Need 25 foot interconnects

I would get Mogami Neglex star quad and some ProFi ends.
You‘ ll be way better off with the MBs at the speaker.

However it is probably best to use that Neglex (or Cardis, Canare, etc) star-quad and fit it with XLRs. Then back at the monoblocks use something like these:

One could start with the XLR cables and use the XLR to RCA adaptors. Neutrik catalog numbers for the more common XLR to female RCA jacks are NA2MPMF (male XLR) and NA2FPMF (female XLT). Better check.
Then if there was no hum you are done. And if there is hum, then look at the isolators like the Jensen??

I usually DIY my own using the Neglex 2534 star quad, in brown to match wood floor colour. All the star-quad design is good stuff… e.x. Canare.

I'm running 20' RCA cables and it didn't make a difference in sound when I used a 3' RCA cable, I compared them in the same room with the same equipment. I'm not saying your balanced output may not sound better, but I don't think that going from 15' to 25' with RCA is going to make any difference, unless you are picking up noise on your RCA cables.

^Entirely likely as well.^
Which is why I first mentioned the star-quad with the ProFi ends.
And coax is also an option.

If that doesn’t work, then desolder and go to balanced.
But he stuff is only $1/ft or less so it is probably just cheaper to order it if doesn’t have a soldering iron.

Maybe you could try one amp (then the other) using an RCA double end male to hook your two shorter cables together…??
If that works with no humming, then just order the right length with RCAs.

I dunno @nymarty - I would do the XLRs either yourself or from some place like BlueJeans with a star quad shielded wire and the XLRs.

Then just use the Neutrix to XLR jobs which are $10-$15 each.
If there is not hum you are done. And if there is hum then try the Jensen’s isolator.

That is assuming that the Cardas is the same as a Neutrik in that it adapts and is not a balanced isolator.(???) so the Cardas should be the same?? 

Basically it’s a couple of baby steps.

• Cable+adapter and no hum = job done.
• Still noise(?), then slip in the isolator.

Would that do the same thing as the Jensen? Or would I just lose the value of the balanced cable by floating the ground at one end?

Yep you lose the balanced with the floating ground

• The adaptor gets the signal to the amp.
• The balanced cable allows you to go to the isolator if there is hum.
• So you can use the isolator later if needed, or if you change to mono blocks that have a balanced input, then you already have the XLR cable.

I would do that before going to a high $ single ended cable, as it has a much higher probability of mitigating hum and noise… having Star-quad balanced + shield + isolator is close to bullet proof.
Not quite as good as a balanced amp, but as close as one can get.

Belden? what kind of cheap monoblocks do you have to use that crappy cable?

Nice gear shaming @urbie -  however solid gold cable also seem to obey the laws of physics.

Spoke too soon about no hum.  It got really quiet in the house tonight and had a good listening session and left the earlier comment where I said "No hum. No noise."  When I stopped playing music and stood up, I heard a slight hum.  I got closer to the speakers and they just have a monotone hum coming out of them.  Going to need to troubleshoot the hum this week and figure out the cause.  Lots of things going on that are different -- also switched from low level subwoofer connection (interconnect) to high level coming off the speaker binding posts, so not sure if it's the 15' interconnect or the high level subwoofer connect that is causing the hum.  Maybe the hum is making the soundstage better.  ;-)

This is great.
Great to find this out now.

Is it easy to run an extension cord to the mono block?
That “test” could allow us to determine if the monos are on a different circuit.
Or you can flip breakers to work it out.

Your trouble shooting plan sounds good.

… so switched back to the Belles Aria Monoblocks, which I just bought.

The gear shaming is getting a bit difficult.

@holmz I was able to try your original suggestion. I was on Emotiva’s website to buy a 12V trigger and they had XLR to RCA adapters, so I bought 2 of them. I hooked up a pair of 20’ balanced XLR cables to my preamp, added the adapter just before my amps and connected a short run of RCA cables between the adapter and the monoblocks. Success. No hum, no feedback, just a silent connection. Sounds petty good, too, when playing music.
Thanks, all, for the help

Glad that worked out.
At least if it didn’t work out, then you would have had the cables needed for the Jensen isolators.

I have a bit of hum seen on a measurement spectrum from the TT, but when I play back file at +12dB I barely hear it with my head against the speaker.
So if it sounds good, then as they say say here, “You’re Larfin.”

Hopefully the next fellow or lady doing a search will find your thread helpful.
Thanks for putting a bow on it.

Stay away from XLR/RCA adapters as they will diminish sound quality.

@ebm ​​​​@ghdprentice how do we explain this from 3 weeks ago:

… Success.  No hum, no feedback, just a silent connection.  Sounds petty good, too, when playing music.  
…

@holmz  I think we’re all right.  Let me explain.  …

^exactly^

I believe that the 2 fellows that said that there is a degradation… also believe that they are correct.
And they are for their experience.

Hence they would have needed the Jensen transformer with the humming gear.

Where as with the Belles you did not.. sometimes one just needs to try it, but a spreadsheet of gear that the ordered from prone to less prone for humming would help.

Let me know what you think of the 3a sigs… They are generally able to consume a lot of one’s time in futzing with their placement, tilt, and toe-in… in order to make them sing in the space.
There is also a forum for that the brand.
And Belles is something that many seem to have used with success to drive them.