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The 5FrancE3 build thread

Discussion in 'Shock Brother's DIY Amps' started by backalleyblues, Jun 14, 2019.

  1. backalleyblues

    backalleyblues Friend of Leo's

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    Well, I FINALLY got all the parts together, and have finally found a bit of time to start putting this project together, my first amp build! I decided on building a 5E3 for several reasons-

    1) Once it's done, I can gig/jam with it, and it will hang with a reasonable drummer

    2) I had an original 5A3 (TV Front) back when I was young and dumb-now that I'm old and dumb, I kinda want to re-live some parts of my youth

    3) I like a good challenge, and I've always been into the electronic side of things-I actually passed the FCC commercial Radio Ops test back in the aforementioned young and dumb days, and while I never worked at a radio station, what I did learn has served me well over the years. Would like to re-stretch some of that knowledge again!

    4) My wife plays harp in the band, and you'd be hard pressed to find a better amp for harp...

    So with that said, here's what we have so far-

    Amp kit with trannys from Boot Hill-I checked over everything, and it appears everything is here...

    Cabinet made by NickFL here on TDPRI-absolutely beautiful work, we talked about how I planned to finish it, and Nick went out and found a wonderful pine board to make the cabinet from!

    Tubes from Tubes And More-I'm using JJ all across, partially because I've had very good luck with them over the years, partially because they're replaceable, partially because I can afford them... I also went ahead and got the handle and various pieces of hardware I needed for the amp at the same time-just enough to get free shipping!

    So where do we start? With the cabinet of course!

    With the small amount of time I had today, and decent weather finally here in Jax (it rained all week) I decided to take advantage and start finishing the cabinet. Now, I've done enough contact cement work to know that I truly HATE working with the stuff, and I love the idea of a natural wood look-I've seen plenty of amps finished naturally to know what I like, sooo-off to Lowe's we go! I was going to stain, then cover in polyurethane (and try some trick sunbursting too!) but when I got there, I was a bit underwhelmed... after looking through the entire section 5 times, and rethinking my plans twice that, I finally decided to use Minwax PolyShade, a tinted urethane. I did a test piece a week ago, and loved the color!

    So here are the first pics of the cabinet, with 1 coat of PolyShade down (I chose Pecan Gloss-kinda gives it that old varnish look that I love!). I hope to get another coat down on Sunday when I get back from visiting Mom... and then start building the guts of this beast!

    More to come, of course, but I'm already digging how this cabinet is turning out!

    Franc Robert
    IMG_4205.JPG IMG_4207.JPG IMG_4211.JPG
     
  2. drf64

    drf64 Poster Extraordinaire

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    Ha ha ha, you said “reasonable drummer!”
     
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  3. backalleyblues

    backalleyblues Friend of Leo's

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    drf64 you might think "reasonable drummer" is a mythical creature, but they DO exist! Used to play with one that could play so quiet I could talk normally to him while we were playing-even my current drummer is not a masher, my ears don't ring when I go home after the gig!

    On a related note to the build, I was debating how to approach soldering with a turret board-saw all sorts of different approaches, but then I stumbled upon this little gem, and it made perfect sense to me...

    https://elsmar.com/pdf_files/Military Standards/Mil-Std-2000.pdf

    Starting on P.115 of the PDF, it breaks down mil-spec soldering with turrets-the whole philosophy is to assemble the circuit so that it would work with no solder at all, and that anyone with a bit of training could replace in the field a bad component. I like this approach very much, so I'll be assembling and soldering as close as I can to mil-spec.

    Franc Robert
     
  4. backalleyblues

    backalleyblues Friend of Leo's

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    OK, got home in time to put another coat on the cabinet-oh yeah, I like how this is turning out!

    Also sprayed the speaker baffle with some rattle-can black I had laying around from another project (I think it was for a road case), this will look very nice and even when the grille cloth is put on...

    I've got some freelance work to bang out tonight (and also some road burn-4 hr trip to see Mom!) hopefully in a day or 2 I can get to stuffing the board...

    Franc Robert

    IMG_4227.JPG IMG_4225.JPG IMG_4228.JPG
     
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  5. backalleyblues

    backalleyblues Friend of Leo's

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    Well, I FINALLY got some clear time (freelance work has been every night for 2 months straight!) and I managed to finish the cab-traditional grille cloth staples along the edges then shrunk tight with a hair dryer, a tip I read somewhere on the inter webs... then put the whole cabinet together, a little tight, but it’s in there now! Added the screws, and the cabinet is now finished-really happy with how this portion of the project has turned out! Now, on to the turret board...

    Franc Robert
     

    Attached Files:

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  6. backalleyblues

    backalleyblues Friend of Leo's

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    Got a good chunk of clear time (the whole evening!) to work on the board-triple checked component locations and connections, all looked good so I cracked out the soldering iron and got it all soldered up. Added the volume and tone pots, along with the jacks-I think the leads to the pots are too long (I had cut and solders them before putting them inside the chassis) but this something I can solve. Put all the sockets in, still have quite a few leads to go before I could say it’s ready to test, but at least I finally got something done on this amp! Please if you see something that looks amiss, let me know! Should have some more time tomorrow to work on this-looking forward to firing her up soon!

    Franc Robert 41816BEA-A813-42CE-84B4-475A0177A729.jpeg 47DF8325-DCAD-43CB-83C2-8CB56B801B85.jpeg 33A736B3-D9A3-484E-A6C6-A215298382AF.jpeg
     
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  7. backalleyblues

    backalleyblues Friend of Leo's

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    Well, it's been quite awhile since I've posted about this amp project, I wound up putting it aside due to work issues (for a long stretch, busier than a 1 armed paper hanger!). Since the pandemic has shut everything down including my freelance work, I finally had some time to work on this beast...

    Over the last couple weekends, I've finished off the board, hooked up all the sockets, grounded everything, double checked, fixed, triple checked, fixed again, one last check... and took the plunge and turned it on...

    IT WORKED FIRST TIME!!!! :D

    I have one simple issue to fix-the standby switch is wired backwards, but that's not too bad...

    A couple things I've noted-one, the volume isn't all that loud-I wasn't expecting Marshall stack loud, but it does sound kinda quiet, a bit anemic actually, and it starts to break up REALLY quick, like on 2. Also, none of the wooliness on the bass that I would expected was present. When cranked, it definitely had the 5E3 growl and grit going on (La Grange sounded like money on this amp!). So what should I be looking for to get this amp up to full snuff? All ideas are welcome!

    Here's a clip of the amp from my FB page, if you're so inclined to listen-ignore the sloppy playing! For the record, I was in the normal channel, with my '83 telly, original neck pup, SD Broadcaster in the bridge-the speaker is a Hellatone (broken in Jensen)

    Nice to be near the end of this journey!

    Franc Robert
     
  8. backalleyblues

    backalleyblues Friend of Leo's

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    Got to look over the amp again today, and I found the volume issue-I had not wired the heater wires for the power tubes correctly (D'oh!) In my thinking, I thought a 6V6 should be getting 6v on the heaters, and in turn wired the heaters in series, thinking the voltage coming from the transformer is 12v (for the 12AX7s, naturally!). Switched the wiring to parallel, and the amp now sounds like it should! Sometimes the simplest things...

    Only issue now is that I do have some hum going on in the amp, and it's definitely controlled by the volume-I haven't put any foil on the back plate yet, was wondering what else should I be looking for? I did a star ground to the chassis, FWIW... any ideas would be much appreciated!

    Thanks,
    Franc Robert
     
  9. Nickfl

    Nickfl Friend of Leo's

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    Just the other day I was wondering whatever happened with this project, glad to see you got the chance to finish it up!

    If the hum seems to be heater related you should try elevating the heater center tap on the cathode of the power tubes. That tends to make for pretty quiet builds in my experience.
     
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  10. backalleyblues

    backalleyblues Friend of Leo's

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    OK, redid the heater wires again, still not as quiet as I like, but it's livable. I'll be putting some shielding on the back panel, that should help cut the noise down a little further as well... I couldn't crank it tonight, stepson has to go to work at 5am (poor kid!) in the meantime, I took some pics of the finished amp, I got the finishing part down alright! Thanks for hanging in with me!

    Franc Robert IMG_5417.jpg IMG_5418.jpg IMG_5419.jpg
     
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  11. Lowerleftcoast

    Lowerleftcoast Friend of Leo's

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    Try elevating the 6.3VAC heaters. This is done by having the heater center tap terminate at pin 8 of the 6v6 tubes or the board turret of pin8 and the bias resistor.

    Use a chopstick to move the wires of the preamp tubes for better lead dress.

    Terminate the HT center tap directly to the first filter cap negative turret.

    Show pictures of the wires on all the tubes, the board, and the input/pot side wiring for more suggestions.
     
  12. tubeswell

    tubeswell Friend of Leo's

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    Try a 'split-ground' - Separate the pre-amp filter cap ground from the reservoir and smoothing filter cap grounds, and keep the pre-amp ground returns (including the PI grounds, with the pre-amp filter cap ground, all on one ground, returning to the chassis at input jack sleeve. The reservoir and smoothing cap grounds and heater winding ground, and HT winding centre tap and 6V6s cathodes and grid leak resistors all go to another ground return point near the other end of the chassis.

    Also try shortening some of the signal wire runs. Wires are inductors (and signal wires, being 'low-current' AC wires, are susceptible to unwanted EMF coupling from each other, and from higher-current AC wires, and from general 'stray' EM fields, including the PT EM field)
     

    Attached Files:

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  13. backalleyblues

    backalleyblues Friend of Leo's

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    OK, getting ready to dive into the amp again-sounds great, just more hummmm than I like...

    LLC, I'm using the BootHill kit, with the ClassicTone transformers- there are 2 wires which are sent to ground on the schematic provided (green-yellow and red-yellow) are these the center taps? If so, which one or both should I tie to pin 8?

    Tubeswell, I'll take your advice on the grounding scheme, I had shortened those wires some after that picture-will check again to see if I can't get them a bit cleaner. I did put the foil on the back panel, that did cut down on the hiss, but not the hum...

    Thanks,
    Franc Robert
     
  14. Nickfl

    Nickfl Friend of Leo's

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    The heater center tap should be the yellow-green wire.

    Is the hum happening with nothing plugged in or only with a guitar? Pictures of your finished wiring, especially around the tube sockets, would help too.
     
  15. backalleyblues

    backalleyblues Friend of Leo's

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    Just got done with testing, moved the heater center tap to the board turret of pin 8, and separated the grounds-MUCH BETTER! Hum is actually down to the level I get out of my Blues JR, so I'm a happy camper now! No pics, as it is a real rat's nest in there, but I did double check the length of my leads, and while not as short as they could possibly be, they're not flopping around loose in there either.

    Thanks again for the help! This project is now officially DONE!

    Franc Robert
     
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