ASTATIC SILVER EAGLE'S

Astatic D104 and 10DA mic sound comparison

Astatic D104 and 10DA mic sound comparison

quick listen of the D104 mic and 10DA Super Sidebander hooked up to a mic tester. D104's are tailored for high frequency cutting audio and 10DA is flat and limits all hi frequency after 3khz's.

Astatic Silver Eagle Trouble shooting and repair PART 2

Astatic Silver Eagle Trouble shooting and repair PART 2

Astatic D-104 Silver Eagle Fet Mod Part 1

D104 Fet modification for better audio on solid state equipment.

Credit: This modification can be found online at Mr. Walter A. Breining is the creator of this information. I do not take credit for his information. But the link above can be downloaded by anyone who wishes to perform the modification. 73's and have fun with this one.

D104 Microphone Source Follower

This video shows how I modified the Astatic D104 microphone and added a JFET source follower circuit to it with a 9V battery. Its a pretty easy mod. I also use a phase switch. I highly recommend using this circuit for the D104. I prefer the source follower rather than a common source type circuit as the D104 mic already has a high audio output and presents a high Z .to the TX speech amp. I have used this circuit in this mic and it has been running for about 5 years with no issues on various transmitters.

How to clean the relay contacts in Astatic D104 with lazy bar stands

How to clean the relay contacts in Astatic D104 with lazy bar stands

Method shown and explained will work with most of the Astatic bases with the lazy bar such as TUP9, Night Eagle, Silver Eagle

Astatic D-104 Silver Eagle Mic Modifications

The D-104 has been around since the 30’s and is still popular today for communications. The current ones are still pretty much the same except that in the early 70’s a two- transistor pre amp was added to the base. The D-104 is considered by many to be the coolest looking mike around.

The early elements used a Rochelle salts crystal but later a ceramic crystal was used to make the element more rugged. These elements are unique in that the diaphragm is convex instead of concave. Although these diaphragms were made of aluminum foil, Astatic used an ingenious method of placing batting in contact with the element. This eliminated the “tin” sound of these elements and they are capable of a surprisingly good sound. The peaky sound that we sometimes hear from these mikes is due to improper loading, not the diaphragm material.
Without the pre amp, these microphones sound very good with tube equipment that provided a very high impedance load to the element.

With solid state equipment these elements do not sound as good by themselves. Even with a high impedance load such as 50k ohms, they are often high pitched and peaky sounding. With some applications this high pitched sound is preferred. But sometimes this results in a thin or nasal, very middy, unnatural sound. These elements exhibit very low impedance at very high frequencies and very, very high impedance at low frequencies. Even at 50K ohms, output voltage is swamped at low frequencies making the sound high-pitched.

If we bridge the element with a very, very high impedance load, several Meg ohms, it will sound much smoother, be more natural and have low end while still retaining presence.