1973 Super Lead circuit

Discussion in 'Let's Talk Vintage' started by Mitchell Latimer, Mar 25, 2020.

  1. Mitchell Latimer

    Mitchell Latimer Member

    Joined:
    Mar 4, 2020
    Messages:
    30
    Likes Received:
    7
    Screenshot_20200325-133357_Reverb.jpg Screenshot_20200325-133404_Reverb.jpg Screenshot_20200325-133410_Reverb.jpg Screenshot_20200325-133416_Reverb.jpg Screenshot_20200325-133429_Reverb.jpg Screenshot_20200325-133451_Reverb.jpg Screenshot_20200325-133445_Reverb.jpg Screenshot_20200325-133438_Reverb.jpg Screenshot_20200325-133705_Reverb.jpg View attachment 69691



    Ok so the 1972 super bass fell through but I found this 73 SL and am thinking about pulling the trigger. So I have heard that the hand wired SL/SB are obviously easier to work on (I am not a tech) but have a less than consistent sound? Do the early PCB (1973) have the same circuit as the hand wired earlier versions? I know they are not as desirable but do they sound as good? how does this one look? There was a master mod at some point put back to stock hence the hole. I dont care about the aesthetic issues as long as it functions properly. There are no numbers on the transformers and one looks cleaner than the others? Original? Thanks!! Asking 2k
     
    jstich likes this.
  2. Matthews Guitars

    Matthews Guitars Well-Known Member

    Joined:
    Aug 17, 2019
    Messages:
    1,422
    Likes Received:
    1,805
    It's had some work done on it, but not much. The three electrolytic caps on the PC board are obviously not original. The early ST1 board is fine, I don't really buy into the notion that the PC board version sounds different from the point to point wired version when both use the SAME components in the SAME circuit in the SAME layout.

    The diodes aren't original, and the solder work on them as is blobby and sloppy as I've ever seen. That needs to be redone correctly.

    Clearly this amp had a tube flameout at some point, hence the incorrect giant screen resistor on that tube socket. That should be replaced with the correct one. I'd recommend replacing all four as a set. I'd go with the set of four green vitreous ceramics.

    https://www.ebay.com/i/264632330287...MIwZ7c_8y26AIViJOzCh27PAieEAkYAiABEgKmfvD_BwE



    The filter capacitors are original. They're 47 years old and they may still be working OK with no performance issues but there's no getting around the fact that they've outlived their intended service life. There will be various opinions on whether they need it or not. For myself, yes, I'd replace them. They can't have much life left in them no matter what. But that topic is a discussion all its own.

    It looks like a solid example of a '73 Super Lead. I see nothing to cause me to disrecommend it if the price is fair. What's a fair price? Well...I don't think 2000 dollars would be excessive if the headshell is in as good shape as is the chassis. But of course I'd try to buy it for less. I'd offer 1500 and try to meet in the middle at 1750.

    It needs only minor work. I'd replace those screen resistors as a set. Give it a fair cleaning to get that burned resistor residue off the inside of the chassis, Clean the exterior surfaces, at least a little bit. Definitely clean the tube sockets.

    As for the transformers, aside from one mounting screw obviously being wrong, they look original to me but I'm NOT the expert on that. They look like what's in my '74 and my '73 and their cosmetic condition seems to be well matched to that of the chassis overall.

    The banding around the wiring between the transformers and capacitors is still present and looks right. I would not think that either transformer has been replaced.
     
    Last edited: Mar 25, 2020
  3. MickeyJ

    MickeyJ Well-Known Member

    Joined:
    Nov 11, 2019
    Messages:
    1,062
    Likes Received:
    575
    that amp is a honey.
    a jewel.
    a tone treasure.
     
    jstich and Mitchell Latimer like this.
  4. Mitchell Latimer

    Mitchell Latimer Member

    Joined:
    Mar 4, 2020
    Messages:
    30
    Likes Received:
    7
    Thanks for the info and recommendation!!!
    Hey thanks so much for the info! Seems like I have a few points for negotiation! That's great. Really appreciate the technical info and advice.
     
  5. Mitchell Latimer

    Mitchell Latimer Member

    Joined:
    Mar 4, 2020
    Messages:
    30
    Likes Received:
    7
    Any other opinions on the transformers being original or the overall look of the circuit?
     
  6. Matthews Guitars

    Matthews Guitars Well-Known Member

    Joined:
    Aug 17, 2019
    Messages:
    1,422
    Likes Received:
    1,805
    Considering prior experience, if any of the more experienced guys here thought the transformers were not original, after I've expressed my belief that they are, they would certainly have spoken up now. Not to reassure you, but to slap me down! :shrug:
     
    Mitchell Latimer likes this.
  7. neikeel

    neikeel Well-Known Member

    Joined:
    Feb 12, 2014
    Messages:
    3,944
    Likes Received:
    2,337
    It all looks correct to me (other than the board electrolytics, the screen resistor and standby switch.

    Odd to replace the V1a cathode bypass cap and leave the main cans, but I guess the amp is in regular use, does not hum or buzz and no signs of leakage. I'll stop there!
     
    Mitchell Latimer likes this.
  8. Matthews Guitars

    Matthews Guitars Well-Known Member

    Joined:
    Aug 17, 2019
    Messages:
    1,422
    Likes Received:
    1,805
    Even I wouldn't be in a mad rush to replace those filter caps. They show no visible signs of failing and lacking any audible issues I'd be content to run the amp.

    Oh, to the prospective owner, don't let the replaced caps on the ST1 board dissuade you. Caps do need to be replaced EVENTUALLY and fresh caps usually mean you won't have to worry about that. It's not a negative thing that those three are not original. It means the amp has been maintained well.
     
    LP Freak likes this.

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice