Modified Blues Jr?

Discussion in 'Amps and Cabs' started by MaxBoogie, Jan 14, 2008.

  1. MaxBoogie

    MaxBoogie Member

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    I just acquired a Tweed Blues Junior.... Not bad, but it's a little flabby and breaks up sooner than I want, and breaks up MORE than I want....

    I know there's a lot of people who can mod these little amps so I'm looking for someone with experience and recommendations. There's the "BillM" mods, and Torres has a p2p upgrade as well... Any other builders out there who want to bother with that little amp?
     
  2. Guitar Josh

    Guitar Josh Resident Curmudgeon Silver Supporting Member

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    Max, do yourself a favor and do the "easy" mods first.

    I swapped out my speaker with a Weber Blue Dog and upgraded the tubes to JJs and installed a beam blocker. Sounds like a completely different amp, about $100 invested and everything is 100% reverseable.
     
  3. MaxBoogie

    MaxBoogie Member

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    Yeah, I just read the complete Torres mod for this http://www.torresengineering.com/bluesjrbouta.html and it's $700!!!! Granted they swap out about everything there is and it all sounds great, but I just traded my unused POD XT Live for this so I'm not inclined to put in double what this amp's worth now! I might as well sell this now, and put the $$$ toward a nice boutique 5E3 amp for that money.

    I do have an old JBL D120 coming this week, so as you said, that's a cheap mod that I can do first! Also, I'll swap out the 12AX7 for a 12AT7 in the phase inverter to help clean it up a bit...

    All that being said, if I find someone who can tweak it nicely for a LOT less than a Torres tweak, I might consider it, assuming I still want MORE... :D
     
  4. teleamp

    teleamp Senior Member

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    s2 amps can almost turn it into whatever you want. I suggest having it converted to the Matchless Spitfire circuit, I think that would fit your needs.

    MikeY
     
  5. arfalax

    arfalax Member

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    s2amps.com in Texas has Blues Junior amp conversions that look interesting.

    edit: Well, looks like teleamp had the same idea about 60 seconds before I did.
     
  6. pickaguitar

    pickaguitar 2011 TGP Silver Medalist Silver Supporting Member

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    S2 can do the mods and/or transform it into a boutique amp...matchless, marshall, fender, etc.

    [​IMG]
     
  7. Lizard Leg

    Lizard Leg Member

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    I have a highly modded BJr and love it - simplest mods for less breakup IMHO would be to swap the speaker for a higher wattage and to change V1 to a 5751.
     
  8. hardys

    hardys Member

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    A more efficient speaker with less breakup will generally allow more clean headroom than a higher wattage one. High watts don't always mean less breakup.
     
  9. Lizard Leg

    Lizard Leg Member

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    I stand corrected - trying to do 10 things at once again.
     
  10. MaxBoogie

    MaxBoogie Member

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    Lizard - How "highly" is yours modded? What did you do/have done?
    Mike - Just curious why you suggested the Spitfire circuit?

    I see that S2 says I lose the reverb circuit because it's a solid state circuit... But I see that Torres gets around that by installing a new tube for the reverb. If they can do it, I bet S2 could do that as well... :)
     
  11. Lizard Leg

    Lizard Leg Member

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    new tone caps, modified tone control circuit, doubled the power stiffening caps, rebuilt into a head unit, weeks spent finding the right tubes for "me" and am in the process of adding a "lead" switch for lack of a better term that drops the entire tone stack out of the signal path as well as adding in an effects loop (hopefully). Mine sounds more like a Ghia then it does a BJr now.

    I've benn working on this thing off and on for a year or so and haven't done anythign with it in a few weeks now - too busy.

    All of the mods I did or variations of them can be found online. Most of them are very easy to do and only cost a few $. With all of the stuff I've done playing around with the BJr, I still say the biggest difference was in changing the tubes and speaker by running it through a 112 cab instead of the combo. Doubling up the power stiffening caps seemed to "tighten" the amp up as well.
     
