Jump to content
ramallo

Zaxcom ERX cable

Recommended Posts

This is my approach 
 
I added a series capacitor for phantom protection (47uF 63V)
 
In the last image the insertion loss (Depends of the input impedance due the RC) (ups! I forgot the 1kHz notch "on")
 
*Sorry for the ugly solder, is a recycled XLR3

 

pim8.jpg

nzp0.jpg

a68a.png

Share this post


Link to post
Share on other sites

Had a shoot the other day with a Canon C300 and mistakenly plugged in my ERX before checking if phantom was engaged (I know better). I panicked and quickly turned it off. But nothing bad happened to my ERX. It still continued to operate as intended.
I want to modify my existing cables I made up just to be safe. Will do better 48v police work but also wanted to help block phantom power getting switched on by mistake, etc. I bought a 10 pack of these capacitors (47uF 63V) cheap. Was just doing some bench testing prior to working with the capacitors. My mix pre D with phantom power engaged shows 44.7v at the male xlr input. When I plug a standard XLR cable, I get the same reading (just to double check). When I plug the original cable I made into the mixer (mine Y's from the 1/8 right angle trs and does not have a capacitor in series yet), the reading i get at the 1/8 connector is 0.5v. Considerably lower than a balanced XLR, but still a small amount of voltage. Voltage is 0.0v when I switch to mic or line level on the mixer.

 

Is my Y cable not allowing the phantom power thru at full voltage because of it being wired unbalanced or some other reason I am missing? Wondering if maybe I am ok without capacitors since i have survived the last one. I do want to put them in anyways just to be safe.

 

1/8 TIP - to - XLR PIN 2

1/8 RING - to - BNC PIN

1/8 SLEEVE - to - XLR PIN 1, JUMPER TO PIN 3 

1/8 SLEEVE - to - BNC SHELL

 

When I wire a capacitor in series at the XLR pin 2 (as appearing in Ramallo's image), with phantom voltage on, I am still reading 0.5v. I was expecting to see 0.0v Am I assembling incorrectly somewhere along the way?

 

Ken

Share this post


Link to post
Share on other sites

osa: " Is my Y cable not allowing the phantom power thru at full voltage because of it being wired unbalanced "

industry standard phantom power for audio (microphones) requires balanced-floating wiring.

Share this post


Link to post
Share on other sites

The ERX cables I've made for others had a 3.5mm TRS plug with TC to the tip & audio to the ring. It really doesn't matter what's where as you can select it in the ERX menu. The audio is wired unbalanced as you've done and the TC is also as you've done with the TC ground connected with the audio ground at the 3.5mm sleeve connection. No resistors or caps are used. Everyone works perfectly all the time as far as I know.

post-22-0-38643400-1412792657_thumb.jpg

Share this post


Link to post
Share on other sites

Thanks Mike and Eric, good to know all around. I will quit soldering while i am ahead. google search cant find the discussion about damaged erx's from phantom power - did i dream it??

 

Ken

Share this post


Link to post
Share on other sites

Thanks Mike and Eric, good to know all around. I will quit soldering while i am ahead. google search cant find the discussion about damaged erx's from phantom power - did i dream it??

 

Ken

There may have been a discussion but as Senator said phantom is a non issue in an unbalanced situation.

Share this post


Link to post
Share on other sites

There may have been a discussion but as Senator said phantom is a non issue in an unbalanced situation.

 

For phantom power (As senator's wrote) you need the hot and cold connected plus ground. For get +48V (With the phantom engaged) you only need any wire (hot or cold) + ground

Share this post


Link to post
Share on other sites

The ERX cables I've made for others had a 3.5mm TRS plug with TC to the tip & audio to the ring. It really doesn't matter what's where as you can select it in the ERX menu. The audio is wired unbalanced as you've done and the TC is also as you've done with the TC ground connected with the audio ground at the 3.5mm sleeve connection. No resistors or caps are used. Everyone works perfectly all the time as far as I know.

I'll vouch for this. I have 3 of Eric's cables and I've not had any problems for the past year & 1/2.  

