The first MagicQuartz unit!

OK, the transformer is not yet fully mounted and there are still some design issues with the 3D printed plastic parts. But all in all, it’s done.

Also note the 3D-printed compartment for the red filter capacitor (just behind the display). This has to be secured because it’s the really dangerous part (high voltage!).

MagicQuartz prototype 1 MagicQuartz prototype 2MagicQuartz prototype 3

7 thoughts on “The first MagicQuartz unit!

  1. LUCA RIGHI

    Hello Sebastian, here in Italy there are many hi-fi vintage enthusiasts that particularly love the Dual turntables 1019, 1219 and 1229. I’m one of them and I know many others so we are really interested in your Magic Quartz kit. Please keep me update about when will be ready some definitive units.
    Congratulations for your idea, it seems you have done an excellent job.
    Best regards,
    Luca Righi
    Mantova (Italy)

    1. Sebastian Mate Post author

      Hi Luca,
      thanks! I will keep you updated. MagicQuartz was designed for the 1219, but the 1019 works as well (tested!) and the 1229 should also work fine. 🙂
      Cheers, Sebastian

  2. LUCA RIGHI

    I’m glad of your reply, because I own a perfectly restored Grundig PS 70, that is a Dual 1219 in Grundig zarge (in white color): but I know some other people that have the Dual 1019 and also the Dual 1229. We have founded a website “www.grundiglove.org” and a Facebok group with the simple name “Grundiglove”. I have written many articles about the Duals commercialized by Grundig as stand-alone console (PS1 -1019, PS 70 – 1019, PS71-1229 and P100-Dual 1249 belt drive), but they are all in Italian language, here you can find the first one: http://www.grundiglove.org/dual-in-grundig-zarge-sassy-shure/
    There are many people that should like to update their Duals. I’ve trried to explain how to update the old Shure cartridges pre-mounted on Duals with new Jico stylus. I think that your Magic Quartz is another way to improve the sound quality of these beautiful classic turntables.
    Best regards,
    Luca

    1. Sebastian Mate Post author

      Hi Luca,

      you Italians are so crazy about Grundig that the eBay prices climbed up strongly in recent years. But you are right, Grundig used to build high-quality gear! It’s a shame that your homepage is in Italian, because the information on it looks so valuable and well-made!!!

      I have a very close relationship with Grundig. I was born and grew up close to Fürth (“Grundig City”), everything in my parents’ home was Grundig. My mother used to work as the main secretary at Grundig’s IT department (“Rechenzentrum”) in the late 70ies / early 80ies before I was born. They got their home stereo (Grundig R30, a Dual 1226, and the 660 speakers) and a Grundig TV for their wedding from the company as a gift. The TV worked for 25 years and they’re still using the R30 for listening. 🙂

      It is such a shame that Grundig declined in the early 80ies, because their devices were built to high standards. Even the lower-end units performed well, Grundig never built crap.

      I’m still running the CD7500, V7500 and T7200, the amplifier mainly to power my rear speakers (I use a Revox A78, A77 and A76 as my main system). For the turntables I use a Dual 1219 (in a luxury Grundig Zarge (PS70?)), 1019 and 701. The 701 also uses a V15-III with a Jico SAS.

      Cheers, Sebastian

      1. Luca Righi

        Hello Sebastian, thank for your appreciation of our website: also here in Italy there are many people saying that our homepage and articles should be translated in English, because thus the site would be useful for a lot of people throughout Europe. Nevertheless it is a heavy work to write these articles in Italian, and we have not really enough time to translate them in English.
        You’re completely right: until the end of seventies and in the very early eighties Grundig made wonderful TV colors, Satellit and Concert Boy Radios, CC and RR radiorecorders series and last but not least hi-fi appliances. I was a fanboy of Grundig from early seventies (I’m 53 years old): my hi-fi system is composed by CD player Marantz CD 17 mkII (only because I’m not able to find a Grundig CD 7500 or CD 7550 at a reasonable price), Amplifier Grundig V20 (I had a wonderful silver Receiver R35A from 1979, but I sold it because of WAF – Wife acceptance factor – Too big for our little sitting room), Loudpseakers : the model before your 660 ones, that is Grundig 650B (1980). Then again I have no space for the best Grundig loudpseakers ever made (IMHO, obviosly) – 1500a Professional (1978-1979) and Audioprisma 703 (1974-1975)
        Now I have two questions for you:
        1) Is it possible, after the platter have reached the right speed, to feed the turntable with a tension lowered to 190 – 200 volt in order to lower the power (and vibration) of the Dual Motor?
        2) Could you refer your listening impressions about sound improvements when Magic Quartz is conncted to Dual 1219?
        Thank you very much for your kind attention.
        Best regards,
        Luca

        1. Sebastian Mate Post author

          Hi Luca,

          thanks for your post and your interesting questions. And it’s nice to see that others appreciate high-quality audio equipment as well! To answer your questions:

          1) No, it is not possible to automatically lower the voltage after the motor has been started. However: you can manually reduce the “on” voltage to around 180V, and the turntable works just as expected. Somewhere below this voltage, the motor starts to “slip” and loses speed. I have not yet done any evaluation how this impacts motor noise, but it *could* work and might be a valuable option for the firmware. Thanks for this idea – I will run some tests! But as I said, you can simply configure MagicQuartz to run the turntable with e.g. 190V, no problem!

          2) I hope that you’re not expecting falling curtains and the clarity of the sound increasing, similar to a cold April’s morning … I guess I’m the more pragmatic/technical guy. 🙂

          Here’s what I experienced: The overall sound character of the turntable does not change. The idler wheel turntables keep their “punchy” tonality, which I can especially notice on my loved 1019. Idler wheel units simply sound different compared to direct drive or belt ones.

          MagicQuartz only takes care of SLOW speed drifts that happen due to (1) decreasing friction when the pickup moves to the center of the record, (2) warming-up of the turntable’s mechanics/bearings and (3) dust collecting at the needle, which also reduces the speed. These effects can be quite significant and can be measured easily (I will come up with some graphical measurements later).

          Also, MagicQuartz decouples the turntable from the varying mains frequency. These changes can be quite significant, see e.g. http://www.mainsfrequency.com/

          What was very striking for me was when I noticed that the speed is now “just correct”. Some of my records offered me a totally new listening experience! Without MagicQuartz, it is very difficult to fine-tune the pitch of the turntable, even though the strobes on these devices are quite accurate.

          I also believe that if it sounds totally different, something would be wrong. You can – and should – actually configure the Quartz Latency parameter in MagicQuartz so that the impact of the regulation is as low as possible (but high enough to keep up with the speed changes).

          I’ll do a full listening session where I try to work out the sonic impact of MagicQuartz. This will be hard, because I do not want to “sell” subjective impressions … and all this voodoo. MagicQuartz is truely for technically experienced freaks who adore well made, vintage hifi equipment that does not need to stick to audiophile “myths”. I believe is true for all upper-range Grundigs, Duals, Revox’, Sabas, and many other European devices … 🙂

          Cheers, Sebastian

  3. Luca Righi

    “MagicQuartz is truely for technically experienced freaks who adore well made, vintage hifi equipment that does not need to stick to audiophile “myths”.”
    I quote the whole post of your, but particularly this sentence. I perfectly agree with your approach, I’m not expecting sound changing “day and night” as many owners of Linn LP12 and Lingo and of Pro-ject turntables and Speed box says: I think that perhaps they are sincere but this demonstrate that their turntable were not so good just out of the box if they need these external PSU to sound at their best.
    This also demonstrate how Dual was a very serious brand from a commercial point of view.
    Best regards,
    Luca

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