如果您的設備有一端是 XLR 標準平衡式輸出，而連到下一級卻是非平衡的 RCA 輸入時，您都怎麼處理呢？製作一對 XLR – RCA 的
cable 連接兩設備，這個主意大概是會最先浮現的念頭吧。2012 年初，譯讀 Rane.com 的「SOUND SYSTEM INTERCONNECTION」（站內標題：「聲音系統的連接」），文中的最後一種方法 – 特殊 cable 組合，就是為這種情境所設。
適逢網兄問及 Studer A721 與
RCA input 擴大機的連接，有機會再複習一下。Studer A721 的輸入與輸出為標準平衡式 XLR 接頭，
Rane.com 文中 XLR → RCA 有兩種組合可能適用：
不過心中隱隱覺得不妥，兩端電路的信號、接地、準位，不管怎麼接都存有運氣的成份，要試才知道，還是問問原廠的意見吧。
很快地原廠有了回覆，這裡貼附回函如下，供有需要的網友參考 …（兩行箭號後的文字為 Martin
先生擷取筆者詢問信中的問題，兩個方法就是前段所列的組合。）
Dear
Mr. Hajazz,
>>> Would you please teach us how should
the cable be made ?
>>> If one of the following
methods can be adopted ...
It’s a good question.
However, please be aware that version 1 will not work since the
XLR plugs are wired as follows:
（第一種方法可能不適用，因為 XLR 的接線如下：）
1 =
Audio shield (which means there is no audio signal on it, it is just a
screen)
2 =
A-Line (hot)
3 =
B-Line (cold)
This
means: Pin 3 of the XLR plug need to be connected to the S (shield) of the RCA
plug! Which means on your drawing:
（這意謂著 Pin 3 需與 RCA 插頭的 S(隔離網) 相連！在你的圖上將是：）
1=NC
(shield)
2=Red
(+)
3=Blue
(-)
Preferable is version 2 where pin 1 and 3 are
liked.
However, please be aware that there could be hum problems (depends
on the equipment on the RCA plug).
Therefore it could be that you need to try out which version suits
best. Possible the mains ground must be insulate against audio ground to prevent
hum.
（第二種方法可能好一點，Pin 1 與
3 是相連的。然而，請注意可能會有哼聲產生 (取決於 RCA 插頭端的器材)。因此你可能需要試試哪一種方式最合適。可能，必須將電源接地與信號接地絕緣以阻絕哼聲。）
Furthermore it could be that you might have a level problem,
especially on the input of the A721.
The best solution (and also the most expensive one) is to
use a balacing unit which electronically adapt the symmetrical XLR signal into
an assymetrical RCA signal and versa visa and matches the
level.
（此外，還有可能發生準位的問題，特別是在 A721 的輸入端。最好的解決方案 (同時也是最昂貴的) 是採用平衡裝置，以電子轉換的方式，將平衡的 XLR 信號轉換成非平衡的 RCA 信號，反之亦然，同時也顧及了準位匹配。）
There
are as well adapters available see below:
（有現成的轉接器可以使用，參考如下：）
Martin
Berner
Technical support
-------------------------------------------------
audiohouse.ch
<http://audiohouse.ch/> gmbh
Grasweg
20
6222
Gunzwil / Beromünster
在電源計畫之前，筆者原有兩個主題在研究著，其一即為「adapter」。
不過 Switchcraft 的
adapter 種類不少，價格頗高，一時拿不定應以何種為優先？
Switchcraft
有一系列的轉接器，XLR → RCA 的圖片
關於 audiohouse.ch 與 Martin 先生
audiohouse.ch was founded in January 2002 by Marcel
Cattani, a former service and support manager of Studer Professional Audio GmbH
over 17 years.End of 2006 Studer Professional Audio has outsourced the earlier Studer products. From January 1st, 2007 audiohouse.ch is the contact worldwide for most of the Studer analogue and digital products, in regards of repairs, spare part supply or for service requests.
audiohouse.ch supplies all the Studer representatives as well as customers all over the world.
Since September 2009 Martin Berner, a former support engineer for professional tape machines of Studer Professional Audio over 35 years, is working for audiohouse.ch.
At present time 7 people are working for audiohouse.ch.