First build. 5E7 PRO.

Discussion in 'Shock Brother's DIY Amps' started by ginomolinari, Oct 28, 2019.

  1. King Fan

    King Fan Friend of Leo's

    Posts:
    4,745
    Joined:
    Jan 1, 2013
    Location:
    Salt Lake City
    Right, to be clearer, I 'train' them into a coil, sorta like this, only in a tweed chassis, bend them up and in more so they don’t extend beyond the board.

    [​IMG]




    Sent from my iPad using Tapatalk
     
    ginomolinari likes this.
  2. ginomolinari

    ginomolinari TDPRI Member

    Posts:
    45
    Joined:
    Aug 21, 2009
    Location:
    Perugia, Italy
    Thanks! Thats a cool trick.
    In regard to my previous statement about proceeding bottom to top I meant first tubes heater, then main board and then control panel. This way the heater wires are tucked away against the chassis. But i have also read that the classic look is with twisted pairs making a bridge above the tube sockets therefore should be done last.
     
  3. King Fan

    King Fan Friend of Leo's

    Posts:
    4,745
    Joined:
    Jan 1, 2013
    Location:
    Salt Lake City
    Both true. :) If under-the-lip, wire early. If flying, wire late.

    I saw a recent discussion thread here about which is 'better.' I've done both. Done right, both are about equally quiet and equally difficult to do. But for homebuilts, under-the-lip has the huge advantage it isn't in the way if you need to do anything from reflow a solder joint to replace a component to revise the board wiring.
     
    ginomolinari likes this.
  4. ginomolinari

    ginomolinari TDPRI Member

    Posts:
    45
    Joined:
    Aug 21, 2009
    Location:
    Perugia, Italy
    Ok then, under the lip it is. Better start wiring. thanks again for sharing.
     
  5. ginomolinari

    ginomolinari TDPRI Member

    Posts:
    45
    Joined:
    Aug 21, 2009
    Location:
    Perugia, Italy
    CHOKE ISSUES!

    Hi there. I have been away from posting but not inactive. The build keeps on going. After a trip to the US I have now some missing parts I needed and a new 20 awg hookup wire from Amplified Parts.
    Anyway, I am moving forward working on the chassis and realised the choke I ordered from Classic Tone doesn't fit on the Weber chassis holes. Well, suspicious, but an honest mistake easily fixable. But I felt it was better to investigate. Turns out, the 5E7 uses a different choke from all the other 6L6 tube amps, specifically a much bigger 200ma (thus the mismatching mounting holes) than the standard 90ma I have. Now I could place an order and pay a bunch of money to have the right choke shipped to me here in Italy but then I started reading more and going down the rabbit hole and there is an actual fix I have found discussed on TheGearPage Forum.
    Over there, Mark Norwine, talks about making a "blackface" mod by diverting the center tap of the output transformer from the screens of the power tubes to "the other side" of the choke. This would put the choke under much less current and the 90ma rating should be fine.
    So, considering that I have no idea what I am talking about, I took a standard 5E7 schematic and made the change the way I understood it. I hope someone here can confirm the mod or correct it.
    Any feedback is much appreciated. Have a lovely weekend and GO CHIEFS!




    5E7_choke.jpg
     
    Wally likes this.
  6. TobyZ28

    TobyZ28 Tele-Meister

    Posts:
    146
    Joined:
    Jan 19, 2020
    Location:
    Vancouver
    Nice Build! I just completed a 5E3 but got a "cheapo" kit from Hong Kong, this helped a tonne, but like you I had to source quite a few sub standard (or even missing) parts in some cases and have my own collection of extra bits n pieces ;). For the most part the kit did help as the chassis would have been a pain to do with limited workspace/tools. The cab is fantastic looking btw!

