RED XLR > MiniQ [Archive]

Anders Holck

03-11-2008, 01:55 PM

I'm wondering what the story is behind the construction of the RED XLR > TA3 cables.

I was a bit surprised to find a resistor bridge in the XLR end of the cable.
The wiring is like so:
http://www.redrental.dk/linked/audiocable.jpg

It seems to boost the signal.

Anyone knows what this circuit does exactly, and why it's there?

(Edit: It does not reverse the polarity. Apparently TA3 connectors have pins 2 and 3 swapped campared to a XLR3)
(Edit2: The Red manual pictures a XLR3 connector without the swapped connectors, not a TA3. This must be a mistake)

Craig Bowman

03-11-2008, 02:10 PM

Without this setup your audio would come out phase reversed. People who are making their own cables are already wondering why their audio signals are mirrored. Its because you can't just make a pass through adaptor.

Anders Holck

03-11-2008, 02:15 PM

Sure, but why put it in the cable and not inside the Red body?

Georg Misch

03-11-2008, 04:46 PM

At least this should be documented somehwere. And yes, this looks very strange. The Mini-xlr connectors are available on many pieces of audio equipment such as the SoundDevices Recorders, where they are used for the Channel 3+4 Input on the 744T for instance. I am not aware that there is any special wiring in those.

A clarification from RED wold be great.

Georg

Alexis Hanawalt

03-11-2008, 04:59 PM

What is "mini Q"? I just bought some mini-xlr to xlr adaptors from a music store - please tell me they'll work...

Anders Holck

03-11-2008, 05:10 PM

Sorry.
TA3=MiniXLR=TinyQ

MiniQ was just me misspelling TinyQ

Kevin Halverson

03-11-2008, 07:02 PM

I'm wondering what the story is behind the construction of the RED XLR > TA3 cables.

I was a bit surprised to find a resistor bridge in the XLR end of the cable.
The wiring is like so:
http://www.redrental.dk/linked/audiocable.jpg

It seems to boost the signal while it also seems to reverse the phase.

Anyone knows what this circuit does exactly, and why it's there?

Your depiction of the mini XLR connector end is incorrect (see attached photograph). You have the label for pins 2 & 3 swapped on the mini XLR end.

This is a common misconception, mini XLR connectors have a different relationship between their physical pin and the numeric assignment when compared to full sized XLRs.

Anders Holck

03-11-2008, 07:16 PM

So the "phase flip" is just because the pin configuration is different on the Mini xlr? Makes sense. I edited the original post.

Any clue to the use of resistors?

Anders Holck

03-11-2008, 08:04 PM

Hmm....from the RED manual:
http://www.redrental.dk/linked/RED.png

Doesn't show pins 2 and 3 swapped as per TA3 spec

Anders Holck

03-11-2008, 09:03 PM

Anyone from RED want to chime in? Stuart?
If this is important, shouldn't it be in the manual or something?
Also that schematic in the Manual, is that wrong? Shouldn't pin 2 be at the bottom?
http://www.switchcraft.com/images/connector_p.23bphoto.gif
Switchcraft TinyQ Manual

I'm glad I did the research on a RED cable before soldering my 12 short cables and two 4 channel snakes. But I know a few guys that didn't get to see the RED cable before making their own...

Wes Printz

03-11-2008, 11:00 PM

AND, there appears to be a 20dB pad included for the price.

Harry Clark

03-12-2008, 01:29 AM

Maybe it's a Red prank... ;)
Harry

Michael Morlan

03-13-2008, 11:26 AM

I really don't understand this. Has RED violated the XLR/Tiny-Q wiring standard requiring a custom cable?

I bought six "standard" cables from a third party. As I understand it, they won't work with the camera?

Michael

Joel Kaye

03-13-2008, 11:34 AM

I bought six "standard" cables from a third party. As I understand it, they won't work with the camera?

Possibly not. At least when it comes to using Phantom Power from the camera you need RED's miniXLR adapter cable (Jarred confirmed this to me). Perhaps cables wired as indicated in this thread would be fine too.

