Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: panhead on September 21, 2011, 10:13:01 am

Title: What circuit is a 1973 Twin Reverb?
Post by: panhead on September 21, 2011, 10:13:01 am

I got a request from a guitarist in a local band to take a look at his 1973 Twin Reverb and do what it takes to make it tour-ready. He says it works fine now, but he doesn't want any problems on the road. From what I've always heard about Twin Reverbs, they are already pretty sturdy, reliable amps. Any ideas of weak points to this amp? Also, what Fender circuit designation goes with this amp?
Thanks

Title: Re: What circuit is a 1973 Twin Reverb?
Post by: phsyconoodler on September 21, 2011, 10:33:14 am

I'm not sure what a 73 Twin circuit is,but if it's not a master volume amp they are pretty decent.They likely have a bias balance instead of a bias adjust which is either good or bad depending on your point of view.
  As with any old amp it needs to have new filter caps and be serviced with new tubes if necessary and a good cleaning and retentioning of the tube sockets.
   All those Twins in that era were nice sounding amps.As they get closer to the mid-late 70's they get stupid with ultra linear OT's and master volumes and stupid,stupid power supplies and the worse lead dress known to man.

Title: Re: What circuit is a 1973 Twin Reverb?
Post by: panhead on September 21, 2011, 11:19:11 am

Thanks

I'll be getting it this weekend. I hate to fix it if it ain't broke.

Title: Re: What circuit is a 1973 Twin Reverb?
Post by: EL34 on September 21, 2011, 11:23:21 am

They are always broke unless they have been serviced recently.

By broke, I don't mean not working
If you don't bullet proof it, Murphy's law will strike the player on one of his play dayes for sure.

Here's all the info I have on how I used to service Fender amps.
Servicing fender Amps (http://www.el34world.com/schematics.htm#Servicing fender amps)

Title: Re: What circuit is a 1973 Twin Reverb?
Post by: panhead on September 22, 2011, 11:56:12 am

Thanks, Doug.