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Re: [micbuilders] LDC Supply?

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  • Scott Helmke
    JLI selling a couple of LDC capsules made by Transsounds - the TSC-1 and TSC-2 (single and double diaphragm). Don t know much about them, and they re not on
    Message 1 of 16 , May 1, 2009
      JLI selling a couple of LDC capsules made by Transsounds - the TSC-1 and
      TSC-2 (single and double diaphragm). Don't know much about them, and
      they're not on the website. Somebody here already mentioned building a
      decent mic with the TSC-2, though.

      The TSC-1 which I bought (but haven't yet used) cost about $28.

      -Scott

      briguy882 wrote:
      > Hi everyone, this is my first post. I have some spare submini tubes that I want to try to make a tube mic out of (phantom powered) and I am thinking I would like to do a large diaphragm condenser type (partly so that I can use the full phantom power for both the capsule and the tube), but I can't seem to find a very good source for capsules. Would I be better of buying something cheap and then gutting the electronics? Other ideas?
      >
      >
      >
      > ------------------------------------
      >
      > Yahoo! Groups Links
      >
      >
      >
      >

      --
      ---- Scott Helmke ---- scott@... ---- (734) 604-9340 ----
      And you'll visualize not taking any chances
      But meet them halfway with love, peace, and persuasion
      And expect them to rise to the occasion
      (from "Glad Tidings", by Van Morrison)
    • phil.hofman
      ... I have a person in Hong Kong who sells me capsules that are from the same place that machines John Peluso s PK67 and PK47 capsules, plus a similar CK12
      Message 2 of 16 , May 1, 2009
        --- In micbuilders@yahoogroups.com, "briguy882" <im_off_my_rocker@...> wrote:
        >
        > Hi everyone, this is my first post. I have some spare submini tubes that I want to try to make a tube mic out of (phantom powered) and I am thinking I would like to do a large diaphragm condenser type (partly so that I can use the full phantom power for both the capsule and the tube), but I can't seem to find a very good source for capsules. Would I be better of buying something cheap and then gutting the electronics? Other ideas?
        >

        I have a person in Hong Kong who sells me capsules that are from the same place that machines John Peluso's PK67 and PK47 capsules, plus a similar CK12 "style" capsule. They are $150 each and they're darn well made. I have tested the K47 capsule side by side with Peluso's PK47 and I honestly can't tell the difference. That raises some questions in my mind about Peluso, but that's for a different topic.

        I can't compete with the price from the person who can get the Chinese factory direct price, but with these you'd at least know you're getting a really good sounding capsule for $100 less than Peluso. The K47 doesn't have any sibilance or brightness issues and the midrange is really good. They sound fat.

        email me if you're interested.
      • userno232000
        ... Sorry for an OT joke, but last time I was in Shenzhen I saw 60 inkjet printers, no fooling around here the ink was loaded in buckets from gallon jugs.
        Message 3 of 16 , May 1, 2009
          --- In micbuilders@yahoogroups.com, "phil.hofman" <phil.hofman@...> wrote:
          > I can't compete with the price from the person who can get the Chinese factory direct price, but with these you'd at least know you're getting a really good sounding capsule for $100 less than Peluso.

          Sorry for an OT joke, but last time I was in Shenzhen I saw 60" inkjet printers, no fooling around here the ink was loaded in "buckets" from gallon jugs.
        • rick chinn
          ok. time to get practical the big limitation that you have creating a phantom powered tube mike is the phantom power itself. you are limited to about 2/3w
          Message 4 of 16 , May 2, 2009
            ok. time to get practical

            the big limitation that you have creating a phantom powered tube mike
            is the phantom power itself.

            you are limited to about 2/3w total power dissipation. That number is
            truly a best case number as it represents the short-circuit power
            available. Best case, maximum power transfer occurs when the mike's
            power dissipation is about 1/2 that value, i.e. about 3400 ohms. This
            has nothing to do with the signal impedances, it has to do with how
            much power the microphone draws from the circuit.

