Correct schematic for Vibro Champ

titchener · June 12th, 2009, 03:31 PM

I'm trying to bring a Fender Vibro Champ amp back to life. Its serial number is A609771, which apparently means it was built in 1976.

Does anyone know (or know how to find out) what the correct schematic number is for this amp?

Thanks,

Paul T.

Wally · June 12th, 2009, 03:45 PM

AA764....the only one.

milocj · June 12th, 2009, 03:46 PM

With the exception of the three-prong cord which your 1976 would already have, I don't think there were ever any changes to the Vibro Champ during it's lifetime. I think the two following schematics would be correct and the last one shows a Champ with a three-prong cord. I've never seen a later schematic than these two for the Vibro.

Vibro Champ and Bronco (same amp, different name)
http://schematicheaven.com/fenderamp...a764_schem.pdf
http://schematicheaven.com/fenderamp...b764_schem.pdf

CBS era Champ:
http://schematicheaven.com/fenderamps/champ_cbs.pdf

muchxs · June 12th, 2009, 03:47 PM

Use this one.

http://ampwares.com/amp.asp?id=41

DH82c · June 12th, 2009, 06:16 PM

I have a late 70s Vibrochamp..
There are differences between that and the BF and or the bronco.
I will have to look but I think
a) voltages in output stage are higher
b) cap can may be 20/20/40 vs 20/20/20 cap.
I will digg tonight after supper and find out.

Wally · June 12th, 2009, 06:50 PM

All of those schematics are virtually the same. YEs, the voltages are higher in some compared to the AA764, but nothing else is different ...except for the CBS scheme. IN that one, there is a 330pf cap in the bais section that is not in the others. IN the 'Bronco' schematic, the first stage capacitor is a 40mfd. You can probably see that cap value in other real-life Champ/V-Champs due to availability of what was on hand at the factory. I would prefer the 40/20/20 as it would help keep the low end firmer.

DH82c · June 12th, 2009, 08:34 PM

Quote:

Originally Posted by Wally

I would prefer the 40/20/20 as it would help keep the low end firmer.

Agreed, especially since the stock speakers were nothing to write home about. :)

titchener · June 12th, 2009, 09:49 PM

Thanks a lot for all the help fellas, I was able to figure out what caps I need and got them ordered.

I can't wait to hear this baby sing, this forum rocks!!

Paul T.

June 12th, 2009, 03:31 PM	#1 (permalink)
titchener NEW MEMBER! Join Date: Jun 2009 Location: Brisbane, CA Posts: 4	Correct schematic for Vibro Champ I'm trying to bring a Fender Vibro Champ amp back to life. Its serial number is A609771, which apparently means it was built in 1976. Does anyone know (or know how to find out) what the correct schematic number is for this amp? Thanks, Paul T.

June 12th, 2009, 06:16 PM	#5 (permalink)
DH82c Tele-Meister Join Date: Apr 2007 Location: Montreal Age: 39 Posts: 479	I have a late 70s Vibrochamp.. There are differences between that and the BF and or the bronco. I will have to look but I think a) voltages in output stage are higher b) cap can may be 20/20/40 vs 20/20/20 cap. I will digg tonight after supper and find out. __________________ DISCLAIMER: Just because I said it doesnt mean you should do it. As always, wear your rubbers, probe with one hand, and make sure you have discharged everything.

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June 12th, 2009, 03:45 PM	#2 (permalink)
Wally Poster Extraordinaire Join Date: Mar 2003 Location: Lubbock, TX Posts: 6,014	AA764....the only one.

June 12th, 2009, 03:46 PM	#3 (permalink)
milocj Tele-Afflicted Join Date: Aug 2005 Location: Michigan Posts: 1,058 3 Photos	With the exception of the three-prong cord which your 1976 would already have, I don't think there were ever any changes to the Vibro Champ during it's lifetime. I think the two following schematics would be correct and the last one shows a Champ with a three-prong cord. I've never seen a later schematic than these two for the Vibro. Vibro Champ and Bronco (same amp, different name) http://schematicheaven.com/fenderamp...a764_schem.pdf http://schematicheaven.com/fenderamp...b764_schem.pdf CBS era Champ: http://schematicheaven.com/fenderamps/champ_cbs.pdf

June 12th, 2009, 03:47 PM	#4 (permalink)
muchxs Tele-Afflicted Join Date: Aug 2004 Location: New England Posts: 1,233	Use this one. http://ampwares.com/amp.asp?id=41

June 12th, 2009, 06:50 PM	#6 (permalink)
Wally Poster Extraordinaire Join Date: Mar 2003 Location: Lubbock, TX Posts: 6,014	All of those schematics are virtually the same. YEs, the voltages are higher in some compared to the AA764, but nothing else is different ...except for the CBS scheme. IN that one, there is a 330pf cap in the bais section that is not in the others. IN the 'Bronco' schematic, the first stage capacitor is a 40mfd. You can probably see that cap value in other real-life Champ/V-Champs due to availability of what was on hand at the factory. I would prefer the 40/20/20 as it would help keep the low end firmer.

June 12th, 2009, 09:49 PM	#8 (permalink)
titchener NEW MEMBER! Join Date: Jun 2009 Location: Brisbane, CA Posts: 4	Thanks a lot for all the help fellas, I was able to figure out what caps I need and got them ordered. I can't wait to hear this baby sing, this forum rocks!! Paul T.

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