Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › Switchbox with both balanced and unbalanced in/out
New Posts  All Forums:Forum Nav:

Switchbox with both balanced and unbalanced in/out

post #1 of 6
Thread Starter 
I have been wanting a Creative Labs E-MU1212 sound card to use exclusively with music. Since it has balanced outs I've been on the look out for something to take advantage of it with... Then I discovered the Studiophile Bx5a speakers by M-Audio. Looks like an awesome match to me! Oh wait, I have headphones that I like to listen to music with too and they're not balanced...

I've had a switch box project in mind for my home setup for a while, but now its complicated! I really want to make a switch box that takes in one balanced signal and another unbalanced. It would also have balanced and unbalanced outputs. The problem is being able to swap which input each output is using... I want to be able to just put on my headphones, flip a switch, hit play, then beautiful music will play over the headphones.

A relay based switch box really appeals to me such as the one from Twisted Pear Audio. Unfortunately I don't see any way to use it for both balanced & unbalanced, just one or the other! I've read a bit about balanced cables and such but I don't really have a clue on how to make a circuit that could switch back and forth like I want. I've built a CMoy, Pimeta and 2 Mini3s but haven't actually designed any circuits myself. My knowledge of electronics just isn't up to doing a project like this without help!

Could someone please let me know if this project is feasible/reasonable? If it is then I would love some help coming up with a circuit diagram for it. I plan on doing some more research on my own into this but there are plenty of experienced folks on here... I at least need a decent starting point on how to convert from a set of balanced ins to an unbalanced out and vice versa. I'm also unsure which circuit diagram application to use. I've heard of Eagle, should I use that?
post #2 of 6
Thread Starter 
Well, I discovered what sort of device I would need in the circuit to switch between balanced and unbalanced... It's called a "balUN" and they're supposed to at least semi-gracefully convert from a balanced signal to unbalanced or vice versa. The only thing that I've found on making one as part of a circuit is here. I can find actual ones that convert for me, but they wouldn't be switchable... Unfortunately there are a number of types of balUN and I'm not sure what to do. Any suggested reading material, anything?
post #3 of 6
Bumping to respond later.

I'm conceptualizing a similar project myself. Maybe we can share notes.

One question, though, why not balance your phones?
post #4 of 6
convert to a common internal format and then convert 'out' from that for the output port types.

nothing at all wrong with picking one format (like unbal) and converting to/from it.

balanced matters more for long cable runs. inside a box, unbalanced is perfectly fine.

the DRV chips and the THAT series of chips also do great bal/unbal to/from conversion.

jensen transformers (expensive!) also can do it passively.
post #5 of 6
Quote:
Originally Posted by linuxworks View Post
jensen transformers (expensive!) also can do it passively.
CineMag transformers can do it passively too. And for less than the Jensens.

k
post #6 of 6
I found this:

Audio Amplifiers - Line Drivers / Receivers - INA137 - TI.com

Might be helpful. Shouldn't be too hard to implement a balanced receiver from this.

Quote:
Originally Posted by linuxworks
convert to a common internal format and then convert 'out' from that for the output port types.

nothing at all wrong with picking one format (like unbal) and converting to/from it.

balanced matters more for long cable runs. inside a box, unbalanced is perfectly fine.
This is good advice. For me, I want to keep my signal balanced since my 'phones are balanced, and that's where I do the bulk of my listening. In my case I might convert to unbalanced right at the output I create for my speaker amp.
New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › Switchbox with both balanced and unbalanced in/out