            From this source, you have to get enough current to run the tube
            filament, enough voltage to supply the plate voltage, and enough
            voltage to polarize the capsule.

            At 3400R, you're going to lose half of the phantom voltage in the
            feed resistors, so you'll have 24v inside your microphone. I think
            this means that you've signed up for a dc-dc converter inside, as
            that is probably the easiest way to handle the disparate
            voltage/current relationships of the tube plate, LDC capsule, and the
            tube filament.

            Neumann got away with using the P48 directly in their FET-80 series
            microphones because their amplifier draws very little current
            (450uA), which pretty much dictated that they use an output
            transformer. At that current, they only lost 1v5 to the phantom feed resistors.

            A study of what Audio-Technica did in their microphone would be
            informative, and so would user comments from a performance
            perspective. I think that Jim (ZapNSpark) posted some earlier
            schematics here exploring this concept. I believe that he also
            identified the tube that A-T used.

            --rick chinn
          • briguy882
            Thanks for your thoughts Rick. I think I should be able to pull it off, the tube that I plan to use is a 5672 power pentode that has a 1.25V filament and at
            Message 5 of 16 , May 2, 2009
              Thanks for your thoughts Rick. I think I should be able to pull it off, the tube that I plan to use is a 5672 power pentode that has a 1.25V filament and at full 48V (on the plates) the entire tube would dissipate about 1/4W, so as long as the capsule doesn't take too much power, I should be okay, I would think. Of course, I have never actually built a mic from scratch, so I trust others opinions much more than my own on most matters.

              I have also contemplated doing one with an electret capsule, which I might do first anyway just to tinker, but I think it would be a lot of fun to have a LDC tube mic that didn't cost me an arm and a leg and that didn't need a big outboard power supply.

              --- In micbuilders@yahoogroups.com, rick chinn <rickc@...> wrote:
              >
              > ok. time to get practical
              >
              > the big limitation that you have creating a phantom powered tube mike
              > is the phantom power itself.
              >
              > you are limited to about 2/3w total power dissipation. That number is
              > truly a best case number as it represents the short-circuit power
              > available. Best case, maximum power transfer occurs when the mike's
              > power dissipation is about 1/2 that value, i.e. about 3400 ohms. This
              > has nothing to do with the signal impedances, it has to do with how
              > much power the microphone draws from the circuit.
              >
              > From this source, you have to get enough current to run the tube
              > filament, enough voltage to supply the plate voltage, and enough
              > voltage to polarize the capsule.
              >
              > At 3400R, you're going to lose half of the phantom voltage in the
              > feed resistors, so you'll have 24v inside your microphone. I think
              > this means that you've signed up for a dc-dc converter inside, as
              > that is probably the easiest way to handle the disparate
              > voltage/current relationships of the tube plate, LDC capsule, and the
              > tube filament.
              >
              > Neumann got away with using the P48 directly in their FET-80 series
              > microphones because their amplifier draws very little current
              > (450uA), which pretty much dictated that they use an output
              > transformer. At that current, they only lost 1v5 to the phantom feed resistors.
              >
              > A study of what Audio-Technica did in their microphone would be
              > informative, and so would user comments from a performance
              > perspective. I think that Jim (ZapNSpark) posted some earlier
              > schematics here exploring this concept. I believe that he also
              > identified the tube that A-T used.
              >
              > --rick chinn
              >
            • Jim G.
              There are 3 commercial tube microphones that run off of P48 phantom power. Audio-Technica AT3060. Probably discontinued by AT but still available in limited
              Message 6 of 16 , May 3, 2009
                There are 3 commercial tube microphones that run off of P48 phantom power.

