"James Chaggaris" <[EMAIL PROTECTED]> made an utterance to the drakelist gang ----------------------------------------------------------------------
Gary: It is my understanding that Drake changed the mic configuration on the TR7's above serial #1500. Also, I think the impedance is around 750K on pin 4 which would be suitable for a amplified D-104. I personally haven't tried it but I do have 2 D-104's (both amplified) that I want to put into service. If I've gotten things backwards, any feedback would be appreciated. 73's Jim N9WW James E. Chaggaris President PowerOne Corp. 1020 Cedar Ave. Suite 110 St. Charles, IL 60174 Phn:(630) 443-6500 Fax:(630) 443-6505 Web: www.pwrone.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Garey Barrell Sent: Tuesday, December 05, 2006 10:11 AM To: [email protected]; [EMAIL PROTECTED] Subject: Re: [drakelist] Re: D-104 Mic on a TR7 Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang ---------------------------------------------------------------------- Frank - The primary reason the amplifier was installed in the base of the D-104 microphone was to isolate the crystal/ceramic mic cartridge from varying load resistances. The load resistance seen by a microphone cartridge of this type affects the frequency response considerably. By adding the amplifier, the cartridge would see a constant load resistance regardless of the external load, allowing the mic to have a consistent frequency response regardless of what transmitter or amplifier it was connected to. The TR-7 came in at least two versions. The early versions had only a single pin (1) of the microphone connector wired for input, and as it came from the factory it was Hi-Z (high impedance). There was an internal jumper that could be installed to convert it to Lo-Z if desired. Later versions had the microphone connector Pin 1 wired as Lo-Z, and Pin 4 wired as Hi-Z. So... Depending upon the age of your TR-7, you may want to connect the D-104 to either of these pins. Easiest way to check is to load the transmitter into a dummy load for SSB, and with the microphone disconnected, touch a small screwdriver to Pin 4 of the microphone connector and touch the metal shaft of the screwdriver with your finger. If the transmitter "keys" (you might have to adjust the mic GAIN or VOX GAIN), you have a later version. If nothing happens, touch the screwdriver to Pin 1 and try again. If still nothing, the controls may have to be turned up further. Regardless, the D104 with the base amplifier will work when connected to either pin, just by adjusting the Gain control on the bottom of the microphone stand. The control will be turned much lower for the Hi-Z input connection. A good article is <http://members.cox.net/n4jk/d104.htm> 73, Garey - K4OAH Atlanta Drake 2-B, 4-B & C-Line Service Supplement CDs <www.k4oah.com> > ---------------------------------------------------------------------- > On Mon, 4 Dec 2006 19:48:52 -0600, [EMAIL PROTECTED] wrote: > > >> Sorry if this is a repost, but I want to interface my "amplified" >> D-104 with a TR7. I have seen reports in the past of doing this both >> "as-is" and in addition, using the QST modification to truly limit >> the upper end of the >> D-104 to 4kHz or so. >> What do the purists say? >> > > ---------------------------------------------------------------------- Submissions: [email protected] Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net ---------------------------------------------------------------------- ---------------------------------------------------------------------- Submissions: [email protected] Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net ----------------------------------------------------------------------
