[sdiy] Phantom power generation

axisair at comcast.net axisair at comcast.net
Wed Jun 22 16:58:04 CEST 2016


I get 48V fine. Hasn't fried yet.
Also, I can't hear 100 KHz, my speakers won't reproduce it, it doesn't show up on the scope and I designed in RFI suppression and CMMR on the amp inputs. So, I'm good.


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-----Original Message-----

From: simon.o at brousant.nl
To: axisair at comcast.net,synth-diy at dropmix.xs4all.nl,timr at circuitabbey.com
Cc: 
Sent: 2016-06-22 12:51:52 AM 
Subject: Re: [sdiy] Phantom power generation

Hi, 

Note that the max. switch collector voltage in the MC34063 is 40V, so you'd need
an external switch transistor if you want 48V output. Also, its switching
frequency is 100kHz, which means you need larger inductor and capacitors than
with LM5002. And for an application such as this I feel a switching frequency
further away from the audio band may be preferable (this is just intuition). 

Best regards
Simon

> Op 21 juni 2016 om 22:27 schreef axisair at comcast.net:
> 
> 
> I used the MC34063. It worked great. Mondo gain on the balanced in had no
> problem with it.
> 
> 
> Sent from XFINITY Connect Mobile App
> 
> -----Original Message-----
> 
> From: timr at circuitabbey.com
> To: synth-diy at dropmix.xs4all.nl
> Cc: 
> Sent: 2016-06-21 1:14:52 PM 
> Subject: Re: [sdiy] Phantom power generation
> 
> I looked at that very chip thanks to web bench. Was the output clean 
> enough? The Mic pre is going to have mondo gain.
> 
> --TimR
> 
> 
> On 6/21/2016 2:24 AM, Steve Lenham wrote:
> > On 21/06/2016 07:59, Tim Ressel wrote:
> >> Hi,
> >>
> >> I need to make phantom power from 12 volts. Anybody got a kewl circuit?
> >>
> >> Thanks!
> >>
> >>
> >> --Tim Ressel
> >
> > Take a look at the TI LM5002 high-voltage boost converter chip. I've 
> > used it for exactly that purpose in a production design. The datasheet 
> > has almost the circuit you need on p15; you just need to tweak it 
> > slightly for the lower input voltage, and the Webench tool on TI's 
> > website will probably do that for you.
> >
> > HTH,
> >
> > Steve L.
> > Benden Sound Technology
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at dropmix.xs4all.nl
> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >
> 
> -- 
> --Tim Ressel
> Circuit Abbey
> timr at circuitabbey.com
> 
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