Asymod™ ES Compressor / Limiter / EQ & Asymmetrical Hi-Fi Modulator Board

$275.00

Asymod ES

Compressor / Limiter / EQ & Asymmetrical Hi-Fi Modulator 


Asymod ES Compressor / Limiter / EQ & Asymmetrical Hi-Fi Modulator for use with mobile or base CB & HAM radio transmitters and transceivers.


Got questions? Visit the new Asymod related FAQs and get answers to the most frequently asked questions and lots of valuable information related to Hi-Fi communications.

Sound Pro mobile or base with the Asymod Asymmetrical Hi-Fi AM Modulator. Get the Hi-Fi audio you want with this compact unit. With this setup you will save in time to come as there will never be the need to upgrade again.


DESCRIPTION

 

The Asymod ES Asymmetrical Hi-Fi AM Modulator has all the basic functions of its predecessor, the Asymod ES but in addition is fully loaded including an onboard compressor, limiter, 3 band equalizer, noise gate, a 6 kHz active second-order 40dB/decade (12dB/octave) stop band roll-off filter and accepts balanced and unbalanced microphone inputs as well as a line input that both can be used simultaneously in mix mode. Now you can have that great sound without external computer based or rack gear audio processors.

 

Perfect for mobile operation, the Asymod ES is a complete solution to give your station the very thought after broadcast sound. Its compact design allows for internal mounting and simple installation in the transceiver with the included hardware and only requires a 12 Volt supply. The Asymod ES expands the transmitter’s audio bandwidth from the stock 3 kHz to over 6 kHz. On board preset active and passive low pass filters can be configured to 6, 8 or 10 kHz roll offs and beyond if necessary. This allows for the entire selected audio bandwidth to be transmitted.

 

The asymmetrical functionality controls the audio loudness level and provides for amplitudes in excess of +300% modulation while not exceeding the negative peaks at -100% without the use of negative peak limiting or clipping methods which produce squaring of the modulation envelope and provides for increased spectral density. The Asymod ES is compatible with most transceivers and it is fully adjustable via the onboard controls and accepts microphone and line level inputs. It offers the flexibility to use a stock hand mic to a high end processing audio chain using a broadcast microphone. This unit will work with all High Level Modulation transceivers by direct coupling to the driver and final’s collectors via the existing transceiver's onboard RF chokes without the need for heavy, costly and large modulation transformers. Low Level Modulation transceivers will require some modification. Instructions for specific multiband HF transceivers is available upon request.

 

The Asymod ES produces modulation levels well above the norm and broadcast levels without distortion, allowing for your station to sound loud and clean. With the Asymod ES in your transceiver of your choice, your mobile or base station will sound just as or better than commercial broadcast stations.

 

The transceiver/radio is only the exciter and should not be expected to generate high levels of RF power, it should be expected, however, to generate a clean, perfectly modulated wide-band Hi-Fi audio RF signal well within the limits of the headroom available without pinching or clipping at the crest or troughs of the modulation envelope which can be later amplified with a class AB, RF power amplifier and is best heard or monitored on a good quality receiver equipped with a 6 kHz AM wideband filter and monitored on an oscilloscope.

 

The Asymod ES is an audio processor, and it does allow for full bandwidth control with the use of the onboard Compressor, Limiter and 3 band equalizer. It too can be used with Pro Tools, a combination of rack gear, or a broadcast multi band compressor / limiter.

 

The Asymod ES onboard audio processing along with a high quality microphone delivers optimum performance.

Additional audio processing for mobile or base operation is possible with the use of the iRig PRE or iRig PRO interface using the companion IK Multimedia's VocalLive Vocal Processor app (not the free version) on your iOS device.

 

Additional audio processing for base operation is possible with the use of rack audio processing gear or computer based processing such as Pro Tools for PC or Mac along with its companion interface such as the Mbox 2 Mini or newer. Pro Tools sessions are free and available for download.

 

FEATURES

 

Recently added features to the new and improved Asymod ES Include on board compressor/ limiter with gain reduction indicator, noise gate, 3 band graphic equalizer, balanced and unbalanced microphone inputs, input and output passive low pass filters and a 6 kHz active second-order 40dB/decade (12dB/octave) stop band roll-off filter which can be configured to provide other preset roll off points,

 

In addition it provides remote control operation via the on board Solid State switch which provides mode switching for ease of installation on multimode transceivers. Enhanced RF suppression circuits have been added and board layout design has been optimized to eliminate and avoid any stray running currents due to RF interference. Single supply operation provides for a very low noise and quieter operation. New onboard SSB Line-Out terminal to feed Hi-Fi audio to the SSB Balanced Modulator input for eSSB operation.

