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Thread: New arrival - budget Ortofon SPU #1

  1. #11
    Join Date: Feb 2010

    Location: Bridgend, Wales

    Posts: 117
    I'm James.

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    Quote Originally Posted by montesquieu View Post
    It seems to me this cartridge is really worthy of consideration, especially when you consider what the competition is at sub-£500. For example it certainly sounds more accomplished and well rounded to me than any Denon 103 that I've heard, even the fancy or modded ones, to say nothing of some of the other 'budget' MCs from the likes of Goldring or Sumiko.
    Indeed. My 103R was sold because of this very reason.
    Nottingham Analogue Spacedeck / Kuzma Stogi S / Benz Micro Ace S L
    Lenco L-75 / Carl Ellis Plinth / Ortofon AS-212 / Ortofon SPU Classic GM E MkII
    Ortofon ST-7 SUT / Croft RIAA

    Cambridge Audio CXU / Theta DS Pro Prime

    Classé Model 30 / Luxman M-383

    Usher Compass X-719


    May contain opinions that others find disturbing.

  2. #12
    Join Date: Jan 2009

    Location: Essex

    Posts: 18,164
    I'm openingabottleofwine.

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    Quote Originally Posted by montesquieu View Post
    Couple of SUT experiments ...

    Output on the #1 is 2 ohm and it sounds pretty fab on the input labelled 3 ohm on the EAR912 (which I gather is x30).

    That got me thinking so I dug out the little Ortofon 2-15k step-up 'dongle' type I got from Barry a while back (also 1:30 I believe), designed for 2 ohm cartridges from the original SPU/SL15 era. It sounds superb with it - not quite as detailed, spatious or refined as the EAR but very lively, tonally accurate and really quite 'right' (indeed it gives it something of a vintage SPU feel). Very enjoyable. This is what I'll be running it into once the Garrard goes back in the study. So all doubt removed - the #1 is a proper SPU!

    Interestingly I tried it with the Bob's Devices Cinemag SUT I got from from Jake Recently, this offers 1:10 and 1:20 .. even on 1:20 (which is the ratio on this ideally suited for a Denon 103) it sounded a bit flat and lifeless .. I guess for all its qualities with other cartridges, 2 ohm is somewhat out of its comfort zone.
    The '2-15K' in-line SUT (kabelübertrager), has a step-up ratio of 1:80.

    Inspection of the data sheet for the SL15 (http://theartofsound.net/forum/showt...turers-Ortofon), shows the output from the SL15 alone is 0.025mV (at 1 cm/s) and is 2mV via the 2-15K SUT, so the step up ratio is 2/0.025 = 80. This tallies with the impedance ratio: the SUT has the designation "2-15K" because when the SUT is loaded with the 2Ohm impedance of the cartridge, the output impedance is 15KOhm, hence the step-up ratio is sqrt(15000/2) = sqrt(7500) ~= 87.
    Have you listened to this month's choice in the Album Club?

    Barry

  3. #13
    Join Date: Feb 2010

    Location: Berkshire, UK

    Posts: 3,160
    I'm Tom.

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    Quote Originally Posted by Barry View Post
    The '2-15K' in-line SUT (kubelubertrager), has a step-up ratio of 1:80.

    Inspection of the data sheet for the SL15 (http://theartofsound.net/forum/showt...turers-Ortofon), shows the output from the SL15 alone is 0.025mV (at 1 cm/s) and is 2mV via the 2-15K SUT, so the step up ratio is 2/0.025 = 80. This tallies with the impedance ratio: the SUT has the designation "2-15K" because when the SUT is loaded with the 2Ohm impedance of the cartridge, the output impedance is 15KOhm, hence the step-up ratio is sqrt(15000/2) = sqrt(7500) ~= 87.
    Interesting. There isn't much if any difference in output volume though between it and the EAR's internal phono om 3 ohm so maybe I have wrong numbers for that too.
    Main: Speakers 'RFC' Tannoy Canterburys / custom crossovers; Amp - Radford STA100; Pre EAR 912; Vinyl: Thorens TD124 MkII + Ikeda IT345-CR1 / Ikeda IT-407 tonearms; Cartridges Stereo - Miyajima Madake, Ortofon SPU Royal N, Ikeda 9C III, SAEC/Excel C3; Mono - Miyajimas - Zero 0.7, Premium 1.0, Sonovox MC-4 1.0, Edison '78' 4.0 conical, and Shure M44 strapped for mono with several Expert Stylus conicals for different eras of 78s; Phono stage and SUT from EAR 912; Esoteric Sound Re-Equalizer for equalisation of early mono and 78, switchable in from tape loop; Digital: Audio Note CDT2/II transport, heavily modded AN Kit DAC + Mutec MC3+USB.

