TOPIC:

Hello,
I am planning on building a system around the flex. I would like balanced out to my amp, but the subs I will be using are single ended. Is it possible to use an adapter to have single ended out to subwoofers?
Would something like this work? www.amazon.com/JOLGOO-Stereo-Interconnec...apter/dp/B082X6F6S4/

If not I can do single ended to the amp, but it seems like doing balanced for $75 more is worth it

www.ranecommercial.com/kb_article.php?article=2107
 

I was having the same question and I had also asked the question to miniDSP support.

Based on the information from RANE that is cited by rvsixer in this thread, configurations 10 and 12 could be used.
Configuration 10 leaves the ring of the TRS jack open.
Configuration 12 connects the ring with the shield and is for cross-coupled outputs only.

miniDSP support team has been giving a configuration similar to ŔANE configuration 10
whereby the ring remains open, but they make use of a 2 conductor cable with additional shield, cf.
support.minidsp.com/support/solutions/ar...-cable-should-i-use-
Clearly, there is not much difference between RANE configuration 10 and the suggestion from miniDSP, in both cases the ring is not connected.
However, this solution excludes adapters or jacks without ring, such as the one from Amazon linked by HawaiianFeeling.
Adapters or jacks without ring create a shortcut between the ring and shield at the Flex device.
Also, adapters between stereo Jack and single RCA usually create a shortcut between ring and tip and should therefore not be used.

I am not aware of any commercially available adapter cable that could be used.
Therefore, I may have to solder such a cable.
 

I think it might be cheaper and better for me to buy the transformer adapter than get into custom cables. The transformers only cost $35 for each sub. It would be great if a custom cable outfit could made an affordable shielded sub cable for this. I rather have a balanced flex and be able to use the new topping PA5 desktop amplifier with the new flex. The devices were made for each other. Unfortunately the subs I want to use are “budget” and don’t have balanced in. It seems like only the very high end subwoofers offer balanced in. 

I have the same application: 
Balanced Flex -> L50 -> PA5
Balanced Flex -> unbalanced Subwoofer

I was also looking at transformers:
Balanced Flex -> transformer -> unbalanced Subwoofer
whereby the connection from balanced Flex to transformer could be a commercially available cable from 6.35mm stereo Jack to XLR.

There are cheap and small transformers (for example from Neutrik), but they have a large impedance mismatch.
Impedance should be high at the transformer at the balanced side, low at the transformer at the unbalanced side.
Furthermore, frequency characteristics are not specified and tested, and they may attenuate or cut off the low frequencies for the subwoofer.

There are better and larger transformers (for example from Jensen), but these are expensive and have configurable switches for grounding
which are supposed to better suppress any noise from ground loops, but which also affect the frequency characteristics.

I believe that transformers should only be used when needed to avoid noise from ground loops.                                                    

Dear All

We've tested with this configuration:  support.minidsp.com/support/solutions/ar...-cable-should-i-use-  on the APX555 and that's the one that gave us the best results. 
Maybe other cables will still work but just not as well.. As other mentioned correctly in this thread, doing balanced to unbalanced is asking for trouble. Chances for having a ground loop are much higher. Using a transformer or active bal to unbal is the best way. 

We're going to push to make a custom cable as we've already made few sample. We're close to Chinese New Year for us so factories are already slowing down on orders. We won't get this set of cables till few weeks I think. Thanks for your patience. 

Devteam

miniDSP devteam suggests to use a cable where the ring of a TRS jack remains unconnected,
and one of the two conductors and the shield are connected at the TRS jack side.
This would mean that a shielded two conductor cable would need to be used between Flex and subwoofer.
But at the RCA side only the two conductors are connected with the RCA plug.

A slightly simpler solution is using shielded one conductor cables which are commonly available with RCA plugs.
In this case, the conductor and the shield are connected with the RCA plug.
This corresponds to configuration 10 in the document from RANE.

Rather than soldering such a cable, I have found an adapter from TRS to RCA which leaves the ring from TRS unconnected,
see www.audiophonics.fr/en/jack-rca-adapters...-adapter-p-7101.html
When buying this type of adapter, it is often not clear if the ring of the TRS remains unconnected, or if ring and tip of TRS are connected,
Therefore, it may be necessary to check the adapter before using it.
The subwoofer can be connected with balanced Flex using this adapter and a standard RCA cable.

Why making a simple task so complicated.  Don't use adapters, you lose the independent shielding along the cable run (ask me how I went from using them to using RANE configured cables - no more hum).  If you can't find the right cable, make one (or a careful snip of a wire can "fix" a commercial offering).

I have the same application: 
Balanced Flex -> L50 -> PA5
Balanced Flex -> unbalanced Subwoofer

That's a really  cool setup because you can use the minidsp both to do REW/Dirac for the speakers but you can use presets for headphone 10 band PEQ. It it for a desktop setup or something for a living room? This sounds like a end game desktop source setup. I'm curious to hear more about your plans. are you doing 2.1 or 2.2?

We're going to push to make a custom cable as we've already made few sample. We're close to Chinese New Year for us so factories are already slowing down on orders. We won't get this set of cables till few weeks I think. Thanks for your patience. 

WOW! Thank You. Please offer multiple lengths. I'm new to the brand, but one of the things I like about you is the moderate pricing. It makes investing into your system have more value. When I heard about the Flex I thought it was such a weird device but it could solve my problem of wanting to do a small 2.2 system with desktop parts to put on a shelf in my small living room. My idea is if I don't have a component rack it's easier to get away with dual subs in a non listening room. What a cool device. It would be worth the price of entry even if all you need is bass management.