                Audio-Technica AT3060. Probably discontinued by AT but still available in limited quantities. Uses a Raytheon sub-mini 6418 tube.
                Uses National LM2665 charge pump chips to derive filament voltage.
                LD electret capsule.
                This model is likely to be based on this patent:
                http://tinyurl.com/d9f98y
                (The patent drawing shows the charge pumps wired incorrectly)
                About $400

                Gefell UM-900. Unknown tube type. Uses inverters to get plate and filament voltages. An op-amp drives the output transformer.
                Standard LD capsule (?)
                ~ $5000 - $6000

                NAIANT MSH-4. Discontinued. Used the 6418 tube. Direct drive output.
                Electret capsule.
                No inverters used for filament voltage. A schematic is available on the NAIANT website.
                A newer tube model microphone may be introduced this year (X-V).

                Then, there is the DIY FrankenTube microphone that I designed.
                You can see the FrankenTube porn in the Photos section of this group.
                6418 tube, National LM2665 charge pumps for filament.
                FET Op-amp direct drive output. 2 models built. Electret capsule and standard LD capsule.

                Cheers.

                Jim G.
                ZAPNSPARK


                --- In micbuilders@yahoogroups.com, "briguy882" <im_off_my_rocker@...> wrote:
                >
                > Thanks for your thoughts Rick. I think I should be able to pull it off, the tube that I plan to use is a 5672 power pentode that has a 1.25V filament and at full 48V (on the plates) the entire tube would dissipate about 1/4W, so as long as the capsule doesn't take too much power, I should be okay, I would think. Of course, I have never actually built a mic from scratch, so I trust others opinions much more than my own on most matters.
                >
                > I have also contemplated doing one with an electret capsule, which I might do first anyway just to tinker, but I think it would be a lot of fun to have a LDC tube mic that didn't cost me an arm and a leg and that didn't need a big outboard power supply.
                >
                > --- In micbuilders@yahoogroups.com, rick chinn <rickc@> wrote:
                > >
                > > ok. time to get practical
                > >
                > > the big limitation that you have creating a phantom powered tube mike
                > > is the phantom power itself.
                > >
                > > you are limited to about 2/3w total power dissipation. That number is
                > > truly a best case number as it represents the short-circuit power
                > > available. Best case, maximum power transfer occurs when the mike's
                > > power dissipation is about 1/2 that value, i.e. about 3400 ohms. This
                > > has nothing to do with the signal impedances, it has to do with how
                > > much power the microphone draws from the circuit.
                > >
                > > From this source, you have to get enough current to run the tube
                > > filament, enough voltage to supply the plate voltage, and enough
                > > voltage to polarize the capsule.
                > >
                > > At 3400R, you're going to lose half of the phantom voltage in the
                > > feed resistors, so you'll have 24v inside your microphone. I think
                > > this means that you've signed up for a dc-dc converter inside, as
                > > that is probably the easiest way to handle the disparate
                > > voltage/current relationships of the tube plate, LDC capsule, and the
                > > tube filament.
                > >
                > > Neumann got away with using the P48 directly in their FET-80 series
                > > microphones because their amplifier draws very little current
                > > (450uA), which pretty much dictated that they use an output
                > > transformer. At that current, they only lost 1v5 to the phantom feed resistors.
                > >
                > > A study of what Audio-Technica did in their microphone would be
                > > informative, and so would user comments from a performance
                > > perspective. I think that Jim (ZapNSpark) posted some earlier
                > > schematics here exploring this concept. I believe that he also
                > > identified the tube that A-T used.
                > >
                > > --rick chinn
                > >
                >
              • matt mcglynn
                ... The capsule in the UM-900 is a dual-diaphragm PVC-membrane M7. http://recordinghacks.com/microphones/Microtech-Gefell/UM-900 -- matt.
                Message 7 of 16 , May 3, 2009
                  --- In micbuilders@yahoogroups.com, "Jim G." <zapnspark@...> wrote:

                  > Gefell UM-900. Unknown tube type. Uses inverters to get plate and filament voltages. An op-amp drives the output transformer.
                  > Standard LD capsule (?)
                  > ~ $5000 - $6000

                  The capsule in the UM-900 is a dual-diaphragm PVC-membrane M7.

                  http://recordinghacks.com/microphones/Microtech-Gefell/UM-900

                  --
                  matt.
                • rick chinn
                  I searched for the A/T or Someone s take on a phantom powered tube microphone in our files area and came up empty handed. According to one source on the
                  Message 8 of 16 , May 3, 2009
                    I searched for the A/T or Someone's take on a phantom powered tube
                    microphone in our files area and came up empty handed.

