All is not right with my new 5E3 build...

Discussion in 'Shock Brother's DIY Amps' started by dunehunter, Jul 21, 2019.

  1. dan40

    dan40 Tele-Afflicted Silver Supporter

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    When choosing the best "lead dress" for your build, you really need to understand what each wire does and whether it is a signal wire, filament wire (ac) or b+ wire (dc). Once you know this, you can make the best choices about how to route each wire. One rule of thumb is that anytime one wire has to pass over another, try to do so at a 90 degree angle. Also try to keep all wires to the sockets as short as possible without being tight. Too much extra wire can begin to act as an antennae and introduce noise into the circuit. It is something that will get easier with each build as your experience level grows.
     
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  2. dunehunter

    dunehunter Tele-Holic Double Platinum Supporter

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    Thanks for all the comments, everybody. Took the day off yesterday to visit with an old friend up here from Arkansas (the university of). Nice lunch, great conversation--good to see him.

    Now, back to the task at hand. I'm going to do this somewhat piecemeal as I'd like to see what the actual problem ends up being. I've already addressed a few "lead dress" issues but still have a few other paths to go down--most notably, the MV and its wiring. But, try the simplest stuff first, so...
    1) I've already changed out the tone and bright caps so will see if that was an issue.
    2) If not, replace remaining tubes one at a time to see if that makes a difference.
    3) If not, replace (and route more correctly) the wiring leading to the MV with more adequately insulated cable (coax).

    I'll keep you all posted on the results as they come. Thanks again.
     
  3. dunehunter

    dunehunter Tele-Holic Double Platinum Supporter

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    Can I ask...what is your source for wire?
     
  4. dan40

    dan40 Tele-Afflicted Silver Supporter

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  5. dan40

    dan40 Tele-Afflicted Silver Supporter

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    I was looking at the picture that D'tar posted in post #14 and it looks like you may need to add a bit more solder to those socket pins. It may not be causing the issue but there does appear to be a few cold solder joints there.
     
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  6. dunehunter

    dunehunter Tele-Holic Double Platinum Supporter

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    Thanks. I'll have a look and reflow on those sockets.
     
  7. dunehunter

    dunehunter Tele-Holic Double Platinum Supporter

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    An update:

    1. Re-flowed solder on my tube joints as suggested by @dan40 , notably at V1 but also at V2.

    2. Replaced the 12AX7 with different tube (7025) that I happen to have had on hand. I think there may have been a short on one side of that old 12AX7 so just put a tube in to make sure...may save that 7025 for something else.

    3. A number of people suggested that I look into lead dress issues; I think it was @D'tar that pointed out a specific one (which is now fixed). Also routed a number of others that were just "hanging" out over the circuit board.

    4. Re-wired and soldered the tone control with new tone and bright caps and took a little more care here.

    5. Ordered some coax from the store--should arrive in the next couple of days-- to deal with the wiring of the MV. Though not yet done, it's still on my list. I've even thought out the routing of those wires that will minimize "air time" over the circuit board.

    6. Plugged it in, and away we go...
     
  8. dunehunter

    dunehunter Tele-Holic Double Platinum Supporter

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    Results:

    1. Motorboating/trem-type sound is gone now. :D

    2. Squealing at medium to high volume on "Bright" channel, gone. :D

    3. Normal behavior from the MV. :D

    4. Mostly good behavior in tone control until I get up to about 7.5, at which point, I'm getting some clear (and loud) feedback. :rolleyes: At least it's not squeal.

    Amp mostly sounds great (except that tone bugaboo) and gets real loud too. The interaction between the volume controls and tone control is really pretty interesting.

    I'm hoping when I change out the wires to the MV, that feedback will go away.

    So far, so good. Thanks to all for your suggestions. Stay tuned!
     
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  9. dan40

    dan40 Tele-Afflicted Silver Supporter

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    Great news!! That shielded wire will likely cure the feedback issue as will shortening any wiring that may be longer than necessary.
     
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  10. dunehunter

    dunehunter Tele-Holic Double Platinum Supporter

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    Addendum, for anyone still tuning in.

