufacturer says. Up to 2.2uF does sound like a lot though.

    As above, the capacitance is probably uF, not pF.

    The numbers for this knob are actually the number of active turns used in the primary coil. The number of turns used determines the primary inductance which does relate to the cartridge coil impedance, in a way. Say for instance that the target for the LF cut-off of the transformer is 10Hz and the cartridge impedance is 5 ohms, a certain primary inductance (and therefore a certain number of turns) will be required to achieve that. If the cartridge impedance was only 2 ohms you wouldn't need so much primary inductance and could use fewer turns on the primary. If the cartridge impedance was 12 ohms you would need more primary inductance and therefore more turns.
    However, that all relates to a certain LF cut-off, arbitrarily chosen at 10Hz. If you chose the LF cut-off point to be some other figure, the turns requirements would be different. But why not simply use the maximum number of turns and get the lowest possible LF cut-off? That would be the best option if the winding wire had zero resistance and there was zero coupling capacitance between windings, but wire like that doesn't exist. In practice it's best to use just enough turns of wire on the primary to keep winding resistance and capacitance down to a minimum.
    The concept of a "correct" setting for any given cartridge impedance is a bit vague and subject to caveats, so I agree with Miyajima - "that the settings should be chosen by ear and not by rigid observation of guidelines".

    That isn't really correct - it's the combination of input coil and output coil which determine the step-up ratio.
    This knob, similar to the previous knob, selects the number of turns used in the secondary coil. The numbers are the number of turns used. Therefore both the "input knob" and the "output knob" are used to calculate the voltage gain. For example, selecting 120 for the input and 4000 for the output gives a turns ratio of 120:4000, or 1:33. Changing the input knob to 180 and leaving the output knob at 4000 would give you a turns ratio of 180:4000, or 1:22.

    The last knob selects a value of resistance load which appears across the secondary coil and is in parallel with the 47k load of the following MM phonostage. Its effect will be mainly to damp ringing in the transformer.

    Yes, the knobs aren't particularly easy to understand and using them is far from intuitive.
    That's the best post I've read regarding the singular, and inconsistent notation of Japanese SUTs. Sometimes the 'impedance' refers to the source inpedance of the cartridge, with others it is the effective loading impedance as seen by the cartridge. All very confusing.

    Unless one knows the cartridge coil inductance and that of both the SUT windings, it will be impossible to choose the number of turns ab initio of the primary winding. No wonder Miyajima suggest this is "done by ear".

    It's not clear to me quite what the "Impedance" control does. If it is, as you say, a simple resistor in parallel with the nominal 47k of the following RIAA nework, then this will alter the impedance as seen by the cartridge, and this will also depend on the selection of the number of turns of both the primary and seconday windings. If it is some form of Zobel nework (a series RC combination placed in parallel with the secondary winding), then for an asymmetric system, some of those values don't look right, as well as there ought to be some means of choosing the capacitiance.

    Clearly the Miyajima ETR Stereo is a versatile SUT, with a comprehensive range of adjustments, but the settings are so arcane I would be spending ages listening for the right combination!
    Barry

  9. #9
    Join Date: Feb 2010

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    Quote Originally Posted by RothwellAudio View Post
    Yes, I spotted that too. 2.2pF would be the capacitance of just a few inches of cable, so that can't be right. Up to 2.2nF would make more sense, though the lower values (0.47nF) would still be a bit too small to do much with most LOMC cartridges. Maybe the values are uF as the manufacturer says. Up to 2.2uF does sound like a lot though.

    As above, the capacitance is probably uF, not pF.

    The numbers for this knob are actually the number of active turns used in the primary coil. The number of turns used determines the primary inductance which does relate to the cartridge coil impedance, in a way. Say for instance that the target for the LF cut-off of the transformer is 10Hz and the cartridge impedance is 5 ohms, a certain primary inductance (and therefore a certain number of turns) will be required to achieve that. If the cartridge impedance was only 2 ohms you wouldn't need so much primary inductance and could use fewer turns on the primary. If the cartridge impedance was 12 ohms you would need more primary inductance and therefore more turns.
    However, that all relates to a certain LF cut-off, arbitrarily chosen at 10Hz. If you chose the LF cut-off point to be some other figure, the turns requirements would be different. But why not simply use the maximum number of turns and get the lowest possible LF cut-off? That would be the best option if the winding wire had zero resistance and there was zero coupling capacitance between windings, but wire like that doesn't exist. In practice it's best to use just enough turns of wire on the primary to keep winding resistance and capacitance down to a minimum.
    The concept of a "correct" setting for any given cartridge impedance is a bit vague and subject to caveats, so I agree with Miyajima - "that the settings should be chosen by ear and not by rigid observation of guidelines".

    That isn't really correct - it's the combination of input coil and output coil which determine the step-up ratio.
    This knob, similar to the previous knob, selects the number of turns used in the secondary coil. The numbers are the number of turns used. Therefore both the "input knob" and the "output knob" are used to calculate the voltage gain. For example, selecting 120 for the input and 4000 for the output gives a turns ratio of 120:4000, or 1:33. Changing the input knob to 180 and leaving the output knob at 4000 would give you a turns ratio of 180:4000, or 1:22.

