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Intro To Tape Head Design

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  • Intro To Tape Head Design

    Myles B. Astor, PhD, Administrator
    Senior Editor, Positive-Feedback.com
    ________________________________________

    -Magico S5 Mk.2 speakers with SPod feet
    -cj 40th Anniversary ART300 monoblock amplifiers
    -cj GAT preamplifier Series 2 preamplifier
    -Doshi V3.0 phonostage
    -VPI Vanquish direct-drive turntable
    -VPI 12-inch 3D Fat Boy dual pivot tonearm, VPI 12-inch 3D Fat Boy gimballed and SAT LM-12 arm
    -Lyra Atlas SL, Fuuga, vdh Colibri Master Signature, MOFI Master Tracker, Sumiko Songbird cartridges
    -Technics RS1506 with Flux Magnetic heads, Doshi V3.0 tape stage (balanced)
    -Assorted cables including Transparent XL Gen. 5, Allnic cables, Skogrand, Viero, Kubala-Sosna, MG Audio, Audience Au24SX, Genesis Advanced Technologies Power Cords
    -Accessories including Stillpoint Aperture panels, Cathedral Sound panels, Furutech NCF Nano AC receptacles; Silver Circle Tchaik 6 PLC, Symposium ISIS and SRA Craz racks, Audiodharma Cable Cooker, Symposium Ultra and assorted SRA platforms.

  • #2
    Thanks for this Myles. There is very little information/discussion on this topic;

    Long time back, I had / took the opportunity to listen between playback heads in as controlled a test as I could. Candidates available were. Flux Magnetics / Studer / Pro Nortronics / Nagra and a Japanese head from possibly a Technics 1500. They sounded different. The best way I can describe the difference was in a loss (or) gain of "information" - I could hear more (or less) going on in the music. Didn't hear noticeable frequency or dynamics differences compared to the above.

    At that time I knew and called Joe Dundovic about this. He was a principal (and one founder I believe) of Nortronics - he has since died. We discussed a number of things and he mentioned a number of variables that could effect the equations, things like the lamination material; its shape and thickness, and the importance of the annealing process. Think I had a similar discussion with John French and he agreed.

    As with many things that appear simple - they ain't

    Charles

    Fascinating factoid from Joe. Nortronics had a business policy that at the end of the year they wanted NO heads left in their stockroom. SO rather than disposing of them otherwise, Joe took them home. For years. He had THOUSANDS of heads in his basement. Probably 80 percent tho were specialized or from home machines or computers. Did buy a few playback heads from him. Should have bought all of them. John French did!

    Comment


    • #3
      These posts by Tim de Paravicini in response to a question on Flux vs Studer butterfly heads on FB got my interest up. (Unfortunately Tim always has to be insulting and condescending to people so those sections were removed.)

      "Because if you look at butterfly. The mumetal laminations are on a taper as seen by the tape. So the low frequencies as read by the head are variable in strength per distance from gap line. Therefore the contour is mostly eliminated.

      There will be an ultimate fall off due to lamination total width. So at 15 ips a 15 Hz signal has 1 inch wavelength. So 180 wavelength is 1/2 inch that is where there is fall off. The 90 degree phase point is a maximum . So my machines with standard Studer heads is minus 3 dB at 7 Hz or 14 Hz for 30 ips.

      With non butterfly I allow a 1.5 dB lift at about 20 Hz @15 ips. The lift is not phase distorted so is not audible. Only semi resonant or lift with Q has phase distortion.

      My square wave response. At 100 Hz. CCIR."

      "The butterfly method overcomes contour effect largely. But cannot be applied to multitrack heads."

      Full track mono is just fine."
      Myles B. Astor, PhD, Administrator
      Senior Editor, Positive-Feedback.com
      ________________________________________

      -Magico S5 Mk.2 speakers with SPod feet
      -cj 40th Anniversary ART300 monoblock amplifiers
      -cj GAT preamplifier Series 2 preamplifier
      -Doshi V3.0 phonostage
      -VPI Vanquish direct-drive turntable
      -VPI 12-inch 3D Fat Boy dual pivot tonearm, VPI 12-inch 3D Fat Boy gimballed and SAT LM-12 arm
      -Lyra Atlas SL, Fuuga, vdh Colibri Master Signature, MOFI Master Tracker, Sumiko Songbird cartridges
      -Technics RS1506 with Flux Magnetic heads, Doshi V3.0 tape stage (balanced)
      -Assorted cables including Transparent XL Gen. 5, Allnic cables, Skogrand, Viero, Kubala-Sosna, MG Audio, Audience Au24SX, Genesis Advanced Technologies Power Cords
      -Accessories including Stillpoint Aperture panels, Cathedral Sound panels, Furutech NCF Nano AC receptacles; Silver Circle Tchaik 6 PLC, Symposium ISIS and SRA Craz racks, Audiodharma Cable Cooker, Symposium Ultra and assorted SRA platforms.

      Comment


      • #4
        I wonder if anyone could help me identify the head. Is it Record or Playback? What's the condition of it?









        Comment


        • #5
          looks like little wear - two track with (space for?) center sync track.

          can't tell if its record or PB without some kind of resistance / impedance measurement. As a rule of thumb Record heads are typically below 10 ohms / 10 mH. Playback heads are up towards the hundred(s) of ohms / mH for feeding transistors and above 300 ohms / mH for feeding tubes.

          FWIW - erase heads are typically below an ohm / mH

          looks like a single screw hole /mount on the bottom. If it were a PB head - would have to be in some kind of shielding (can?). Don't understand why there are 8 terminals on the back.

          Comment


          • #6
            Charlie is a pro. However, if you want other opinions, try the Tapeheads.net Forum website. They have a lot more tape enthusiasts for this kind of question. Larry
            Analog- VPIClassic3-3DArm,SoundsmithZephyrII+MiyajimaZeroMono, 2xAmpex ATR-102,Doshi3.0 BottleheadPhonoPre,Herron VTPH-2A
            Dig Rip-Pyramix,IzotopeRX3Adv,Mykerinos,PacMicroModel2
            Dig Play-mchNADAC, LampiPac, Roon, HQP, Oppo105
            Electronics-Herron 360Pre,CJ MET1mchPre, Cary2A3monoamps
            Speakers-AvantgardeDuosLR,3SolosC,LR,RR
            Other-512Engineer/Marutani Symmetrical Power, ArtKelmGround1, AudioDiskVinylCleaner,AirTightRecordFlat, Scott Rust Interconnects,
            Music-15KRecs(90%classical),1KR2Rtapes,50TBrips

            Comment


            • #7
              Charlie is correct: you need to measure the inductance to tell if it's record or play. Looking at the gap under a microscope can also tell you: compare a known play head gap to the gap of the mystery head.

              8 leads is normal for many pro heads. Often the heads are made one-half at a time. Each half has one coil so two terminals for the coil. Then the two halves are glued together. You couple the coils electrically with the short jumper you see in the photo.
              -Tim Leinbaugh
              -Professional RTR restoration and modification for 45 years.
              [email protected]
              www.MusicTechnology.com

              Comment


              • #8
                Thanks Tim for the "heads up" info on them being made in two pieces!

                Comment


                • #9
                  I really appreciate your advises. I'll try to inquire via tapeheads.net

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