Adding balanced XLR output to a pedal

[Jopn]

Alrighty, I've got an extra 1590DD laying around so here's my project:

I'd like to build a box to work as an amp substitute for jamming straight to a PA.  I'm thinking of the following requirements:

- Amp emulation preamp, I've got a Black '65 built that I'd mod for this.
- Effects loop
- Balanced XLR output (as well as 1/4 unbalanced out)
- Speaker emulation (I've got a few that I'll breadboard and audition)

So I'm comfortable with all this except the balanced XLR output.  Does anyone have a schematic, layout, or example where they've branched off a balanced XLR on a pedal?

Cheers,

John

[johnk]

I  drew up a vero for an active XLR direct box using Tech21's circuit out of their BDDI.
I haven't built it yet but i'm 99.9% sure that this one will work for you:

REMOVED DUE TO ERRORS!!!!!!!!!!!!!!

see new layout below.

i'm sure that you already know this, but keep in mind that it's always best to run a cab sim before it if using an OD/distortion/fuzz pedal so the highs won't have too much sizzle.

[Jopn]

Awesome John, cheers!

[Lazy Swamis]

The 10k resistor on the top row is not connected to anything? I was going to build this up, but that doesn't seem right.

[johnk]

I just forgot to remove 1 cut on the top row. it is corrected now.

[Lazy Swamis]

Thanks John! Gonna try it in the morning.

[johnk]

Lazy Swamis wrote

Thanks John! Gonna try it in the morning#

don't build it yet!
I built it this morning and it didn't work at all so I redrew a completely different one designed by Jack Orman.
the new layout is posted below but I haven't built it yet so it's not verified yet.

[Lazy Swamis]

It's got that dangling 10k on the top row again.

I built it this morning but I guess that saves me the trouble of testing it. Oh well, I need the practice.

[johnk]

Lazy Swamis wrote

It's got that dangling 10k on the top row again.

OOPS! Damn it!
FIXED!

[johnk]

I built it and it works properly and sounds great BUT it has a VERYy low ouput.
i'm giving up on the first and second layouts a completely new one is posted below

[johnk]

well, I tried ALOT of things but i'm giving up on that one.
so...................I drew up a completely new one designed by Jack Orman.
hopefully, this one will work. (fingers crossed)

[johnk]

I built jack orman's and it works.(YAY!) it has a TON of output so i'm working on that part of it since it's too easy to distort the front end, so it basically needs an input attenuator but it sounds great if you don't feed it too much signal.

[Lazy Swamis]

Cool. I am not familiar with the power arrangement on this one. +9v, -9v, and ground. How do you go about wiring that up?

I was thinking it would need a trimpot or something at the input anyway as I am sticking this in a box with a pre-amp and compressor so that my buddy doesn't have to lug a drumset and a bass amp around.

Thank you so much for all the hard work on this one John. I certainly appreciate it! I hope others do too!

[Lazy Swamis]

That dog will hunt. Got this built up and it worked like a charm. Thanks again John!

[Lazy Swamis]

I have this one working. I intend to put it in a box with a Sadowsky Preamp and a compressor.

The grounding scheme on the DI is a little different though. On the other two circuits ground and -9v seem to be the same. On this layout, they are separate.

Do I need to isolate the power supply for the DI circuit from the others? If so, do any of you smart people, know a good way to go about it?

Thanks!

[johnk]

this is what Jack Orman said about the grounding:
"The “GND” point should be isolated from the chassis but Vee can be connected to chassis."

[johnk]

I came up with another one that has a less complicated grounding scheme. it's designed to run on 18 volts so use an 18V charge pump for it. here's the verified vero:

[Lazy Swamis]

Nice. I will have to try this one as well.
I built the first one and it worked very well. Boxed it with the Sadowsky pre-amp and the Mr Squishy. Gave the compressor a footswitch, and added a toggle to allow the DI to be stand alone or post effects. Everyone who tried it wanted one.
Thanks again John!

[johnk]

cool!
for anyone interested, here's a smaller layout of the second one:

[Heath]

Hi, JohnK

Where would the unbalanced outs go on this most recent layout?

Would it be something like this (be gentle, I'm stupid)?



I'd test this out before asking, but It'll be a while before I'm back in my work space to try it out.

Thanks!