    The last knob selects a value of resistance load which appears across the secondary coil and is in parallel with the 47k load of the following MM phonostage. Its effect will be mainly to damp ringing in the transformer.

    Yes, the knobs aren't particularly easy to understand and using them is far from intuitive.
    Thanks Andrew that's really helpful in understanding what's going on.

    When I referred to the second knob controlling gain, that's pretty much how it operates in practice - what I've done is to initially select the recommended coil for the cartridge impedance. The third knob for the output coil then effectively controls gain and also shapes the overall sound. What I do from there is adjust either knob up or down to what sounds best to me - of course as you pointed out, once the output coil is selected, changing the input also has an effect on gain.


    Quote Originally Posted by Barry View Post
    Clearly the Miyajima ETR Stereo is a versatile SUT, with a comprehensive range of adjustments, but the settings are so arcane I would be spending ages listening for the right combination!

    All part of the fun!
    Main: Speakers 'RFC' Tannoy Canterburys / custom crossovers with Tannoy ST50 supertweeters; Amp - Silvercore 833C monoblocks; preamp TBA watch this space; Vinyl: Schopper'd Thorens TD124 MkII + Ikeda IT345-CR1 9 inch and Ikeda IT-407 12 inch tonearms; Cartridges Stereo - Miyajima Madake, Miyajima Takumi, Ikeda 9TT, vintage Ortofon SPU GE; Mono - Miyajimas - Zero 0.7, Premium 1.0, Miyajima/Edison '78' 4.0 conical, and Shure M44 strapped for mono with several Expert Stylus conicals for different eras of 78s; Phono stage Allnic H7000V used with Miyajima ETR-Mono and ETR-Stereo SUTs; Digital: Audio Note CDT2/II transport, heavily enhanced AN DAC based on kit but aspiring to DAC5 spec.

    Study: Speakers - Tannoy DC6; Amp: Marantz PM-4; Digital: CDP Sony CDP-X3000ES & Arcam rBlink; Vinyl: Garrard 401 with AT 1503 MkI broadcast arm, Ortofon SPU Classic GM, Ortofon 2-15k SUT and Puresound Tenuto platter mat

  10. #10
    Join Date: Feb 2010

    Location: Berkshire, UK

    Posts: 3,860
    I'm Tom.

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    Quote Originally Posted by RothwellAudio View Post
    Sorry for any adverse effect on yer noggin
    Yes, the maths/theory behind it might be a bit heavy but in practice it isn't so bad. Let me summarise:

    1) The first knob affects the capacitive load seen by the cartridge. Even when set to zero the cartridge will see capacitance from a variety of sources, so the numbers can't be taken too seriously and the effects are somewhat unpredictable. Basically, suck it and see.

    2) The second knob controls the number of turns on the primary winding. There really isn't a "correct" number of turns for a particular cartridge, so again, suck it and see.

    3) The third knob controls the number of turns on the secondary winding. The ratio of primary turns to secondary turns gives you the turns ratio. Use this knob in combination with the previous knob to set the turns ratio you require. There's quite a bit of leeway when choosing the ratio and there really isn't any optimum or perfect match for any particular cartridge, so basically, suck it and see.

    4) The fourth knob selects an additional load for the transformer (in addition to the 47k of the following mm phonostage). It will alter the load as seen by the cartridge and it will change the effects of inter-winding capacitance and leakage inductance on the transformer's frequency response. Without access to some measuring equipment the user cannot really know what effect the knob is having - other than listening for changes - so the only thing you can do is ... you guessed it ... suck it and see.
    Looks like my random approach is the correct one then!
    Main: Speakers 'RFC' Tannoy Canterburys / custom crossovers with Tannoy ST50 supertweeters; Amp - Silvercore 833C monoblocks; preamp TBA watch this space; Vinyl: Schopper'd Thorens TD124 MkII + Ikeda IT345-CR1 9 inch and Ikeda IT-407 12 inch tonearms; Cartridges Stereo - Miyajima Madake, Miyajima Takumi, Ikeda 9TT, vintage Ortofon SPU GE; Mono - Miyajimas - Zero 0.7, Premium 1.0, Miyajima/Edison '78' 4.0 conical, and Shure M44 strapped for mono with several Expert Stylus conicals for different eras of 78s; Phono stage Allnic H7000V used with Miyajima ETR-Mono and ETR-Stereo SUTs; Digital: Audio Note CDT2/II transport, heavily enhanced AN DAC based on kit but aspiring to DAC5 spec.

    Study: Speakers - Tannoy DC6; Amp: Marantz PM-4; Digital: CDP Sony CDP-X3000ES & Arcam rBlink; Vinyl: Garrard 401 with AT 1503 MkI broadcast arm, Ortofon SPU Classic GM, Ortofon 2-15k SUT and Puresound Tenuto platter mat

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