Results 1 to 9 of 9

Thread: Technical Info needed

  1. #1
    Master Navigator kd8dey's Avatar
    Join Date
    Aug 2008
    Posts
    1,009

    Technical Info needed

    Anybody know what the peak output voltage is for an unamplified astatic DN-500 .

    Anybody got one with access to an O-scope?

    Don't care if you speak, whistle, shoot, or lob nasty farts in it's direction as long as I get the numbers
    Honorary Old Fart
    Dirty Old Mans club Junior Auxillary
    (Dirty Old Man in waiting)
    Get off My Lawn.
    ===========================
    4 out of 5 Seniors Prefer the taste
    of Alpo over other leading National Brands

  2. #2
    Whacker Knot WØTKX's Avatar
    Join Date
    Aug 2008
    Location
    Lakewood, CO
    Posts
    26,758
    About 2-3 volts P-P. It depends on the "load" the testing puts on the circuit. I'm guessing your using maybe a 1 meg probe?

    The old VTVM meters with 50K Ohms/Volt would show about half that. AFAIK the old "salt crystal" elements were a little hotter.
    "Where would we be without the agitators of the world to attach the electrodes
    of knowledge to the nipples of ignorance?" ~ Professor "Dick" Soloman



  3. #3
    Master Navigator kd8dey's Avatar
    Join Date
    Aug 2008
    Posts
    1,009
    Don't have that kind of equipment here at home. I have the amplifier for the d-104 duplicated in multisim BUT I do not know what kind of signal voltage is being fed from the microphone element/transformer INTO the amplifier .
    not up to it this late but I got the formula somewhere to figure the input impedence.....
    Last edited by kd8dey; 09-27-2010 at 10:53 PM.
    Honorary Old Fart
    Dirty Old Mans club Junior Auxillary
    (Dirty Old Man in waiting)
    Get off My Lawn.
    ===========================
    4 out of 5 Seniors Prefer the taste
    of Alpo over other leading National Brands

  4. #4
    Pope Carlo l NQ6U's Avatar
    Join Date
    Jun 2010
    Location
    Maritime Mobile
    Posts
    29,890
    Can't find info on a DN-500 but according to this site, a DN-50 has a 38 ohm impedence
    All the world’s a stage, but obviously the play is unrehearsed and everybody is ad-libbing his lines. Maybe that’s why it’s hard to tell if we’re living in a tragedy or a farce.

  5. #5
    Master Navigator kd8dey's Avatar
    Join Date
    Aug 2008
    Posts
    1,009
    Quote Originally Posted by KJ6BSO View Post
    Can't find info on a DN-500 but according to this site, a DN-50 has a 38 ohm impedence
    Is that at the output transformer ? :)
    Honorary Old Fart
    Dirty Old Mans club Junior Auxillary
    (Dirty Old Man in waiting)
    Get off My Lawn.
    ===========================
    4 out of 5 Seniors Prefer the taste
    of Alpo over other leading National Brands

  6. #6
    Pope Carlo l NQ6U's Avatar
    Join Date
    Jun 2010
    Location
    Maritime Mobile
    Posts
    29,890
    Quote Originally Posted by kd8dey View Post
    Is that at the output transformer ? :)
    I have no idea. If you followed the link I provided, you know as much as I do!
    All the world’s a stage, but obviously the play is unrehearsed and everybody is ad-libbing his lines. Maybe that’s why it’s hard to tell if we’re living in a tragedy or a farce.

  7. #7
    Master Navigator kd8dey's Avatar
    Join Date
    Aug 2008
    Posts
    1,009
    It was late. I must have been asleep at the switch. didnt realize the link was there lol.
    Honorary Old Fart
    Dirty Old Mans club Junior Auxillary
    (Dirty Old Man in waiting)
    Get off My Lawn.
    ===========================
    4 out of 5 Seniors Prefer the taste
    of Alpo over other leading National Brands

  8. #8
    Pope Carlo l NQ6U's Avatar
    Join Date
    Jun 2010
    Location
    Maritime Mobile
    Posts
    29,890
    Quote Originally Posted by kd8dey View Post
    It was late. I must have been asleep at the switch. didnt realize the link was there lol.
    I shouldn't have tried to be clever and just done it like this:

    http://www.jt30.com/jt30page/oldsite/micids/astid.html
    All the world’s a stage, but obviously the play is unrehearsed and everybody is ad-libbing his lines. Maybe that’s why it’s hard to tell if we’re living in a tragedy or a farce.

  9. #9
    Master Navigator kd8dey's Avatar
    Join Date
    Aug 2008
    Posts
    1,009
    I got a chance to hook it up to a O-scope today. Didn't get much of a reading out of it lobing farts in it's general direction but acting like a CB'er and whistling like mad into it I saw around 150mv peak :) Didn't see any distortion looking at the amplifier and Multisim seems to like the numbers as well.

    I checked the specs and it looks like the mic will handle 5k ohms max input impedence to the XCVR. and frequency responce starts at 100Hz and starts falling off rapidly at 3Khz

    The DN-500 "Commentator" has a response from 50Hz all the way to 10 KHZ :) maybe I should open it up ESSB (Wide 2) Style (50Hz-6.05Khz) :)

    I have seen 2 different resistor values going to the 1st stage collector in different copies of the schematic. Some list a 1 meg while others list 10 meg. I will have to open it back up and check for myself :(

    Since the output from the first stage is taken off the emitter(emitter follower) I'm pretty sure that stage is just a buffer between the head and the actual amplifier stage.





    BUT you can see that output goes from the center tap of a 5k pot through a 5uf capacitor then a 33k ohm & 800 pf cap(parallel RC) going to ground.
    I would guess that the 5uf passes anything over 100Hz and the 33k ohm &800pf shunt the higher frequencies to Ground??
    Honorary Old Fart
    Dirty Old Mans club Junior Auxillary
    (Dirty Old Man in waiting)
    Get off My Lawn.
    ===========================
    4 out of 5 Seniors Prefer the taste
    of Alpo over other leading National Brands

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •