SOLD MFJ-616 Speech Intelligibility Enhancer

Discussion in 'Ham Radio Gear For Sale' started by W9MT, Nov 22, 2019.

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  1. W9MT

    W9MT Ham Member QRZ Page

    I'm selling this unit for a colleague. I've fully tested it and it works FB. It has a few more minor surface scratches than the spare unit of my own that I sold here on last Saturday. The most noticeable one is on the bottom. If you want to make this unit pretty, a steady hand, skinny brush, and some Revell glossy black paint can do wonders. That won't change the superb electronic performance one iota, though.

    These things work!!! The ham to which I sold my spare MFJ-616 had hearing difficulties and while not a perfect solution to his own situation, the MFJ-616 helped him enough to enjoy operating that he said it would become a permanent part of his own station. They are keepers (unless you have one too many). Snap up this one, delivered, for less than half the price of a new 616 from MFJ. Following is the write up from my previous listing. Photos are of the actual MFJ-616 you will be buying. Same copy of the manual/schematic, same stipulations on the sale. The price is the same $120, shipped CONUS to you. (No international sales, Alaska/Hawaii contact me for an exact shipping quote.) If you use PayPal, I will send you my PayPal alias when you're ready to purchase.

    73, Tony (W9MT)


    This is a great accessory for shaping receive speech audio for maximum intelligibility. This is not a DSP-based carrier tone nor receive white noise and static crash reducer. But it is an audio bandpass shaping device that can attenuate or boost audio centered around 300 Hz, 600 Hz, 1200 Hz, and 2400 Hz by +/- 20 dB.

    Moving the 300 Hz control below its 12 o'clock setting dramatically reduces the rumble in the received audio that carries very little intelligence but contains the lion's share of the (useless) audio power.

    Boosting the 600 Hz, 1200 Hz, and 2400 Hz from their 12 o'clock positions to about 2 PM or so boosts the receive audio band in ranges where its power is normally low. This makes the clarity of the received voice literally jump out of the mud making it much more understandable. 600 Hz and 1200 Hz can be readily boosted to their full CW positions, but don't do this to 2400 Hz because you will increase the received "hiss" which consequently will negatively affect its overall understandability. 2400 Hz can be set below 12 o'clock under conditions of a lot of excess white noise or when used with a radio with a lot of high frequency hiss in their audio (like my Swan 270). Radios like these can be difficult to listen to for long periods of time, and can cause headaches in certain people. The MFJ-616 placed between such a radio's audio output and an external speaker can make reception much more tolerable and (dare I say it?) even enjoyable.

    The MFJ-616 simply passes through the normal receive audio when the red button is used to power it off. Its internal 2.5W audio amplifiers can be used to increase or decrease audio volume without shaping the audio when the bypass button is engaged. The MFJ-616 allows two input sources (A & B) to be used one at a time. If your ears hear differently, the MFJ-616 can feed either the A or B channel to two speakers where the heard audio can be balanced to sound the same to both ears with a balance control.

    You don't need to be an old timer with bad hearing to enjoy what this device can do to improve the intelligibility of your received audio. I actually couple my other MFJ-616 to two ClearSpeech speakers to take advantage of both DSP noise reduction and the MFJ-616's. My ClearSpeech speakers are in oddly positioned places on the station desk, so the balance control takes care of centering the audio.

    I wouldn't do my HF work without one. This one is an extra unit I no longer need. It is not beat up, nor modified. But there are some very minor scratches and dings on the housing from normal use. There's lots of life left in this well working unit. MFJ's current price is $229.95, plus shipping. My price, including CONUS shipping, is only $120. (No international shipping. Alaska and Hawaii buyers need to contact me for their added shipping costs...I've shipped stuff there before, and it does cost more.)

    The manual with schematic diagram will accompany the shipped MFJ-616.

    The MFJ-616 will leave my shack in 100% working condition. No returns due to parts swappers or if you suddenly develop buyer's remorse. I pack very well to assure safe arrival at your QTH. The MFJ-616 will be wrapped in Saran Wrap to assure that shipping peanuts to not get inside of it. The ample cushioning will assure shipping survival even if the American Tourister Gorilla handles the parcel. (You younger hams look for the commercial on YouTube if you don't know what I'm talking about.)

    I accept PayPal for payment, as well as a Money Order if you want immediate shipment upon me receiving your funds. A personal check drawn from a US based bank is also acceptable as long as you are willing to delay my shipping by 10 business days for the funds to clear the banking system. If you choose to use PayPal, contact me via my email on my page and I will email you back with my PayPal alias.

    Don't underestimate what this MFJ-616 can do. It sounds very simple in concept, but...boy does it make a difference you don't expect !!!

    73, Tony (W9MT)
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    KA8UGB and KE9OL like this.
  2. WZ9Q

    WZ9Q XML Subscriber QRZ Page

    I bought the one Tony sold last Saturday. Looks and works great! Well packed and shipped via priority mail.
  3. W9MT

    W9MT Ham Member QRZ Page

    Moderator, please mark this item as SOLD, with my thanks.
  4. QRZ
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