Converting WOPL inputs to XLR...

[mlucitt]

If you tie pin 1 and pin 3 together, you defeat the purpose of a balanced cable. Plus, you are grounding half the signal from the differential output of the preamplifier - reducing your signal by 6db. A well made coaxial cable is just as effective at eliminating interference (noise), but the true value of an XLR balanced cable is to reduce noise caused by noise on the ground wire from the mains (earth). That is why one wire contains the signal and one wire contains the opposite phase of the signal, any other ground noise in the shield is cancelled. Lee can put his AP on the ground of his pre and see if he is suffering mains ground noise. If not, he does not need a balanced cable.
I believe the Clean Box Pro contains a transformer that is an impedance matcher for balanced wires on the primary and single ended wires on the secondary. Not much circuitry needed, but I've never opened one to look inside.

 

[laatsch55]

Lee can if you can tell him how...

 

[grapplesaw]

Here is my take on Balanced vs unbalanced

Pro audio decided that with long runs between amps preamps and mics they needed a higher voltage signal to drive a 0 dB level. It is about 1.4 times the level of unbalanced. Also the spec calls for a true + &- signal with a separate ground shield.

The two ways to convert the signal from high Balanced signal to lower unbalance is through a dropping transformer or through a ic chip. With the transformer there is no need for power or any other components. It also can be used to convert the signal from balanced to unbalanced or unbalanced to balanced. Only requirement are high quality transformations. The Rane BB44/88 do an excellent job with minimal sound quilt loss.

As for the ic method the options a great. Any ic we currently use work well. As far as design they are only one direction. Either unbalanced to balanced or balanced to unbalanced. One design Cannot use be for both as like the transformer. It is a small ic board so can be fittted inside the amp. As for transformers they may or may it be fitted inside the space available.
That is why an outboard set up works well.


Overall the balanced setup is required when adding pro Grade components. Such as Lee’s preamp my sunfire preamp and other items like DBX processors and electronic crossovers that I am setting up.


Overall both systems work well. Balanced is more cumbersome but has advantages. Unbalanced is best for most of our uses

 

[laatsch55]

Thanks Glen....

 

[Gepetto]

Some of the road warrior "band amps" were converted from RCA to 1/4" because the 1/4" plugs and jack connectors were more common (used on all guitars and speaker cabinets) and Speakon connectors were not around then. Older Crown amps used 1/4" jacks, too. Some people like them better than RCA jacks.

I hate them on the Crowns because the nickel plating oxidizes and becomes non-conductive/intermittent.

 

[mlucitt]

I used crocus cloth on mine to polish most of the nickel off and then I had to keep them preserved with De-Ox-It. Gold plating would be a good solution.