Share this post


Link to post
Share on other sites

post-22-0-08335600-1412953105_thumb.jpg

I'll vouch for this. I have 3 of Eric's cables and I've not had any problems for the past year & 1/2.

Oh shit now you've done it. My marketing representative will have to pay you a visit. His picture attached for your protection.

Share this post


Link to post
Share on other sites

For phantom power (As senator's wrote) you need the hot and cold connected plus ground. For get +48V (With the phantom engaged) you only need any wire (hot or cold) + ground

In my younger days I infamously wrecked a G3 receiver by plugging it into a 48V input.  That uses an unbalanced cable.

The Zaxcom units, given their price tag, may have protection against this sort of thing built in.  

Share this post


Link to post
Share on other sites

I had my erx3tcd serviced, the antennaboard is replaced, does this imply it is 'protected' to phantom power?
I also have a erx1, I want to make a cable with a build in protection, where do I put the capacitor?

Share this post


Link to post
Share on other sites
On 6/10/2016 at 1:20 PM, boodschap said:

I had my erx3tcd serviced, the antennaboard is replaced, does this imply it is 'protected' to phantom power?
I also have a erx1, I want to make a cable with a build in protection, where do I put the capacitor?

A capacitor in series block the DC. XLR3 pin 2 to ERX output 

IMG_4113.jpg

Share this post


Link to post
Share on other sites

There is no phantom power to or from an ERX. The TC from the tip is just line level audio (36khz sq wave), the ring outputs your program audio at line level. Both are unbalanced signals.

Share this post


Link to post
Share on other sites
30 minutes ago, Eric Toline said:

There is no phantom power to or from an ERX. The TC from the tip is just line level audio (36khz sq wave), the ring outputs your program audio at line level. Both are unbalanced signals.

Just to offer some geek clarification: with an ERX the time code can be output on the tip, ring, or both, with the same options for the program audio.

 

Share this post


Link to post
Share on other sites
On 10-10-2016 at 4:41 AM, Eric Toline said:

There is no phantom power to or from an ERX. The TC from the tip is just line level audio (36khz sq wave), the ring outputs your program audio at line level. Both are unbalanced signals.

if erx is hooked up to an input set to mic + phantom, you damage your erx-output (it did happen to me). Better safe than sorry...
Of course I can make another unbalanced cable, then I can workaround the phantom problem...

Share this post


Link to post
Share on other sites

Great thread! I am however struggling with the xlr.

 

minijack tip goes to BNC tip

minijack ring goes to xlr 2

minijack sleeve goes to ban sleeve, xlr 1 and 3

 

Am I doing it right? (I know, there is no phantom protection.)

Share this post


Link to post
Share on other sites

 

Actually, quite some time ago Zaxcom added phantom protection to the ERXs.  It was maybe a third of the way into the ERX2TCD runs, but that's only a guess.

 

3 hours ago, Frode L Hvatum said:

Great thread! I am however struggling with the xlr.

 

minijack tip goes to BNC tip

minijack ring goes to xlr 2

minijack sleeve goes to ban sleeve, xlr 1 and 3

 

Am I doing it right? (I know, there is no phantom protection.)

 

You can use the tip or the ring either way as Time Code Out can choose Left, Right, or Both.

Share this post


Link to post
Share on other sites
6 hours ago, Frode L Hvatum said:

Great thread! I am however struggling with the xlr.

 

minijack tip goes to BNC tip

minijack ring goes to xlr 2

minijack sleeve goes to ban sleeve, xlr 1 and 3

 

Am I doing it right? (I know, there is no phantom protection.)

You are doing it right. The grounds for TC & audio get tied together on the 3.5mm TRS and pins 1 & 3 in the XLR are grounded together for an unbalanced audio connection.

Share this post


Link to post
Share on other sites

Thanks for the help!

 

Weird. I can hear a faint whisper of the timecode, but nothing else.

 

I tried with another minijack to phono and phono to xlr cable + phono to bnc. Worked perfectly. So the ERX is ok.

 

So I made one from scratch and that one works perfectly. There must be a break in the cable or plug I was using.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×