# Internally bridging Zapco AP amplifiers



## whoever (Nov 21, 2008)

I’m looking to internally bridge the inputs on my Zapco AP 400.2’s and 150.6’s. 




  








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whoever


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2 mo ago












  








Zapco rca input




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whoever


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2 mo ago








So it looks like the center pin will be signal + and I’m assuming the 6 surrounding pins will be signal -


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## bnae38 (Oct 3, 2015)

You mean connecting the inputs in parallel (y-split the inputs basically)?

Bridging probably not the best term to use. Usually refers to outputs and usually in reference to going from half bridge (ground referenced) to full bridge (signal on both outputs) IE twice the signal amplitude.

Anyway, if you just are connecting input rcas in parallel, I don't see any big issues.


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## whoever (Nov 21, 2008)

Bnae, yes, I’m looking to connect the inputs internally instead of using a Y adapter externally.


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## cman (Aug 24, 2020)

Just use little jumper wires and solder in parallel.. you can use continuity mode (aka measuring resistance) on your multimeter to confirm you connect the correct ones together.. obviously its just pos to pos and neg to neg.. 

as @bnae38 mentioned, using the word bridge would normally seem OK in any other situation (not amplifier related), but since it is in the context of an amplifier in which the word bridge has a much different meaning (for bridging the outputs) it could cause confusion. 


If you put some flux and fresh solder on the little board it will allow the old solder to flow much easier without burning the board or anything.


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## whoever (Nov 21, 2008)

Finished internal input linking on my Zapco 400.2’s, channels 3&4 and 5&6 on the Zapco 150.6’s. I bench tested each amplifier after I finished the modification, it worked out great. 




  








Zapco 150.6ap channel 5+6 internal input link




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Zapco 400.2ap internal input linking.




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2 mo ago


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