  12. teleamp

    teleamp Senior Member

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    The Spitfire circuit sounds great, georgous cleans and the OD isn't over the top. You cou PM him, his TGP member id is s2amps, and tell him what you are looking for.

    You ever notice that Matchless Spitfires rarely hit the used market, that speaks to how good they are. Same with the original Lightnings and Bad Cat Cubs.

    As far as Torres goes, read ALL the reviews you can find on the internet.



    MikeY
     
  13. Steve Dallas

    Steve Dallas Supporting Member

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    Thanks for the recommendations, guys! I'll go my best to answer a couple of questions without running afoul of the rules...

    It is technically possible to keep the reverb if:

    1. There are 1.5 preamp tubes available after the rebuild
    2. You don't mind paying for a new tank to correct the Z mismatch
    3. I add a separate filament transformer

    Though I've never found any published information on the BJ power transformer, I've deduced it puts out about 2.5A filament current by increasing the load and measuring the voltage drop. With the complement of tubes it already has, the amp draws (.8 + .8 + .3 + .3 + .3) 2.5A filament current, meaning the transformer has zero headroom to support another tube or channel switching relay or anything else. So you either have to upgrade to a MM power transformer or you have to add another filament transformer.

    Then you have to consider the original SS verb uses a tank with a high Z input. Fender style tube reverb has a low Z (8-10 Ohms) input, so a new tank is required. I think a standard tank will fit the BJ chassis if you cut the ears off.

    We also have to look at space on the boards, space in the chassis, and some other stuff.

    At the end of the day, it adds about $200 to the price of the conversion after the parts, labor, and inbound FOB are added up. So leaving it out has a lot to do with the cost/perceived value proposition.

    Most of the target circuits I build never came with reverb to begin with, so it doesn't make sense to try to add it. Only the black face one does, so that is the only one missing out. Once I explain the added cost and complexity to prospective customers, they tend to decide against it.

    What I would rather do is put in an effects loop for a reverb pedal or rack processor. Or since none of these are really high gain designs, a pedal in front of the amp works almost as well.

    HTH,

    s2
     
  14. MaxBoogie

    MaxBoogie Member

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    Well, I just sent you a lengthy PM before seeing your reply here. I hear you about the associated costs with keeping reverb in there using a REAL reverb circuit... I guess that's why the Torres mod costs so much! I'm not against changing a transformer, as there'd likely be additional benefits from that as well.

    I'll wait for you to wade through my PM... :)
     
  15. The Smith

    The Smith Supporting Member

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    I did the mods a bit at a time, over the course of a year as follows:

    1. JJ Power tubes and EH AX7s. Noticed big difference.

    2. Crex speaker. A lot of the shrillness went away.

    3. 2X12 Avatar cab with 2 Crexes. Very open and big sounding.

    4. Billm tonestack mod and adjustable bias. Playing sounds much more "percussive", with tight bass response. Honestly, I thought the Billm mods would turn out to be mostly hype. I was wrong; even my wife immediately noticed the difference.

    5. Billm also mentions rebending the ribbon cable from V3 so that it touches the shielding on the backside of the amp. I assumed I had a microphonic tube that needed replacing, but when I did this "mod" the microphonic sound went away.


    I always play through the amp clean (Master wide open, Volume on 2 1/2 - 3), and mike-up. I still don't like the tone of the amp's overdriven sound, so I use pedals for dirt. I'm very satisfied with my sound, and plan on doing the power stiffening next.
     
  16. The Smith

    The Smith Supporting Member

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    I'd love to see a pic of that! I've googled Blues Jr. heads before, to no avail.
     
  17. Lizard Leg

    Lizard Leg Member

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    The cabinet is over at my uncle's house (he's got a phenomenal wood working shop) waiting on me to get a free weekend to go over and redo one last section. The tolex came in last week. The problem is I don't have a free weekend to go over until at least the end of Feb.!!!
     

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