                    According to one source on the internet, the tube that A/T used was
                    the 6418, aka CK548DX. This tube requires 1.25v/10mA for the
                    filament. Yours requires 1.25v/50mA for the filament.

                    Either way, you are within the power value available, but you will
                    also need to build some sort of down-converter to run the tube
                    filament because you can't afford a dropping resistor. It's just too
                    inefficient (effectively it maps the tube's filament voltage to what
                    is available, but does not change the current drawn; that remains the same).

                    I'm guessing that the converter's efficiency will be around 75%,
                    (there is no free lunch!). The 5672's filament is 25R, so the down
                    converter has to make it look like about 22k to the phantom source.
                    That said, then you will lose about 6v in the phantom feed resistors,
                    leaving 42v to run the rest of the microphone. This might actually
                    work (yes, I know that A/T did it), but you'll note that their
                    microphone is now discontinued.

                    Remember that for every miliampere of current drawn by the rest of
                    the microphone, you lose 3.4V in the phantom feed resistors. You
                    can't run the tube and still have 48v at the phantom feed source to
                    run the capsule. the 3k4 phantom feed resistors turn this into a
                    seesaw. You have 3k4 on one side, and your total power requirements
                    on the other. If you can match 3k4 in terms of your power
                    requirements, then you get half the phantom feed voltage, and for
                    every bit that you can reduce your power requirements, you get that
                    much more of the 48v at the top of the 3k4 feed resistors. But the
                    only way to get 48v there is to draw zero current, and that's not
                    possible (in this universe, at least).

                    The capsule requires no POWER (watts), but it does require high
                    voltage at zero current. You have to make that as well. The inverter
                    is not 100% efficient, although it will be close since there is no
                    current required by the load.

                    Good Luck!
                    --rick chinn
                    ===================================================================


                    Posted by: "briguy882" <mailto:im_off_my_rocker@...?Subject=
                    Re%3ALDC%20Supply%3F>im_off_my_rocker@...
                    <http://profiles.yahoo.com/briguy882>briguy882




                    Sat May 2, 2009 11:07 am (PDT)


                    Thanks for your thoughts Rick. I think I should be able to pull it
                    off, the tube that I plan to use is a 5672 power pentode that has a
                    1.25V filament and at full 48V (on the plates) the entire tube would
                    dissipate about 1/4W, so as long as the capsule doesn't take too much
                    power, I should be okay, I would think. Of course, I have never
                    actually built a mic from scratch, so I trust others opinions much
                    more than my own on most matters.
                    I have also contemplated doing one with an electret capsule, which I
                    might do first anyway just to tinker, but I think it would be a lot
                    of fun to have a LDC tube mic that didn't cost me an arm and a leg
                    and that didn't need a big outboard power supply.
                  • John Lundsten
                    the IEC 61938 or DIN spec allows 48v phantom to be between 44 & 52v. So you could get a few more mW by having your own 52v supply and still be legal . May be
                    Message 9 of 16 , May 3, 2009
                      the IEC 61938 or DIN spec allows 48v phantom to be between 44 & 52v. So you
                      could get a few more mW by having your own 52v supply and still be "legal".
                      May be a good idea anyway as not so many P48 supplies can actually deliver
                      10ma.
                      John L

                      ----- Original Message -----
                      From: "rick chinn" <rickc@...>
                      To: <micbuilders@yahoogroups.com>
                      Sent: Sunday, May 03, 2009 6:20 PM
                      Subject: [micbuilders] Re:LDC Supply?