Michael Morlan

03-13-2008, 03:44 PM

Possibly not. At least when it comes to using Phantom Power from the camera you need RED's miniXLR adapter cable (Jarred confirmed this to me). Perhaps cables wired as indicated in this thread would be fine too.

So, color me confused. Despite non-standard connectors, R.D.C. has managed to conform to an amazing array of industry standard protocols. Why would they fail in the analog audio chain?

Michael

Anders Holck

03-13-2008, 03:51 PM

Possibly not. At least when it comes to using Phantom Power from the camera you need RED's miniXLR adapter cable (Jarred confirmed this to me). Perhaps cables wired as indicated in this thread would be fine too.

That IS the new type RED XLR cable pictured in post #1

Michael. Check the the third party cables you got. Simply open the XLR3 connector and see if the resisters are in place. If not they wont work as intended.

Anders Holck

03-13-2008, 04:10 PM

The final XLR3 end should look something like this:
http://www.redrental.dk/linked/audiocable2.jpg

But WITH isolated wires

Joel Kaye

03-13-2008, 06:38 PM

The final XLR3 end should look something like this:

But WITH isolated wires

I bet someone's going to come out with a right side of the camera upgrade where you send it in and they swap the whole thing out with all this kind of stuff in place.

Michael Morlan

03-14-2008, 01:24 PM

Nope. Mine are simple end-to-end connections. Looks like it's time to whip out the box o' resistors and soldering iron.

What a mess.

Michael

Adrian Van Rossum

03-14-2008, 03:03 PM

Was ordering mini-XLR adaptors and noticed this over at http://www.finalcutuser.com/ regarding the return of phantom power and the new cable arrangement -

"Note: Regarding re-activation of +48V Phantom Power. Use of +48VPhantom Power not recommended unless using the new RED XLR-to-mini-XLR cable adaptor (single cable with integrated adaptor). Use of XLR-to-mini-XLR adaptor and mini-XLR-to-mini-XLR cable (an adaptor and a cable) should NOT be used. If you need this new XLR-to-mini-XLR cable adaptor, please contact RED for a replacement."

I'm planning to tether four Samson wireless microphone receivers (mini-XLR outputs on all of them) to my Red One, so this is important info. I won't be using phantom power, so does anyone know if the new RED XLR-to-mini-XLR cable adaptor (single cable with integrated adaptor) affects a non-phantom audio feed into the camera?

Kevin Halverson

03-16-2008, 08:48 PM

I'm planning to tether four Samson wireless microphone receivers (mini-XLR outputs on all of them) to my Red One, so this is important info. I won't be using phantom power, so does anyone know if the new RED XLR-to-mini-XLR cable adaptor (single cable with integrated adaptor) affects a non-phantom audio feed into the camera?

Yes, these adapter cables provide a number of features. If you plan on connecting your Samson wireless receivers directly to your RED ONE without using the RED supplied adapter cables, there are a few things that you should realize.

First, it is essential that you do not activate phantom power in the camera for any of the channels.

Second, without the cables, the Fs (clipping point) for the camera will be 2V RMS (+6 dBV or +4 dBU) as opposed to 6.6V RMS (+16 dBV or +14 dBU).

A 2 Volt clipping point is fine for most consumer line level signals, but you run the risk of clipping with many professional level signals.

If your Samson's offer output level adjustments, and you configure it so that you do not clip the converters in the camera, you are safe to proceed, but the warning not to activate phantom mode still applies.

Kevin Halverson

Matt Gottshalk

03-16-2008, 09:01 PM

http://www.trewaudio.com/audioflow/2008/03/12/are-you-redy/

"The internet has provided a lot of information on the topic of audio for the RED. A few users have confirmed my suspicions, and rewritten the manual before RED could. On some select cameras the TA3 inputs may be out of phase. This could be an issue with the mislabeling of the connector graphic in the manual; either an internal mistake in the camera, or the cable was made to the graphic and not the chart. Beware."

