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please help! ear splitting 5e3x2

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  • please help! ear splitting 5e3x2

    I hate to beg , but Im really at my wicks end on this one....I have posted in a few other forums to avail. I built a weber 5e3x2. From all the sound samples I have heard on the net and a couple of 5e3's I have played through, one scratch built and one original fender, they all sound fantastic. The tone is on the dark side(where it should be?), fat, rich and thick. At the 2 shows that I played this amp I think I got hearing damage, lol, its EXTREMELY!!! bright and edgy . I have gone over this amp more times than I can count, checking wiring, values of the components and voltages. I replaced the speakers with a vintage 30 and a "greenback", I also replaced all the tubes. These changes helped only slightly. The only thing that looks "odd" are the voltages on the PI. Plate v is 210, grid v is 3(odd) and cathode v is 47. These are not the voltages I see commonly posted for this amp. Generaly the grid voltages I see are about half the cathode. Other than the excesive top end brash, it seems to run *ok*...gets pretty loud and starts to break up at around 3 with single coils (Kinmans in a Tele).
    If anyone could help Me with this It would be MOST appreciated!

    Thank You, Manic

  • #2
    Don't measure grid voltage directly between grid and ground, your DVM will draw a little current FROM the grid and show false reading. That's why "half cathode voltage on the grid" you refer to is unreliable, it will vary depending on what meter you use to measure it.
    Take a measurement across the 1.5k resistor i.e R15 on the 5E3x2 schematic. It should read ca 1.1V give or take. 47V on PI cathode or thereabout seems ok but do you have correct A,B & C supply voltages? What are they?
    Aleksander Niemand
    Zagray! amp- PG review Aug 2011
    Without the freedom to criticize, there is no true praise. -Pierre Beaumarchais, playwright (1732-1799)

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    • #3
      ahhh...thnx for clearing that up for Me Alex. A guy posted that in another forum...err I honestly thought he was pulling My leg when He mentioned a "valve voltmeter".
      A 389v
      B 328v
      C 237v.... Amazingly enough its very close to the Mission scem I have that states voltages for a 5e3. Thats using a WZ34 or a GT-5AR4...both are within 10 volts of eachother at points A,B and C during idle.

      ....TY, Manic

      Comment


      • #4
        Originally posted by Manic View Post
        ahhh...thnx for clearing that up for Me Alex. A guy posted that in another forum...err I honestly thought he was pulling My leg when He mentioned a "valve voltmeter".
        A 389v
        B 328v
        C 237v.... Amazingly enough its very close to the Mission scem I have that states voltages for a 5e3. Thats using a WZ34 or a GT-5AR4...both are within 10 volts of eachother at points A,B and C during idle.

        ....TY, Manic
        What are the Mission Amps 5E3 voltages you have?
        All the MA 5E3s have a NOS 5Y3GT and none have 390vdc on the first node.
        A V30 and GB12 would not be my first choice but you should still be able to tame the cab and speakers with the simple tone control found in the 5E3, as they are a little bit dark with the tone knob set to 5 or less.

        When I did those 5E3X2 amps for weberVST they wanted to use all the Chinese trannys that he already had in stock and didn't want to buy anything else for this project... that meant you'd get what's in stock and that's it.
        For the most part it means an amp with too high of B+ voltages unless you use the right rectifier and correct cathode biasing resistor.
        The other thing was, they did not want to supply or buy any 12AY7s from Russia (or New Sensor) for the first preamp, even though that is what the amp called for... I guess they only wanted to use those cheap $1.95 Chinese 12AX7s and unmatched bulk 6L6s.
        Getting some better tubes was a step in the right direction... get a 12AY7 too.
        Bruce

        Mission Amps
        Denver, CO. 80022
        www.missionamps.com
        303-955-2412

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        • #5
          Here is the scem I was referring to, Bruce. Maybe I have My nodes bass ackwards?

          The tone that Im shooting for would be something like the samples at Victoria.

          http://www.victoriaamp.com/mp3%27s/2...Riff%20Sam.mp3

          I noticed something about that sample of the Vic. If ya listen at the end of the track, I thought I heard a keeley compressors release rate . I called Vic and talked at Mark Baier about that sample. He swears we are hearing nothin but 52' Tele a cable and a Vic 5e3. The volume swell at the end of the track he suggested "might" have been Sam rolling into the volume control on His guitar. He said He was there when those samples were recorded. I hear a lil uneveness when it gets louder on that last sustained note, which may again suggest a volume pot move and not a compressor releasing.
          The 5e3 is a sag-compression monster, which to Me is one of the main things that is appealing about this circuit. Which is what I thought I was hearing though the majority of that track.

          BTW are there any nice audio samples of a Mission 5e3 ?...I would really like to hear them too. Thnx for the suggestions Bruce.

          Manic
          Attached Files
          Last edited by Manic; 03-20-2007, 12:22 PM.

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          • #6
            Victoria builds a great 5E3 and uses all good supporting parts and high quality transformers.
            Hmmm... I don't think there is any extra pedal(s) on that mp3 file either... it sounds more like a player who knows how to eek out some of the extra tweed tones using subtle guitar techniques while playing.

            The schem you are looking at is a mod amp from Sean using the Mission 5E3 kit schematic back in 2002.
            Even though the TMI and Thordarson trannys were excellent, I don't use those two transformers anymore.
            I'm not sure but I don't think I wrote those voltages in that schem and the listed B+ is higher then it should be for a vintage or classic amp setup anyhow.
            Over the years (as money permits) I have been tweaking the transformers and now have the OT I like the best and PT voltages where I want them using a NOS 5Y3GT rectifier.

            I've been doing repair work for a semi-major studio here in Denver over the last 6 months and trading my labor for theirs so we can bring all the tweed and Aurora amps in for a real studio sound sampling, including demos and some cuts with live playing in a group situation so potential buyers can hear what these amps really sound like with a band.
            Hopefuly that will be coming in the next couple months.
            Bruce

            Mission Amps
            Denver, CO. 80022
            www.missionamps.com
            303-955-2412

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            • #7
              ......Here is the source of that scem. I'm liking the tones hes getting.

              http://www.kilback.net/homebrewtweak...s.htm#tweed5e3

              In the mean time I have upgraded the OT with a MM Jim Kelly. Its a different ballgame now, but its not there yet. I'm considering the Paul c mod next.

              I thought it was interesting that I gained 10 volts at the B+ after installing the new OT.
              Last edited by Manic; 08-05-2007, 08:19 AM.

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              • #8
                Speakers

                A double tweed deluxe sounds fantastic.
                In my Victoria I have a 1230-55,30w ceramic and a 30w ceramic Blue Dog.
                A nice combo as is a Blue Dog and a Silver Bell.
                That V30 speaker has an upper mid SPIKE that hurts !

                JJ

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                • #9
                  thnx man, yeah I agree theres a spike in the upper mids that is focused and painful.

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