Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: plexi50 on August 06, 2014, 09:05:52 pm

Title: 1994 Fender Twin Amp Schematic
Post by: plexi50 on August 06, 2014, 09:05:52 pm

Is there a schematic for the  1994 Fender Twin Amp? 

Title: Re: 1994 Fender Twin Amp Schematic
Post by: DummyLoad on August 06, 2014, 10:06:36 pm

maybe this one?
http://support.fender.com/schematics/guitar_amplifiers/Twin-Amp_schematic.pdf (http://support.fender.com/schematics/guitar_amplifiers/Twin-Amp_schematic.pdf)


--pete

Title: Re: 1994 Fender Twin Amp Schematic
Post by: eleventeen on August 06, 2014, 10:21:11 pm

Thanks for that, DL! I have one of those amps I acquired in a trade. I hope I don't have to fix it! I actually would like to sell it. The external bias points are very convenient and truth be told, it has lots of flexibility. I wish I could chainsaw it in half and have 2 qty 50 watt single-12" speaker combos. That should be an option for any Twin Reverb.

Title: Re: 1994 Fender Twin Amp Schematic
Post by: Willabe on August 06, 2014, 11:16:38 pm

Quote from: eleventeen on August 06, 2014, 10:21:11 pm

I wish I could chainsaw it in half and have 2 qty 50 watt single-12" speaker combos. That should be an option for any Twin Reverb.

                 :l2:

Title: Re: 1994 Fender Twin Amp Schematic
Post by: DummyLoad on August 06, 2014, 11:37:59 pm

Quote from: eleventeen on August 06, 2014, 10:21:11 pm

Thanks for that, DL! I have one of those amps I acquired in a trade. I hope I don't have to fix it! I actually would like to sell it. The external bias points are very convenient and truth be told, it has lots of flexibility. I wish I could chainsaw it in half and have 2 qty 50 watt single-12" speaker combos. That should be an option for any Twin Reverb.

you're welcome!


and


 :laugh:     :BangHead: 

Title: Re: 1994 Fender Twin Amp Schematic
Post by: plexi50 on August 07, 2014, 07:23:21 am

No that schematic  does not match this amp. I as well am thinking of taking a hacksaw to it. It sounds very distorted with low crappy volume on all channels. Thought it may be a bias issue but that is not the problem. R119 has a diode that some one has tacked on across it.



DummyLoad R119  is a screen resistor on the schematic you provided. Wanted to maybe hear what it sounded like before doing an axis of evil thing on the chassis


UPDATE: A ceramic resistor has a 1995 date code so i may have been in error on calling it a 1994 model
Edit: Board pic date 1994 & revision (C) circuit


I believe the dust on the amp logo and weird white pilot light may be of more value than the amp itself  :laugh:
Edit: Boy was i wrong

Title: Re: 1994 Fender Twin Amp Schematic
Post by: plexi50 on August 07, 2014, 02:56:02 pm

I finally found the correct 1994 schematic here:
http://allpartsuk.files.wordpress.com/2012/03/94-twin.pdf (http://allpartsuk.files.wordpress.com/2012/03/94-twin.pdf)


Tech notes explain why R119 has a diode across this resistor
Man what a hard schematic this was to find. Only been 3 weeks or more in my spare time

Title: Re: 1994 Fender Twin Amp Schematic
Post by: plexi50 on August 07, 2014, 03:40:18 pm

On a roll//////// 100K PI Plate resistor R72 is open. Changing now/

Title: Re: 1994 Fender Twin Amp Schematic
Post by: plexi50 on August 07, 2014, 07:02:24 pm

Wow! I have it all done and back in it's 212 cab. I am really surprised at how good this thing sounds.  :worthy1:

All i ever have heard were bad things referring to the Evil Twin. Thats what i originally thought this amp was.
But this is not the Evil Twin Amp so i feel better knowing i have a more desirable model


Revision (C ) was made in 1995. All 3 channels are unique and sound great. Reverb is especially nice and not runaway over the top.

I am very pleased!

Title: Re: 1994 Fender Twin Amp Schematic
Post by: Willabe on August 08, 2014, 12:29:32 am

Very nice, good job!


              Brad    :icon_biggrin:

Title: Re: 1994 Fender Twin Amp Schematic
Post by: DummyLoad on August 08, 2014, 09:53:41 am

glad you got it working.   :icon_biggrin:


--pete

Title: Re: 1994 Fender Twin Amp Schematic
Post by: plexi50 on August 08, 2014, 06:08:24 pm

Thanks all! My ears are ringing.