Vincent S

03-17-2008, 01:08 PM

I'm a little confused, I just bought some cables from coffey sound. Are these now no good?

http://www.coffeysound.com/home.php?cat=133

Adrian Van Rossum

03-18-2008, 12:40 AM

Thanks for your reply khmus. I'll be getting 6 of the Red mini-XLR to XLR cables (2 spares, just in case) so I should be okay. The Samsons have a switch for three different levels of output from the receiver to the camera (no phantom required), so I'll experiment with various settings and cable arrangements to find the combo that best avoids audio clipping. Cheers!

Anders Holck

03-18-2008, 02:01 AM

Could someone at RED please fix the TA3 diagram on page 59 of the RED manual.
As of build 15 (2.1.4) it still incorrectly shows an XLR3 connector instead of a TA3.
This is confusing A LOT of people!

Here is a grab from the latest version of the manual:
http://www.redrental.dk/linked/RED.png

The connector on the RED camera is a TA3 which has Pin 2 in the bottom and pin 3 next to pin 1.
The thing is that when people see this diagram they will wire their cables with the wrong phase.

Harry Clark

03-28-2008, 11:25 AM

I'm giving this thread a bump because, although sound is not my department, as a camera owner I want to have the right tools available for the mixers that I work with.
Sooooooo.... anyone from the Red Team going to chime in here? It seems as though, if we want "-20" from a pro mixer to be "-20" on our cameras we need "pads" built into our adapter cables.
Is this true?
Is Coffey sound or another vendor making these? I already have a set of pass-though adapters.
I just want to have the sound guy love my Red as much as I do!
Cheers,
Harry

Wes Printz

03-28-2008, 02:21 PM

Harry Clark

03-28-2008, 02:47 PM

Oh hi Wes...
I was thinking it would be useful to have both. I'll email you cause I need some other cables anyway...
Cheers,
H.

Andrew M.

04-02-2008, 07:35 PM

200K resistor is for bleeding of the 48v phantom power. I experienced it myself when checking phantom power polarity. After I disabled the phantom power, the 48V was staying there for a long time.
610 ohm resistor is for protecting the camera input I think.
Most mikes with phantom power have large capacitor across the 48V supply lines.
When you connect such mike fully charged to the camera that is fully discharged or vice versa then you are asking for trouble. Just unplugging it from one channel and plugging it in to the other fully discharged channel will bring some peak currents, if not on the mike then on the camera. Mikes are protected though very well so the camera is getting all the current spikes.
Well, most engineers designing the audio equipment knows that stuff.
I guess this one didn’t research the subject well enough.

So we did end up with the extra circuitry in the RED-mike-cable that will be moved to the new revised version of the audio board.

Anybody blew up the audio channel on the camera lately?

Michael Morlan

04-02-2008, 10:19 PM

If this is true then we should be receiving four adapter cables, not just one.

Hmm.

Miltos Pilalitos

04-02-2008, 11:08 PM

Why no official statement yet on the subject? All this is very confusing...

Andrew M.

04-03-2008, 02:39 AM

Priorities and again priorities. What do you want to be fixed first REDCINE or audio?
Audio will take it turn one day.................

I would love to have a list of features/projects that are concerning the RED and let people to vote what comes first. Well again I may not like the outcome anyway and you are removing the element of surprise.

Maybe that is why we do not know our future, if we did, life would be boring

Miltos Pilalitos

04-03-2008, 03:14 AM

I don't think the team that develops Redcine is the same as the one responsible for audio. They are both top priority and if i should choose i would actually choose the audio.

Andrew M.

04-03-2008, 06:27 PM

Actually I need both, can't work without audio and I have to have simple workflow to begin with.

Rainer Fritz

04-07-2008, 06:16 AM

I built today a cable regarding the resistor array what anders posted. Sent 0dB line signal in, and -24dB were recorded. Can't imagine that this will be correct. It was not possible to adjust the gain. Every setting I made had no effect. Probably the cam is waiting for a standard line signal if this is activated in the menu. Didn't tested the micro impedance setting.
Are there any news on the phase shift ?

thx
rainer

Stuart English

04-07-2008, 06:23 AM

I built today a cable regarding the resistor array what anders posted. Sent 0dB line signal in, and -24dB were recorded.

That is not correct. I will post more details on this subject shortly.

The polarity issue is under review, again more news very soon.

Andrew M.

04-07-2008, 06:28 AM

The resistors are 200K to bleed the 48V phantom power capacitor and 600 ohm one is to protect the RED input against the surges from mike side (phantom power mikes have its own capacitor)

So if your mixer has 600 ohm output impedance you will lose 6db, providing that RED has 600 ohm input impedance.
If you lost 24 then it looks like you have something like 10K ohm output impedance on your mixer?
Impossible, maybe you put 600 ohm across and 200K in line instead? But then you will loos more then 24.
Check your resistors and connections again.
Remember 200K across and 600 ohm in line.

But if you switched phantom power off on the camera side why do you need the resistors anyway?
Mixer doesn’t have any 48v coming out of it

Rainer Fritz

04-07-2008, 07:39 AM

Thx Stuart for the fast replay.

I will double check, but I measured it anyway, and think 680 Ohms in line and the 200k to ground. We used a 3channel Sounddevice output switched the 1k tone on and the meter said 0dB output.

OK... so we can make straight cables when we look to switch off the phantom power?

thx
rainer

Andrew M.

04-07-2008, 07:54 AM

But when you switch off the phantom power let it drain 48V for some time or connect cable with 200K accross to do it faster (1 minute)
My camera works great without phantom power, no hiss no noise.
With straight cable you will get slight boost of levels but you can corrct it in the line level setup.

Mark L. Pederson

04-07-2008, 05:55 PM

based on a bunch of tests, we made custom cables with a -10 db pad in the cables for LINE in -

Mark B.

04-12-2008, 01:21 AM

Could someone post a schematic of the appropriate way to wire the line converter to get phantom audio from the mini to a full XLR, along with recommended resister values? I'm getting mixed understandings about the situation from the way this thread is rolling out, so it would be nice if a definitive solution was drawn up by someone.

BTW, for those people manufacturing these cables for others... please do NOT add red colors to the wire coat - keeping everything black is the best way to keep the camera from showing up in reflections. Covering everything up with black electrical tape is always a bit of an ugly solution.

Jack Kelly

04-15-2008, 02:19 AM

Hi there,

Please may I ask for a confirmation that we do NOT need any resisters in our XLR cables if we're not using Phantom power (e.g. if we're feeding the RED ONE a line-level feed from an SQN mixer).

Many thanks,
Jack

Kevin Halverson

04-15-2008, 08:12 AM

based on a bunch of tests, we made custom cables with a -10 db pad in the cables for LINE in -

That is one of the three functions of the RED adapter cables. When the camera is in line mode, they raise the input compliance level from 2V RMS (+6 dBV) to 6.6V RMS (+16 dBV).

Michael Morlan

04-16-2008, 09:28 AM

Mark,

What is the schematic for those -10db cables? My audio guy couldn't get his line level output low enough to avoid peaking on my RED this week.

Michael

Kevin Halverson

04-16-2008, 09:35 PM

Mark,

What is the schematic for those -10db cables? My audio guy couldn't get his line level output low enough to avoid peaking on my RED this week.

Michael

Try a RED sourced cable and all will be fine.

Sean

04-23-2008, 03:53 PM

This thread sorta probably answers my latest question, which is:

The mini-XLR to XLR adapter cable I got from Red is a proprietary device right? So I can't just go to the local audio guys and get another one? It must be Red's?

Kevin Halverson

04-23-2008, 05:07 PM

Get them from RED unless you have a really good reason not to (which for the life of me, I can't imagine what that might be).