                      |I searched for the A/T or Someone's take on a phantom powered tube
                      | microphone in our files area and came up empty handed.
                      |
                      | According to one source on the internet, the tube that A/T used was
                      | the 6418, aka CK548DX. This tube requires 1.25v/10mA for the
                      | filament. Yours requires 1.25v/50mA for the filament.
                      |
                      | Either way, you are within the power value available, but you will
                      | also need to build some sort of down-converter to run the tube
                      | filament because you can't afford a dropping resistor. It's just too
                      | inefficient (effectively it maps the tube's filament voltage to what
                      | is available, but does not change the current drawn; that remains the
                      same).
                      |
                      | I'm guessing that the converter's efficiency will be around 75%,
                      | (there is no free lunch!). The 5672's filament is 25R, so the down
                      | converter has to make it look like about 22k to the phantom source.
                      | That said, then you will lose about 6v in the phantom feed resistors,
                      | leaving 42v to run the rest of the microphone. This might actually
                      | work (yes, I know that A/T did it), but you'll note that their
                      | microphone is now discontinued.
                      |
                      | Remember that for every miliampere of current drawn by the rest of
                      | the microphone, you lose 3.4V in the phantom feed resistors. You
                      | can't run the tube and still have 48v at the phantom feed source to
                      | run the capsule. the 3k4 phantom feed resistors turn this into a
                      | seesaw. You have 3k4 on one side, and your total power requirements
                      | on the other. If you can match 3k4 in terms of your power
                      | requirements, then you get half the phantom feed voltage, and for
                      | every bit that you can reduce your power requirements, you get that
                      | much more of the 48v at the top of the 3k4 feed resistors. But the
                      | only way to get 48v there is to draw zero current, and that's not
                      | possible (in this universe, at least).
                      |
                      | The capsule requires no POWER (watts), but it does require high
                      | voltage at zero current. You have to make that as well. The inverter
                      | is not 100% efficient, although it will be close since there is no
                      | current required by the load.
                      |
                      | Good Luck!
                      | --rick chinn
                      | ===================================================================
                      |
                      |
                      | Posted by: "briguy882" <mailto:im_off_my_rocker@...?Subject=
                      | Re%3ALDC%20Supply%3F>im_off_my_rocker@...
                      | <http://profiles.yahoo.com/briguy882>briguy882
                      |
                      |
                      |
                      |
                      | Sat May 2, 2009 11:07 am (PDT)
                      |
                      |
                      | Thanks for your thoughts Rick. I think I should be able to pull it
                      | off, the tube that I plan to use is a 5672 power pentode that has a
                      | 1.25V filament and at full 48V (on the plates) the entire tube would
                      | dissipate about 1/4W, so as long as the capsule doesn't take too much
                      | power, I should be okay, I would think. Of course, I have never
                      | actually built a mic from scratch, so I trust others opinions much
                      | more than my own on most matters.
                      | I have also contemplated doing one with an electret capsule, which I
                      | might do first anyway just to tinker, but I think it would be a lot
                      | of fun to have a LDC tube mic that didn't cost me an arm and a leg
                      | and that didn't need a big outboard power supply.
                      |
                      |


                      --------------------------------------------------------------------------------



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                      14:23:00
                    • matt mcglynn
                      ... Not unknown any more. :) http://recordinghacks.com/microphones/Microtech-Gefell/UM-900 The UM900 uses either a DL67 or DL651. Both are submini types. The
                      Message 10 of 16 , May 11, 2009
                        --- In micbuilders@yahoogroups.com, "Jim G." <zapnspark@...> wrote:

                        > Gefell UM-900. Unknown tube type.

                        Not unknown any more. :)

                        http://recordinghacks.com/microphones/Microtech-Gefell/UM-900

                        The UM900 uses either a DL67 or DL651. Both are submini types. The above profile links to the RadioMuseum.org pages on the tubes and a PDF showing the April, 1950 spec describing the DL67.

