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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 thought I'd document a build here. I've built amps but never posted things online before.
    I'm enjoying the forum so much I thought I'd join in on the fun!

    I've sourced almost all the parts I need for both amps and should start rolling my sleeves up one day next week. Going to be using the following this time around:
    • Victoria transformers and blemished chassis
    • Miflex capacitors
    • PRP 1W resistors
    • Jupiter alnico 10" speakers in both amps
    This is a mix/recipe of parts that I'm really loving in my Champ. I find it exceptionally musical (to my tastes), rich, detailed and quiet so I thought I'd replicate the choice of components in these two builds.

    Miflex Caps.jpg
     
    Last edited: Nov 27, 2020
  2. gabasa

    gabasa Tele-Meister

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    Here's the last amp I built, my 1x12 Champ. It originally had Jupiter Yellows caps, which I liked, but I wanted copper foils in it because of my memories of an old Clark 1x12 Champ I used to own and love. I missed that amp and wanted one at least as good.

    Champ.jpg

    New Caps.jpg
     
    Last edited: Nov 27, 2020
  3. gabasa

    gabasa Tele-Meister

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    I'm definitely going to install a choke and 470r screen resistors in the 5E3, replacing the 5K resistor in the power supply.

    This brings me to my first question here. If I do the same thing in the Harvard, the choke will replace a 470r resistor. A 3H choke with a 60Hz power supply has an inductive reactance of about 1.1k, plus the resistance of the coil itself. So the impedance at that point of the circuit will go from 470r to over 1.1k.

    Do you see any issues with that? I actually think it might be good for the amp and the sound coming out of it. Thanks.
     
  4. Nickfl

    Nickfl Friend of Leo's

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    When I saw the words "Audio Capacitor" printed on those I knew they were going to be $$$, but I just looked them up and holy ****... :eek:

    Pretty sure I've built amps where the cost of every capacitor combined was less than one of those, definitely less than two... They are pretty though!
     
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  5. gabasa

    gabasa Tele-Meister

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    The Jupiter Red Astrons that a lot of people use are $11.50 at PartsConnexion for a single 0.02 cap. These copper foils are $12.83, so $1.33 per cap more than what a lot of builds use.

    The way I look at it, it's $2.66 more for a Champ vs the Red Astrons.
     
    Last edited: Nov 27, 2020
  6. rjtwangs

    rjtwangs Tele-Afflicted Silver Supporter

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    My Clark Webster/Harvard....
    20190322_141352.jpg It has a 1961 Jensen P10Q with the original cone in it and it sounds wonderful!! Good luck with your builds. I'm wondering why you're going to put a 10 inch speaker in your 5e3 and not a 12 inch speaker? Not a criticism just curious. I'll be watching, your thread sounds really cool....


    RJ
     
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  7. jsnwhite619

    jsnwhite619 Friend of Leo's

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    I normally use a 1k there in place of a 470R. It usually ends up closer to the published voltage drop that way. 470R only drops a couple volts if I remember correctly. Maybe because of the higher levels I'm starting with? Not sure.
     
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  8. gabasa

    gabasa Tele-Meister

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    That's a nice looking Clark amp! I had a Webster years ago, when they first came out. It had a Weber alnico speaker and I really, really enjoyed it.

    I have two 10" Jupiter alnico speakers collecting dust in storage, so I told myself I'd build an amp around each one. The Harvard was an easy decision, but I thought that a more compact, portable 5E3 could be really usable for band rehearsals and gigs. To be honest, I like Jupiter's 10" alnico more than most 12" speakers, so why not? It's fuller than any 12" I've ever played with a small magnet, like a 12A125, so I'm crossing my fingers it'll turn out.
     
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  9. gabasa

    gabasa Tele-Meister

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    Exactly my thinking, thanks.
    Speaking of 470r... did you happen to install screen resistors in yours?
     
  10. gabasa

    gabasa Tele-Meister

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    Now I'm really curious, since there's been so much talk about B+ in the other Harvard thread. Have you ever measured it on the Webster? I wonder where Mike Clark decided to zero it in, it's a great sounding amp.
     
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  11. gabasa

    gabasa Tele-Meister

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    These are the transformers.

    Is there anything to be gained by using Classictones or Hammonds? Are they better built in any way? I actually think I might have some lying around from 15 or 20 years ago, not sure. If I can find them maybe I could use them instead, not sure.

    Iron.jpg
     
    Last edited: Nov 28, 2020
  12. Nickfl

    Nickfl Friend of Leo's

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    Those Jupiter caps (along with sozo etc) qualify as :eek: in my book too...

    Sounds like you found a pretty good price though. When I googled them earlier, the first place I saw them had the 0.022 for about $18 I think.

    Either way, I bet I could cap an entire 5e3 for less than that if I used the generic mallory style poly caps and radial electrolytics.

    FWIW, I'm not trying to give you a hard time here, I agree that these are definitely cooler than the Jupiters and while I am way too cheap to spend that much on caps for a guitar amp, I've spent just as much on caps that ended up in Hi-fi speaker crossovers so I can't judge.
     
    Last edited: Nov 28, 2020
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  13. Nickfl

    Nickfl Friend of Leo's

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    IMO, no. Hammond and classic tone aren't any better made or sounding than the better quality asian made transformers from what I've seen. Edcor are nicer looking if you want a US made transformer that stands out.
     
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  14. gabasa

    gabasa Tele-Meister

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    Ok, thanks for the info, I appreciate it.
     
  15. gabasa

    gabasa Tele-Meister

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    Little update ... I've been listening to Steve Cropper all night, I can't help it.

    I still have to tidy it up and double/triple/quadruple check everything, but the Harvard board is together. I thought I'd post a pic. Some resistors are behind those massive caps, you can't see them, but they're there. There's one resistor missing, which is where the choke will hook up. Other than that, I wish that the one electrolytic on the left side of the board had longer leads; I had to put extensions on it. Still though, doesn't look too bad.

    I'm going to try to start the 5E3 now, my cabinet maker said that the cabs should be done mid week. I'm crossing my fingers that the two amps turn out without any issues.

    5F10 Board.jpg
     
  16. jsnwhite619

    jsnwhite619 Friend of Leo's

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    I have to ask -- what is the reason for using sticks of dynamite for coupling caps?
     
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  17. gabasa

    gabasa Tele-Meister

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    I love copper foil caps, ever since I used to play Clark amps. I did a handful of amp builds about 15 years ago with the same Jensen caps that Clark used to use in the past and remember them fondly. Jensen Capacitors has gone out of business and their products aren't available anymore, while these are the most reasonably priced, good alternatives.

    One of the best sounding amps I've ever played (to my tastes) has been my 1x12 Champ, which has these caps. I'm mimicking the component choices in that amp to see how they fare here.

    I only paid 5 or 6 dollars more for the four caps in total than I would have for Red Astrons; I felt it was worth the upgrade.
     
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  18. jsnwhite619

    jsnwhite619 Friend of Leo's

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    So, that's $100+ worth of capacitors on that board?
     
  19. gabasa

    gabasa Tele-Meister

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    Nope, cheaper than a lot of builds you'd find online.
    • With Jupiter Reds and Sprague Atoms, the cap cost would have been $76.06
    • With these copper foils, F&T filter caps and the two small electrolytics: $71.62
    Actually, if you take into account the cost of generic carbon comps for the 1/2 watt resistors in addition to the caps:
    • Jupiter Reds, Sprague Atoms, generic carbon comps: $96.86
    • Those caps and resistors on my board: $80.07
     
    Last edited: Dec 6, 2020
  20. gabasa

    gabasa Tele-Meister

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    The L-brackets I've used in my last few builds for the third chassis bolt on the PT (these ones) don't seem to fit perfectly.
    Looks like I'll be off to one of my friend's machine shops this week to mill it to fit.

    Just wondering what brackets you may have found that do this job well.
     
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