Astatic EchoMax 2000 Desk Microphone


This is truly a new product. Echo mics aren’t new, but digital echo for CB is new. Those of you who detest echo mics, please don’t skip this article. I know the majority of echo users are out to annoy the world, but digital echo can be an enhancement rather than a detraction.

After all, digital delay, echo, reverb, and slapback echo are used in the recording industry as well as in surround sound reproduction. The first thing I spotted was the pink label on the outside of the box. FREE STEREO HEADPHONES. I thought it was only an unrelated promotional gimmick.

After noticing a phone jack on the rear panel of the mic next to a small shaft labeled EAR, I checked the instruction sheet to confirm that the jack is for monitoring yourself with headphones. No need for talkback here. Talkback is almost useless with a desk mic, anyway.


Most operators want to talk a foot or two from the mic and to do that, the mic must be tuned up to be more sensitive, causing feedback when talkback is used.

Complete documentation is included. It covers maintenance, including cleaning the windscreen, features, controls, settings, specifications, dimensions, and even a schematic.

I’ve never seen an echo mic with a schematic before, but Astatic traditionally supplied schematics for their amplified mics. With the latest trend of manufacturers supplying less information to their customers, it’s a pleasant surprise to see Astatic continue their old tradition.

Here’s a list and descriptions of the major features incorporated in this mic:Echo: This is an effect that is familiar to most people. A word spoken into the mic will repeat and decrease in volume until it fades away.

The delay time between each echo is set with the Digital Delay control from a short reverb to a long repeat echo of close to one second. You could easily speak five quick words before the echo repeats itself.

Slapback Echo

Slapback echo works exactly as Echo but only repeats once. A short delay adds fullness to your voice, almost like two people speaking at the same time. A touch of this effect does make your audio sound full on the sideband.


ETS stands for End of Transmission Signal, Commonly known as “Roger Beep.” There are two selectable tones. One is a single tone, and the other is a multiple tone (three different quick tones). The tones are generated digitally and are easy on the ears, or should I say nerves.

Headphone Jack

This will drive a Walkman type stereo headphone set or an amplified speaker. It has a high-quality output and comes from the same amplifier stage that is fed into the radio. So the sound you hear is what’s going on the radio.

To the left, Figure 1, is a top view that will help you better visualize the controls as they’re described, and the following are descriptions of these controls and the effect they have per the manufacturer’s instructions and my experience.

Mic Gain

The Mic Gain is a slide control that sets the level into the digital circuitry. This control should be adjusted so that the level indicated on the VU meter doesn’t exceed “+3” on voice peaks.

This meter is quite accurate. Distortion in the echo started at +3 of the VU meter. The setting of this control will vary depending on how far away from the mic you speak.

Digital Delay

The Digital Delay control adjusts I the delay time of the Echo and Slapback echo effect. Setting the control to the center position turns off the echo effects.

Turning the control counterclockwise activates the Echo effect and sets the echo delay time. Turning the control clockwise activates the Slapback echo effect and sets the Slapback echo delay time. In either case, turning the control towards MAX increases the delay time.

Effects Gain

The Effects gain control adjusts the volume of the Echo and Slapback echo effects. Setting this control completely counterclockwise will act the same as turning off the effects.

With this control set completely clockwise, the volume of Slapback and Echo repeat will be at maximum and sound as loud as the original sound picked up by the mic. At MAX, the echo the mic tested repeated approximately ten times, around nine seconds.



This push button controls the ETS (Roger Beep) and is in the out position.

ETS Single/Multi

This push button selects the single or multi-tone ETS. Single is in the out position. Master Gain Control: This control is labeled GAIN and is located on the rear panel of the microphone base near the gooseneck. Use this control to set the overall level of the mic. This control is set after the mic gain is adjusted as described above.

Headphone Volume Control

This is also on the rear panel of the mic. Located next to the ear jack it is used to adjust the headphone or amplified speaker volume. The use of headphones will drain the battery more quickly. Astatic offers a wall transformer, which eliminates that problem.

This mic is of heavy steel construction with four soft rubber feet to keep it from sliding around. The base is black with gold lettering and trim. The digital control knobs are black with red inserts. The ETS buttons are red. The Mic Gain graphic display and Digital Delay area are blue with gold trim. The PTT and Lock bars are blue.

The gooseneck is a black flexible type. The nameplate on the front proudly displays “ASTATIC made in U.S.A.” in gold. The top panel is a tough laminated plastic label that will resist scratches much better than silk screen-painted surfaces.

