How does a Super Bass "voice" differ from a Super Lead?

Discussion in 'Amps and Cabs' started by abnerfm, Mar 1, 2012.

  1. abnerfm

    abnerfm Member

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    Hi, guys. I decided to put a master volume in my 1970 JMP 100 Watts Super Bass, so I sent it to my amp tech. As this amp doesn't have much gain, he recommended changing it to Super Lead specs.

    Apart from more gain, how will it sound like after changing to Super Lead specs? Thanks in advance.
     
  2. RedhouseNorton

    RedhouseNorton Member

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    The voicing is very similar. I have both SLs and SBs and I can tell you with 100% certainty that there definitely isnt any gain difference between the two. The gain has a lower/mid voicing on the SB , but its not any more or less. The difference between the two is literally just one or two numbers on the presence knob. SL is just a bit brighter.
     
  3. abnerfm

    abnerfm Member

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    Thank for your reply. Do you think the Super Lead can sound "better" at higher volumes or clearer with pedals (fuzz/od/boost)?
     
  4. Shiny_Beast

    Shiny_Beast Member

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    Most notably the superbasses had the larger output caps so they had more bottom end.

    I would expect they were more likely to have a shared cathode on V1 and less likely to have a bypass on V2, or large feedback resistors.

    The various marshall circuits were constantly changing, and in general got more and more edgier and gainier over time. There's a couple good pages out there about it.
     
  5. Roe

    Roe Member

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    superleads tend to be somwwhat more gainy, not just brighter
     
  6. sws1

    sws1 Member

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    Super lead is a bit gainier, brighter, and less low end, due to the tweaks.

    I had a 68 Super Bass that was converted to Super Lead.
     
  7. abnerfm

    abnerfm Member

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    How did you like it?
     
  8. Hawkeye

    Hawkeye Member

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  9. Geetarpicker

    Geetarpicker Member

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    I've owned several Superleads and currently have a '68 Plexi Superbass. The Superbass definately has more of a mid scoop, less gain, and more bass. You can approximate the tone of a SL on the SB by turning the mids full up, the other tone knobs to 4, and the volume on 10. The Superbass is in some ways similar to a JTM45, but with some 100 watt attributes. Personally, I like a Superlead better if I'm doing hard rock and want to plug straight into the amp and go pedal free. I like the Superbass if I want more variety, but plan to also run my pedal board. The lower gain, and more Fenderish EQ of the Superbass seems to make it more pedal friendly than a SL at least to me.
     
  10. sws1

    sws1 Member

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    It was absurdly too loud to use for the tone that I wanted. Put a PPIMV in, but was still too loud.
     
  11. abnerfm

    abnerfm Member

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    Did you find it got "harsher" in anyway after the mods?
     
  12. DonP

    DonP Member

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    One resistor and one capacitor in the tone stack. I've wired this up to a puch/pull pot to switch between the two. It does sound different. The Lead has more mids, the Bass is more scooped.
     
  13. sws1

    sws1 Member

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    The PPIMV wasn't very good until the amp was turned up pretty high. Didn't sound good at low vols.

    Without the MV, the amp wouldn't distort until it was simply too loud. Even playing through greenbacks, there's no way I could have used it with my band without using pedals for dirt.

    A JCM800/900 w/ MV, while not exact, has the lineage of the SL, but with a much better sound down low.
     
  14. sws1

    sws1 Member

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    You also need to change the change the output caps to remove some of the low end of SB when going to SL.

    If I remember correctly, there is a simply change to the cathode of tube 1, a capacitor to be added in the tone stack, and a change of output caps.
     
  15. scott

    scott Member

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    I found that with the ppimv....
    It still has to be turned up to at least two o-clock to sound good.
    If you hit a chord and turn it up you can feel it come on.
    Like attenuators(I find) they are only really good for shaving off a few dbs but they re good at that. Tames it a bit.
     
  16. Roe

    Roe Member

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    no there's much more to it than this - look at the cathode of V1 and v2a and v1b's coupling cap and the bright cap
     
  17. Steve73

    Steve73 Member

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    I've owned both and I say leave it with Super Bass specs. The metal panel Super Leads are just so bright, I couldn't use them. I run a treble booster in front of my '74 Super Bass if I want more gain. Sounds amazing!

    Again, it depends on what tones you are going for. For Van Halen type gain, the Super Lead might be better. For Clapton-ish Cream stuff, the Super Bass spec is excellent.
     
  18. Roe

    Roe Member

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    yes, bass or jtm for EC
     
  19. abnerfm

    abnerfm Member

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    My amp tech said although he modded the preamp to Super Lead specs, the amp is not going to lose any bass because he is not changing the coupling capacitors. If I get it right, there will be an increase in presence (or high-mids, maybe?), but without decrease in bass. Now I'm just waiting for a set of new tubes to arrive, then I can take them to my amp tech and it will be done.

    :stir
     

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