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Sessionette:75 - Celestion G12-80 dead?

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  • Sessionette:75 - Celestion G12-80 dead?

    About 20 years ago, I bought this Sessionette:75 for a fair price, considered the wear. I can't recall exactly when the sound problem occured first, but there was some loud crackling/distortion with heavy chords. I temporal "solved" the problem by an extra resistor between the pre- and power-amp.

    After not used the amp for many years, the crackling/distortion was back. So I removed the temporal resistor and it sounded fine again (don't ask why).
    After a few days the sound was completely gone except for heavy chords which produced static/crackling/distortion. Then suddenly the pre-amp died except for the reverb.

    Because I really like this amp, I decided to really solve the problem, knowing this is a pain because of the short cabling (see attachment).

    I replaced all op-amps, checked the Voltages, sprayed the pots, followed the signal and concluded there should be no problem.
    The headphones worked fine, but the speaker remain dead.
    My multimeter told me the resistance of the speaker was 11 M-Ohm and not the 6.4 Ohm that it should be.

    And now my question: Can a speaker die this slowly and give the sound issues described above?

    I'm hesitating to swap with a G10-50 for testing, while I'm not sure what the cause was for the problems and the dead of my G12-80.

    BTW. The 680R/3W resistors (R32, R33) are extremely hot, could the 2N3053 dissipate that much power for it is maybe defect?

    Thanks.
    Attached Files

  • #2
    Update

    I just tried the amp with the G10-50 and it the sound is terrible. Ugly distortion on the clean channel. With the headphones the clean channel sounds clean, crispy the way I like it.

    Could the HY244P module be faulty? I don't have a clue how to deduct this problem. Please some advice!

    Comment


    • #3
      Please?

      Comment


      • #4
        Hi Marcel.
        A speaker can, yes, die along some time, crackling a lot along the way, because corroding speaker wires, aggravated by humidity and even worse, closeness to the sea.
        In the Netherlands many are, technically, living in the (reclaimed) bottom of the sea!!
        Anyway, your power module might be dead too.
        Make the following tests.
        1) Bypass it by soldering a shielded cable to pins 3 (in) and 4 (gnd) and plugging the free end into some amp's loop in. You will hear your full preamp sound into the auxiliary amp.
        2) To bypass any amp to speaker connection problems, solder two wires to pins
        2 (out) and 4 (Gnd) and hook them directly to your external speaker-
        *If* that works, I would strongly suspect the headphone jacj, which cuts the main speaker line, and the external speaker jack, which does the same because it's a series connection, bypassed by a flimsy and probably very rusty jack contact, change both .
        Good luck.
        PD: Award Session Website. Welcome to award-session.com [AwardSession Website], guitar amps and music amplifiers is still very alive and can supply a replacement power module if necessary.
        Juan Manuel Fahey

        Comment


        • #5
          SESSIONETE 75

          Just finished putting one back togeather
          speaker is no good
          measure for voltage before hooking speaker up
          amp kicks buttttt!!

          Comment


          • #6
            Sessionette 75

            If anyone has some info on where i could get the
            chrome logo "sessionette 75" for the speaker grill
            let me know

            Comment


            • #7
              The link I posted above is Mr Ward himself, nobody better for all things Sessionette.
              Juan Manuel Fahey

              Comment


              • #8
                Hi
                If you ever need the amp to be serviced, I have had a few thru my workshop. Great little amps and fantastic sound.
                I can also supply and/or install a new replacement power amp for the Sessionette 75 and other session models and matches the exact input and output specs of the old albeit now more reliable.

                Comment


                • #9
                  And whereabouts on planet earth might said workshop be located?

                  I'm assuming it is on Earth... Anyway please fill in your location info.
                  "Enzo, I see that you replied parasitic oscillations. Is that a hypothesis? Or is that your amazing metal band I should check out?"

                  Comment


                  • #10
                    (Unfortunately) true message I find at my answering machine, *at least* once in a week:
                    - Ring ... Ring ... Ring ...
                    (Follows my own greeting message)
                    - Hi Juan, it´s me !!!
                    - Do you remember what we talked about last week (Month/Year/Geological Era) ?
                    - I got the money !!! Go ahead, build it !!!!
                    - Call me when ready !!
                    ........................................................ .
                    -Ah !!! Remember I already gave you my number !
                    - Click !
                    Juan Manuel Fahey

                    Comment


                    • #11
                      I am based just north of Ipswich on Earth. Just a small independent workshop.
                      I have updated my profile to reflect.!

                      Comment


                      • #12
                        Which would be ? .............
                        a)
                        It is the county town of Suffolk, England. Ipswich is located on the estuary of the River Orwell.
                        or
                        b)
                        Ipswich, one of the oldest towns in the United States, founded in 1633, is centrally located on the North Shore of Massachusetts, approximately 28 miles north of ...
                        or
                        c)
                        The University of Queensland’s Ipswich Campus provides a high quality teaching and learning environment in a supportive, friendly campus community ....... Established in 1999 on a heritage site in Ipswich, ........
                        or
                        d)
                        Ipswich, the county seat of Edmunds County, is only 25 minutes from the third largest city in South Dakota - Aberdeen. Located at the junction of US Highway 12 and SD Highway 45, Ipswich is only 100 miles from ....
                        or
                        e) ........ somewhere else ........................... (still on Earth, of course).
                        .
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                        .
                        .
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                        Sorry, just kidding , couldn´t resist.

                        Blame it on a feeble mind
                        and, WELCOME TO THE FORUM !!

                        EDIT: last but not least, congratulations on keeping these great amps alive.
                        I love them.
                        Juan Manuel Fahey

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