# Early Super Reverb Silverface (Blackface Wiring)



## GuitarsCanada (Dec 30, 2005)

So tomorrow I am going to get down to finding out if my early Silverface Super Reverb actually has the AB763 wiring or the silverface. The labels for the AB763 were used for some time after they made the change to Silverface and many of those amps are in fact mis-labeled. This one is very early and stands a chance of having the balckface wiring but it's time to open her up and find out for sure. I will take some pictures as I go along and post them up. Might help some others later on in indentification.

There are a few ways to make the determination from what I have been able to gather from several articles I found floating around.

The first indicators that a early Silverface may in fact be a Blackfaced, AB763 wired amp is the black lines separating the front control panel. These were found on amps into late 1968 but were then removed. Not all blackline amps had the true blackface wiring but any amp without the blacklines surely did not. So that is the first thing to look for. Second was the presence of the drip edge (border) around the front of the amp. My amp had the drip edge, photo's do not show it as I had removed it prior and never replaced it. 

If the amp has these two characteristics it is then eligible for some further investigation.


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## Wild Bill (May 3, 2006)

GuitarsCanada said:


> So tomorrow I am going to get down to finding out if my early Silverface Super Reverb actually has the AB763 wiring or the silverface. The labels for the AB763 were used for some time after they made the change to Silverface and many of those amps are in fact mis-labeled. This one is very early and stands a chance of having the balckface wiring but it's time to open her up and find out for sure. I will take some pictures as I go along and post them up. Might help some others later on in indentification.
> 
> There are a few ways to make the determination from what I have been able to gather from several articles I found floating around.
> 
> I thought we had a a few blackface/silverface threads on here already but I cant find them.


Scott, The Fender Amp Field Guide lists 4 different schematics for the SF SR. The AB763 is preferred, of course. Still, 2 of the others are not that bad with their differences. The one to watch out for is the AB568. This is easy to identify as it's the only one with cathode resistors on the 6L6's. Look for pin 8 on the bottom of the sockets. It should be grounded on both tubes, usually with a short piece of flexible bare wire direct to a pool of solder on the chassis. If it's the AB58 instead you'll see a large power resistor of about 150 ohms or so connecting pin 8 to ground on each tube.

This is the worst sounding version and I've had two SF SR amps in over the past few years that were this way, even though they were marked AB763.

Good Luck!

BTW, this reminds me, I'll put your Tom Scholtz amp back together in the next few days and let you know when its ready for pickup. It'll be no rush - whenever is good for you.


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## GuitarsCanada (Dec 30, 2005)

Sounds good, Bill. I will come up one day when I can get some time. On the Super, so far I have determined via chassis code and transformer codes that they are all 1967. Chassis code comes back to October 1967 to be exact. Also, this one has all cloth wiring as well. I will check this pin thing tonight. I have a bunch of pictures to post as well.


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## GuitarsCanada (Dec 30, 2005)

The first year Silverfaces had the drip edge (trim) around the outer edge of the grill cloth. This amp had it as well but I took it off a few years ago and screwed it up and did not put it back on. So just as a note, the early ones had the drip edge trim. Also note the black lines separating the front panel. All Silverfaced amps that made it through with the AB763 wiring had these black lines on the front. There are some out there that ended up without the AB763 but certainly all that did, had these black lines.










The tube chart of course does not signify for sure if the amp has the blackface wiring. Fender had a bunch of these labels left over and many of the Silverface amps got them, just becuase it has the AB763 listed on the label, does not mean thats whats inside


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## GuitarsCanada (Dec 30, 2005)

*Chassis*

The chassis code comes back to the 43rd week in 1967


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## GuitarsCanada (Dec 30, 2005)

*Transformers*

Transformers come back as 1967 as well.


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## GuitarsCanada (Dec 30, 2005)

So, from the information gathered and from the inspection of the innards we can determine that this amp is in fact a true AB763 blackface wired carry-over from the early Silverface runs. According to all sources, the complete transformation into the Silverface wiring was complete by mid 1968.


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## Wild Bill (May 3, 2006)

GuitarsCanada said:


> Transformers come back as 1967 as well


The pictures don't show the bottoms of the 6L6 sockets very well. I can make out the 470 ohm screen resistors but I can't tell if there's any cathode resistors. I don't think so - they're big enough that they should be rather obvious.


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## GuitarsCanada (Dec 30, 2005)

Wild Bill said:


> The pictures don't show the bottoms of the 6L6 sockets very well. I can make out the 470 ohm screen resistors but I can't tell if there's any cathode resistors. I don't think so - they're big enough that they should be rather obvious.


I will get some pics of the sockets in a few moments, then we will know for sure.


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## nonreverb (Sep 19, 2006)

That is definitely a Blackface in silver clothes..it is a blackline amp... the earliest of the silverfaced ones and they all were blackface. 
The blackline variety disappeared very early.


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## GuitarsCanada (Dec 30, 2005)

power tube sockets


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## Wild Bill (May 3, 2006)

Nope! Not AB568!

From the pictures I can't be sure of the colour of the bands on the resistors so I can't be sure of their values but it looks like the resistors around the PI are blackface values.

You may very well have an AB763.


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## nonreverb (Sep 19, 2006)

Wild Bill said:


> Nope! Not AB568!
> 
> From the pictures I can't be sure of the colour of the bands on the resistors so I can't be sure of their values but it looks like the resistors around the PI are blackface values.
> 
> You may very well have an AB763.


