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The RA-201 REVERBERATOR made in Japan was one of the first purpose manufactured Echo units for CB operation. On the front panel is a rotary On/Off switch with Reverb volume control and power LED (usually red when unit powered on) and a 4-pin Mic socket. Common to most electronics made in Japan the construction quality and components used are excellent. RA-201 was different in that it utilises a pair of 'metal springs' supported on the chassis by a substantially thick foam sticky pad, designed to protect the springs from excess movement. Your audio is directed from the Mic input socket on the front panel, via the Electronics (see below picture), through the springs and out via a Grey coloured, non-coiled Mic lead. The springs are what give the RA-201 a very unique sound, described by some users as 'Cavernous' if the volume control is turned up to MAX. Set correctly the RA-201 can add a nice amount of analogue Reverb sound to enhance transmitted audio. Pictured above/below are the two different revisions of RA-201 manufactured. Notice the subtle differences between the two units shown. The RA-201 on the left of the picture above has a short white line on the Reverb volume control, compared to the right had unit, which has a white line extending from the top to the bottom of the control knob. In the picture below the impedance switch has different wiring colours when compairing the two revision. Interestingly middle-right of the PCB, the left RA-201 has a Green capacitor, the right hand side RA-201 has an Orange capacitor. On closer inspection several components have subtle component value changes between the two revisions of RA-201. Right hand unit missing inline glass fuse.



















              RA-201 Metal Springs Unit (REVERB).

            Notice the two vertical Springs shown.

           Your voice physically travels along the springs!













The back panel of the RA-201 REVERBERATOR shows the pre-wired 9-15 Volt DC input supply cable (red & black). The Grey OUTPUT wire shown (previously mentioned) is the audio output with 4-pin Mic plug attached (not shown), this connects to the Transceiver. An IMPEDANCE switch with HIGH and LOW positions is mounted central on the back panel to allow for High or Low impedance microphones to be used with the RA-201. The RA-201 does not have a Mic gain control for amplifying input modulation. Mobile operation unless static mobile or portable is not possible with the RA-201 due to unwanted spring vibrations within the unit making Tx modulation sound unintelligable. Full RA-201 Specifications below.

































The next generation of CB Echo Chambers came in the form of the ES-880.













The ES-880 IC ECHO CHAMBER offered several refinements over the RA-201 type of Echo chamber. The ES-880 was a BBD (Bucket Brigade Delay) and first type of analogue echo chamber which has a greater capability to reproduce reverb and slap-back/delayed echo effects. The ES-880 is also much smaller in size than the RA-201 and could also be used mobile unlike the RA-201 because of spring vibrations caused by mobile operation would make Tx modulation unintelligable. The front panel of the ES-880 has a 4-pin MIC socket, MONI (Talkback) headphone socket for monitoring output audio of the ES-880, POWER ON/OFF, 3-Bar Green & Red LED modulation meter and a rotary Echo volume control. The back panel has an audio output lead (Black) with a 4-pin Mic plug, pre-wired 13.8V DC input supply (Red & Black) lead. The back panel also has a small hole allowing for a screwdriver to adjust the Echo Delay control inside the unit.












Following the success of the ES-880 came the ES-990.







The ES-990 is how the ES-880 should have been made from the beginning. Exactly the same spec in every way except the inclusion of the Echo Delay Control (REPEAT) assigned to the front panel and the MONI headphone socket now moved to the back panel. The ES-990's front panel is mirrored when compared to the ES-880. The ES-880 and ES-990 ruled the Echo Box division for years during the 1980's, with many established operators and DX'ers using them. Several Manufactures including Sadelta produced the ES/EC type Echo Chambers but around this stage many cheaper 'clones' also appeared on the market, some with really poor quality sounding Echo effects. The ES-880/ES-990 and Sadelta range were regarded as the best quality and best sounding analogue mobile Echo Chambers available at the time.