 

The Asymod ES compact design allows for easy mounting inside your transceiver and offers all the combined features comparable to high end, very expensive broadcast gear and other available Hi-Fi mods upwards of $1000, and makes for the most important part of a Hi-Fi AM station. Hi-Fi Audio is very thought after by many radio operators nowadays and the Asymod ES delivers all the necessary functionality and stands as the backbone of the station.

 

Now you can make your mobile or base station sound like you always wanted it to at an affordable price. If you are tired of spending on expensive gear or trying different combinations and still don't have the Hi-Fi audio you want for your CB or Ham AM radio station setup this is the way to go.  With this setup you will save in time to come as there will never be the need to upgrade again.

 

  • Noise gate attenuates signals by a fixed amount and allows only signals to pass through only when it is above the set threshold with enable/disable capability.
  • Signal Processor operation that reduces the volume of loud sounds and amplifies quiet sounds by narrowing or compressing the audio signal's dynamic range.
  • Limiter allows signals below a specified input power or level to pass unaffected while attenuating the peaks of stronger signals that exceed the compressor threshold.
  • 3 band equalizer provides audio enhancement and bandwidth control, 10 Hz to 10 kHz.
  • SSB audio out for eSSB operation.
  • Mobile or base operation, ease of use and simple installation; only a 12 Volt, 5 Amp power supply is required.
  • Rugged design built on a tough PCB to provide years of continuous use.
  • Audio gain control allowing for proper drive from the microphone and line level input.
  • Modulation Level control allows for final audio control and is set in combination with the Carrier and Asymmetry controls to achieve the level on modulation desired.
  • Carrier controls sets the reference carrier level (dead key) to set the modulation and asymmetry levels.
  • The Asymmetry control maintains the negative peaks at -100% modulation while allowing for positive peaks of excess of 300% without pinching or clipping.
  • Remote ON/OFF control.
  • Input voltage polarity protected
  • Power status LEDs for the 12V and onboard 24V supply.
  • Modulation peak indicator.
  • Gain reduction indicator.
  • Easier installation.
  • Convenient mount holes.
  • Heavy duty screw terminal block connectors for the line in, power in, modulator output, pre-in and pre-out connections.
  • TO-220 and TO-247 on-board compatibility for mounting single or dual modulating stage transistors.

 

MODULATOR CONFIGURATION

The Asymod ES may be set up in any one of the three following configurations:

 

A- Single MJE3055T transistor (Q7) with a maximum collector current of 10 Amps.

B- Dual MJE3055T transistor (Q6 & Q7) with a maximum collector current of 20 Amps. (Request)

C- Single TIP35C transistor (Q8) with a maximum collector current of 25 Amps. (Request)

 

Due to new installation method, configuration A will work fine with most 4 watt transceivers, heavy use or higher output transceivers, such as dual final transceivers by implementation of the Pre-Driver / Driver modulation and bias modulation methods. Configurations B or C can be used which withstand higher duty cycles at lower temperatures and are available upon request.

 

Be advised that the Asymod ES appearance will vary depending on the requested configuration and combination of modulator final output stage transistors used.


SPECIFICATIONS

 

The Asymod ES features a microphone balanced bridging input, which may be connected unbalanced if desired which can be used with microphones with impedances of 150 Ohms or greater. Additionally is also has a Line In unbalanced input that can be used simultaneously in conjunction with the microphone input for mixed programing of audio playback.

 

The onboard three band equalizer control provide active equalization, each controlling a separate audio band. These bands were carefully selected to yield a module that works effectively in a wide variety of configurations. Each band’s center frequency can be either boosted or attenuated by +/-20 dB.

