[600MRG] Preamp transistors

[david vanhorn]

I understand, but I am looking to update an existing piece of equipment, so
changing the circuit topology that drastically isn't an option.
My input is low impedance.

On Wed, Jan 4, 2017 at 10:38 AM, Brian Pease <bpease2 at myfairpoint.net>
wrote:

> 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
>>>
>>>
>>
>>
>
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-- 
K1FZY (WA4TPW) SK  9/29/37-4/13/15