Sadelta's version called the EC-980







SADELTA produced the EC-980 shown above and below. Exactly the same Spec as the ES-880, except to the keen eye 0-10 is printed around the Echo volume control instead of lines on the 880 and the inclusion of SADELTA, EC-980 and ECHO CHAMBER. ES-880 prefers IC ECHO CHAMBER and lines. Both the ES-880 and EC-980 are electrically identical inside, pcb etc.



















Throughout the 1980's and 90's Sadelta continued to produce popular Echo Boxes.



In more recent years 2000 onward, Sadelta produced the EC-2000.


















Made in Spain (Espania) the Sadelta EC-2000 is essentially a Sadelta 'Echo Master Plus Base Mic' but without the Mic and Mic Pre-Amp (not a bad thing?). Luckly everything else has been ported across to this Excellent BBD Analogue Echo, Famous Sadelta Bleeps & Effects Box. Connect the Microphone of your choice and add genuine SADELTA analogue Echo and Twin Bleeps straight from their World Famous Base Mics. Very Nice.










The front panel of the SADELTA EC-2000 the following features are pictured above, from left to right; 4-pin MIC socket, OFF/ON power switch with red LED when powered on, ECHO DELAY rotary control marked 0-10 fully analogue can produce very short Reverb Effects to S L O W delay Effects. 3-position switch marked ECHO/ROGER BEEP this gives the options; No Echo, Echo, Echo with Famous SADELTA Twin-Bleep (Dual-Bleep) Roger Bleep. Next is ECHO volume marked 0-10 and adjusts the amount of Echo added to your input audio, VU MODUL (Modulation) mod meter for correct adjustment of incoming/outgoing Mic level.
















Anyone familiar with the inside of a SADELTA 'Echo Master etc' Base Mic will recognise this PCB. Nice uncluttered PCB design, internally fused 500mA with 5 IC's and 1 Tx/Rx relay and 1 adjustable internal pot, all the switches and rotary controls are mounted direct to the main PCB. The quality of Echo is good for an analogue unit and the SADELTA EC-2000 has more Echo Delay range (S L O W E R and faster) than a standard SADELTA Echo Master etc Base Mic. The built quality is very good and heavy duty feeling. The pcb is populated with quality components (Philips) used throughout.























SADELTA EC-2000 back panel has 13.8 Volt DC pre-wired input supply cable (red & black), Headphone socket (Talkback) for monitoring outgoing audio from the EC-2000, audio cable (Black) with wired 4-pin Mic plug.






































VC-100 Voice Control








Following on from the very popular ES-880/990/980 Echo Chambers, the next generation of Echo, Bleep and Effects box was introduced in the late 1980's/ early 90's and came in the form of the VC-100 VOICE CONTROL Box made in Japan. The VC-100 was badged under the STARLINE name in the UK and RF LIMITED in the USA (see above and below pictures). The VC-100 VOICE CONTROL unit as with most Electronics manufactured in Japan was very well constructed and the quality of components used are excellent. The VC-100 managed to squeeze a whole host of goodies and gadgets inside the box (Echo Effects, Voice Scrambler/De-Scrambler, Voice Compressor, Mic Gain Control, Roger Bleeps, Melody Tunes) which is not much bigger in size than the ES-880.








The VC-100 front panel (left to right) has a 4-position rotary control marked; OFF (unit power off), ECHO BBD Analogue Echo (echo on), SCRAM (voice scramber on), COMP (voice compressor on) Excellent Compressor works really well, mutes all background noise when you talk, very effective. SHIFT is the next control, this is used when the unit has the SCRAMbler function enabled and acts like a Clarifier to Decode (tune-in) Scrambled transmissions. Next is a dual pot control ECHO. The inner pot TIME controls the Echo Delay (Speed) and the outer pot VOL controls the amount of Echo added to the modulation (Echo volume) MIN ECHO MAX is marked below the control. Next to this another dual pot control this one marked MON MIC. The inner pot MON controls the amount of talkback audio from the internal speaker (see below picture) on Tx or the amount of Volume for listening to Scrambled transmissions, or the amount of audio routed to the headphone socket on the back panel, MIN MAX is marked below the control. A 3-position vertical lever switch is positioned next to the Mic input socket, on the right hand side. This switch is used to select OFF (no bleeps etc), PEE (Roger Bleeps choice of 2 switchable on back panel) and MELO (Melody tunes played in a loop, Greensleeves etc, choice of 2 switchable on the back panel). Above the controls on the front panel are 6 LEDs, each for a different function and a useful modulation meter LED, MOD.






