Old-time CB veterans may remember CPI (Communications Power Inc.) used these on the face of all their products, including the CPI 2000 base radio. Many of these radios are still around and many of the face plate labels still look new on the 15+ year old classics.

The 9-volt battery can be changed by removing one screw from the rear panel. The instructions recommend the use of an alkaline battery, but I would say it’s required and not an option. Powering the mic with a 9-volt lithium battery (Radio Shack # 23-665) should increase battery life 5 times and only cost 3 times the price of its alkaline counterpart.

Ant the shelf life of a lithium battery is about 10 years. If you choose to eliminate the battery, its compartment cover has a small hole for the wire of the optional wall transformer.

A look inside the mic and the quality engineering and workmanship is immediately evident. The circuit board is computer generated and glass epoxy, not the phenolic boards used in most other mics.

The meter and microphone elements are terminated with connectors, so when the cover is removed, they can be unplugged, and the cover can be completely detached from the main body of the mic.

The push-to-talk and lock bar are rugged and designed in such a way that even pressure is applied to the PTT switch. No switch failures or scratchy transmissions due to side pressure from poor mechanical designs.

The switch should last a long time in this mic. Looking at the schematic, I noticed two amplifier stages dedicated to audio tailoring.

This is how they got the sound of the D104 using an electret condenser mic element. In my opinion, the mic sounds better than a D104. It has more low-end audio, giving it a deeper tone while maintaining the high-tone response that the D104 is famous for.

On the next page is a copy of the schematic. Even someone who doesn’t understand it can see that there are a lot of electronics in this unit. Sorry for the poor quality; this is a copy of a copy. The original is no longer available.

Looking at the schematic in the digital delay control area, it looks as if one might be able to increase the delay by playing with the values of R16 and R17. Playing with the values of R47 and R48 would increase the echo gain, but I’m sure that changing any values will result in a deterioration of sound quality. On the air, the results were incredible.

Nobody had heard anything like this before. I must admit, I went overboard with the effects and enjoyed it, too. Usually, I don’t go in for this type of stuff, but with the flawless repeat echo, it’s too tempting to show it off.

For my taste, I found that setting the Digital Delay to the first line inside the Slapback effect range and the Effects Gain at 7 on the sideband gave a fuller effect without a hollow sound. On AM, I found increasing these settings slightly gave a fuller sound to my audio.

Playing with the headphones on, I found that by setting the Mic Gain to 5 and the Effects gain to 10, I had a reverse echo. What I mean by that is that the echo was louder than the spoken word.

This is a unique and interesting effect not mentioned in the instructions. I’m sure there are other effects that can be created with the infinite amount of control this mic offers. I did notice two minor things. One is inconsequential, actually.

Using the headphones with the Mic Gain very low, some digital noise was detected. This was extremely low and probably should be expected. Anyway, this computer noise was not transmitted over the air and probably wouldn’t have been noticed except I was listening for background noise specifically.

The other is that on some radios, the ETS won’t work. When the mic is un-keyed, the mic drops transmits momentarily before the beep. Some radios have a half-second delay before they transmit audio from the time the mic is keyed.

This momentary drop of transmit causes some radios to miss the beep tones. This isn’t unique to this mic. The very popular Sadelta Echo Master Plus has the same problem. It only happens on a few models and is easily corrected.


A 10 W capacitor on the transmit line in the radio or mic will give enough delay on the transmit line so that momentary drop-out isn’t detected by the radio.

The mic cord is terminated with an RJ-45 type connector like those used on telephone equipment and the new ham radio gear. This makes it possible for the end user to change the mic cord if it goes bad.

It also allows you to have multiple mic cords pre-wired for all your favorite radios in your closet. Want to run a different radio, just unplug the mic cord from the back of the mic and replace it with one wired for the radio of your choice.

Here’s a list of Astatic options and replacement parts:42577-00-00 Windscreen 43838-00-00 Detachable Cable EM-KIT Wall Transformer And Headphone Set CTI Audio, Inc.341 Harbor St.Conneaut, OH 44030(440) 593-1111 FAX (440) 593-5395 This is a product that exceeded my expectations on all fronts. Engineering, assembly, and performance it’s quality all the way! It’s a pleasure to be able to say that, especially about a product made in the USA.

Whether you like echo or not, this mic has studio-quality audio without the effects.