bigbert Posted January 8, 2011 Share Posted January 8, 2011 Hello I've come across this balun on CPC> linkyDoes anyone own a pair? I am curious as to what is inside them. I'm presuming they must have some electronics rather than the signal going straight down the Cat5!?If it is as simple as that I'd make some sets up but if not I think I'll be buying. Thanks Bert Link to comment Share on other sites More sharing options...
ceecrb1 Posted January 9, 2011 Share Posted January 9, 2011 As they are passive and require no power, its clear to me that they are just converting from one cable type to another... Link to comment Share on other sites More sharing options...
bruce Posted January 9, 2011 Share Posted January 9, 2011 If it is indeed a passive balun (BALUN - BALanced-UNbalanced converter), there will be a small transformer inside. Link to comment Share on other sites More sharing options...
TomHoward Posted January 9, 2011 Share Posted January 9, 2011 We have got the Muxlab balun boxes that are also listed on CPC - there's some passive electronics inside them, I guess impedance matching and stuff. Link to comment Share on other sites More sharing options...
kitlane Posted January 10, 2011 Share Posted January 10, 2011 Impedance matching transformer. I've considered making my own but the cost of the component is suprisingly high (suprising to an electronics novice, anyway) and it didn't seem worth it. Link to comment Share on other sites More sharing options...
Shez Posted January 10, 2011 Share Posted January 10, 2011 I've got a similar CV / audio balun from CPC. All that's inside it is a small transformer for each signal. At the end of the day, all it does is convert from 75 ohm impedance to 110 ohm and back again. Link to comment Share on other sites More sharing options...
rgye Posted January 10, 2011 Share Posted January 10, 2011 They are not simply changing the impedance - the transformer converts the unbalanced signal to a balanced one and back again. This is a three wire system, and means the signal cables carry identical signals relative to earth; in effect, any interference induced in the cables is picked up equally by both conductors so it cancels itself out. It works in exactly the same way as a balanced audio connection (eg XLR) in comparison to an unbalanced two wire system (eg jack plug). The active units are also amplified to overcome transformer losses, so tend to have a better range than passive units. Link to comment Share on other sites More sharing options...
bigbert Posted January 10, 2011 Author Share Posted January 10, 2011 thanks guys. I did suspect there would be some components inside. Looks like I'll be buying a pair. Out of interest, could some one tell me what sort of impedance matching transformer would be used inside? bert Link to comment Share on other sites More sharing options...
Shez Posted January 10, 2011 Share Posted January 10, 2011 the transformer converts the unbalanced signal to a balanced one and back again. Alright, you got me, I forgot that bit. But if we're being pedantic... This is a three wire system, and means the signal cables carry identical signals relative to earth... A balanced system doesn't need an earth reference as each leg is referenced to the other. In the case of the box I've got, it squeezes two CV and two audio lines down one CAT5 cable - that's four signals down four twisted pairs, no earth required. You could shoe-horn a couple of phantom circuits down there too but then it just starts getting silly ;) Link to comment Share on other sites More sharing options...
BoogieBear Posted January 11, 2011 Share Posted January 11, 2011 Hi Bert We use these LINK over a 30m CAT5 run and they work perfectly well :) CheersAnton Oh! What happened to the link? Help please Admin. It shows up in the editor, so what am I doing wrong?CheersAntonModeration: Just a minor syntax issue Anton, you had http: twice at the start, so I've fixed it for you. Link to comment Share on other sites More sharing options...
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