Anybody have instructions for Bill M mods?

Discussion in 'Glowing Bottle Tube Amp Forum' started by chronax, Jun 21, 2019.

  1. chronax

    chronax TDPRI Member

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    Hi TDPRI,

    Long time no see. Missed you all. <3

    Anybody have a bill of materials (no pun intended) and/or directions for installing Bill M mods on a Blues Jr III? It looks like his store is still open, but sadly not shipping. Last I heard, his son was running things but it looks like that's not the case.

    I know I could buy the Fromel mods, but I've already started buying parts here and there and I don't need their complete kit. I _do_ love Fromel though, have bought other stuff from them in the past.

    Would really be great if I could just get the rest of what I need together from Mouser and get some directions to install everything. I have no idea how to even wire in the Switchcraft jack -- let alone the bias trim pot or new caps and resistors.

    Any info or advice would be super appreciated. I've Googled, searched this forum and gone pretty deep on other forums but haven't been able to find any complete information.
     
  2. lowatter

    lowatter TDPRI Member

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    If I'm not mistaken Bill M passed a few years ago but there should be plenty of info on the Blues Jr mods out there. Mouser is WAY too huge and tedious for me to navigate but you could try Hoffman Amps for most any parts for the mods. They have a great schematic library there too.
    https://hoffmanamps.com/
     
    Last edited: Jun 21, 2019
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  3. Bill Moore

    Bill Moore Tele-Afflicted Silver Supporter

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    I worked on one a while back that had the mods, different cap values for tone caps, larger OT, added filtering on the first filter cap. This one also had an added adjustment for bias.

    Here's the jack wiring, the hole is big enough to use isolation washers.

    Original Fender pin #
    1= shield, center/sleeve on Switchcraft,
    2=signal/tip
    5=shorting switch
     
  4. tarheelbob

    tarheelbob Tele-Meister Platinum Supporter

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    I have BillM Blues Junior III mod directions for:

    Presence Control installation
    Compact OT (ie. T020) installation
    Bias Control (bias trimpot)
    Tone Stack Stiffening (tone stack mod, Twin Stack, and coupling cap install)

    Message me offline if any of these would help.

    - Bob
     
  5. chronax

    chronax TDPRI Member

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    Thank you so much, Bob! I sent you a message (I think). Would love the last two on your list.

    Thank you Bill! It's crazy that you replied to my thread, because one of those I found in my search was from you on another forum!

    Despite your help and the photo in the other thread - I'm still lost. I think the original plastic jack has four solder points on the board, right?

    The new Switchcraft Jack has three. Do I wire those three as you suggested, and omit the fourth?

    Bill M's original kit includes a "Mogami low-noise coaxial cable." Do I need this? Can I just use something like 20 or 18 gauge jumper wire?

    Thanks again for any info - I'm a total newb, despite having an undergrad in computer science.
     
  6. middy

    middy Friend of Leo's

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    My favorite Blues Jr mod was trading it for an AC15 :D
     
  7. TequilaCaster

    TequilaCaster Tele-Holic

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    New Updated BillM mods.... IMHO.

    1. Save your money. Mods ain't gonna make your BJ any better than what it is.
    2. Sell your unmodded BJ.
    3. Use your saved $ and proceeds from sale of BJ to buy a better amp, such as a Princeton Reverb or Deluxe Reverb.
    4. Get on with your musical life.
     
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  8. chronax

    chronax TDPRI Member

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    I don't disagree with you, but the point of this project is to have a little fun upgrading a small boxy tube amp.

    Plus, I've followed Bill M's site and projects for years and it feels apropos to honor his legendary work after he passed. He used to chime in with help around here all the time and I've always wanted to do his mods. They're almost folklore at this point.
     
  9. TequilaCaster

    TequilaCaster Tele-Holic

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    I agree that modding amps is fun and educational. I learned from modding my friend's BJ. The tonestack mod and the speaker mod gives the most bang for the effort. It sounded a little better, but it did not change a frog into a prince(ton). It always had a boxy, constricted sound. The cabinet is just too small. All IMHO, of course. It's really a 10" speaker sized cab.
     
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  10. tubelectron

    tubelectron Tele-Meister

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    I'd like to find a BJ in good cosmetic condition for cheap and non working, to rip its guts and built mine instead...

    But it's me, OK ? :D

    A+!
     
  11. jimgchord

    jimgchord Tele-Holic

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    This is good advice, you should take it.
     
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  12. macatt

    macatt Tele-Holic

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    In my experience, a modded Blues Jr was way better than a Princeton in these ways:
    Louder, cleaner with more headroom, plus it has the versatility of a master volume.
    I've been playing through a Blues Jr for years with the octal mod with 6V6 power tubes in a loud band.
    It's very good.
    I played through another one for 15 years with the standard mods and a 300 Watt EVM12L speaker. It did a better job than not only a Princeton, but a Deluxe Reverb re-issue.
    No boxy sound at all. Billm did the mods himself.

    S Mac
     
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  13. FenderGuy53

    FenderGuy53 Poster Extraordinaire

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  14. Uncle Daddy

    Uncle Daddy Tele-Holic

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    Better still, build one.

    P1120663.JPG
     
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  15. ppg677

    ppg677 Tele-Meister

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    I got a billm kit shipped to me about 10 months ago.

    It definitely improved the amp. Particularly the reverb modification on the original blues jr.
     
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  16. Bill Moore

    Bill Moore Tele-Afflicted Silver Supporter

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    The one I picked up sounded a lot larger than it looks! Had a lot more bottom than I would have thought possible from it's size. I installed a C12N it, and it seemed to be a good match, I don't think much of the cheesy dots!

    Just wire the jack as I noted, all will be fine!
     
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  17. tarheelbob

    tarheelbob Tele-Meister Platinum Supporter

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    Good luck! Modding them, learning, developing new skills and a better understanding is half the journey. It's worth the investment. Whether you end up with the proverbial Princeton down the road (like I did, and others have mentioned), I truly enjoyed the process and the result.

    - Bob
     
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  18. jrblue

    jrblue Tele-Afflicted

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    Speaking from actual experience -- though modding a PJ rather than a BJ (I much prefer the PJ) -- I can say that some of the Fromel; and BillM mods can make a vast difference in that amp and are well worth doing if you know how to work on an amp safely. I was able to get exactly what I want out of the amp, and get compliments on its distinctive, great sound all the time. Te mods are everywhere on the web, and I did those that tamed the fizzy top end, cleaned up the sound overall, tightened and deepened the bass, and added lots of headroom. I won't go through the exact list here, but I tuned it in stages and it's phenomenal now. People who play through it, including a very expert amp expert here, think it's a great amp, so it's not just me. But would this approach work for you? Better check in advance, as people like all kinds of different amps, and you could do all these mods, end up with a really fine result, and still not like it. BTW, I found the PJ to be super easy to work on, and in real life it bridges studio and gig use in a way better than a BJ.
     
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