Does anyone have an AC568 Twin schematic/layout? That is actually legible? :)

[22uf]

Just picked up another knackered old 73 SFTR and I'm totally bored of AB763. This time I'm trying to nail that Sticky Fingers tone instead.

I figured I'd go for a SG as above in to an AC568 circuit.

I even still have those eminence legend 1258 speakers in a box ... ! 

Does anyone have a schematic/layout that is legible? I only found these (attached) and my old eyes can't read the squiggles like they used too.

[sluckey]

Here's another. Your look better.

     https://el34world.com/charts/Schematics/files/Fender/Fender_showman_ac568_schem.pdf

[66Strat]

I thought that the Stones used Ampegs for the Stickey Fingers album.

[PRR]

> old eyes can't read

I bet it is 99% the same as other Fenders of the period. The six main rectifier diodes nails the period within a few years. What part do you think is different?

[22uf]

Here's another. Your look better.

     https://el34world.com/charts/Schematics/files/Fender/Fender_showman_ac568_schem.pdf

Maybe 20 years ago. Now that's just a blur. 

[22uf]

> old eyes can't read

I bet it is 99% the same as other Fenders of the period. The six main rectifier diodes nails the period within a few years. What part do you think is different?

I don't know exactly, that's why I want a legible schematic. 

I figure there'll be the snubber caps on the power tubes and an extra bias filter cap, different dropping resistor values and the usual lower SF PI values..

I also read they briefly used some kind of fixed bias arrangement but I have no interest in that naturally (other than to know what they biased it at) hehe.

[22uf]

Here we go ..

That's quite different to AA270. Looks like the tag board is some kind of fixed/cathode mix!?

Also those huge 7w resistors ..

[Latole]

Look at this one ;

https://www.thetubestore.com/lib/thetubestore/schematics/Fender/Fender-Twin-Reverb-AC568-Schematic.pdf


 

[22uf]

 

[Bieworm]

this reminds me of the first digital camera images. 

[sluckey]

Here's the best I have. I can read everything on this copy. If you still can't see it you may need some more powerful reading peepers... 

[pdf64]

Wow, that’s better!
How to get that to replace the one in the schematic library?

Note the non polarised ecaps on the cathodes.

It may be worth bearing in mind that ‘mixed bias’ era was pretty short lived, new fixed bias designs came along in ‘69.

[sluckey]

It's already in the library...

     https://el34world.com/charts/Schematics/files/Fender/Fender_twin_reverb_ab568.pdf

Note... This is an AB568 rather than AC568. Probably not a nickel difference.

[Latole]

Here's the best I have. I can read everything on this copy. If you still can't see it you may need some more powerful reading peepers... 

That is the best one !

[SILVERGUN]

I remember a very respected member saying that the '72 Twin was one of his favorites.
He posted some here and more on other threads: (search : 2deaf   - Twin) he has had a lot to say about these amps
'70's Fender Twin Reverb Trilogy of Schematics (el34world.com)

[22uf]

Cheers sluckey! o7o7o7o

I remember a very respected member saying that the '72 Twin was one of his favorites.
He posted some here and more on other threads: (search : 2deaf   - Twin) he has had a lot to say about these amps
'70's Fender Twin Reverb Trilogy of Schematics (el34world.com)

Yeah I dig them all tbh. Sadly the best one I ever had was the "Ultralinear" 135w. It was absolutely SUBLIME tone.

This is that very amp:

I can't speak highly enough of those Eminence Legend 1258's. They are absolutely tight as nuns. Every single frequency gets projected and the bass hits you in the chest like a teenage DUI.

I sold it for $700 

I asked the guy recently if I could buy it back and he said no. I even offered him $1400. He said NOT A CHANCE is he ever selling that amp.

RAGAFRAGSHAHAHAGRRR. 

[tubeswell]

That's quite different to AA270. Looks like the tag board is some kind of fixed/cathode mix!?

Also those huge 7w resistors ..

Yep hybrid bias, and the 7W rating is overkill - probably had a bunch of 150R 7W lying around.