    Taking your time is a good thing if you have time! I took forever to build mine because i was double/triple/quadruple checking everything every step of the way, but because of this I somehow managed to fire it up the first try :D!
     
    lavrgs and ginomolinari like this.
  7. FenderLover

    FenderLover Poster Extraordinaire

    Posts:
    5,250
    Joined:
    Jun 11, 2009
    Location:
    Minnesota
    That connection will work. it's pretty much what they went to in the 6G7 Bandmaster. The 5E4/7/8 all used the CLC with the plates connected after the choke. The Twin changed in its next version (5F8) to what you show, and the Bandmaster and Super changed to it in 6G7/6G4 versions.
     
    Last edited: Feb 3, 2020
    Wally, King Fan and ginomolinari like this.
  8. ginomolinari

    ginomolinari TDPRI Member

    Posts:
    45
    Joined:
    Aug 21, 2009
    Location:
    Perugia, Italy
    Glad to hear that. I keep reading and watching videos and every time I learn how much I was ignorant. It is a fun process. A bit extenuating at time. I’m also going to build a light bulb testing device which is going to be a lot of “fun” since here in Italy there is no plug orientation. Wish me luck.
     
  9. ginomolinari

    ginomolinari TDPRI Member

    Posts:
    45
    Joined:
    Aug 21, 2009
    Location:
    Perugia, Italy
    Thank you! What is a CLC? Sorry, I’m ignorant! I guess I should check the 6g7 schematics as well.
    Thank you again!
     
    Wally likes this.
  10. FenderLover

    FenderLover Poster Extraordinaire

    Posts:
    5,250
    Joined:
    Jun 11, 2009
    Location:
    Minnesota
    That's the order of the capacitor/choke/capacitor components in the power supply filter
     
    ginomolinari and Wally like this.
  11. ginomolinari

    ginomolinari TDPRI Member

    Posts:
    45
    Joined:
    Aug 21, 2009
    Location:
    Perugia, Italy
    So that answer my other question. I should keep the choke between the first and second filter cap.
    Thank you.
     
  12. Lowerleftcoast

    Lowerleftcoast Tele-Holic

    Posts:
    538
    Joined:
    Dec 30, 2019
    Location:
    california
    Fun Fact:
    The symbol "L" for inductance and the symbol "H" (Henry) for the measurement of inductance comes from the name Heinrich Lenz. He was one of the pioneers working with coil/inductance back in the day.
     
    ginomolinari likes this.
  13. ginomolinari

    ginomolinari TDPRI Member

    Posts:
    45
    Joined:
    Aug 21, 2009
    Location:
    Perugia, Italy
    Good morning everyone, while I prepare to drill a couple of new holes on my chassis (one for the smaller choke and two for the bias regulation circuit) I'm still wiring up the control panel. First of all the question about ground. I have seen circuits where at least 3 distinct leads ground different pots. Then I've seen builts with a common ground bus. So I've got inspired by both. Specially because there was no way to make anything stick on that presence pot.
    Second question is about the two caps in the tone stack. Has anybody seen this configuration?
    Thank you.
    5E7_019.jpg 5E7_020.jpg 5E7_021.jpg
     
  14. ginomolinari

    ginomolinari TDPRI Member

    Posts:
    45
    Joined:
    Aug 21, 2009
    Location:
    Perugia, Italy
    So, it was a beautiful day here in Italy and I decided to take the workshop outside and do some of the carpentry work that needed to be done. I love working with wood but is a messy process I was waiting for warmer days to do it.
    First thing was to enlarge the controls opening to fit the 5E7 chassis. I have used this cabinet before for other amplifiers thus the random mounting holes.
    then it was time to build and glue the shoulders that would hold the back panel. And finally i cut and shaped the back panel. Still need to white stain it and shellac it.
    Overall a good sunday. Hope it was a good sunday for ya’ll as well. 3C0042F5-13DE-41E7-B797-5A1820393F02.jpeg E60A3D29-F81A-4FB2-955C-268150802ABE.jpeg 71BE8D5B-4B94-4BA6-A523-C029C4594C90.jpeg
     
    King Fan likes this.
  15. BobSmith

    BobSmith Tele-Meister

    Posts:
    227
    Joined:
    Feb 12, 2018
    Location:
    San Jose,CA
    Weber layout uses a brass bus plate like you have, you may want to checkout their design. Personally, I prefer not to ground to pots anymore, or use a plate like Weber (seems like they are creating multiple paths to ground) but rather a bus bar (various ways to do this). Just a matter of taste or preference, good builds both ways.

