speaker degradation

Discussion in 'Ampage Area' started by ruggero78, Feb 21, 2021 at 6:28 PM.

  1. ruggero78

    ruggero78 Electromatic

    41
    Mar 12, 2019
    Italy
    I've restored an old Marshall Master Lead 30: new pots, new capacitors... It's a 1982-1985 one. It lacks of definition... I mean that the difference between a stratocaster and a gretsch humbucker is audible but there are no details. The same details I hear using a digital equipement (speaker sims).
    Do you think it's a matter of the speaker?
    The speaker itself mounts a Celestion G12M-70...
     
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  2. pmac11

    pmac11 Country Gent

    Mar 4, 2018
    Toronto, Ontario
    It's worth consideration...many people find that changing the speaker can have a big impact on the tone of the amp. Do you have access to a different speaker?
     
    ZackyDog likes this.
  3. Gretschtim1

    Gretschtim1 Country Gent

    Dec 4, 2012
    Dundalk, Md
    It could be the speaker. It also could be a crappy output transformer.
    Many people including myself have gotten rid of dead sounding Marshall amps. I wish I knew then how much a crappy output transformer could ruin the sound and punch and clarity of an amp. Drake transformers were very inconsistent. Some sounded great while others sounded really bad.
    I've played through Korg era Vox amps that had the same problem - they also used Drake transformers during that time.
     
  4. pmac11

    pmac11 Country Gent

    Mar 4, 2018
    Toronto, Ontario
    This is a solid state amp...does it have an output transformer?
     
  5. wildeman

    wildeman Gretschified

    May 10, 2015
    norcal
    I'd try a speaker before giving up on it. I have a Lead 12 from that same series and while it sounds okay with the stock speaker, it kicks ass with a great speaker.
     
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  6. Ricochet

    Ricochet I Bleed Orange

    Nov 13, 2009
    Monkey Island
    While arguably not the worse speaker, 40 years is a long time to hold up, for any electronic component really.

    Maybe the bias(resistor) has drifted?
     
    Rmccamey likes this.
  7. michelb

    michelb Synchromatic

    Age:
    30
    611
    Mar 27, 2020
    Belgium
    speakers are idd a big part of the amps sound, tone and feel.
     
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  8. El Marin

    El Marin Gretschie

    226
    Oct 4, 2018
    Madrid, Spain, EU
    I would try... try to check the speaker... then try to check the amp
     
  9. Gretschtim1

    Gretschtim1 Country Gent

    Dec 4, 2012
    Dundalk, Md
    Oh I didn't know that but no transistor amps do not have output transformers.
    Not knowing what those old Marshall transistor amps from the 80s sounded like I have no way of comparing. The best thing would be to try some different speakers and see if it brings the amp to life.
     
  10. pmac11

    pmac11 Country Gent

    Mar 4, 2018
    Toronto, Ontario
    Welp, some SS circuits had an OT, but they were typically crap. I don't think Marshall even went that route... Usually the output stage in a SS amp is a pair of big capacitors. I agree with @Ricochet, there are a lot of components that could easily have drifted off spec over the decades.
     
    Ricochet likes this.
  11. Ricochet

    Ricochet I Bleed Orange

    Nov 13, 2009
    Monkey Island
    It’s funny, I had the power transformer changed in a cheap ss practice amp. While not as dramatic as an OT swap in a tube amp there was a subtle difference. Every EE says there shouldn’t be(220V being 220V) but here we are.
     
  12. Ricochet

    Ricochet I Bleed Orange

    Nov 13, 2009
    Monkey Island
    If I can be bothered enough, I’ll swap out the speaker in mine. Don’t hold your breath. ;)
    Any particular Celestion you want tested?

    50D5B7C3-06B7-4C5D-9643-EF133E4C8E46.jpeg
     
    Last edited: Feb 23, 2021 at 4:57 AM
    pmac11 likes this.
  13. lathoto

    lathoto Synchromatic

    543
    Apr 23, 2020
    Ohio
    One dose of an EVM12L is the cure.
     
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  14. Gretschtim1

    Gretschtim1 Country Gent

    Dec 4, 2012
    Dundalk, Md
    I don't work on transistor amps - not much tweaking you can do to them so they don't interest me...:). The ones I do like such as the Roland JC amps usually never blow up...:D.
     
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  15. pmac11

    pmac11 Country Gent

    Mar 4, 2018
    Toronto, Ontario
    Roland makes great stuff. There was also a 60W, 12" combo made by Acoustic Control Corporation in the late 70s. Fantastic SS amp. Would love to find one again. Quilter makes good solid state these days.
     
  16. ruggero78

    ruggero78 Electromatic

    41
    Mar 12, 2019
    Italy
    a Jensen 4 ohm :)
     
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  17. Ricochet

    Ricochet I Bleed Orange

    Nov 13, 2009
    Monkey Island
    Sorry, no Jensens! I’m not even sure I have a 4Ohm speaker.
     
  18. Gretschtim1

    Gretschtim1 Country Gent

    Dec 4, 2012
    Dundalk, Md
    I used an Acoustic Control 135 2-12 combo back in the 70s (73-78) for about 5 years. It had a nice clean tone but I was unable to get any kind of good distortion out of it without the use of distortion pedals.
     
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  19. pmac11

    pmac11 Country Gent

    Mar 4, 2018
    Toronto, Ontario
    The 60W 1-12 was similar.
     
  20. hcsterg

    hcsterg Friend of Fred

    Feb 13, 2012
    France
    Well, If the speaker hasn't been mistreated (schocks, deformations, poor storage with pression on the cone, dust, humidity), I don't think he his the culprit. If not already done, I would check the amp and tubes beforehand.

    That said, you may want another speaker and that's fine. But IMHO suspect the amp circuit and tubes first... ;)

    A+!
     
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