Modernising Crest CA9 to speakon..

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   Got an old crest CA9 with binding posts and apparently no bridge switch that I can find.

Have bought a panel to screw onto the back of the case and NL4MPs. I'm fine with hooking these up to the binding posts to run it stereo but if I wanted to have a third NL4MP for a bridge output how would I go about wiring that up?

Could I leave that third bridge speakon constantly hooked up and if so what connections do I need to make with it on top of the other two speakons which will be used for stereo use.

Whats the deal with the lack of bridge switch? Can the amp be bridged just at the output terminals or does that missing switch do something to the input stage?

Any tips much appreciated..

Cheers

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charlysays Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 16 June 2015 Location: Wales Status: Offline Points: 413	Post Options Post Reply Quote charlysays Report Post Thanks(0) Quote Reply Topic: Modernising Crest CA9 to speakon.. Posted: 18 August 2017 at 2:36pm
	Got an old crest CA9 with binding posts and apparently no bridge switch that I can find. Have bought a panel to screw onto the back of the case and NL4MPs. I'm fine with hooking these up to the binding posts to run it stereo but if I wanted to have a third NL4MP for a bridge output how would I go about wiring that up? Could I leave that third bridge speakon constantly hooked up and if so what connections do I need to make with it on top of the other two speakons which will be used for stereo use. Whats the deal with the lack of bridge switch? Can the amp be bridged just at the output terminals or does that missing switch do something to the input stage? Any tips much appreciated.. Cheers

kedwardsleisure Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4949	Post Options Post Reply Quote kedwardsleisure Report Post Thanks(1) Quote Reply Posted: 18 August 2017 at 3:00pm
	yes the bridge switch duplicates the mono input and reverses its phase before inserting it into the other channel.
	Kevin North Staffordshire

radi Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 22 October 2014 Status: Offline Points: 21	Post Options Post Reply Quote radi Report Post Thanks(1) Quote Reply Posted: 18 August 2017 at 3:29pm
	If it doesn't have the 3-way AB external switch, it should have either jumpers or a switch located inside, "hiding" on a board near the output terminals. Edited by radi - 18 August 2017 at 8:24pm

radi Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 22 October 2014 Status: Offline Points: 21	Post Options Post Reply Quote radi Report Post Thanks(1) Quote Reply Posted: 19 August 2017 at 7:58pm
	As for wiring, Channel A+ goes to speakON 1+, Channel B+ to speakON 1-. To prevent damage to equipment, loss of life or worse, I would not suggest leaving it wired up permanently as planned.

charlysays Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 16 June 2015 Location: Wales Status: Offline Points: 413	Post Options Post Reply Quote charlysays Report Post Thanks(0) Quote Reply Posted: 20 August 2017 at 12:06pm
	Thanks guys... I think I'll stick to using it stereo mode mostly!