Inovonics 222

Discussion in 'Amplitude Modulation - AM Fans' started by KA4KOE, Dec 1, 2017.

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  1. AC0OB

    AC0OB Subscriber QRZ Page

    We did order one as a backup for one of our 500 Watt M&P stations.

    Will be going out tomorrow to run some audio tests and see what it can do for $99 plus shipping.

    KC2ZFA likes this.
  2. N2DTS

    N2DTS Ham Member QRZ Page

    Let us know what you think, I was looking at one on ebay for $66.00.
    I am having fun with the home brew tube stuff, but for that price I might try it!
  3. AC0OB

    AC0OB Subscriber QRZ Page

    Finally got the levels set and while it's not an Omnia.7 AM or an ORBAN 9100A it is doing quite well for Christmas Music on the "MUSIC" setting and is quite "airy". For speech only the "SPEECH" setting is probably best.

    Once I got it set for the most aggressive material (The Trans Siberian Orchestra, Tracks 6 and 8), it seemed to compress and limit all other material, including voice, just fine.

    It does have RF filtering on the input and sitting next to the BE AM-1A 500 Watt transmitter (with Antenna just outside the blockhouse) there was no RF intrusion whatsoever.

    You need at least 500mV of audio voltage for the -10dbV input V setting and about - 5 dBu for the +4 dBu input V setting.

    For a backup unit it is not too bad for the price.

    Last edited: Dec 8, 2017
  4. N2DTS

    N2DTS Ham Member QRZ Page

    Does it overshoot, or hold the modulation under 100% negative?
    That is the real problem with most cheap compressors, the initial audio gets through before gain reduction....
  5. AC0OB

    AC0OB Subscriber QRZ Page

    In this compressor the raw audio is analyzed by an RMS circuit for compression while the peak value is used to control the limiter gain block (in real time), so it's fairly tight.

    BTW, don't rely on meters like the MFJ power meters to tell you about peaks. The circuits in those meters will tell you the peak power, but the circuitry and metering is too slow to show you the actual peak in real time. I.e, it will capture the peak, but that peak has occurred long before the indication.

    I do like the fact that the audio is split into two bands for tighter control. It reminds me of some of the earlier split band BC compressors/limiters.

  6. KC2ZFA

    KC2ZFA Ham Member QRZ Page

    so Phil, is this a good buy for a neophyte ? and being stereo means you can set up two settings and switch between the two via cables, no ?
  7. AC0OB

    AC0OB Subscriber QRZ Page

    I think so, and one could certainly do that.

    Another method is to chain the two channels and use one channel as a compressor and the second one as a hard limiter.

    KC2ZFA likes this.
  8. N1BCG

    N1BCG Ham Member QRZ Page

    Wouldn't it be better to not chain them and have the unit operate in "dual mono" so that the compressor channel and limiter channel gain reduction operate independantly?
  9. G0GSR

    G0GSR Ham Member QRZ Page

    Phil, is there anything to limit the bandwidth if you use one of these on air?

  10. AC0OB

    AC0OB Subscriber QRZ Page

    This unit has a freq. response of about 20 to 20kHz minimum.

    No, there is no way to limit bandwidth in the unit proper. One would have to put an equalizer in front of if you wanted to roll off the highs.

    In our case, the audio chain does have an equalizer in it.


    Last edited: Dec 9, 2017

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