Fender 5E5 versus 5E5-A: Which one to build?

Discussion in 'Shock Brother's DIY Amps' started by tweedy_woodpecker, Apr 3, 2020.

  1. tweedy_woodpecker

    tweedy_woodpecker Tele-Meister

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    I am starting to build a Tweed Pro with a 15 inch speaker for a friend of mine and I am still a little undecided which version to base it upon. My friend leans towards the 5E5 (First he wanted a 5E3 but he has these great sounding NOS 5881 Tungsol tubes, also he heard that Keith Richards just bought one plus he probably does not really need the additional power of the later version...)

    I'm a bit uncertain which version would best suit him. Here are my thoughts so far:

    Input section: I am inclined to use the input of the 5E5-A with only one 12AY7 (the same as the 5E3 Deluxe) since the 5E5 seems to "waste" whole 12AY7 by using one tube for each channel. Or am I missing something here? Does the 5E5 input version bring something to the table the other one has not?

    Tone stack: Anybody has with experience with both tone circuits? Again I lean twoards the simpler 5E5 tonestack (one pot tonestack, volume pots, mixing resistors), on the other hand the 5A5-A (molume pots, mixing resistors, two gainstages, two tone pots) has two additional gainstages and might be more versatile. I could probably use the simpler tonestack an still add another gainstage. Hm...or maybe add a tremolo circuit with the "leftover" tube? Or a one tube reverb?

    Power supply:

    I am thinking 5e5 values and maybe add the choke of the 5E5-A better filtering (maybe upping the first cap to 33mf?)

    Bias circuit: I might install a cathode/fixed bias switch or just use cathode bias

    NFB Poti or switch: I like this option in all of my amps, you can have both amp versions, off for 5E5 and on for 5E5-A, or anything in between.

    So basically right now I would build a 5E5 plus adjustable feedback loop and bias switch.

    Other things I might add: 470 Ohm Power tube screens resistors, elevated heater voltage...

    I would love to get you input on this.
    Thanks!
     
  2. boredguy6060

    boredguy6060 Poster Extraordinaire

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    The 5E5 uses octal preamp and the 5E5-A uses a 12aX7 if I remember correctly.
    If so, I go with the 5E5 and 6SL7.
    It’s been quite some time since I hung out in the Shock Bros forum but most agreed that the Octal front end was superior in tone to the 12AX7.
    I haven’t researched anything, so it’s possible I have it backwards, if so just disregard this post.
    The elevated heater voltage would be necessary for noise reduction as well.
    Good luck,
     
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  3. The Ballzz

    The Ballzz Tele-Afflicted

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    I often ponder a similar conundrum concerning the incestuous marriage of a low power Tweed Twin to a 5E3 power section. Here's my take, broken down in your format:
    Input Section: I have been intrigued about the concept of using a whole tube (both triodes in parallel) for each channel and then possibly even including a way to jumper both channels for parallel operation. My hope would not be so much for added gain, but the possibility of greater tonal complexity? Having never used a circuit such as this, I'm also not certain what it does or doesn't bring to the table!

    Tone Stack: Just remember that every added tone control component/pot sucks at least some gain!

    Power Supply: The addition of a choke is a good idea, but I would still keep the screens separated from the OT center tap as on the 5E5. I would be careful on going too high on the filtering, for not wanting the feel to get overly "stiff!"

    Bias Circuit:
    I would almost always opt for cathode bias (I'm looking for tone, not volume/watts/efficiency), but combined with that glorious cathodyne phase inverter, I don't believe you could add any effective tremolo. You might think about going back to the 5D5 paraphase PI, if you wanted to use a tremolo.

    NFB Poti or Switch: Not a bad choice! A switch takes the loop completely out of circuit, whereas a pot.....

