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Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com

Identifying Black Line, Drip Edge Fenders OR another NAD, '68 Deluxe Reverb!

Discussion in 'Glowing Bottle Tube Amp Forum' started by ShawnRocker, Aug 8, 2016.

  1. ShawnRocker

    ShawnRocker TDPRI Member

    39
    Dec 18, 2015
    San Francisco area
    In the last 8 months a friend of mine in another state and I have become pretty adept at dating Drip Edge Silver Faces; particularly the Black Line ones; and more specifically the Black Line ones containing the Black Face circuits inside.

    It all started when I picked up this Princeton Reverb from the 3rd week of 1968 followed by this Super Reverb from the 6th week of 1968 that you all helped me with a ton. Now, both these amps were found in and around where my friend lives, and he picked up a Bandmaster from the 5th week of 1968 at around the same time. I don't want to give away the fishing spot, but black line, drip edge Fenders keep popping up on Craigslist in his area at a clip you wouldn't believe. I have to believe the #1 Fender salesman in 1968 had to be out that way.

    In the meantime, I serviced and repaired a Black Line Super Reverb he found in the area along with a couple other Fender amps of the era we've helped friends get into.

    A couple weeks ago he picked up a Deluxe Reverb that was sold as parts, not working. He sent it to me and its 5th week of '68, exact same as his Bandmaster which is pretty cool. Its still here actually. I found that the rectifier tube was shorted out from damage caused by the filter caps being dead shorted. I replaced all that, plus found several fried resistors, including the 1M across the input jack which was causing a loud hum. There was/is also a kinda green, powdery coating on the outside of the chassis I'm not sure about, but its not on the inside.

    Pictured here is his Deluxe along with my Super Reverb and Princeton Reverb. All 3 amps were built within 3 weeks of each other. I like to say they all came out of the same pile of parts.
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    So, that Deluxe is sounding so great now that we pounced on another Black Line, Drip Edge Deluxe Reverb that popped up on his CL this weekend. The amp we picked up today is super clean except for a couple spatters of white paint somebody got on it (any tips on how to remove paint from the grill cloth?). The guy who sold said he believes no work has ever been done to it. It includes the original foot switch, cover and, get this, the warranty card, promo material, user manual and schematic that came with it!
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    Here's where it gets interesting and we'd appreciate any input, history, or feedback you guys can provide.

    From the ad on Craigslist I noticed that the back plate on the amp we picked up today called for a 1amp SloBlo fuse and I recalled his as calling for a 2 amp fuse, which I then verified. Thinking maybe this one had a later circuit than AB763 I did some research and found that black face AB763's originally called for a 1 amp fuse but it was later changed to 2 amp, and all the subsequent silver face versions had 2 amp fuses.

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    So he picked the amp up and we found a couple other things. The speaker and PT are stamped early 68, but the choke is from 1966? He also found a date stamp on the outside of the chassis, sometimes there is one outside we've found, and it indicates 20th week of 1968.

    The last significant thing I noticed is that in addition to his back plate calling for the 2 amp fuse, his just says Fullerton, CA on the upper right, where mine says "Fender Musical Instruments Santa Ana, CA", they both say Fender Musical Instruments on the front plate btw.

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    Of the other handful of early 68 amps I've had come across my workbench in the last 8 months they've all had the Santa Ana location. I cant figure out why his has Fullerton? Further, the chassis SN on back of his chassis (near the Reverb input) indicates his should be a mid-67 model if you follow Greg Gagliano's system, yet the date stamp clearly says 1968.


    It's our theory that a pallet of chassis arrived with Serial Numbers already stamped in them and they were then grabbed in no particular order, and parts like transformers and whatnot were also grabbed in no particular order and once it was complete it got ink stamped with a date code. That would explain the engraved Serial Numbers not being being chronologically aligned with the date stamps. I figure the back plates and whatever else coulda been grabbed out of order too, we all know they kept those AB763 Tube Charts on them for years after the AB763 was long gone.

    What I can't figure out is why his would have the "new" 2 amp fuse call out along with the, what I think is older, "Fullerton" back plate, while mine has the opposite. All I can guess is that his has a black plate left over from the Fullerton black face era where it had been updated to a 2 amp fuse, and mine has a new back plate from the Santa Ana era and they erroneously had 1 amp on the initial run?

    Thoughts, history, insight and discussion into this or any other oddities about amps of this era are greatly welcomed.
     
    xafinity, WigWam and AlbertaGriff like this.

  2. Wally

    Wally Telefied Ad Free Member

    Mar 17, 2003
    Lubbock, TX
    I suppose that you are dating the week of the year by the chassis date stamps? That is a good way to know that the amp as a whole can be no older than that, but it does not establish when exactly the amp was 'made whole'...chassis and speaker in a cab and working. When Fenders had tube chart date stamps, we could know what month they were made whole. After that, which ended in April of 1967 and did not come back into use until January of 1990, all we can really know is a 'no older than' date from such things as that chassis date stamp. We are generally happy enough to know the year.
    Those serial numbers from the charts are generally quite accurate, but nothing is written in stone. You are correct in understanding that chassis, tube charts, neck plates, etc were not used in a sequential manner....and sometimes there occurs a strange situation because of that.
     

