FDP Forum / AB763: The only stranded wires in the whole amp circuit. Why?/ 7 messages in thread.

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211



USA

Mar 31st, 2016 11:13 AM        

In the process of restoring a '77 AB763 Showman. <br /> All bone stock before starting this project. <br /> <br /> Having to rebuild the whole power tube socket section but I found two stranded jumper wires going from pin 3 to pin 3 of sockets one and two and sockets three and 4.<br /> <br /> Other than the transformers, these are the only vinyl-insulated stranded wires in the whole circuit. In fact they almost look like the same size color and gauge of the brown wire coming from the output transformer. <br /> Like they snipped off two 3-inch sections to make these connections. <br /> <br /> <br /> Anyone know the story behind this? <br /> Trying to keep this restoration as original as possible but this may be the two wires I have to deviate from.



amp mad scientist



USA

Apr 1st, 2016 07:20 AM        

These are the plate wires; there is 2 tubes in parallel on (each side of) 2 sides of the primary output transformer.<br /> Pin 3 is hooked to pin 3, and this is hooked to 1/2 OT primary. (then repeat for other 1/2) This wire jumpers the 2 plates from 2 output tubes together in parallel.<br /> <br /> Nope it does not matter solid or stranded...as the rating of the wire (voltage and current) is as good or better than original(?)<br /> It would be nice with push back cloth wire...<br /> <br /> But considering,<br /> Higher voltage is thinner wire, less current, thinner wire is all that it needs, it's less than squat ma per tube (provided speaker impedance is correct).



211



USA

Apr 6th, 2016 02:17 PM        

Great, thanks. <br /> As part of my parts list I ordered some black (as well as green) 18Ga push back cloth wire. Turns out it was stranded and not solid like I thought. Either way it worked out perfectly for these two leads. <br /> <br /> Resto, coming along quite nicely. Getting excited for the first start-up tests.



BbendFender

Contributing Member
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American Patriot

I'm on guard these days.
May 31st, 2016 04:17 PM        

Are you sure your amp is a '77 AB763? This doesn't jibe with the Fender Amp Book. There was an AC568 and an AA768. In 1976 the Silverface Duel Showman REverb was referred to as the TFL5000D. Did you mean 1967?



211



USA

Jun 8th, 2016 12:50 PM        

yes,<br /> '67... Single Showman, AB763, SF, drip edge, black line, 14" JBL in speaker cab, horrible typo on my part. <br /> <br />



BbendFender

Contributing Member
*********

American Patriot

I'm on guard these days.
Jun 8th, 2016 01:26 PM        

Oh, the one with that pesky old 14" speaker. I always hated those. Did you mean 15" speaker?



211



USA

Jun 9th, 2016 01:05 PM        

officially done with this new android hybrid swipe keyboard. <br /> buh-bye. <br /> <br />



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