    Study: Speakers - Tannoy DC6; Amp: Pass Aleph 'Mini'; preamp - Firebottle custom; Vinyl: Garrard 401 with AT1503 tonearm and vintage Ortofon SL-15e with matching Ortofon 2-15k SUT; Phono Stage: Firebottle Plus; Digital - Trichord Genesis III CDP + Arcam rBlink; Schiit Multibit DAC.

  4. #14
    Join Date: Jan 2009

    Location: Essex

    Posts: 18,164
    I'm openingabottleofwine.

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    It's more a question of gain, rather than impedance. What is the gain of the phono-stage of the EAR amp in both the MM and MC mode?

    I expect the "3Ohm" setting refers to the coil impedance of the cartridge, rather than the input impedance of the amp. This is a Japanese convention; the actual input impedance is more likely to be 33Ohm or more.
    Have you listened to this month's choice in the Album Club?

    Barry

  5. #15
    Join Date: Feb 2010

    Location: Berkshire, UK

    Posts: 3,160
    I'm Tom.

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    Quote Originally Posted by Barry View Post
    It's more a question of gain, rather than impedance. What is the gain of the phono-stage of the EAR amp in both the MM and MC mode?

    I expect the "3Ohm" setting refers to the coil impedance of the cartridge, rather than the input impedance of the amp. This is a Japanese convention; the actual input impedance is more likely to be 33Ohm or more.
    Not sure the stats are available in this form. The preamp gain on the EAR 912 is 14db.

    Re-reading Stereophile's review the step-up gain is published in db, not in 1:XX - so that's 30db (not 1:30) for the input marked 3 ohm, 26 db for 6 ohm, 23 db for 12 ohm and 20 db for 40 ohm - not sure how ratios can be calculated from that.

    There is an additional transformer with three positions (0db, -6db and -12db) in between the phono section and the preamp, providing attenuation for gain matching purposes. I suspect that this complicates things when it comes to calculating gain. Without any attenuation the output on the lower impedance settings can be pretty high - keeping the phono output at appropriate levels is what the VU meters are for. When I first got it I thought I could detect a degredation in quality when the intermediate transformer was used but I'm satisfied now that that's just an artefact of the gain drop and that with levels matched, it can't be heard. Most of my cartridges are pretty low output though so it's not needed that much.

    What I have found is that's it's possible to get a good sound out of every MC cartridge I've tried in it from 2 ohm at the coil right up to 100 ohm, at a variety of outputs from 0.05mv to 1mv, while the 47k ohm MM stage on its own is also superb. It really is a Swiss army knife of preamps and I've been delighted with it. I was actually skeptical before Petrat brought his down and we compared it against my Hashimoto HM7 + Aurorasound Vida + Modwright 36.5. But within a few weeks of hearing his I had tracked one down on the French-Belgian border and drove over on the chunnel to buy it.

    Specs as published:

