1971 cap question

Discussion in 'Let's Talk Vintage' started by Chris4189, Oct 4, 2019.

  1. Chris4189

    Chris4189 Well-Known Member

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    What are the blue caps circled in red?
     

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  2. South Park

    South Park Active Member

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    Power supply filter caps. It takes out the dc ripple going to the plates
     
  3. anitoli

    anitoli Well-Known Member

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    What the hell? Are those caps on top of the chassis mounted ones?
     
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  4. TAZIN

    TAZIN Active Member

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    The blue colored ones are filter caps. Looks like someone left the old caps in place (disconnected?) and just put new ones inside. The value of the caps should be 50uF+50uF/500vdc. The orange colored one is the cathode cap (250uF thru 320uF) for preamp tube V1.
     
  5. Chris4189

    Chris4189 Well-Known Member

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    I thought they were filter caps but just wanted to make sure I wasn’t crazy. I have no idea if they are connected or what. I was looking at the amp on reverb and just like Anitoli I was like what the hell.
     
  6. South Park

    South Park Active Member

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    It looks like the caps have been replaced at one time.you can remove the old and have holes there or just leave them .
     
  7. Chris4189

    Chris4189 Well-Known Member

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    I wonder why they didn’t take the old ones on the board out and replace them right way versus doing this?
     
  8. ampmadscientist

    ampmadscientist Well-Known Member

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    Somebody disconnected the original can caps, and substituted radial PC mount caps.
    This would have saved quite a bit of money.
    The PC caps cost about $1.69 each as opposed to the can caps which are 10 times more expensive.
    The PC caps are a smaller diameter and do not fit into the cap clamps mounts.

    One disadvantage: is that the PC caps do not have the high current rating that can caps have.

    2. Somebody changed the power transformer looks like.
     
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  9. Chris4189

    Chris4189 Well-Known Member

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    Thank you guys so much.
     
  10. Chris4189

    Chris4189 Well-Known Member

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    Besides the caps, PT replacement and the master volume you guys seeing anything else that would worry you?

    Trying to decide between this one and a 1959HW. Looking for something to tinker around with circuit wise.
     
  11. ampmadscientist

    ampmadscientist Well-Known Member

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    More close-up pictures of the insides, zoom in on each section with plenty of light.
     
  12. Matthews Guitars

    Matthews Guitars Well-Known Member

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    1900 bucks for it seems a bit stiff given what's been done to it but I know that when you get closer to the 60s the price goes up, too.

    Is that board attached to the side original? I haven't seen that before but it looks like factory Marshall workmanship and the usage of Erie capacitors fits.
    Looks like that'd be a voltage selector board.

    Pity that the master volume was added to the row of front panel controls in place of the indicator hole. And relocating the indicator to under the polarity switch....give me a break!!! No chance of it being restored to original condition now. A new front panel could cover that damage but the hole in the chassis is there forever.

    This is just me talking, but I don't pay high prices for amps modded in an irreversible manner. I'd try to talk the seller down by a few hundred bucks. I do value originality or at least the possibility of it being able to be restored to original shape. Any extra hole added eliminates that possibility.
     
    Last edited: Oct 6, 2019
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  13. Chris4189

    Chris4189 Well-Known Member

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    I agree with your points as they are valid. I have pointed out the obvious mods to the sellers and he has dropped the price down significantly which makes this one tempting.

    Right of the top you’ll have $60 bucks in caps and the cost of a face panel replacement. The polarity switch, master volume is elbow grease work.

    Obviously the biggest ding to me is the PT replacement but reissue 1959HW on the used market consistently command north of 2k, 1959slp’s seem to average 1200-2000k, we all know the prices the true plexi’s command and by looking at Reverb and flea bay metal panels all seem to be priced 1900k and plus so is this one that out of line?

    My plan would be to remove the MV completely, recap, disconnect the polarity, replace the front panel and take it to a ‘69 circuit and maybe replace the PT with an old Metro PT I have on hand. A
     
  14. Matthews Guitars

    Matthews Guitars Well-Known Member

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    If you get it, I can help you with the front panel. I make metal (not plexi) replacements that are as exact as I can make them. And that's pretty close!
     
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  15. Chris4189

    Chris4189 Well-Known Member

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    Awesome!! I sent you an email already today and you promptly replied.
     
  16. neikeel

    neikeel Well-Known Member

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    And the OT has been aout as well (look at the primary wiring and excess around the secondaries) probably a replacement.

    That amp has had its problems...........Caveat emptor!
     
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  17. ampmadscientist

    ampmadscientist Well-Known Member

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    I want 3 of them...and a spare.
     
  18. Matthews Guitars

    Matthews Guitars Well-Known Member

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    I refer you to my website for ordering information. (I do need to update it, but read there and email me from there.)

    As a result of this topic I have added the 1971 variant back panel with four jacks separated by a blank space.
    I could use a close-up photo showing the dots on the back panel on the right hand side, so I can duplicate those with a degree of precision.
     
  19. Trapland

    Trapland Well-Known Member

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    @Matthews Guitars is right on the price. In my area that $1900 is a good starting point for a $1500 amp. And it MUST have the original OT. If it wasn’t hacked up that 1900 would be 500-800 too cheap here.
     
  20. Trapland

    Trapland Well-Known Member

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    One more thing. Here’s how I value a 71 smallbox in my area. I own one.

    Mint 4000
    Played but nice 3500
    Roughed up but decent 2500.


    Choose one:
    One hole in back -$500 or
    One hole in front -1000
    then add

    Multiple holes -500 more (-500 for any number more)

    ‘Choose one
    Changed PT -500 (super common for the era)
    Changed OT -1000
    Extra tube -1000
    Replaced cabinet -1000

    Then chose any or all:
    Changed caps except bias, filter -200
    Changed dome feet -300
    Missing back panel -200
    Retolex -500

    If it’s playable, it’s probably not worth less than $1000 no matter what.

    Mine is:
    Played but nice. +3500
    Changed PT -500
    Missing changed caps -200
    Missing back panel -200
    —————————————-
    =$2600

    AGAIN This is how *I* would value a ‘71 smallbox 4 holer (model 1985/1986/1987/1989) in my area. Some guys give more value to the 1987 model, I don’t. Ya’ll are free to choose your own method and results.
     
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