It is an AB763. As stated, it's what's called a Blackline amp. The black dividing lines on the faceplate on either side of the logo is the earliest example of the silverface line. According to the majority of the publications on the subject and my own observations, this distinguishing characteristic disappeared May '68 when the Super's AB568 circuit was introduced. As long as the amp is not modified, it will be an AB763.


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## GuitarsCanada (Dec 30, 2005)

Still have the original CTS speakers for it as well. Two of them are not working. I had them all out with replacement Jensens in there. While I had it apart I put back in the two working CTS speakers and two Jensens. Sounds wonderful. Need to have the other two CTS speakers looked at and possible repaired.


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## tbellisario (Apr 14, 2010)

Yes you certainly have a blackface AB763.
Other identifying traits including the component numbering, black lines and drip edge are:
cloth covered wire vs. plastic.
Set screw attached skirted dial knobs vs. push on.
"Snowman" figure "8" numerals on skirted dial knobs.
Have one just like yours, the best amp I ever played through.


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## gtrguy (Jul 6, 2006)

The bias circuit is always the giveaway to me. The post blackface amps used a slightly different arrangement that's immediately obvious when you look at that section of the circuit.


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## Bobby67 (Jun 11, 2010)

I want to thank you so much for starting this thread. Thanks to you, and a few other experts, I have determined that I also have a Silverface SR, of approximately the same vintage, with the AB763 circuitry. I pulled the chassis and the GL6 is wired the same as yours . I peeled of the sticker on two of the speakers and they are stamped "137 749N." So, mine was a little later than yours, with those numbers and, the number on the transformer, pointing to December 1967. 

I am the original owner. I bought it at a store that sold all types of things, not just musical items, in the Spring of 1968. I remember there was a guy in there trying to talk me into buying a "Sound City " amp but I stuck with the SR. Tragically, I've been told the owner of the store, was killed during a robbery in the late 70's.

Please do not flame me but in the early 80's I had the non-reverb channel modified as an overdrive channel. However, the reverb channel retains the original sound and while it may now not qualify as a museum piece, it is a great players' amp. Also, there is a small gouge under the bass control of the modified channel but does not effect the sound. Other than that, it is in very good shape. The speakers are original and sound great, though there is some minimal rust on the frame of the lower left speaker. The grill looks brand new and the tolex is in excellent shape.

Hopefully, I'll be able to share pictures with you soon but I need some special software to download the pics from my cell phone. Once again, thanks for giving me the impetus to look into the history of the amp. And, I did it without electrocuting myself!


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## GuitarsCanada (Dec 30, 2005)

Pictures would be great. I am glad this thread helped you to determine that your amp is another blackface in disguise


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## nonreverb (Sep 19, 2006)

Bobby67 said:


> I want to thank you so much for starting this thread. Thanks to you, and a few other experts, I have determined that I also have a Silverface SR, of approximately the same vintage, with the AB763 circuitry. I pulled the chassis and the GL6 is wired the same as yours . I peeled of the sticker on two of the speakers and they are stamped "137 749N." So, mine was a little later than yours, with those numbers and, the number on the transformer, pointing to December 1967.
> 
> I am the original owner. I bought it at a store that sold all types of things, not just musical items, in the Spring of 1968. I remember there was a guy in there trying to talk me into buying a "Sound City " amp but I stuck with the SR. Tragically, I've been told the owner of the store, was killed during a robbery in the late 70's.
> 
> ...


Pictures would be good. '68's are hit and miss with respect to Blackface electronics as the changes started taking place in that year.


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## GuitarG. (Apr 1, 2010)

nonreverb said:


> Pictures would be good. '68's are hit and miss with respect to Blackface electronics as the changes started taking place in that year.


That is true. Just to add too that, when changes occured some amps may have flipflopped in circuit types. You may find an AB568 made in an earlier week of the same year than a earlier AB763 circuit made in a later week of that same year. I have seen some Twin Reverbs with a master volume dated 1972 but there is always the odd non-master volume (earlier circuit) Twin dated 1973. I'm guessing this was sometimes due to the availability of parts when changes were made to a circuit and/or Fender just trying too get rid of remaining stock.
Wild Bill and nonreverb are right. Pictures of the actual circuit are the best way too tell.


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## peter benn (Mar 29, 2007)

I'm wondering if this isn't the one sold at Ring about seven years ago. Square speaker arrangement, distorted at 4. Nice sounding amp. Sat in there for almost a year before it sold at $999 I think.


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## nonreverb (Sep 19, 2006)

GuitarG. said:


> That is true. Just to add too that, when changes occured some amps may have flipflopped in circuit types. You may find an AB568 made in an earlier week of the same year than a earlier AB763 circuit made in a later week of that same year. I have seen some Twin Reverbs with a master volume dated 1972 but there is always the odd non-master volume (earlier circuit) Twin dated 1973. I'm guessing this was sometimes due to the availability of parts when changes were made to a circuit and/or Fender just trying too get rid of remaining stock.
> Wild Bill and nonreverb are right. Pictures of the actual circuit are the best way too tell.


Very true guitarG...possibly the best example of this was the BF/SF Bassman. It had many factory rev's done to it over a short time and the rev tags aren't always accurate so it's hard to tell what version it is without looking inside.


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## Bobby67 (Jun 11, 2010)

nonreverb said:


> Pictures would be good. '68's are hit and miss with respect to Blackface electronics as the changes started taking place in that year.


Here's some pics. I apologize for the quality...done on a cell phone and obviously it's not too good for close up work:

Picasa Web Albums - btr4858 - Super Reverb


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