    The problem returned :( although not quite as bad as before. On the bright input, (and to a lesser extent the "normal" input), squealing at maximum from both volume and tone control was clearly audible. So I redoubled my efforts, rolled up my sleeves and started to poke around.

    One of the original suggestions ala @Dacious was to flip around the wires from the output transformer. As this amp has no feedback loop, I had not done this before, but I gave it a shot as it was an "easy" fix. Also recommended elsewhere by @Wally I think. At any rate, as @Dacious suggested was possible, no difference.

    So I'd tried swapping tubes (some success--did find that my 12AX7 had a short) but that didn't solve the problem completely. Also replaced the ground and signal wires to the new master volume with coax--Occam's Razor (note to @King Fan -- spelling! :D) would suggest that was my problem in the first place. Again, slight change but still no complete remedy.

    Finally decided to plug a guitar in and, with all controls at highest setting, poke around inside the chassis with a chopstick. Nothing, nothing, nothing, then...hit the wire from the coupling cap to the MV output and...absolutely squealed like a pig at a slaughter house. So for all those making the suggestion of "lead dress': spot-on. I re-routed the wire to run right next to the chassis in as short a configuration as possible. Squeal gone on both channels. Success.

    This REALLY opened my eyes to the concept of lead dress! Thanks to ALL who pointed me in this direction.
     
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  11. Dacious

    Dacious Poster Extraordinaire

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    Excellent resolution to problem. Like many things I've discovered with amps and guitars

    1. There's always a solution, not always obvious
    2. Little things often make a big and unanticipated difference.
     
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  12. dunehunter

    dunehunter Tele-Holic Double Platinum Supporter

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    Unfortunately, I still have one issue.

    When nothing is plugged in, the amp is dead quiet--not a peep. At high volume, at low volume--nothing. Splendid silence. However, when I plug a strat into either input, I get hum on all the single coil settings (1, 3, and 5 on the guitar switch) but nothing on the "humbucking" settings of 2 and 4. Sounds to me like 60 cycle hum and increases with volume. Gets pretty loud, actually.

    I'm wondering if this is really another lead dress issue. Right now, I have all the heater wires twisted vertically above the tube sockets.

    On these vertical Tweed chassis, do you folks run those wires flat to the chassis or stand them up? I noticed on @robrob 's build, they are laying down on the chassis. What is best practice here?

    As usual, thanks to all.
     
  13. dunehunter

    dunehunter Tele-Holic Double Platinum Supporter

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    Thanks for your support, @Dacious ; really appreciated!
     
  14. Paul G.

    Paul G. Friend of Leo's

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    Sounds right to me. The hum is coming through the guitar. Look around the room, something is probably interacting and making normal hum worse. The fact that the humbucking settings eliminate the hum proves that. As far as routing heaters, I've done both ways, flying heater wires, and lay down. As far as I can tell, there is no difference. If you do lay them against the chassis, make sure they cross signals at right angles, preferably with some air between.
     
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  15. Wally

    Wally Telefied Ad Free Member

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    Don’t blame the amp for single coil,hum.
     
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  16. dunehunter

    dunehunter Tele-Holic Double Platinum Supporter

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    Agreed.

    But I guess i'm wondering, have I done what I can do to minimize it? This is the first time I've heard hum this loud from my single coils. I'm wondering if I've done something else wrong.
     
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  17. Wally

    Wally Telefied Ad Free Member

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    How close to the amp are you and what orientation of the pickups to the amps is there? Sometimes you can rotate the guitar 90-180 degrees and the hum will decrease. Move away from the amp if you are within 6 feet of it.
     
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  18. Bill Moore

    Bill Moore Tele-Afflicted Silver Supporter

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    Always turn off the neon beer sign above the bandstand!
     
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  19. Wally

    Wally Telefied Ad Free Member

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    Or...could it be....turn off the band stand over the neon beer sign! Beertender give me another bar!!!
     
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  20. dunehunter

    dunehunter Tele-Holic Double Platinum Supporter

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    So, yeah, sitting pretty close. Like around 4'. And when I move away, it does seem to improve.
    Wonder how far Larry Carlton was from his 5E3 when he recorded with Steely Dan?

    Btw, the further I get from the amp, the less orientation seems to make a difference. But close? Yeah, orientation makes a huge difference.
     
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