[Elecraft] USB Audio CODEC (Was: Planning the next filters)

[Joe Subich, W4TV]

On 3/9/2018 11:00 AM, Johan Ymerson wrote:
 > And why is there no clear option to enable/disable the "software
 > pre-amp" in Windows?

With the current drivers in Windows 10, disabling the preamp is
automatic.  One configures the level control in the Sound Control
Panel (Recording) to display in dB ... any setting above 0 dB
enables the preamp, any setting below 0 dB disables the preamp.

I assume the change had propagated to Windows 8.1 before it ended
mainstream support in January but I would not expect it in Windows
XP, NT, 2000 or any other version of Windows that has been out of
"mainstream" support for several years (obsolete).

73,

    ... Joe, W4TV


On 3/9/2018 11:00 AM, Johan Ymerson wrote:
> On Friday, 9 March 2018 16:29:19 CET Joe Subich, W4TV wrote:
>>> Probably the biggest problem with the Signalink USB is not the
>>> interface itself, but the Windows builtin drivers for the ADC. It
>>> thinks the ADC is a microphone and add +30 dB of gain in software.
>>
>> That issue is not with Windows ... it is with the device maker who
>> has selected a device that identifies as microphone level.  Using
>> the proper device/device ID will cause Windows to see it as a line
>> level input and set the drivers correctly.
>>
> 
> That can be debated, no other OS (MacOS/Linux/*BSD) identifies it as a
> microphone. And why is there no clear option to enable/disable the "software
> pre-amp" in Windows?
> 
> On the filter discussion; I have (apart from FM filter) 2.8 KHz filters and
> 400 Hz filters. Very pleased with that. I am not a contester so I want the
> full SSB bandwidth, mainly for waterfall view in digital modes. 2.8 KHz
> because I couldn't be bothered with filter matching in main and sub
> receiver...
> 400 Hz is kind of the smallest BW usable for digital modes anyway. If you want
> to go tighter than that (for CW or possibly PSK31), use the DSP filter is my
> advice.
> 
> /Johan
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