    You may want to scratch up the surface of the prescence pot, apply a lot of flux and heat and it will flow. The other pots you have done already could probably benefit from more solder too. One of the advantages to the back of the pot bus bar scheme is mechanical strength to keep knobs from coming loose. I would beef those up.

    Also, there seems to be a crowded area where the 2 caps and resistor are. These are weak leads and easy to accidentally bend into something else and short (another component or the chassis). You may want to consider making an insulating jacket with a piece of stripped wire insulation cut to length. You can even do it in cloth if you want to keep a vintage vibe.
     
    ginomolinari likes this.
  16. ginomolinari

    ginomolinari TDPRI Member

    Posts:
    45
    Joined:
    Aug 21, 2009
    Location:
    Perugia, Italy
    Thank you BobSmith! I appreciate your suggestions and will implement them for sure. My sense of aesthetics has no electronics/mechanical basis so what I think it looks “pretty” is not necessarily tube amp savvy.
    Digging trough old posts and scavenging for other more experienced builders is always a good investment of my time. thanks again.
     
  17. ginomolinari

    ginomolinari TDPRI Member

    Posts:
    45
    Joined:
    Aug 21, 2009
    Location:
    Perugia, Italy
    This morning I installed the transformers and the choke. As you can see I am sticking with the smaller choke therefore will have to modify the circuit to later version Bandmaster. Help me God.


    5E7_022.jpg

    I have looked around and studied my options and looks like the OT should be mounted with the secondary on the tube sockets side. Am I correct? At that point the choke wires should go through the same grommet (tube socket side) instead of the closer one (control side). What's the right choice?
    5E7_024.jpg

    Finally just a note about some weirdness with the power tranformer. Magnetic Components is quite cheaper than Mercury Magnetics but is popular among builders. Everything looks well built and oversized but a tad sloppy with goop/varnish a bit everywhere. But that's just a optical issue. I did notice though that all mounting screws and nuts have a plastic grommet/washer besides one that had 2 metal washers. It is on the chassis side so I thought it was for grounding. Am I right?


    5E7_025.jpg

    That's it for today. Back to job-job and more coffee. Thank you for watching.
     
  18. Lowerleftcoast

    Lowerleftcoast Tele-Holic

    Posts:
    538
    Joined:
    Dec 30, 2019
    Location:
    california
    I would try to keep the run to the tube sockets as short as possible. (Brown and Blue wires).
    Traditionally the brn, blu, red, and choke wires run through same grommet.
    Yes. The transformer mount to the chassis is a common place to ground the "power side" of the amp.

    Point of information: The power cord ground should have a separate bolt to the chassis dedicated only to the power cord. As per IEC/NEC electrical code. (The old amps did not do this).
     
    BobSmith and ginomolinari like this.
  19. ginomolinari

    ginomolinari TDPRI Member

    Posts:
    45
    Joined:
    Aug 21, 2009
    Location:
    Perugia, Italy
    Thank you! Yes, the chassis has a bolt for grounding. Good to know. I’ll reserve that for the power cord. Should i use the transformer bolt for all other grounding then?
     
  20. Lowerleftcoast

    Lowerleftcoast Tele-Holic

    Posts:
    538
    Joined:
    Dec 30, 2019
    Location:
    california
    I usually ground the filter caps, for the 5e7 all but the one that supplies the first two 12a_7s, on the power side of the chassis. The center taps for power and heaters. The bias supply as well. The preamp side, I ground towards the input section. (You already have a ground scheme on that side.)
     
    ginomolinari and Mr Ridesglide like this.
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.


  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.