    This Should Be A Lively Discussion,
    Gene
     
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  4. Mr Ridesglide

    Mr Ridesglide Friend of Leo's Silver Supporter

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    The Ballzz has a very informative take.
    I have built both a 5E5 and a 5E5-A.
    Both were/are phenomenal amps. I use the 5E5-A as my stage rig for most gigs with a drummer and I use an outboard reverb tank. I use it with 5881 tubes as well. I always have the inputs jumped. I prefer the bass and treble controls myself and the presence helps me out too when the band is too loud... well okay, when I am up on the dials riding it hard.
    I made mine with an adjustable fixed bias and the 5E5 that was for a friend was cathode biased. Cathode biased or not, it had plenty of hop to it and was very loud. It had 6L6GT type.
    You won't be going wrong with either.
    I stayed simple, no real mods on either and they both sound terrific.
     
  5. tweedy_woodpecker

    tweedy_woodpecker Tele-Meister

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    Thanks guys, good points!

    @boredguy6060: The 5E5 schematic shows two 12AY7s as input tubes, so no octal tubes as far as I know.

    @The Ballzz: I guess the additional 12AY7 before the tonestack in a 5E5-A is partly to make up for the gain loss of the tone circuit. I agree on not going overboard on the filtering, my ieda was just to use a 33mf cap instead of the two first 16mf caps in the 5E5-A. I would use a big enough NFB poti so it effectively takes out the NFB at max.

    @Mr Ridesglide: Thanks for your infos, maybe the best route is less is more in this case.....
     
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  6. boredguy6060

    boredguy6060 Poster Extraordinaire

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    You’re very kind, I should have done some research instead of relying on my deteriorating memory.
     
  7. tweedy_woodpecker

    tweedy_woodpecker Tele-Meister

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    No problem, I can totally relate as my brain experiences the same issue with age :)
     
  8. Nickfl

    Nickfl Tele-Afflicted

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    What is the starting point here and what is the goal? It kind of sounds like the only prerequisites you're starting with are 5881 power tubes and a 15 inch speaker, because other than that the circuits you are talking about have very little in common. The 5e5 ais basically a 6 l 6 version of the Tweed deluxe (oversized coupling caps, interactive vol/tone, cathode bias), while the 5e5a is basically a low power tweed twin amp with a 15" speaker (cathode follower, separate treble and bass tone controls, local and global negative feedback, fixed bias...). These are two wildly different amplifiers despite the shared power tube and speaker selection.

    Personally I'd go with the 5e5a, the idea of just throwing some 6l6 tubes into a tweed deluxe has always seemed pretty uninspired to me...

    Also if you're just looking to build something with those power tubes and that speaker you could also consider something along the lines of a supro thunderbolt. It has a 15 inch speaker and 5881 power tubes, but a paraphase pi makes it something different.
     
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  9. sds1

    sds1 Tele-Afflicted

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    Dang, no kidding. With -A in the model number you'd think it was just a update/variant to its predecessor.
     
  10. Nickfl

    Nickfl Tele-Afflicted

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    And then there is the fact that the 5F4 and 5E7 are nearly the same as the 5e5a but with different speakers (and maybe different OT primary impedance too?).

    Also the 5E4a, which is a 6v6 version of the 5F4. I'm presently very tempted to make that my next build using a set of transformers I pulled from an old console record player.
     
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  11. sds1

    sds1 Tele-Afflicted

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    So based on the requirements and leanings I gleaned from your post, here's what I might do:

    - 5E5 circuit
    - single channel
    - add choke
    - add screens
    - add cathode/fixed bias because that "5881 sound" you are trying to keep might be in fixed bias mode (you didn't say, but fixed bias is how I would run it)
    - add NFB switch
    - elevate heaters and any other "mods" that make the amp quieter/safer to use

    So, basically all your ideas!

    Very Tweed but with some cleanup. Still plenty of character to go around. Simple build. I dig it.
     
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  12. tweedy_woodpecker

    tweedy_woodpecker Tele-Meister

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    Thanks @sds1! We are getting closer.... ;)

    I will probably keep the 2 channel layout because I am sure my friend likes to get the control interaction of the original design but I am still not decided if I should use the one triode per channel (5E3 or 5E5-A) or doubletriode per channel (5E5) input design. The later seems a waste of a whole tube somehow, or is there a sonic advantage? (The other question being what to do with the leftover tube...maybe tremolo if I decide to have the fixed bias option...)
     
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  13. sds1

    sds1 Tele-Afflicted

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    A good reason to keep it! :)
     
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