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I want to build a flexible 5E3!

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  • I want to build a flexible 5E3!

    I have finally decided to build a 5E3! This will be my first amp build but want to build it so I can swap 6V6, 6L6, and 5881's. Can this be done, if so how? I have posted a similar question on another forum and been told this may be possible with no mods other than upgrading the power transformer and output transformer, and changing the rectifier depending on which tubes I would be using. Since I have read of others that "swap" tubes I thought I would get some input from 5E3 Pro's. I realize that changinge tubes can change the character of the 5E3 circuit but I would like the opportunity to experiment. I would appreciate all inputs and guidance. I also would like to build from a kit so information regarding necessary mods would be helpful.

  • #2
    That is going to be a pretty ambitious build for your first build and I don't know of any kits that are available that would allow you to swap any octal power tube in a PP amp. Cliff Hurley over at AX84 use to supply a kit for a SE amp that you could switch power tubes in. It was set up with external bias adjustment. Believe it was called SEL. I have one amp that I swap between 6V6's and EL34's in. You have to get the transformers right to do that. ie; you need a PT rated for about 220 ma for the EL34's where as you could get by with about 120 ma. for the 6V6's. If this is your first build I think I would just buy the Mission kit and build the 5E3 then first then start moding.

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    • #3
      It can be done but the mods would change the amps typical character IMHO.
      All depends on the sound you're after. The typical sound of a 5E3 is not clean, but somewhat "dirty" when you (almost) crank it.
      It puts out about 15 watts which is enough for every club. If you need more headroom you could use a second cab or mic it.
      If you need more clean headroom I'd prefer a different circuit instead of modding a good sounding stock 5E3.

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      • #4
        Thanks for the input! I appreciate everyone's idea's and opinions. Although this will be my first amp build I believe I have enough electronics background to get me through. My intention is to build a Mission kit because from what I have read is well documented. I guess I am a bit confused now though. So what I understand, "swapping 6L6,6V6 or 5881, this may be possible with no mods other than upgrading the power transformer and output transformer, and changing the rectifier depending on which tubes I would be using", this is not possible?? I realize that stock bias may not be optimal for the various tubes, but the intention is to be able to audition the various tubes and experiment. Realizing of course that changing tubes and rectifiers will change the character of the sound. Thanks in advance for your inputs!

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        • #5
          Originally posted by sjturbo View Post
          Thanks for the input! I appreciate everyone's idea's and opinions. Although this will be my first amp build I believe I have enough electronics background to get me through. My intention is to build a Mission kit because from what I have read is well documented. I guess I am a bit confused now though. So what I understand, "swapping 6L6,6V6 or 5881, this may be possible with no mods other than upgrading the power transformer and output transformer, and changing the rectifier depending on which tubes I would be using", this is not possible?? I realize that stock bias may not be optimal for the various tubes, but the intention is to be able to audition the various tubes and experiment. Realizing of course that changing tubes and rectifiers will change the character of the sound. Thanks in advance for your inputs!
          Of course it is possible.
          The standard set of transformer for a 5E3 uses a PT at less then 110ma and an OT rated at around 18 watts. Not a great combo for a pair of cathode biased 6L6GCs with a 5Y3 GT rectifier tube.
          Should be OK though if you build it with a larger, 30-35 watt power and output trannys and use a 300 to 360 @ 10 watt power tube's biasing resistor. Then you could just swap the rectifier tube to a stiffer one for the 6L6s/5881s and keep a NOS 5Y3GT in it for the 6V6s. Just about everything else could be left alone.
          What I would do is use a 33uF-450v to 500v E- cap for the main filter followed by two 22uf-450 to 500v caps with a 2K2 2 watt resistor between the first two caps and a 22K 1 watter between the second and third E cap.
          Bruce

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

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          • #6
            As Bruce suggested, change the OT for something larger..I would only add to include an adjustable bias and try a NOS 5V4 rectifier. I have done this with my deluxe inspired build and it sounds fanastic.
            Click image for larger version

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            Mandopicker

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            • #7
              Originally posted by Mandopicker View Post
              As Bruce suggested, change the OT for something larger..I would only add to include an adjustable bias and try a NOS 5V4 rectifier. I have done this with my deluxe inspired build and it sounds fanastic.
              [ATTACH=CONFIG]15808[/ATTACH]
              That's very nice.. is the adjustable bias cathode/self biased with a variable resistor in the cathode... the pot? Or is there some other circuitry on the other side we don't see?
              Bruce

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

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              • #8
                Thanks for the kind words...I'm always learning from you.

                Yes it is a pot...200ohm, I think in this one...with a resistor. Both 5 watt in size. This gives me plenty of range for most 6L6/5881 tubes used. The resistor attached is the 1 ohm that connects up to the bias test lead points to the left of the rect. tube.

                I really enjoy this amp and still seems to sound very 5E3 ish, but louder.
                Mandopicker

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                • #9
                  I use a hammond transformer I gutted from a organ running a 5u4gb switchable to diode and mullard xf4's I used mercurys dual tap trans and a celestion blue, "can't you hear me knockin" perfect. Switchable filtering on the mains 64/32 2K dropper 50 on the screens 10k dropper 16 on the PI, 10k dropper 10 on the pre, guess it ain't a 5E3. I built a metro kit before, before the intranet I read kendricks books over and over pittmanns too, that cathode pot seems dangerous to me, but I'm sure there's plenty I don't know....J
                  Last edited by jonamojo; 02-02-2012, 02:05 AM.

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                  • #10
                    Weber has such a kit.
                    Weber Classic 50's American Kits
                    http://taweber.powweb.com/store/5e3p_layout.jpg
                    Maybe you could clone some of it.
                    T
                    "If Hitler invaded Hell, I would make at least a favourable reference of the Devil in the House of Commons." Winston Churchill
                    Terry

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