48v from 24v dc wall wart

[Rocinante]

I'm building a Helios 69 mic pre eq module.  It measures 8 x 8 inches. Its a tight fit since im using input and output xfmrs but i have a little leg room.  I feel like i might have noise problems if i stuck a power transformer and psu in there.  I do have an external psu i could use but I'd like to try to make it transportable. I have a 24v 2a Epson ps-180 universal psu (wall wart type)
https://www.amazon.com/Epson-PS-180-Universal-Power-Adapter/dp/B0002F2G2S
that I'd like to use but have read that i cant just make a simple voltage doubler for my 48v phantom as the psu is dc.
What can i do to get my 48v?
What is a good circuit that will allow me to double the voltage?
On Ebay they have various voltage boosters, has anyone used them?
I read several threads on this but i couldn't find any with a viable solution, other than; get an ac psu or build your own.  Either is an easy enough option i suppose but i think building a psu in an external case that is nearly the same size as the module seems a bit overkill and using a wall wart would make it much easier.  What do the pro companies use that have wall warts?
Anyone try something like this?
Thanks in advance.
Dylan 

 

[midwayfair]

I know I've breadboarded something in the past that doubled 24V, but I can't remember what project it was, and I remember it being VERY noisy and sagging more than I expected with a microphone attached.

It might actually be easier (and maybe even cheeaper) to get a 48V supply and drop the voltage for the preamp. I pay about $10-$14 for a YU4801 wall lump on Ebay, with free shipping. (It's three-prong, 48V, 2A, 2.1mm barrel.) It's not that much more than the cost of some caps and active components and a circuit board. You could just connect the phantom power feed to the PSU input and then use a regulator for the preamp feed. I use the same supply for my FETboy variant and for the JLM stuff I built -- I can even get away with daisy chaining a few devices without noiticeable extra noise.

EDIT: This un: http://www.ebay.com/itm/New-AC-85-245V-To-DC-36V-48V-1A-2A-Power-Supply-Adapter-Universal-Switch-/321560628355?var=&hash=item4ade81cc83:m:m4zyffLHak0DubOJv7Ywqpg

 

[Rocinante]

Thank you. Yeah getting a 48v psu is probably the best idea.
Yeah i think Joe from JML does something similar and in his various pcb's. Iirc theres an optional onboard regulating circuit (I'm fairly certain the Dingo has one) if using one of his 48v psu and xfmr's.
Thanks again

 

[john12ax7]

You could also get an AC wall wart,  then you could generate any DC voltages you need.

If you wanted to stick with the DC wall wart then you would need a DC-DC converter. 

 

[Rocinante]

Thanks John. I'll check out 24v ac wall warts.

 

[abbey road d enfer]

Anyone try something like this?

I had a similar concern for a lunchbox. I used an isolated 24:24 DC/DC converter, with the output in serioes with teh input, effectively doubling the voltage. The reference is XP POWER - JCD0624D24 - DC/DC CONVERTER, 6W, +/-24V, DIP-24

 

[midwayfair]

Thanks John. I'll check out 24v ac wall warts.

If you find a good one, let me know ... I would like one for a tiny API-ish build.

 

[Rocinante]

If you find a good one, let me know ... I would like one for a tiny API-ish build.

Will do.

 

[john12ax7]

I haven't used them,  but Jameso has a decent selection of wall warts.

This might work
http://www.jameco.com/z/ADU240100D5531-AC-to-AC-Wall-Adapter-Transformer-24-Volt-1000mA-Black-Straight-2-1mm-Female-Plug_140599.html

 

[David Kulka]

Wow,  I wouldn't use a DC wall wall wart for any kind of audio project. In my experience they are often noisy, poorly regulated, and failure prone. But how about an AC wall wart, and then a rectifier/regulator in the project enclosure?

 

[Rocinante]

Wow,  I wouldn't use a DC wall wall wart for any kind of audio project. In my experience they are often noisy, poorly regulated, and failure prone. But how about an AC wall wart, and then a rectifier/regulator in the project enclosure?

Thats the plan. I am awaiting the ac wall wart and have several psu's to pick from, although they aren't as small as I'd like but should be alright.

 

[Tekay]

This is what we used in our Vintagedesign desktop preamps  M73 and M81

 

[L´Andratté]

This is what we used in our Vintagedesign desktop preamps  M73 and M81

One question: how is the Ground rail on the phantom supply derived (it is not the Earth symbol used for the +24V supplys...)?

 

[Tekay]

One question: how is the Ground rail on the phantom supply derived (it is not the Earth symbol used for the +24V supplys...)?

It's the same ground! I just mixed up the symbols.
/
TK

 

[L´Andratté]

Thanks! 

 

[Rocinante]

Teekay, i just saw this. And in an insane coincidence its that board (the old tommytones) I'm probably using.   Thanks!!!!!!