The back panel of the VC-100 VOICE CONTROL (from left to right) MIC OUT a pre-wired (Black) non-coiled audio lead supplied with 4-pin audio plug. AF INPUT (Black) an audio input wire fitted with 3.5mm mono Jack plug, this connects to the extension speaker socket on your Transceiver enabling the VC-100 to decode received Scrambled signals when used inconjunction with another operator using a VC-100 unit. EXT SP used for connecting an external speaker, disabling the internal VC-100 speaker. MELO is for selecting between the 2 different looped Melody tunes, the Melodys are routed through the Echo Chamber so Effects can be added to the tunes. PEE is used for switching between the 2 different Roger Bleeps, the choice is between a 'Ding-Dong-Ding' Avon type sound and a series of morse code type 'dits' sounding like a telephone briefly ringing, the Roger bleeps can be routed through the Echo chamber to add effects to them also. On the far right side is the pre-wired 13.8V DC (Red & Black) input wire.










The Starline VC-200 was identical in size to the VC-100 with some different features and a Sliver finish compared to the Black VC-100. Exactly the same front panel layout as the VC-100 except the VC-200 loses the Voice SCRAMBLER function but gains more Roger Bleeps and Melodys, the Voice Compressor and BBD Analogue Echo functions are unchanged. Starting at the left hand side of the front panel we find a 3-position rotary control; OFF (unit power off), ECHO (echo on) and COMP (voice compressor on). Next is MIC MIX, this is effectively a balance control between having Echo effects and no effects, Melodys etc, like a wet and dry mix setting. ECHO VOL / ECHO TIME is a dual control, the inner pot determins the amount of Echo (volume), how many repeats the Echo reproduces and the outer control ECHO TIME determins the Echo delay time (Speed). Next is the 3-position vertical lever switch marked PEE, MELO SELECT and OFF. In the OFF position, no Roger Bleeps or Melodys transmit. The PEE enables the 8 Roger Bleeps selectable from dip switches on the back panel. MELO SELECT is a momentary position on the switch and is used to select from the 10 Melody tunes available on the VC-200. 












The VC-200 has an internal speaker for talkback monitoring similar to the VC-100, multi colour LEDs highlight the selected modes on the front panel.












The back panel of the VC-200 (from left to right) MIC OUT, audio output lead (Black) non-coiled fitted with a 4-pin Mic plug. PEE SELECT, this is a small bank of 8 micro switches numbered #1-8 and is used to 'program' the sound of your Roger Bleep. Basically this is an 8-tone Roger Bleep with each tone being independantly switchable on and off, not to be confused with 8 different Roger Bleep types i.e.Astatic MobileMax. Each number 1-8 produces a different sounding tone, up is the ON position, micro switches in the down OFF position do not add a tone to the Roger Bleep. The INT switch is used for selecting between the internal speaker or to the back panel mounted line audio RCA socket. AF INPUT is used to connect the headphone socket on your Transceiver to route audio to the VC-200 internal speaker. EXT SP is a 3.5mm mono Jack socket for an external speaker. EXT is an audio line level output, used for recording both sides of a conversation when used with the AF INPUT lead. VC-100 (top) and VC-200 back panels shown below.













When the VC-100 was last avaliable it retailed for £140 new.


