 

MICROPHONE INPUT

Input: 150Ω or greater balanced or unbalanced bridging; mic-level

 

LINE INPUT

Input: 600Ω balanced; Line-level typical 700mV P-P

Input Range: -15 dBu (400mV P-P) to -6 dBu (1V P-P)

 

EQ TYPICAL PERFORMANCE

THD:    < 0.030%; 0.010% typ. (1 kHz, +4 dBu ref.; flat response)

CMRR:             > 50 dB @ 100 Hz

Frequency Response: 10 Hz to 10 kHz (EQ set flat; +/- 0.5 dB)

Noise: < -80 dB below +4 dBu

Center frequencies:

Low Band: 80 Hz / Bandwidth: 20 Hz to 300 Hz

Mid Band: 1 kHz / Bandwidth: 200 Hz to 3 kHz

High Band: 4 kHz / Bandwidth: 2.5 kHz to 10 kHz

 

NOISE GATE

Maximum Input Level: -6 dBu (1V P-P)

Noise Floor:

Gate Closed -105 dBV

Gate Open:

HISS -100 dBV

MID -100 dBV

FULL -96 dBV

Bypass: 0

 

COMPRESSOR / LIMITER

Variable compression and limiting

COMP at 0: Limiter off, compressor 1:1

COMP > 0: Limiter on, compressor 1:2 – 1:10

 

LOW PASS FILTER

6 kHz active second-order 40dB/decade (12dB/octave) stop band roll-off.

 

FREQUENCY RESPONSE

Input: 20 Hz – 20 kHz

Output: 20 Hz – 6 kHz.    Expandable to 20 kHz.

 

TOTAL SYSTEM DISTORTION (@ 300% modulation)

<0.01% THD 20 Hz – 1 kHz

<0.02% THD 1 kHz – 5 kHz

<0.03% THD 5 kHz – 14 kHz

<0.05% THD 14 kHz – 24 kHz

 

MODULATOR OUTPUT:

 

*The following values were recorded using configuration A, modulating an AM transceiver manufacturer rated at 4W carrier and 16W peak with a 1 KHz tone.

 

Refer to the captured oscilloscope pictures in the Asymod ES Operation & Troubleshooting Guide.

  • @100 % modulation: 3W carrier, 12W peak. (4X carrier = 100% modulation).
  • @200 % modulation: 2W carrier, 16W peak. (8X carrier = 200% modulation).
  • @300 % modulation: 1.0W carrier, 15W peak. (15X+ carrier = 300% + modulation). 

 *The following values were recorded using configuration B, modulating a CRE-8900 transceiver with one IRF-520 driver and two IRF-520 finals with a 1 KHz tone, manufacturer rated at 12W carrier, 48W modulated. 

 

•          @100 % modulation: 15W carrier, 60W peak. (4X carrier = 100% modulation).

•          @200 % modulation: 7.5W carrier, 60W peak. (8X carrier = 200% modulation).

•          @300 % modulation: 4W carrier, 60W peak. (15X carrier = 300% modulation).

   

*For higher RF output power levels use a class AB amplifier. It is best to generate your original modulated signals at lower levels and use the amplifier to amplify your output to the desired level.

 

Shielded cable should be used in all audio connections and RF bypass capacitors where ever possible.

 

 

BALANCED MICROPHONE INPUT

 

The Asymod ES features a microphone balanced bridging input, which may be connected unbalanced if desired which can be used with microphones with impedances of 150 Ohms or greater. The balanced configuration is recommended for areas susceptible to RF interference. Additionally is also has a Line In unbalanced input that can be used simultaneously in conjunction with the microphone input for mixed programing of audio playback.

 

EQ

 

The onboard three band equalizer control provide active equalization, each controlling a separate audio band. These bands were carefully selected to yield a module that works effectively in a wide variety of configurations. Each band’s center frequency can be either boosted or attenuated by +/-20 dB.


The Asymod is NOT designed to give transceivers more RF power, more swing, or loud distorted modulation. It is however, to be used with the appropriate audio processing to produce a broadcast quality transmission.


The Asymod ES comes with:

Asymod ES Manual

Asymod FAQs

• Mounting hardware
• TO-220 / TO-247 Thermal Silicone Rubber & Fiberglass Composite Insulator
• Single MJE3055T transistor (T2), configuration A. Configuration B or C available upon request
• Downloadable Pro Tools sessions


For advice on Hi-Fi audio processing you may visit http://www.nu9n.com/am.html


Please Read Before Buying: 

Please do all research and ask all questions before buying.

Take a look at the pictures and the oscilloscope captures for actual results, browse through the manuals and ask questions as needed.

Unit ships out within 1 to 3 business days of cleared payment if unit is ready otherwise as soon as the unit is ready.

*EV RE20 microphone shown in pictures is not included.


 Read through all related documents, including the Asymod FAQs and manuals to see the requirements for an effective Hi-Fi setup before committing to purchase. All sales are final and there are no returns. If the unit breaks, please send it back for repair. All repairs are free within the first two months after the sale.