  3. ShawnRocker

    ShawnRocker TDPRI Member

    39
    Dec 18, 2015
    San Francisco area
    Ya, that's the code I'm talking about, the ink stamped on onside the chassis. I always figured it got mated with a cabinet within a couple weeks of that. The only one I've worked on that had the date stamp on the tube chart was my friends '66 Super Reverb, on his both the stamp in the chassis and the one on the tube chart placed it to August 66
     

  4. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    The ink stamps are meaningless. Some are dates, some are not, and chassis parts could sit around of years without being used if someone forgot to rotate stock.

    The serial number and features will get you in the ballpark. I've actually ounce the serial numbers to be fairly accurate, based on amps I've seen that had original receipts.

    Black lines ("VBL's) are generally going to fall int mid-'67 to early '68, and have BF circuits. From mid-'68-on (wth the exception of the Champ, Princetons and Deluxes - reverb and non-reverb, as these models underwent no mods that significantly affect tone. Speakers, tubes and proper service make FAR more difference) it's a crapshoot - you could have any of 3-4 different wiring schemes on the larger amps - my favorite (to UNDO) is CBS's infamous combo cathode/fixed bias. What a mess!

    But ALL can be brought into BF specs...at least close enough...without irreversible mods.
     

  5. ShawnRocker

    ShawnRocker TDPRI Member

    39
    Dec 18, 2015
    San Francisco area
    This Deluxe Reverb got to me yesterday. Wow. Great sounding amp, and as clean as you'll find. I didn't play it long. It still has the 2 prong cord so I removed the chassis to due maintenance. The date stamp inside says the 9th week of 68; that sets a pattern with 3rd and 6th week found in my other two Black Lines. Definitely an untouched AB763 circuit inside and in need of caps. Tubes look to be a mix of original RCAs and Telefunkens. I hope this amp sounds the same with a new set of caps as it does now. I've been installing F&Ts.

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    Funny that the owners manual shows blackface versions,

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    WigWam likes this.

  6. Wally

    Wally Telefied Ad Free Member

    Mar 17, 2003
    Lubbock, TX
    IMe, that amp will sound differently with some fresh e-caps in it. The bottom end will be more articulate and will not exhibit out of tune sub-harmonics. The high end will sparkle more, and the amp will exhibit a 3-dimensional sound stage instead of a flat stage. IN short, it will come alive. I have heard too many 'before and afters' for too long a time to think that anything else will occur. Those caps in that map are NOT doing what they originally did.
    Really nice amp there. Congrats.
     
    King Fan likes this.

  7. ShawnRocker

    ShawnRocker TDPRI Member

    39
    Dec 18, 2015
    San Francisco area
    Thank you Wally, you've been very helpful to me as I've been learning these amps. None moreso than when you answered my question with something that should have been obvious from the schematic. I learned to do my homework before asking the Internet for help from that.

    So let me ask you, this is probably something you know. I found something peculiar on the blackline Deluxe Reverb of my friends I saved a couple weeks ago.

    When I was done with it there was still a slight hum I was tracking down. In doing so I found a .002 cap coming off of pin 2 of the inverter tube that looked tired. However the schematic shows it should be a .001. So I stuck a .001 in there and it sounded fine, but I thought maybe a little thinner but it may have been in my head. I looked online and read that Fender changed that value a few times to allow more bass through. I ended up putting a .002 back in there. Do you know anything about that cap and is there a value you prefer in that spot?
     
    Last edited: Aug 16, 2016

  8. AlbertaGriff

    AlbertaGriff Tele-Meister

    248
    Mar 2, 2016
    Alberta, Canada
    I just picked up an early SF Bassman head and cab. It's at the doctors, though, so I'll have to get back to you with the specifics of the back plate. I know it's asking for a 2 amp fuse but I can't remember the location, etc.

    But the date stamp inside the chassis is the 40th week of 67, and the transformers all date to 67 as well.
     

  9. Wally

    Wally Telefied Ad Free Member

    Mar 17, 2003
    Lubbock, TX
    Shawn, that PI capacitance can be adjusted to preference. You are correct in hearing that the .001mfd yields the thinner sound compared to the .002mfd....a small difference. IN the Sf amps, Fender went to a .01mfd which is a richer sound still. People have gone to as large as .02mfd....I like the .01mfd....meatier sonic.
     
    ShawnRocker likes this.

  10. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    FWIW, seeing the pictures of the electrolytic filter caps I would not turn the amp on at all until they are replaced.
     
    Wally likes this.

  11. AlbertaGriff

    AlbertaGriff Tele-Meister

    248
    Mar 2, 2016
    Alberta, Canada
    Got my Bassman back, and checked the back plate. It says Santa Ana, CA.

    I wonder if that 1 Amp, Fullerton, CA backplate is not original to the amp?
     

  12. jazzguitar

    jazzguitar Tele-Afflicted

    Mar 17, 2003
    Germany
    Congrats! Looks very nice.

    I agree these filter caps are a hazard. New filters and bias cap and you should be good to go!

    Regarding your opening post, I think the switch to a 2 amp fuse may be related to the transition from GZ34 rectifiers of the blackface circuits to the 5U4 used after.

    As for the phase inverter input capacitor, 0.001 appears awfully small a value in comparison with the other values used in the signal chain.

    However the phase inverter is a differential amplifier with bootstrapped input impedances (the input resistance works like many megaohms even the actual resistor only is only 1M or even 330k in some amps). I think the CBS engineers forgot that when they upped the input capacitor value to 0.01
     

  13. telex76

    telex76 Doctor of Teleocity Silver Supporter

    Age:
    66
    Jun 24, 2006
    Fort Worth,Tx.
    Sure a clean one, congrats.
     

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