The Palomar VC-300 been included although Cobraworxshopz has never actually seen one and we have limited information other than made by PALOMAR, has a Digital voice recorder/playback capability, Microphone mixer, 2 Roger Bleeps, Melodies, Digital Echo chamber, Voice compressor, Talkback and other features.




Digital Microphone Processor











The MobileMax was manufactured into the 21st centuary by Astatic, like all excellent Astatic radio products sadly this is no longer made. Fast becoming a collectors item like all the Echo, Bleep and Effects boxes mentioned on this page. The MobileMax was only produced for a few years and during this time the MobileMax went through a dynamic change. Cobraworxshopz will try to highlight the differences between the 2 revisions of Astatic MobileMax. Both the revisions, old and new, Mk1/Mk2, early/late versions shown below.















Cosmetically there are no differences between the two revisions, the later REV2 is on the left of the picture and the older REV1 (with bracket attached) is on the right. Later REV2 box shown in background above.

The original REV1 MobileMax was manufactured until August 2001, then the REV2 MobileMax was the replacement. To understand what changes were made between the REV1 and REV2, the original specification of the REV1 MobileMax is required, read below.



Manufactured until August 2001










 REV1 & REV2 MobileMax's are cosmetically identical as previously mentioned but there are visible differences between REV1 and REV2 when they are powered up and identification is made easier.

The REV1 when powered on has the ability to display the following characters ( - 0 1 2 3 4 5 6 7 8 9 A P ) on the 7-segment ETS DISPLAY (currently showing 9 in the above picture) this is because the REV1 has 9 different ETS (End of Transmission Signal) or Roger Bleeps, number 9 is a random Bleep sequence mode. The REV1 has a 6-second SBR (Sound Bite Recording) capability, this gives you 6 seconds to record your own personal sound bite and play it back over the air.



Manufactured after August 2001









The REV2 MobileMax manufactured after August 2001 is shown above, when powered on the 7-segment ETS DISPLAY (currently showing E in the above picture) can only display the following characters ( 0 E A P )* This is because the REV2 only has 1 ETS (End of Transmission Signal) or Roger Bleep, when selected the letter E is displayed, a Kaytone Dah-Di-Dah, Roger Bleep is enabled. 0 on the ETS DISPLAY is Bleep Off. The REV2 has a 28-second SBR (Sound Bite Recording) capability, this gives you 28 seconds to record your own personal sound bite and play it back over the air. *except when counting down during SBR Record.


The decision by Astatic to change the specification of the MobileMax in 2001 is seen by many users to be the direct result of the unit being discontinued. An early critisism of the REV1 is that it should have had more SBR (Sound Bite Recording) time, 6-seconds is not very long. Cobraworxshopz believe Astatic, facing dropping sales of the MobileMax due to falling user numbers within the CB hobby, aimed the unit more at the Amateur Radio / DX Contester market, the K-tone and longer SBR time making it attractive to Dx Contesters. Most CB'ers agree Astatic's descison to expand the SBR time to 28 seconds to be excellent but not at the cost of losing 8 ETS Roger Bleeps. So to recap the REV1 has 9 Roger Bleeps and a 6-second record/playback function (SBR) and the REV2 has 1 Roger Bleep and a 28-second record/playback function (SBR). All other functions are exactly the same, Echo effects, Mic gain etc. Which unit would you want REV1 or REV2?



Printed on the MobileMax PCB (printed circuit board) below, a reminder for Tech's not to pour a bucket of water into the MobileMax, no matter how frustrating a repair may become ;o)









With the covers removed both Revisions look virtually identical.












Below is a closer view of the MobileMax PCB and descriptions of the various parts, numbered.






















Astatic MobileMax 
numbered description;

1) CB Speaker Volume control, rotary pot control for adjusting the input volume from the CB Transceiver when connected to the back panel CB Speaker Input Jack socket.

2) Uniden 3-pin type 13.8V DC power input socket, uses standard Uniden/Cobra power lead.