Michael Morlan

04-24-2008, 09:16 AM

Proprietary? Hardly. Just bust open the XLR shell and note the resistor setup within. Very easy to replicate and RED is hardly in the business of making bank from these. Their money is elsewhere. ;-)

Kevin Halverson

04-24-2008, 12:49 PM

Proprietary? Hardly. Just bust open the XLR shell and note the resistor setup within. Very easy to replicate and RED is hardly in the business of making bank from these. Their money is elsewhere. ;-)

No, not exactly "Proprietary", but rather specific to the RED ONE. As long as one is very confident that they can execute the exact same configuration, having someone else produce them is an acceptable alternative concept, but remember, they must be done correctly.

Cüneyt Kaya

04-24-2008, 01:11 PM

will someone make a 300-500 Dollar (cheaper would be niiiiice) audio breakout box with some controllers regarding this issue.....dont want to order mini xlr-to XLR cables every two months....

Anthony S. Lenzo

04-24-2008, 01:18 PM

will someone make a 300-500 Dollar (cheaper would be niiiiice) audio breakout box with some controllers regarding this issue.....dont want to order mini xlr-to XLR cables every two months....

It's in here http://www.toys4red.com/product_info.php?products_id=35 .

Cüneyt Kaya

04-24-2008, 01:25 PM

It's in here http://www.toys4red.com/product_info.php?products_id=35 .

is your box covering the hdmi out and headphone connector?---and i only see 3 XLR outputs...

it is a little bulky and seems to be heavy....

Do you have something smaller for audio only?

----but the product looks nice for studio conf.

Anthony S. Lenzo

04-24-2008, 01:38 PM

Those that have seen it at the REDuser party can tell you that its not heavy nor bulky. Its slightly wider than the full size XLR connector at the back. Any thinner, not possible...unless you want to go back to Mini-Q? The HDMI & USB ports are accessible thru the panel, It has an opening for them to pass. We are using the audio monitor output (5pin) for audio monitoring from the panel on the camera (3.5mm jack). The output level to the jack has a volume control pot as well.

Best,

Anthony S. Lenzo

04-24-2008, 01:41 PM

i--and i only see 3 XLR outputs...

.

Sorry...forgot to address this. Yes, only 3 (when using the IOP4R-1 panel) otherwise, the panel would be bigger. When tethered to the Break-out box, you can feed 4 channels.

Respectfully,

Cüneyt Kaya

04-24-2008, 01:41 PM

dmartos

05-03-2008, 12:48 PM

r39525

05-07-2008, 02:57 PM

If it's a matter of welding three resistors, it can't be too difficult to have it done right. Big reasons for me would be would be: a)custom lengths and b)custom connectors at the other end. I personally would like to have four longer miniXLR-XLR leads that I can secure on a universal mount at the back of the camera plus some miniXLR-minijack(locking) to connect to the Sennheiser wireless receivers without the need of going to and from big XLR. Could anyone summarize clear instructions on how the wiring should be done and the value of the resistors if we want custom cables that work the same way as Red's? Thanks.

TRIVIA ANSWER TO "WHAT ELSE CAN A RESISTOR PAD BE CALLED?"
FYI, when two resistors are connected this way, in addition to being called a 'pad', it's also called a voltage divider. With reference to the pictorial diagram shown earlier, the voltage at the output is the input voltage divided by the ratio R2/(R1+R2) or Vout = Vin * (200K/(681K+200K)) or Vin * 0.227

Mitch Deoudes

06-01-2008, 04:34 PM

Did stuart ever post the information promised here? Link (http://205.234.134.160/forum/showpost.php?p=189914&postcount=36)

Been trying to search the forums for info on this topic, "special" cables, hiss, etc. Slow going. (And no page on RedHax, sadly.)

Andrew M.

06-01-2008, 04:37 PM

There is no polarity issue, there was just a misprint on the mini xlr picture in the pdf file that was corrected.

The phase on the audio ch 1 to 4 is correct. ver 15

Forrest Forbes

06-03-2008, 11:01 AM

Coffey Sound has made many input cables for the Red Camera. Before we received feedback that headroom is optimized with a pad in the cable, we made them without the pad. Please note that all cables now in stock and all future cables will have the pad installed. Also, previously sold cables will have the pad installed at nominal charge.

Forrest Forbes
Service Manager
Coffey Sound LLC