Speech Compressor for FT-817, 818

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Speech Compressor - unleash your DX potential

***apparent improvement can be up to 6dB!***

Available ready-built or as as an easy-to build kit. Build time approx 40 minutes

817に効きます! その差は歴然。JH4DUQ - via Twitter

The FT-817 FT-818 is a great radio but the SSB speech power does lack "punch". This great little external AF dynamic compressor from Germany Box 73 will aid readability and maximise the performance of your radio (essential when using QRP). Speech Compressors work by raising the average level of your audio signal, giving greater "talk power".

Plug and Play! Connects between the radio and microphone (lead included). The compressor function can be switched in or out, the module draws its power directly from the transceiver (approx. 10mA). The compression level is adjustable. Modifications to the microphone or transceiver are not required.

Click here for instructions.

The compressor is also suitable for use with the FT-900, FT-857, FT-897 and FT-450 (all versions)


Speech compression is not recommended for use on FM

Occasionally people have problems plugging their microphone into the compressor. This is because the Yaesu microphones are fitted with an oversized rubber boot that shrouds the RJ45 connector. If the RJ45 connector does not click firmly into the body of the speech compressor, gently retract the rubber boot a few millimetres and the connector will engage properly (100% success rate!).


 Also available from our international agent(s):  



52 Reviews Hide Reviews Show Reviews

  • 5
    speech compressor

    Posted by Steve on 4th Apr 2020

    Easy to build works great .

  • 5
    Great so far

    Posted by james roff on 17th Jan 2020

    Purchased after looking at many options on the internet and for overall price I went for this. Definitely notice the improvement in voice level and has made an improvement to my qrp 2m activity just an 818 2 element Yagi about 4m above ground.

  • 5
    Speech Compressor for FT-817, 818

    Posted by Wayne Montague on 4th Dec 2019

    Item shipped quickly to Canada. The build involved 2 pots, 2 sockets and a large SMD capacitor. The only thing to really pay attention to is to put the pots in the right place. Plugged the completed assemby into the FT-817 and the difference between IN and OUT was obvious. The "tune" feature is a really nice touch. It gets a 5 for value, fast shipping, ease of assembly and working as advertised.

  • 5

    Posted by Albert on 3rd Nov 2019

    great product to combine with the original 817 microphone in ssb I always had excellent reports

  • 4
    Speech compressor

    Posted by Victor on 1st Nov 2019

    Works well. Only problem was a loose connection from microphone. Only solution was to use a rubber band.

    [Admin: thanks for your review. I suspect that your microphone is not locking in properly. Retract the rubber boot on the mic connector and all will be well.]

  • 4
    +1 S unit at least

    Posted by oh1bpp on 24th Oct 2019

    Product keeps what is promised, much better reports keep coming and audio is better. Only negative thing was that in the kit version, in the box the holes for mic cables were too tight and I had to enlarge those. Too tight holes resluted in loose mic connection and nothing happened when I pushed the PTT

  • 1
    I didn't know it was a kit. So I am disapointed. I have not yet soldered it

    Posted by JULIEN LE TALBODEC on 23rd Oct 2019

    Why you didn't say before bying that the product was a kit one,

    [Admin-thanks for your review. We sell the processor as a kit or a built unit. You selected the kit option - so that was what we sent. Feel free to return it to exchange for a built unit if you wish.]

  • 5
    I love it

    Posted by Frank Leon on 22nd Oct 2019

    It gives me more 6db with my modified MH-31 mike! I always work from the field with QRP. SSB now is a great fun!
    The local delivery company is not the best, but Aaron from the Sotabeams customer service helped me as quicly as possible to find my parcel.
    Great job, thanks!

  • 5
    Does what is says

    Posted by Michael Cox on 2nd Oct 2019

    After completing the assembly that was very easy I plugged it in to my ft818 and it worked. My first QSO was on 20m from my home in central France to a contact operating portable on the sea front in Blackpool who gave me a 59 signal report. I was using a half wave endfed antenna and my contact a quarter wave vertical. I have never managed an SSB QSO before with the ft818 so think this a success for the speech compressor.

  • 5
    Speech Compressor for FT-817

    Posted by Bill on 11th Sep 2019

    Does what is says on the can. Perfect plug and play, just adjusted the rig mic gain for excellent results.