    Input impedances, phono: 47k ohms, moving-magnet; labelled 3, 6, 12, or 40 ohms, moving-coil.
    Output impedance: 600 ohms.
    Line-stage gain: 14dB.
    Phono-stage gain: 50–80dB
    Signal/noise ratio: 68dB phono (ref. 2.4mV), 90dB line (ref. 1V).
    Frequency response: 20Hz–20kHz, –0.3dB.
    Distortion: <0.1% at 1kHz, 3V output.
    Main: Speakers 'RFC' Tannoy Canterburys / custom crossovers; Amp - Radford STA100; Pre EAR 912; Vinyl: Thorens TD124 MkII + Ikeda IT345-CR1 / Ikeda IT-407 tonearms; Cartridges Stereo - Miyajima Madake, Ortofon SPU Royal N, Ikeda 9C III, SAEC/Excel C3; Mono - Miyajimas - Zero 0.7, Premium 1.0, Sonovox MC-4 1.0, Edison '78' 4.0 conical, and Shure M44 strapped for mono with several Expert Stylus conicals for different eras of 78s; Phono stage and SUT from EAR 912; Esoteric Sound Re-Equalizer for equalisation of early mono and 78, switchable in from tape loop; Digital: Audio Note CDT2/II transport, heavily modded AN Kit DAC + Mutec MC3+USB.

    Study: Speakers - Tannoy DC6; Amp: Pass Aleph 'Mini'; preamp - Firebottle custom; Vinyl: Garrard 401 with AT1503 tonearm and vintage Ortofon SL-15e with matching Ortofon 2-15k SUT; Phono Stage: Firebottle Plus; Digital - Trichord Genesis III CDP + Arcam rBlink; Schiit Multibit DAC.

  6. #16
    Join Date: Jan 2008

    Location: Wrexham, North Wales, UK

    Posts: 79,405
    I'm AudioAl'sArbiterForPISHANTO.

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    Interesting (and informative as usual) write-up, Tom

    I'm not surprised that the 'baby SPU' sounds good, as I had both it and the elliptical version, before going for the (then) top model, the Royal GM MKII, and enjoyed them both, although marginally preferring the spherical version, which I considered to be more musical sounding.

    One small upgrade you can do, which I found significantly beneficial, is upgrade the stock (thin) internal headshell wires (unless Ortofon have done so already on the new #1 model), with these: https://www.ortofon.com/lw-6n-p-437

    I found it 'tidied up' the sound overall, which as you've described is already very good, but the 6N copper lead wire removes a slight opacity, and notably 'fleshes out' the bass, curing the issue you've outlined above (one I can also relate to, as I heard the same thing myself).

    It's a nice little upgrade and simply finishes things off nicely, releasing the full potential of the cartridge. Don't be tempted to go for the silver version of the leads, as they make the cartridge sound a little bright, and impacts adversely on musicality. The copper versions are the ones to go for. Once fitted, don't forget to reset VTF, as the new leads will be considerably heavier.

    Enjoy!

    Marco.
    http://www.thestainedglasscompany.com

    "A man is a success if he gets up in the morning and gets to bed at night, and in between he does what he wants to do" -- Milan Kundera.

    BE HAPPY EVERYDAY!

  7. #17
    Join Date: Jan 2009

    Location: Essex

    Posts: 18,164
    I'm openingabottleofwine.

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    Thanks for your detailed reply Tom.

    True it is not easy from the published specification of your EAR preamp to relate the input impedance settings with the corresponding gain, but they are only loosely related: cartridges having a low output tend to have a low impedance because they have fewer turns on the coils.

    Looking at the spec, the gain of the phono stage is 50dB when in MM mode, and up to 80dB when in MC mode on the "3Ohm" impedance setting. The additional gain of 30dB corresponds to a voltage step-up ratio of 1:31.6, which tallies with the 1:30 of the Cinemag SUT you have tried.

    So what about the 1:80 ratio of the Ortofon SUT? Well the increase in gain is by a factor of 80/30 = 2.6, which translates to a gain increase of ~8.5dB and will be noticeable, unless you have adjusted the interstage transformers that you mention.

    Whatever the speculations, the fact that you enjoy using the Ortofon devices is all that matters; it is far too easy to become obsessed with specs and figures, and not "hear the wood for the trees" (apologies for the 'bent' metaphor).
    Have you listened to this month's choice in the Album Club?

    Barry

  8. #18
    Join Date: Feb 2010

    Location: Berkshire, UK

    Posts: 3,160
    I'm Tom.

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    Quote Originally Posted by Marco View Post
    Interesting (and informative as usual) write-up, Tom

    I'm not surprised that the 'baby SPU' sounds good, as I had both it and the elliptical version, before going for the (then) Royal GM MKII, and enjoyed them both, although marginally preferring the spherical one, which I considered to be more musical sounding.

