Can I make two inputs from one??

[Jazz_3_4_5]

Gents, & Ladies if that be the case....May I indulge my curiosity for a moment?

I have recently acquired a Japanese made Audio Mixer. that has seen some abuse. and as a learning experience,
I wish to bring it back into the fold for home use.

The Power supply is missing, and the Headphone Jack was smashed. I have found a replacement Headphone Jack, and will replace that when it arrives. In the meantime I have searched out the schematic, and this unit has a 3 legged power supply... two Positive legs and a Negative leg.

I am wondering if it is possible to use a 2 wire wall wart, and put a jumper in place of the second positive,
as shown in the schematic I included.
My thinking is that since the mixer, only draws 500mA maximum, a jumper should cover this situation.
Since I have no need for the Phantom power, as all my Mic's are Dynamic, & not Condenser types,
I'll disable it, by removing R101 A thru 104 A, and the 47 uF cap.

If you disagree with my diagnosis, please elaborate, and Possibly offer me an alternative.
I'm 80 yrs old, and trying to keep my mind as sharp as Possible, as I plan to keep using it
for at least another 30 years, and hopefully more!

You have my gratitude!

 

[Nigel Goodwin]

If you've got the schematic, then post it - or at least post the make and model, so we can look it up.

As it is, your question is too vague, and possibly your assumptions are incorrect?. Generally in mixers they run off split supplies (for the opamps), so I would expect the three connections to be +18V, 0V and -18V.

However, the phantom power requires a higher voltage, so it 'could' be +18V, 0V, and +48V for the phantom power, if you post the full schematic we can tell you. I'm a bit dubious about it not having a split supply, though, and a single 18V supply sounds a bit on the low side (the +/-18V gives plenty of headroom).

However, as the phantom power is fairly low current, it 'could' generate that inside the mixer?.

I recently had to build a PSU for a medium size mixer, and that had a four pin socket for the PSU, +17V 0V, -17V, and +48V phantom power. As it was for gigging, we didn't need the phantom power, so I ignored that, bought two cheap Chinese 24V SMPSU's and modded them for 17V. It worked perfectly, and we did a gig a few weeks ago with it.

 

[sarahMCML]

The "Plug AC Female" that you show your 18V DC adapter pointing to in your diagram is NOT where you need to input its supply, that must go in somewhere else (not shown)! The "Plug AC Female" is for a microphone input.

 

[Nigel Goodwin]

The "Plug AC Female" that you show your 18V DC adapter pointing to in your diagram is NOT where you need to input its supply, that must go in somewhere else (not shown)! The "Plug AC Female" is for a microphone input.

Well spotted, I presumed the schematic part was just to show the existence of Phantom power, it never occurred to me, he might be trying to plug power in there

Like I said above, he needed to post the schematic, or at least the make and model.