Slow Start Phantom

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corgan4321

Well-known member
Joined
Nov 30, 2008
Messages
205
Location
Brooklyn, NY, USA
I built Martin's 1290 preamps and added the slow-start circuit he linked to. I looked at the output of the phantom on a scope and found I'm getting a rise time around 50ms. Not too much of a slow start...

When I did a search for slow start here I found most people talking about a circuit with some sort of FET or other active device. It is impossible to achieve slow-start phantom power with passive components? Or did I just do something wrong with this little circuit?

I've attached the circuit I used which was linked to by Martin in the 1290 thread.
 

Attachments

  • Slow start ramped48v.pdf
    6.6 KB · Views: 95
That is definitely not a slow start circuit; it is just regular decoupling of the phantom supply that you might use on a per channel basis.

Cheers

Ian
 
I am curious as to why you would need it ... I can see a reason for slow start where there is substantial current involved ... is it just so as to mitigate pops and thumps when switching, or is there some other benefit?

 
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