    One small upgrade you can do, which I found significantly beneficial, is upgrade the stock (thin) internal headshell wires (unless Ortofon have done so already on the new model), with these: https://www.ortofon.com/lw-6n-p-437

    I found it 'tidied up' the sound overall, which as you've described is already very good, but the 6N copper lead wire removes a slight opacity, and notably 'fleshes out' the bass, curing the issue you've outlined (one I can also relate to, as I heard the same thing myself).

    It's a nice little upgrade and simply finishes off the product nicely, releasing the full potential of the cartridge. Don't be tempted to go for the silver version of the leads, as they make the cartridge sound a little bright, and impacts adversely on musicality. The copper versions are the ones to go for. Once fitted, don't forget to reset VTF, as the new leads will be considerably heavier.

    Enjoy!

    Marco.
    Cheers Marco, I am in the habit of using better leads but I haven't got round to swapping these ones out yet. Will give it a shot. I took a bet on the spherical for instinctive reasons, though I'm sure the eliptical must be pretty good as well.

    I believe the SPU Royal N which I have is the same cartridge, without the Ortofon headshell, as the Royal GM MkII (same gold coils and Replicant 100 stylus). I consider it an out and out bargain in terms of performance/sound per pound.

    I actually have a Royal GM headshell for it that I picked up on ebay but somehow it sounds better to me in my favourite Fidelity Research FR-S3 headshell, I also have a few of these for my mono Miyajimas (with nice headshell wires natch).
    Main: Speakers 'RFC' Tannoy Canterburys / custom crossovers; Amp - Radford STA100; Pre EAR 912; Vinyl: Thorens TD124 MkII + Ikeda IT345-CR1 / Ikeda IT-407 tonearms; Cartridges Stereo - Miyajima Madake, Ortofon SPU Royal N, Ikeda 9C III, SAEC/Excel C3; Mono - Miyajimas - Zero 0.7, Premium 1.0, Sonovox MC-4 1.0, Edison '78' 4.0 conical, and Shure M44 strapped for mono with several Expert Stylus conicals for different eras of 78s; Phono stage and SUT from EAR 912; Esoteric Sound Re-Equalizer for equalisation of early mono and 78, switchable in from tape loop; Digital: Audio Note CDT2/II transport, heavily modded AN Kit DAC + Mutec MC3+USB.

    Study: Speakers - Tannoy DC6; Amp: Pass Aleph 'Mini'; preamp - Firebottle custom; Vinyl: Garrard 401 with AT1503 tonearm and vintage Ortofon SL-15e with matching Ortofon 2-15k SUT; Phono Stage: Firebottle Plus; Digital - Trichord Genesis III CDP + Arcam rBlink; Schiit Multibit DAC.

  9. #19
    Join Date: Feb 2010

    Location: Bridgend, Wales

    Posts: 117
    I'm James.

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    I've taken Marco's advice and purchased some of those copper leads. Should be here after the bank holiday, will let you know
    Nottingham Analogue Spacedeck / Kuzma Stogi S / Benz Micro Ace S L
    Lenco L-75 / Carl Ellis Plinth / Ortofon AS-212 / Ortofon SPU Classic GM E MkII
    Ortofon ST-7 SUT / Croft RIAA

    Cambridge Audio CXU / Theta DS Pro Prime

    Classé Model 30 / Luxman M-383

    Usher Compass X-719


    May contain opinions that others find disturbing.

  10. #20
    Join Date: Feb 2010

    Location: Bridgend, Wales

    Posts: 117
    I'm James.

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    Installed. They do seem to have led to more clarity and openness, though it's marginal. Not unhappy though
    Nottingham Analogue Spacedeck / Kuzma Stogi S / Benz Micro Ace S L
    Lenco L-75 / Carl Ellis Plinth / Ortofon AS-212 / Ortofon SPU Classic GM E MkII
    Ortofon ST-7 SUT / Croft RIAA

    Cambridge Audio CXU / Theta DS Pro Prime

    Classé Model 30 / Luxman M-383

    Usher Compass X-719


    May contain opinions that others find disturbing.

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