2. tech-talk
  3. 1137309857

XLR/RCA adapters problem - Electrocompaniet

I have and Electrocompaniet EMC-1UP and a VAC Avatar Super.
I read that the EMC was designed to use the XLR output and sounds better when used this way. So, I decided to get the Cardas adapters to try it out since the VAC is single ended only. I plug them in and there's alot of noise which is reduced if I touch the cables which suggests a grounding problem.(?) Worse still is when I play music. There is alot of distortion. So I took a set of cables and reterminated them with XLRs (the hot and the ground) which was a bit better but still noisy unless I touched the cables. Then I plugged in the extra rca plugs while still connected through the XLRs and it cut the noise considerably. So the question is why go through all this trouble? Well the darn EMC does sound better throught the higher ouput XLR jacks. Any idea what's going on here before I open up the CDP and check if there's something wrong with the ground? Thing is is that I have good cables I would like to use but there's no way I'm going to butcher them. The EMC is still great sounding single ended but I would like to experiment.
I am relatively handy and can figure out simple elctrical problems but this is beyond me.
Anyone have any suggestions? Any other Electrocompaniet users have a similar problem?

Thanks
stuartbranson
10 responses Add your response
kenn39
75 posts
 
You should check with the company to see how XLR to RCA conversion should be done.

The usual way is shorting pin 3 and pin 1. In the case of Benchmark DAC1, pin 3 must not be connected to avoid grounding problem. I wonder if you have a similar problem with your Electrocompaniet.
rwwear
2,867 posts
 
First of all make sure your equipment uses pin 2 as the hot or positive. Most european and Japanese gear use pin 3 as the positive. Second make sure the adapter is wired so the ground is connected to the ground pin and not jumped to the negative pin. Be sure if you make your own cables you use balanced cables to begin with. You can reverse the positve and negative if need be to match your equipment.
ghostrider45
449 posts
 
By using the adapter route, you're still running singe ended, not balanced, even though you're using the "balanced" outputs. Balanced connections rely on the difference in signal between the "hot" and "cold" conductors. Done right, this is why they sound better. The adapters merely use the pin 2 "hot" signal (usa of course) and reference it to ground. It doesn't really buy you anything in this application.
Post removed 
stuartbranson OP
183 posts
 
Firstly, thanks for all the helpful information.
Second, I realize that using adapters is still single ended but I think I'm taking advantage of the 3.2V output from the blanced outs as opposed to the 1.6 V with the RCA's.

The pin configuration is on the back of the EMC and is as follows:
1 Grnd
2 +
3 -
So if I just groung the 3 pin along with the 1 should it stop the hum?
I guess I will take my Cardas adapters apart to see how they're configured and make any necessary changes.

I figured it had to bbe something with the EMC because the adapters worked fine with my friend's Wadia.

I guess this could be troubling with all sorts of gear matches. I never thought that a standard would not exist.
stuartbranson OP
183 posts
 
Well, I opened up one of the Cardas adapters and with the pin information on the back of the EMC it looks like everything is correct. 2 is the hot and 1 and 3 are grounded. Should I lift the connection of 3 to the ground?
ghostrider45
449 posts
 
Each leg (hot/cold or +/-) of the balanced connection runs 1.6 volts max. The cold or "-" leg caries a 180 degree out of phase copy of the signal on the hot or "+" leg.

A balanced input inverts the signal on the cold leg and adds it to the signal on the hot leg, yielding the 3.2 volt max signal.

The single ended adapter only uses the hot leg and thus the signal remains at 1.6 volt max.
rwwear
2,867 posts
 
If 1 and 3 are jumped it will cause a hum. They should not touch each other.
stuartbranson OP
183 posts
 
Still 1.6V eh? I see....Well I took the Cardas adapters apart and with the outer shell dismantled I found that the left adapter with 1 and 3 grounded and the right with the 3 lifted reduced the hum to almost nothing. So I put them back together that way and now it seems the jacketting is causing the hum so the 3 on the right must be touching the casing of the adapter. I think I will just give up and run single ended. Oh well... thanks for all the help. Learned something.
Post removed 
Log in to respond
More to discover
80x80
Ayon Audio S-10 II Signature Network Player DAC Preamp
AWARD WINNING - REMARKABLE!
80x80
KEF Reference 5
80x80
RSX MUSIC SERVER RSX MUSIC SERVER