3) Philips IC 74HC373D Octal D-type transparent latch; 3-state. The "373" consists of eight D-type transparent latches with 3-state true outputs. When LE is HIGH, data at the Dn inputs enters the latches. In this condition the latches are transparent, i.e. a latch output will change state each time its corresponding D-input changes. When LE is LOW the latches store the information that was present at the D-inputs a set-up time preceding the HIGH-to-LOW transition of LE. When OE is LOW, the contents of the 8 latches are available at the outputs. When OE is HIGH, the outputs go to the high impedance OFF-state. Operation of the OE input does not affect the state of the latches. The "373" is functionally identical to the "533", "563" and "573", but the "563" and "533" have inverted outputs and the "563" and "573" have a different pin arrangement.

4) Audio Isolation RFI transformer, the transformer reduces all types of RFI especially RF feedback from hampering the modulation through the MobileMax.

5) "Main Brain" Programmable CPU and one of the only differences between the REV1 and REV2. see below

MobileMax REV1 uses an ATMEL 'AT90S4414 4JC 0014' (Below Left)












MobileMax REV2 uses an ATMEL 'AT90S8515 4JI 0106' (Above Right)

For all the Tech's interested;

The ATMEL AT90S4414 microcontroller

The AT90S4414 is a low-power CMOS 8-bit microcontroller based on the AVR RISC architecture. By executing powerful instructions in a single clock cycle, the AT90S4414 achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed. The AVR core combines a rich instruction set with 32 general purpose working registers. All the 32 registers are directly connected to the Arithmetic Logic Unit (ALU), allowing two independent registers to be accessed in one single instruction executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs up to ten times faster than conventional CISC microcontrollers. The AT90S4414 provides the following features: 4K bytes of In-System Programmable Flash, 256 bytes EEPROM, 256 bytes SRAM, 32 general purpose I/O lines, 32 general purpose working registers, flexible timer/counters with compare modes, internal and external interrupts, a programmable serial UART, programmable Watch-dog Timer with internal oscillator, an SPI serial port and two software selectable power saving modes. The Idle Mode stops the CPU while allowing the SRAM, timer/counters, SPI port and interrupt system to continue functioning. The power down mode saves the register contents but freezes the oscillator, disabling all other chip functions until the next external interrupt or hardware reset. The device is manufactured using Atmel’s high density nonvolatile memory technology. The on-chip in-system programmable Flash allows the program memory to be reprogrammed in-system through an SPI serial interface or by a conventional nonvolatile memory programmer. By combining an enhanced RISC 8-bit CPU with In-System Programmable Flash on a monolithic chip, the Atmel AT90S4414/8515 is a powerful microcontroller that provides a highly flexible and cost effective solution to many embedded control applications. The AT90S4414 AVR is supported with a full suite of program and system development tools including: C compilers, macro assemblers, program debugger/simulators, in-circuit emulators, and evaluation kits.

6) The Memory Chip, memory module is the SAMSUNG KM68V1000BLT-7L, 128K X 8bit Low Power and Low Voltage CMOS Static RAM.

7) Lithium Battery for memory back-up, soldered onto pcb.

8) TX/RX Relays, Over-Spec HANKUK HR94C. 28V DC @ 1 Amp. (same make as used in Cobra 200 GTL-DX)

9) Multiway Connectors x 2. Used to connect the main PCB to the front PCB via 2 ribbon wire connectors (unplugable)

10) Voice Transfer Display, Multicoloured LED Bar Graph Display, uses 20 LEDs, 11 Green, 5 Yellow and 4 Red. The display acts like a VU meter when you talk, this feature enables you to effectively set the microphone gain control. (13)

11) Effects Gain Dial, this pot controls the volume/amount of Echo added to your transmission.

12) Effects Delay Control, neutral in the centre-slot 12o'clock position, turning clockwise adds Slapback 'Double-talker' effects, turning anti-clockwise controls the recursive Echo Time Delay and enables very long repeats with several seconds delay.

