Balanced to RCA

@mike_in_nc   I'm unsure regarding your comment below. Can you elaborate?

I was very concerned about this very issue and a number of folks helped me out. Al ( @almarg ) was a primary advisor on this. Perhaps he can comment and add his usual dose of clarity to the discussion?

I also reached out to the designer and manufacturer of both the Preamp and Amp. Both verified that the approach @almarg and others recommended was safe. I also verified with Richard Gray who is local to me, before moving forward. 

Thanks.

Adapters from unbal to bal sometimes ground one of the active pins (2 or 3 of XLR), but that is not advisable going from bal to unbal, as you would be grounding one output of your source component, which could damage it.

For a definitive answer, I’d go with the recommendation of the manufacturer of the balanced-output source component. (Some manufacturers even provide wiring diagrams for their recommended method of going from balanced to unbalanced.)

It makes me uneasy to short any output to ground, but I’m not an EE nor a circuit designer, so there’s a lot I don’t know.

@david_ten

Thanks for the mention, David. Most (but not all) XLR-to-RCA adapters ground the signal on XLR pin 3, i.e., they connect pin 3 to pin 1, which is the ground pin. In the case of most (but not all) components providing XLR outputs that kind of adapter should not be used, for the reason @mike_in_nc stated. And the same considerations apply in the case of an XLR-to-RCA cable.

Following is an excerpt from what I had said when we discussed this issue via PM in November 2018:

An adapter that shorts pin 3 to pin 1 would be appropriate when adapting an RCA output to an XLR input, and would be appropriate and sometimes even necessary with **some** designs (especially some tube-based designs having transformer coupled outputs) when adapting an XLR output to an RCA input. However in many cases, especially cases involving solid state designs having low output impedances, such a short could cause adverse sonic effects, buzzing, or even damage, eventually if not sooner. I once diagnosed a severe buzzing problem that occurred with a member’s CD player which was caused in exactly that manner. When he went to an adapter cable which left pin 3 open everything worked fine.

You subsequently received a response from the designer of your Grandinote preamp stating that pin 3 should be left open (unconnected) when adapting its output to an RCA input.

And chances are that would also apply to the OP’s situation, but not necessarily. For a firm conclusion to be reached he should either ask the manufacturer of the component providing the balanced output (as I see Mike suggested just above), or let us know the specific make and model of the component and we may be able to determine the answer.

Best regards,
-- Al

I am going through the same labyrinth
I have a before-amplifier ( not to be confused with the preamplifier) (It is a dox drive rack) which I’ll be using as an external crossover. It has female XLR inputs and male XLR outputs. My question is what is the best way to convert
RCA to XLR (cd player to dox)
and
XLR to RCA. (dox to amplifier)
  

-typically on the second half Im wondering which would be preferred ?
1. xlr cable from the dox to either: 
     A. Cardas Audio Male RCA to Female XLR Adapters plugged onto my amplifier (McIntoish 2105)
     B. A transformer. (SO max}

What I like about A. Is there is only one set of cables versus B. Two sets of cables.

depending on my speaker choice Ill need need to be bi-amping or tri-amping… so cost is a consideration x2 or x3…

2.???


My brain isn’t intended to be used in complex matters such as this...

Im just trying to go from:

 CD player to dbx
(balanced to balanced?) 

then

dbx to amplifier (balanced to unbalanced?)

• (Pin 2 is connected to the center RCA pin and Pins 1-3 are grounded to the RCA chassis body)

• (Pin2 is connected to the center RCA pin, Pin1 is grounded to the RCA chassis, while Pin3 is connected with a 10 ohm resistor to the RCA chassis)
  
  

• (Pin 2 is connected to the center RCA pin and Pins 1-3 are grounded to the RCA chassis body)

• (Pin-2 is connected to the center RCA pin, Pin-1 is grounded to the RCA chassis, while Pin-3 is connected with a 10 ohm resistor to the RCA chassis)