It is currently Mon Mar 16, 2020 5:51 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 20 posts ]  Go to page Previous  1, 2
Go to page Previous  1, 2
Author Message
Post subject: Re: My '69 Twin Just Blew Up.
Posted: Tue May 07, 2013 10:02 am
Offline
Hobbyist
Hobbyist
User avatar

Joined: Sun May 13, 2012 6:04 pm
Posts: 26
My cabinet is running at exactly fourteen ohms, because it has an eight ohm speaker and a six ohm speaker wired in series. I will get back to you on the circuit later today, because I will be at my little workspace until around five or six today. I should be able to identify it later today.


Edit: It looks like the circuit is a AA769. Minus weird differences in the balance pot which don't match any twin schematics.


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: My '69 Twin Just Blew Up.
Posted: Wed May 08, 2013 12:36 am
Offline
Professional Musician
Professional Musician

Joined: Fri Jun 26, 2009 6:53 pm
Posts: 2252
Location: Harvard IL
Neat man, the speaker disparity is outrageous!!! (in a good way, if you dig the sound)!!! Glad to hear it's a 769. Wonder if the bias(hum) control and circuit was modified to a true bias control? Art

_________________
None of Us are free, if One of Us is chained !


Top
Profile
Post subject: Re: My '69 Twin Just Blew Up.
Posted: Wed May 08, 2013 7:48 pm
Offline
Hobbyist
Hobbyist
User avatar

Joined: Sun May 13, 2012 6:04 pm
Posts: 26
Well, I would have said that, but even the original solder joints are out of place. It is wired the same as a blackface. I say even the original solder joints because I melted one of the wires a while ago and had to replace it.


Top
Profile
Post subject: Re: My '69 Twin Just Blew Up.
Posted: Wed May 08, 2013 11:16 pm
Offline
Professional Musician
Professional Musician

Joined: Fri Jun 26, 2009 6:53 pm
Posts: 2252
Location: Harvard IL
Think I undestand, Ian. So are you going to take it in to a tech, or go about this yourself ? BTW When I started working on these amps, my meter was a Simpson 260 analog guy. "DVM" meant nothing to me either. Art

_________________
None of Us are free, if One of Us is chained !


Top
Profile
Post subject: Re: My '69 Twin Just Blew Up.
Posted: Sat May 11, 2013 7:44 pm
Offline
Roadie
Roadie

Joined: Sat Mar 09, 2013 12:27 pm
Posts: 207
Replace the filter caps under the can first. Note the values of the caps and replace with same values. It's OK to go a little over in value, but don't under. My BMR had 70 uf/350V and 20uf/525v. I used Sprague Atom 80uf/450v and 20uf/500V. The bias caps are probably 50uf/70V. I used 50/100. Most of the preamp electrolytics are 25uf/25v and 5uf/25v for the bias cap. I used 25/50 and a 5/50. If the amp was modified, you can always put it back to stock. I think they sound better that way. Don't mess with the blue coupling caps, unless they are damaged. I like Jupiter yellow coupling caps. I completely rebuilt a 69' Princeton and a 73' Twin that someone had hacked to death. They sound great now. Good Luck. This is the best Fender resource on the net.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 20 posts ]  Go to page Previous  1, 2
Go to page Previous  1, 2

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: