Harvard and Deluxe Builds - My first TDPRI Journal

Discussion in 'Shock Brother's DIY Amps' started by gabasa, Nov 27, 2020.

  1. gabasa

    gabasa Tele-Meister

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    Hey all, I've been working on these amps lately whenever I've got the time. I've read a number of times that 22awg wire is fine for everything and usually 20awg or 18awg is used for the heaters. I have a quick question about this though. Because the voltage rating for cloth wire is lower than PVC, is it ok to use 22awg cloth wire for the two wires that connect to the standby switch? Basically, rectifier tube to standby switch and standby switch to B+ connection on eyelet board.

    Thanks.
     
  2. David Barnett

    David Barnett Doctor of Teleocity Ad Free Member

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    That's what you'll find in an old Fender.

    But why would you need a Standby switch in a Harvard or a Deluxe?
     
  3. gabasa

    gabasa Tele-Meister

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    Because there's a labeled Standby hole in the chassis. Thanks for the info!
     
    Last edited: Dec 17, 2020
  4. Blue Bill

    Blue Bill Poster Extraordinaire Ad Free Member

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    Gabasa, I just found this thread, I'm enjoying the show. I agree with you: It's fun to spend a few extra bucks on cool caps. The money you save by building it yourself pays for hot-rod components. Those cabinets are sharp-looking, too.
     
  5. gabasa

    gabasa Tele-Meister

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    Thanks for that, I'm having a lot of fun here!

    I agree, spending extra on some components (and less on others) can make things really fun and give you something unique. I figure this 5E3 will cost me a grand less than a something like Clark, Milkman or Swart, even with the premium caps. No complaints!
     
    Last edited: Dec 17, 2020
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  6. Lowerleftcoast

    Lowerleftcoast Friend of Leo's

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    22 AWG can carry the current. Iirc, the cloth cover is rated for 300V. As pointed out Fender used cloth covered wire for that part of the circuit back in the day.

    Are you willing to be liable for the fire damage when the inspectors decide under-spec cloth covering was contributory to the fire?

    Use the *Standby* hole for a mute. Nobody will know but you. Hah!
     
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  7. gabasa

    gabasa Tele-Meister

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    This is where things get confusing. So many posts everywhere saying that 22 awg cloth wire is ok everywhere, even the heaters, but I get what you're saying.
    Do you really believe a fire hazard exists? I can swap it out with PVC wire if there's a genuine safety issue.
     
  8. Lowerleftcoast

    Lowerleftcoast Friend of Leo's

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    For such things I use the 22AWG 600v cut-off remnants from the PT.

    Any time electricity is used there are hazards. Cover your fannie.
     
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  9. gabasa

    gabasa Tele-Meister

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    Just to add to the confusion, there's actually no true voltage spec on Gavitt cloth wire, or any other cloth wire for that matter. Nobody would ever stamp an official safety certification on it. Gavitt's has an extra textile layer underneath the outer cloth layer, I don't know if this makes it able to handle more or not.

    You'd have to be willing to be liable for fire damage even if you use it at 50V. We should ban cloth!
     
  10. gabasa

    gabasa Tele-Meister

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    I will, and I appreciate your input. Looks like I have some rewiring to do in my 5E3, which is almost done.....
     
  11. gabasa

    gabasa Tele-Meister

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    I've put some thought into this. I'll make sure that everything in my current builds up to the B+ dropping resistor or choke is wired with the 600V offcuts from my PT, but going forward, I might spring for solid core copper/teflon wire. It would be cool to try one day.

    Hey, I thought I said I'm done building after these?!?
     
  12. gabasa

    gabasa Tele-Meister

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    Done! Amp is now safer than it was!
     
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  13. gabasa

    gabasa Tele-Meister

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    Amp #1, the 1x10 5E3 is done. It's not an exact 5E3 with the smaller speaker, choke and screen resistors, but man does it ever sound great. Everything works perfectly, it runs nice and quietly and the overall sound and feel is quite incredible. So rich, organic and oozing with harmonics. The balance from low to high is spot on and the grind is amazing. Love it! I'll post some sound samples in a little while, after I get the Harvard up and running.

    Blonde 5E3.jpg
     
  14. gabasa

    gabasa Tele-Meister

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    Under the hood, four out of five tubes are NOS.
     
    Last edited: Dec 19, 2020
  15. gabasa

    gabasa Tele-Meister

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    The 1X10 5E3 was done a few days ago (see pic above) and the Harvard is now up and running. I'm really loving the sound of both amps and appreciating the Harvard because I haven't heard that sound since I sold my Clark Webster so many years ago. I can post a pic, but it looks exactly like the 5E3 above, minus the logo. Some thoughts:
    • I was initially shocked at how different the 5F10 and 5E3 sound. After an hour of playing it, I'm appreciating those differences.
    • The Harvard's cleaner, fixed bias tone is a breath of fresh air when you're used to playing colorful sounding amps like a tweed Champ or Deluxe. It's a WYSIWYG kind of tone in the prettiest way imaginable.
    • The Harvard is not a substitute for a 5E3, but a complementary amp for a different kind of sound. I love how the basses aren't pumped, while the lack of cathode-biased compression gives it a nice openness.
    • It's dead quiet in operation, almost freaky how there's no amp noise or hum while playing.
    • I used an audio taper pot for the volume, because it's what I could get at the time. The taper may actually be too slow and linear is the way to go as per the schematic.
    • The big sound of the Jupiter 10LA seems to work well with this circuit.
    Great initial impressions, it's a fantastic little amp. I can't wait for COVID to be a thing of the past so that I can try gigging with it!
     
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  16. David Barnett

    David Barnett Doctor of Teleocity Ad Free Member

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    Are those Silmic II cathode bypass caps?
     
  17. gabasa

    gabasa Tele-Meister

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    Yes, nice catch, wow!
     
  18. gabasa

    gabasa Tele-Meister

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    Here's a pic of it. Done, minus the logo which is en route to my place.

    Harvard.jpg
     
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  19. David Barnett

    David Barnett Doctor of Teleocity Ad Free Member

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    Assembled gut shots please!
     
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  20. jmp81sc

    jmp81sc Tele-Meister

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    Fantastic looking amps! Now I'm thinking about Harvard's. I would also like to see the gut shots.
     
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