[Ham-Mac] Griffin iMic

[Steve Hellyer]

I have a similar setup to Dick (AA5VU).  Except I run a Kenwood 2000.  
Maybe makes all the difference, but I would have thought not.
We had a go around a while back was trying to help him.

Anyway it can be tricky setting up these audio level as there are many 
possible areas for adjustment.  I have been playing with my radio for 
about a year and think I have it figured out. :-)

Using the accessory port on the Kenwood you control audio out and in 
using a menu (level 0 thru 9). But if you tell the Kenwood that it 
accessory is 9600 baud rather and 1200 baud then control is lost. IE. 
It doesn't get processed by AF amp stages in radio at all.
Not sure level of output as never really tried it in practice. The 1200 
setting is fine for PSK31 and RTTY and allow me control audio level.
I think the accessory port was thought to connect for Packet (hence the 
menu option names) but can be used for any digital really.

Next you have the SignaLink which has internal adjustments, both in and 
out and the PTT (or VOX) threshold.

The iMic has a voltage level switch which Chris has detailed function.

And then you have you Macintosh which also has adjustment in and out.

Also watch out for Stereo L/R channel.  I used mono cable to eliminate 
that issue.

Well as you can see there are lots of variables.

I found setting everything at mid level and made adjustment from there.
Ie Kenwood menu set to 5 AF in/out
iMic set to line level input.
MAc set to mid values

Then adjust Signal link pots so that these level would drive and hear 
PSK31 to full extent (with no ALC kicking in).
Then I closed it back up. I now can make fine adjustments up and down 
with Kenwood menu or the Macintosh.

Another high quality Audio in/out would be M-Audio Transit 
High-Resolution Mobile Audio Interface.

http://www.m-audio.com/index.php?do=products.list&ID=mobileinterfaces

Better quality than iMic.  It is a 24 bit vs 16 bit.  Older iMic used 
to be 20 bit but current ones are 16 bit.
The PSK31 waterfall is much cleaner when the band is near dying, or is 
quiet.  But it does cost a bit more.

cheers,

Steve - VA3SPH



On 1-Mar-05, at 6:36 PM, Dick Kriss, AA5VU wrote:

> Steve,
>
> There is no issue with the Yaesu FT-1000 rig. The interface issue 
> seems to
> be unique to the Kenwood TS-570. Other FT-1000 users have no problem 
> with
> the Griffin iMic.  The only reason I selected the SignaLink SL-1+ 
> interface
> was there Auto-PTT that was a clean way to key the radio and let me 
> ditch
> the VOX.
>
>
> On 3/1/05 5:22 PM, "Steve Lawrence" <SMLX at earthlink.net> wrote:
>
>> FYI:
>>
>> I use an iMic between a G4 and a Yaesu FT1000D.  I parallel the stereo
>> headphone audio out across a Heil Proset. I inserted 600-600 ohm mini
>> telephone modem xfmrs in each audio-out line to the iMic and the iMic
>> output to the rig Mic input. This solved a bad hum problem and levels
>> are fine.
>>
>> I started with MultiMode and went to a lot of work to get an
>> iso-coupler circuit to key the PTT including what turned out to be a
>> needless expense for a Keyspan serial adapter. The VOX works great 
>> with
>> MM but I didn't tilt to this until I accidently came across Chen's
>> masterpiece and tried VOX with MM. MM got me started but its quickly
>> become an antique.
>>
>> 73 - Steve WB6RSE
>>
>
>
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>
73
Steve
VA3SPH