13) Microphone Gain Control, allows the user to set the microphone gain to the optimum level (10) for best performance. This control has enormous amounts of gain and makes any Mic sound excellent, worth owning a MobileMax for this feature alone.

14) ETS Select (Roger Bleep), Red push button allows the user to select from 9 ETS Tones*, turns the ETS on/off or have the MobileMax randomly select tones 0-8 each time you unkey the microphone. (* 1 ETS Tone for REV2)

14) S.B.R. Select, Red push button with Play/Rec marked below the button. The SBR (Sound Bite Recording) feature gives you 6 Seconds* to record your own personal sound bite (eg.CQ Call) and play it back over the air at the push of a button. (* 28 Seconds for REV2)

14) Power On/Off.

15) 4-pin Microphone input.

















REV2 MobileMax shown above, notice the yellow plastic surround on the Lithium Battery centre and to the right the of ATMEL CPU, the words 'PROGRAM' are printed on the PCB, next to 5 holes used for programming the ATMEL CPU. The MobileMax is programmed on the production line using an SPI Serial bus connector and computer.










03/29/00 *DMAN&MOR*    

Etched into the PCB on both REV1 and REV2 MobileMax's is the above date and name, presumably 29th March 2000 was the PCB finalisation date. *DMAN&MOR* are the designers?






























MobileMax back panel (from left to right) Audio output lead pre-wired (Black) coiled Astatic rubberised quality. CB Transceiver audio input, Speaker Volume control and on the right hand side, the Uniden 3-pin 13.8 V DC power input connector.


















The above picture shows both revisions of Mobile max, REV2 in the plastic packaging and REV1 on top. This is a complete package including all original supplied accessories and two new Astatic 'Teardrop' 575-M6 Microphones. The original and boxed 575's and MobileMax's have only been taken from their original packaging for photographic purposes for this page.



Analogue Tape Echo Chamber











The MELOS range of Analogue Echo Chambers were very popular in the 1980's used by various Stations. The Melos range were initially Analogue Cassette Tape units, to be later updated with Analogue BBD electronics. Melos made various Echo Chambers in their product range with the Melos EM-110 being a popular unit used on CB.






















































The Roland RE-201 SPACE ECHO was the Cream of Analogue Tape Echo Chambers back in the 1970/80's.














In 1973, Roland created the Space Echo system that utilized multiple play heads to create warm, highly adjustable echo effects, which added wonderful tape character and chaos to performances and recordings. The Space Echo can be heard on numerous recordings, from 70’s space rock like Pink Floyd and David Bowie, to countless Reggae and Dub albums, to more recent bands like Portishead and Radiohead. See below the tape looped inside the cassette and the multiple heads on the right hand side.
















RE-201 SPACE ECHO back panel below.























All the Echo Chambers featured on this page are sadly no longer manufactured, each unit is a collectors item in it's own right.

Manufacturer BOSS have teamed up with Roland to produce a close as you can get to the original RE-201 SPACE ECHO Analogue Tape Echo Chamber in the guise of the BOSS RE-20 ROLAND SPACE ECHO RE-201, currently manufactured, see below.


















The Rebirth of a Roland Classic
One of the most beloved echo effects ever made, the Roland RE-201 Space Echo, has been reborn as the BOSS RE-20 Twin Pedal! Roland and BOSS have recreated every sonic detail and nuance of the original. Experience the legendary tape-echo sound of the RE-201, and get “lost in space” with this retro-modern marvel.


  • Amazing simulation of the famous Roland RE-201, with the spacious, analogue tone of the original Space Echo
  • Faithful modelling of the RE-201’s tape flutter and magnetic head sound saturation
  • Tap input pedal allows delay time to be set by hand or foot
  • Longer delay time than the original RE-201
  • Control parameters such as REPEAT RATE, INTENSITY, and more via Expression pedal
  • MODE SELECTOR knob with 12 placements just likes the original Space Echo.



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