[sdiy] Phantom power generation

Tim Ressel timr at circuitabbey.com
Wed Jun 22 17:35:11 CEST 2016


Thanks for all the input.

I was fearful of using a switcher, but it seems its okay. I just need to 
do careful layout, which you have to do with switchers anyway, and add 
some extra filtering.

--TimR

On 6/22/2016 7:58 AM, axisair at comcast.net wrote:
> 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.
>
>
> Sent from XFINITY Connect Mobile App
>
> -----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
>>>
>>> _______________________________________________
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>>> 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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-- 
--Tim Ressel
Circuit Abbey
timr at circuitabbey.com




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