                        --
                        matt.
                      • Jim G.
                        ... Many thanks Matt. Have I said this yet? You have an outstanding website for getting microphone information. Cheers. Jim G. ZAPNSPARK
                        Message 11 of 16 , May 11, 2009
                          --- In micbuilders@yahoogroups.com, "matt mcglynn" <anon-yahoo@...> wrote:
                          >
                          > --- In micbuilders@yahoogroups.com, "Jim G." <zapnspark@> wrote:
                          >
                          > > Gefell UM-900. Unknown tube type.
                          >
                          > Not unknown any more. :)
                          >
                          > http://recordinghacks.com/microphones/Microtech-Gefell/UM-900
                          >
                          > The UM900 uses either a DL67 or DL651. Both are submini types. The above profile links to the RadioMuseum.org pages on the tubes and a PDF showing the April, 1950 spec describing the DL67.
                          >
                          > --
                          > matt.
                          >

                          Many thanks Matt.
                          Have I said this yet?
                          You have an outstanding website for getting microphone information.

                          Cheers.

                          Jim G.
                          ZAPNSPARK
                        • psi2006@yahoo.com.ar
                          Hi everyone, Just curious if schematics for the UM-900 tube mic has been published elsewhere. Best, Nestor b. LDC Supply? Posted by: Jim G.
                          Message 12 of 16 , May 12, 2009
                            Hi everyone,

                            Just curious if schematics for the UM-900 tube mic has been published elsewhere.

                            Best,

                            Nestor



                            b.
                            LDC Supply?
                            Posted by: "Jim G." zapnspark@... zapnspark
                            Mon May 11, 2009 3:33 pm (PDT)


                            --- In micbuilders@ yahoogroups. com, "matt mcglynn" <anon-yahoo@ ...> wrote:
                            >
                            > --- In micbuilders@ yahoogroups. com, "Jim G." <zapnspark@> wrote:
                            >
                            > > Gefell UM-900. Unknown tube type.
                            >
                            > Not unknown any more. :)
                            >
                            > http://recordinghac ks.com/microphon es/Microtech- Gefell/UM- 900
                            >
                            > The UM900 uses either a DL67 or DL651. Both are submini types. The above profile links to the RadioMuseum. org pages on the tubes and a PDF showing the April, 1950 spec describing the DL67.
                            >
                            > --
                            > matt.
                            >

                            _______________________________________


                            Yahoo! Cocina
                            Recetas prácticas y comida saludable
                            http://ar.mujer.yahoo.com/cocina/
                          • Jim G.
                            Hi Nestor. It s very likely that this Gefell UM-900 mic. information is proprietary. i.e. no schematics are publically available. Cheers. Jim G.
                            Message 13 of 16 , May 13, 2009
                              Hi Nestor.

                              It's very likely that this Gefell UM-900 mic. information is proprietary. i.e. no schematics are publically available.

                              Cheers.

                              Jim G.

                              --- In micbuilders@yahoogroups.com, "psi2006@..." <psi2006@...> wrote:
                              > Hi everyone,
                              >
                              > Just curious if schematics for the UM-900 tube mic has been published elsewhere.
                              >
                              > Best,
                              >
                              > Nestor
                              > b.


                              > LDC Supply?
                              > Posted by: "Jim G." zapnspark@... zapnspark
                              > Mon May 11, 2009 3:33 pm (PDT)
                              > --- In micbuilders@ yahoogroups. com, "matt mcglynn" <anon-yahoo@ ...> wrote:
                              > >
                              > > --- In micbuilders@ yahoogroups. com, "Jim G." <zapnspark@> wrote:
                              > >
                              > > > Gefell UM-900. Unknown tube type.
                              > >
                              > > Not unknown any more. :)
                              > >
                              > > http://recordinghac ks.com/microphon es/Microtech- Gefell/UM- 900
                              > >
                              > > The UM900 uses either a DL67 or DL651. Both are submini types. The above profile links to the RadioMuseum. org pages on the tubes and a PDF showing the April, 1950 spec describing the DL67.
                              > >
                              > > --
                              > > matt.
                              > >
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