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1970 Bassman head

Discussion in 'Amp Central Station' started by dannyh, Feb 27, 2021.

  1. dannyh

    dannyh Tele-Afflicted

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    75F9B183-468E-435C-81CE-00B954B258BD.jpeg 84319A15-E736-4723-9078-D9AA99DA0915.jpeg Looking at this head I ran across. Looks like the e caps on the board have been replaced, the filters in the doghouse look original, but the brown paper “housings” on the filter caps will spin freely, so I’m wondering if somebody replaced them and put the old housings over the new caps. Seems weird to change the e caps on the board but not the filters.

    Trannys appear to be original (mid to late 69 date codes).

    I know what to look for with Black and brownface amp guts as far as originality goes but I’m not that familiar with the SF era. Wondering if any experts out there could give me their thoughts as far as the originality of this amps circuit as it sits? That white wire running to V1 looks a little odd at first glance, but like I said I’m no SF expert.

    Would appreciate any thoughts....
     
  2. dannyh

    dannyh Tele-Afflicted

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    54FBFD64-7727-4F79-A52E-93AC6758F683.jpeg 7F56C19B-0ABE-49A8-8516-3BF2936ECEFE.jpeg Couple more pics....
     
  3. J. Bonkosky

    J. Bonkosky Tele-Meister Silver Supporter

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    Nice amp! All those white Mallory electrolytic caps are original. I am guessing the filters are too.
     
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  4. dannyh

    dannyh Tele-Afflicted

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    Thanks! I gotta learn more about SF amps...
     
  5. AlbertaGriff

    AlbertaGriff Tele-Afflicted

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    Yeah those white caps on the board would be original. Looks pretty untouched to me in general. I had a 69 Deluxe Reverb up until a couple of days ago that had a ton of little skinny wires, white included.
     
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  6. Intubator

    Intubator Tele-Holic

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    The cardboard outer casings on the filters do spin freely most of the time so that is not unusual. Nice amp, only thing Id touch are the filters and maybe a toasted resistor or two. Unless there is a compelling reason I'd leave all those coupling caps alone.
     
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  7. sllsll

    sllsll TDPRI Member

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    Get rid of the brown turd capacitors and it will sound 100% better. Also replace every electrolytic capacitor. Then "blackface" the output stage.
     
    Last edited: Feb 27, 2021
  8. schmee

    schmee Doctor of Teleocity

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    I appears to me that none of those caps are replaced. Those white Mallory coupling caps are originals. I love those early SF Bassman heads.
    I have yet to decide if those brown turds sound any different than others myself. I think you may be hard pressed to tell.
    It appears to be the AA270 circuit. I only see one thing replaced, the 470 ohm resistor on power tube 1. That's a common problem with Bassman's for some reason.
    I once bought a non working Bassman dirt cheap, all that was wrong was a burnt apart 470 ohm resistor. Why it was problematic without that resistor I have no idea, it ought to still work. I would replace the other one with a metal oxide 2 watt etc.

    [​IMG]
     
    Last edited: Feb 27, 2021
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  9. dannyh

    dannyh Tele-Afflicted

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    I’ve never seen any that the casings spun freely, but then again I’m not sure I ever tried to spin them before lol.
     
  10. dannyh

    dannyh Tele-Afflicted

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    Thanks for the input. Still looking at it at this point. Glad to hear the e caps are all original, I’d prefer an untouched amp, though I would replace those first thing if I got it. Tried it out briefly, sounds kinda weak right now, which would make more sense if the filters were original. Good bargaining chip too. Not sure about the dog turds; I’d probably leave them alone initially, see how it sounded with them before I decided whether or not to keep them. We’ll see how it goes.
     
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  11. Ringo

    Ringo Poster Extraordinaire

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    If you get it for sure change the filter caps and bias cap, then play it before you do any other mods.
    Also that amp may have the balance control instead of an actual bias control.
    Fender did that sometime in the SF era.
    The last couple of later SF amps that I owned I had them wired for bias and balance best of both worlds.
    The Bassman heads are creeping up in value, a LOT of amp for the $ and they sound great!
     
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  12. Dacious

    Dacious Poster Extraordinaire

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    I wouldn't automatically replace the brown caps in that era.

    I'd bet replacing filters including the white Mallorys, a general spruce up would return it to good audio function.

    Not everyone likes these for guitar - big and full like a Marshall but without the breakup.

    You can get them cranking but that's freakin' loud. Many get hacked up with MVs etc
     
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  13. Intubator

    Intubator Tele-Holic

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    Can you take a pic of the filters, they're probably original if they have a cardboard casing around a solid aluminum cap. They're also dated. The other question is what is going on with the solder "pool" on lower part of the PT?... Do the leads coming from the PT solder joints look original? What is the SN# of the PT and the OT?
     
  14. dannyh

    dannyh Tele-Afflicted

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    The filter caps look original, I’m familiar with what they looked like originally. The OT, PT and choke date codes all point to 1969. The serial number points to 1970 according to the information on the ggjaguar website. I’ll post some more pics including the doghouse caps and trannys later.
     
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  15. dannyh

    dannyh Tele-Afflicted

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    Got it home and opened up again to document (I'm a camera nerd). Some pics if anybody is interested:

    IMG_0596.JPG IMG_0634.JPG IMG_0613.JPG IMG_0610.JPG IMG_0609.JPG IMG_0618.JPG IMG_0617.JPG IMG_0616.JPG IMG_0612.JPG IMG_0611.JPG
     
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  16. dannyh

    dannyh Tele-Afflicted

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    IMG_0606.JPG IMG_0604.JPG

    This was kind interesting. I've never seen this on a Fender Amp before...

    IMG_0619.JPG
     
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  17. dannyh

    dannyh Tele-Afflicted

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    A lot of the tubes look like they might be original. Or maybe just old lol.

    IMG_0631.JPG IMG_0630.JPG IMG_0629.JPG IMG_0628.JPG IMG_0626.JPG IMG_0625.JPG
     
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  18. mexicanyella

    mexicanyella Friend of Leo's

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    Man, that thing looks to be in pretty nice shape. Cool.
     
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  19. The Ballzz

    The Ballzz Tele-Afflicted

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    Ooooohh! Amp Porn!

    image.gif :D
     
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  20. J. Bonkosky

    J. Bonkosky Tele-Meister Silver Supporter

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    I bet those tubes are good. Definitely keep em! That head is a really nice find. Get her going and enjoy!
     
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