Topic: mini-jack to 2x XLR with attenuation

[yousef]

I wonder if anyone could give me some advice about making a cable to link my Sound Pro's battery box to the XLR inputs on an AD-20?

I'm using DPA 4060s and a Microtrack so I'd like this cable to act as an attenuator too - the 4060s run a little to hot for my liking when going line-in to the MT and I believe that the AD-20 adds a minimum of 17dB gain. So I guess I'd be needing 20dB of attenuation.

For reasons of stealthability and reducing strain on inputs, I'd like to avoid using those in-line XLR attenuators.

So I'm looking to make a cable that runs from a 3.5mm stereo socket to two male XLRs. I guess I'm asking for resistor values and where to solder them.

Also, with the mics being unbalanced and the AD-20's inputs balanced, should I be linking two of the XLR pins together as discussed here:

http://taperssection.com/index.php/topic,82553.0.html

Cheers!

[Evil Taper]

Hosa sells 3.5mm M to dual XLR M or F for $17.  Buy than and either switch the 3.5mm connector to F or solder your battery box to the cable directly.  If the signal is running so hot just use an inline attentuator or pad on the AD20 output cable.  You're not going to get around the attentuation unless you can turn the input volume down on your recorder.

[Jamos]

Hosa sells 3.5mm M to dual XLR M or F for $17.  Buy than and either switch the 3.5mm connector to F or solder your battery box to the cable directly.  If the signal is running so hot just use an inline attentuator or pad on the AD20 output cable.  You're not going to get around the attentuation unless you can turn the input volume down on your recorder.

I think he wants to run digitally out of the AD-20 into the MT...
which would mean the attenuation would need to happen pre AD-20.

Seems like you should be able to make this work...although if you're trying to be low-pro and are only really using the AD-20 for its A>D, an Edirol R-09 would be a much smaller overall package.

[Evil Taper]

i guess you could just solder an attenuator/pad in place (heat shrink around it too) when linking the batt box to the Y cable.  there's really no way around it that would be less fool proof.

[yousef]

Thanks for the replies.

I quite like the idea of using the in-line attenuators and heat-shrinking them into place.

And, yep, the Edriol would've been a much smarter decision all round - one lives and learns...

Edit: can anyone advise me about the XLR pin linking issue?

[Evil Taper]

pin 1 is positive hot
pin 2 is negative hot
pin 3 is ground

[Jamos]

And, yep, the Edriol would've been a much smarter decision all round - one lives and learns...

AD-20 -> ~$150-200
MT24/96 -> ~$200

With that money you could have a brand new R-09
Atleast that's what I would do...

[yousef]

AD-20 -> ~$150-200
MT24/96 -> ~$200

With that money you could have a brand new R-09
Atleast that's what I would do...

But there's no digital-in on the R-09 - which is what convinced me to go for the MT. Later on I'll have the option of upgrading my ADC... Also, I wasn't too keen on the Edirol's backlight or input jack problems. But, yes, in the short-term the R-09 is probably a better choice.

[yousef]

pin 1 is positive hot
pin 2 is negative hot
pin 3 is ground

Thanks for that but what I really wanted to know was if I needed to link together two of the pins to compensate for the unbalanced signal that the 4060s are provided (vs the balanced one that the AD-20 is expecting). There was some discussion of it in the thread I've noted above but I'm not really sure I understand what is being done and why.

[Evil Taper]

that's taken care of in the Y cable already.  You're just connecting your 3.5mm unbalanced to the Y-cable 3.5mm unbalanced.

[yousef]

that's taken care of in the Y cable already.  You're just connecting your 3.5mm unbalanced to the Y-cable 3.5mm unbalanced.

But what's go t me thinking are Chris Church's comments (in the previously mentioned thread):

You have an ad-20 that has balanced inputs. If you are using them. You must "unbalance" the input by connecting pin 1=ground to pin 3= Signal negative to each other.. This unbalances the input of the AD-20 and allows you to use your unbalanced microphone with this preamp. If you do not connect pin 3 to anything its floating and it can pick up stray RF signals and inject them into your recording because pin3 must be terminated by a microphone or by grounding it out. If you were plugging in a balanced microphone to this input there would be no modifications necessary.

[Evil Taper]

Hosa are professionals:

Tip to Pin 2 Left
Ring to Pin 2 Right
Sleeve to Pins 1 & 3 of both XLRs

The mini plug is TRS (Tip +hot, Ring -hot, Sleeve ground) so the Y-Cable just splits the L/R to the XLRs and grounds the other pins, just connect your gear and you're ready to tape.

[yousef]

Tip to Pin 2 Left
Ring to Pin 2 Right
Sleeve to Pins 1 & 3 of both XLRs

I see - thanks for that. Time to get that soldering iron heated up then...

[Todd R]

pin 1 is positive hot
pin 2 is negative hot
pin 3 is ground

This looks wrong to me --- I've never heard of XLRs ever being wired this way.  For XLR connections, pin 1 is always ground.  Typically, pin 2 is signal(+) and Pin 3 is signal(-).  Sometimes this is reversed with pin 3 = signal(+) and pin 2 = signal(-)

Most typically with modern equipment you have:
Pin 1 = Gnd
Pin 2 = Signal(+)
Pin 3 = Signal(-)

[Evil Taper]

weird...all of my teachers and textbooks have the standard config like I listed.  1 hot, 2 cold, 3 ground....and to do this sort of wiring you'd tie low to ground as shown in the y-cable schematic.