[600MRG] Preamp transistors

[Brian Pease]

In most of my projects I have used low noise op-amps, often chosen to 
roughly noise match the source (R=En/In).  The design money seems to be 
on ICs these days, not on discrete low power transistors.  Low noise op 
amps often have good data sheets.  For high impedance sources (high-Q 
tuned loops) I use jfet input op amps and swamp out the input noise with 
the large thermal source resistance.

On 1/4/2017 12:24 PM, david vanhorn wrote:
> Anybody??
>
> I've spent a few days searching, and this information seems to be about
> impossible to find.  I thought this group would know if anyone would.
>
>
> On Tue, Dec 27, 2016 at 10:08 AM, david vanhorn <kc6ete at gmail.com> wrote:
>
>> Failing any transistor recommendations, any pointers to information on
>> selecting transistors for this application would be very useful.
>>
>> I have been searching digikey and similar, but where I can even find noise
>> data, it's typically specified in the audio region.
>>
>> Double bonus points for anything that shows rbb on the transistors in
>> question.
>>
>> On Thu, Dec 22, 2016 at 2:19 PM, david vanhorn <kc6ete at gmail.com> wrote:
>>
>>> I'm looking for a very good preamp transistor for a loopstick antenna
>>> project.
>>> This will be a common emitter amplifier.
>>> NPN, SOT23 or very similar, and as low a noise as I can get.
>>> I will have less than 3V to work from.
>>> I'd like to keep the collector current below 2mA if possible.
>>> Impedance coming into the amp will be about 4 ohms.
>>> Currently using BC847C, but it's proving rather noisy at 690uA collector
>>> current.
>>>
>>> Any recommendations?
>>>
>>> --
>>> K1FZY (WA4TPW) SK  9/29/37-4/13/15
>>>
>>
>>
>> --
>> K1FZY (WA4TPW) SK  9/29/37-4/13/15
>>
>
>