[Ham-Mac] Re: Still trying to go digital (with SignaLink, iBook G4, Cocoamodem, iMic)

[Wes Bennett]

   After I read the posted reply from Rich KI4FW, I realized that you 
are discussing linking an iBook with your Tranceivers in your  Ham 
radio shack. Sorry 'bout that.

Wes Bennett
N2UOF


On Sep 27, 2005, at 4:29 AM, Dick Kriss, AA5VU wrote:

> On 9/26/05 11:51 PM, "Richard Cincotta" <ki4fw at hotmail.com> wrote:
>
>> Dick,
>>
>>    I communicated with you awhile back, and was unable to get my
>> Cocoamodem/iBook G4 setup to work (and I was too busy traveling to 
>> worry
>> about it).  Well, I'm back.
>>
>>    Here's my problem.  I need to use an iMic for my input soundcard, 
>> which
>> is placed in between the SignaLink A/D converter, and my iBook G4 USB 
>> port.
>> But, the audio cord hookup -- going from the SignaLink to the iMic -- 
>> does
>> not seem to work.  If I jiggle the plug that's stuck into the iMic 
>> input
>> jack (showing the microphone) I only momentarily see the gain 
>> indicator,
>> oscilloscopic ovals or PSK waterfall on Cocoamodem's screen display.  
>>  I
>> can't sustain that input, however -- no matter how I hold the plug 
>> that's
>> stuck in the input side of the iMic it only goes on for a fraction of 
>> a
>> second.
>>
>
> Richard KI4FW,
>
> I am the wrong person to ask about receiving via an iMic.  I never 
> could get
> it to pass a useful signal from my Kenwood TS-570.  The only way I 
> managed
> to get a useful Rx audio signal from the Kenwood to the Mac was to run 
> a
> standard stereo cable from the output of the SL-1+ to the Line-in
> (Microphone Port) on the back of the G4.  Every time I tried to use 
> the USB
> port the iMic acted like an attenuator and the signal level was too 
> weak at
> the Mac.  I gave up on the iMic but others have had success.  Maybe 
> they can
> help. FYI, Steve WB6RSE, contacted Griffin and found the iMic 
> specifications
> to be
>
>> Input is 6630 ohms
>> Output is 18 ohms
>
> I suspect the 6630 ohms may be incompatible with my Kenwood TS-570 
> output as
> modified by the SL-1+.
>
> Please note my comments are regarding the receive audio only.  I 
> transmit
> from the Mac's USB Port to the iMic and in turn to the SL-1+ to the 
> Kenwood.
> The iMic works FB on the transmit side.  The ONLY reason I use the 
> iMic for
> transmit is to maintain the system beep sounds in the Mac.  If you use 
> the
> output port on the back of the Mac, it mutes the internal speaker.  By 
> using
> the USB port I can maintain the internal sounds. Yes, I tried a 
> Y-connector
> with one side going to powered external speakers but that was 
> something I
> did not like.
>
>
>>    I know there's the issue of SignaLink only using the tip of the 
>> stereo
>> audio plug & ground to communicate. If that's the problem, what do I 
>> need to
>> do?  I guess another possibility is that my iMic is malfunctioning.
>>
>
> I recall a very good comment from Chen that may explain the jiggle 
> problem
> you mentioned.
>
> ".... Be aware that the SL1 uses a mono phono jack and the iMic uses a
> stereo jack.  You CANNOT just plug one into the other without
> shorting out the right stereo channel (or worse) -- so it is best to
> buy a mono plug for the SL1 end and a stereo plug for the iMic end
> and wire between them appropriately.
>
> The "usual" stereo-mono wiring is to wire the tip of the stereo plug
> to the tip of the mono plug.  Likewise, wire the sleeves (ground) of
> the plugs together, and leaving the "ring" of the stereo plug unwired.
>
> For best noise/hum immunity, use shielded twisted pair between the
> plugs, the two wires of the twisted pair runs from tip to tip and
> sleeve to sleeve as described above.  The shield of the twisted pair
> is then bonded only to one end of the connection -- usually the
> "input" end, which is the iMic microphone end for the A/D cable and
> the SL1 SPKR end for the D/A cable"
>
> Richard, have you tried the recommended Mono/Stereo cable?
>
>> Any help from you or your knowledgeable comrades would be appreciated,
>>
>> Rich, KI4FW
>>
>
> Please let me know if you break the code on how to receive via an 
> iMic.  As
> noted I gave up. Some things are just too hard and my setup works fine
> without he iMic in the receive path.
>
> Dick AA5VU
>
>
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