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):  



53 Reviews Hide Reviews Show Reviews

  • 5
    Speech Compressor for FT-817ND/FT-818ND

    Posted by Gust ON6KE on 17th Aug 2018

    I had a 590 set-up with just a patch lead connected to it. A simple test but boy does it MAKE a difference transmitting on the 818ND with the processor on and off, a great deal of difference! It also feels as if the TX bandwidth is narrower with the processor in switched on.

  • 4
    speech compressor

    Posted by Thom Jonsen VE7CNA on 9th Aug 2018

    Works as specified, a good product at a reasonable cost.

  • 5
    Speech Compressor FT 817

    Posted by Clive Smith on 2nd Aug 2018

    I received the kit very quickly and the construction went well. When tried on test equipment the FT817 showed a reasonable increase in average power.. I am happy with the unit and will go with me on a trip to NZ.

  • 5
    Speech Compressor

    Posted by Ray carpenter on 19th Jul 2018

    I got my speech compressor for ft817nd this morning over the moon with it thanks


  • 4
    FT-817ND Speed Compressor

    Posted by Unknown on 12th Jul 2018

    The compressor seems to working well. I would suggest better guidelines/help for the interactive adjustment with mic gain in the 817, mic level in the compressor and compression level. There must be better guideline available for a standard step by step procedure. The case would be improved with two small holes suitable for a jewllers screwdriver for pot adjustment without splitting ithe case. The plastic taps on the RJ-45 plugs on the interconnect cable are very susceptible to damage and should be protected, they are a weak link in the design. Other than that, first reports are good and I am optomistic.

  • 4
    Sotabeams speech compressor

    Posted by M3HME on 12th Jul 2018

    Brilliant little gizmo makes my 5 watts seem more

  • 4

    Posted by sv2oyo on 12th Jul 2018

    it is nessesary if you don’t want to keep your voice ...loud...it is useful ..

  • 5
    Speech Compressor for FT-817, 818

    Posted by Chris Maxwell on 11th Jul 2018

    Great product, easy to construct and easy to use.
    Gave me plus Two "S" Points in use.

  • 4
    FT817 Speech processor

    Posted by Andy on 5th Jul 2018

    Works well, does what it says on tin, only thing did find was using a local mini loop there was a slight increase in background noise on 7MHz, but considering the aerial only 2 feet from rig and the unit is unscreened this would be expected.

  • 5

    Posted by TERRY on 1st Jul 2018

    This works well with the 817, 857 as I have both radio's and did see a lot of difference when in use.