Saturday, 5 May 2012

Keeley Java Boost

Info from Keeley Electronics:

The Java Boost is a germanium based Treble Booster designed to give you classic tones from the 60's and 70's. It is not a clean boost.

It must be used with a cranked amp that is overdriven or distorting a bit already. Cranking the amp and pedal will result in more creamy, beautiful, sustaining distortion with the Java Boost.

The Java Boost is most widely used with a tube amp set to a bit of overdrive or clipping which is the key to getting a great sound from this pedal. Setting the java boost in front of a very clean amp with the volume on 1-2 will surely result in a fairly weak guitar tone! Set the amp for some breakup, then click the Java on. There, you'll have a fantastic sound and see why people rave about the Java Boost.

Features

    * Modern Dallas Rangemaster Circuit
    * 3 way Switched Treble-Booster - Locking 3 way switch so your setting is not moved.
    * Stock Vintage Rangemaster (Center), Mid-boost (Right), and Full Range (Left)
    * Metal film parts for low noise
    * The ULTRA RARE MULLARD OC44 !!!!!!!!!!!!!!!!

The Java Boost is not related to the TS9 or Blues Driver, or any other distortion or overdrive pedal. Boss and Ibanez do not make anything like it!

This product is a Treble Booster by design, not a typical overdrive or distortion pedal. That means, the higher the note played, the more it gets amplified and then, by your amp, distorted. Bass notes get cut in two modes on the Java Boost!

Some people don't have experience with treble boosters. This can make using the Java Boost difficult if you try to use it with a huge power amp that has tons of headroom or doesn't distort easily. The trick to get the Java Boost to outperform any other pedal is to have the right amp settings. The amp should be on the verge of breakup or greater. This is where the wealth of tone will is possible.

Another way to run it is before an overdrive pedal. This is the pedal to get if you want a two pedal overdrive setup. Couple this in front of a TS9 or BD-2 and the results are simply amazing. This will add sparkle and life to your solos like no other pedal can.

So what if your amp is set to super clean?!?! No problem, I've found that I love the Java Boost in front of most other overdrive pedals! Yes, simply use the Java in front of your blues driver, TS, DS, BD, SD, FF type pedal and you get similar results when the standard overdrive pedal is on.







56 comments:

  1. Hi.! Why there is a special output for the led.. I also notice that in a skreddy layout..

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    1. I will add a current limiting resistor for the LED if there is room in a layout, just to save everyone from having to mess around putting the resistor somewhere offboard which can be awkward sometimes (and never looks good IMO to have a wire tack soldered to a resistor floating around somewhere in the box). If you prefer it offboard, or don't use and LED then you can omit the wire and the resistor from the board.

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    2. Thank you very much.! You could add also something like this. http://www.muzique.com/lab/led.htm. What's is your opinion?

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    3. I've never had popping from LEDs to be honest with you, but it should be easy enough to add if it's caused a problem for you.

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    4. Thanks IvIark.. You are the best!!

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  2. Can this be daisy chained? All this pnp/npn still confuses me...

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    1. Yes it can.

      Can't see any reason why not. It's just the way PNP transistors are used in the design.. For example, Fuzz Factory accepts negative negative tip DC, while there is classic fuzz face transistors in it.

      PNP and NPN work in different ways - the current flow is reversed. I found a bit confusing article: http://www.satcure-focus.com/tutor/page4.htm

      Anyway. If you're not interested in the physics of PNP/NPN, you can safely daisy chain every circuit/layout that says 9V. If it says -9V, then you're going to need a pump...
      +m

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    2. Ok, cheers Mirosol.. quite fancy building this. Just need to find some OC44's now ;o)

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    3. On the datasheet those are rated at 100hfe, so i guess you'll be fine with this: http://www.musikding.de/Active-parts/Transistors/Germanium/AC122-PNP/AC122-hFE%3D100-110::547.html

      ..Or anything similar.
      +m

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    4. Cool.

      What about these? ...

      http://www.ebay.co.uk/itm/350186067093?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649#ht_1549wt_954

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    5. So, I thought that this was a positive ground circuit, like most (all?) Rangemaster circuit that use a PNP device. This is negative ground?

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    6. Yes it's negative ground. It uses PNP transistor but in the reverse of how they would be used in a positive ground circuit, so the emitter where you would expect the collector to be, and obviously vice versa.

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  3. Hmm. Very cheap and nice lot. I think i'm going to get these too. :)

    But for this design... Don't know. It says: "h(fe) Min. SS Current gain.=40" - Guess that this means that the ones in this lot are anything between 40 and 100 hfe. I don't know what is used in the original, so i think someone should try it out :)

    Could work just perfectly with lower hfe's. If i was building this, i would probably try those, AC122s with hfe=100 and probably even some russian MP41s (which are way cheaper)..

    And note that you can't measure germanium transistors for hfe with your multimeter in same way you measure silicon transistors. There is always leakage that shows up as very high hfe values. This article applies: http://www.geofex.com/Article_Folders/ffselect.htm

    If you come up with a butter zone hfe for this particular boost, let us know :)
    +m

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    1. I will do, I'll get them anyway just to experiment.. and I'll get a few at a 100 hfe so I can compare.. might be a while but I'll update

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    2. No luck Mirosol... I get a constant whine that gets louder/quieter when adjusting the trimpots. With both knobs at max I get unity with a VERY mild, harsh, un natural sounding break up and the bottom two switch positions sound identical. The top position gives a substantial boost but still sounds un natural.

      Note; I did test it with 5 different AC128's.... win some, lose some ;o)

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    3. Hmm. Did you twist the legs? Pinout in the layout is B-E-C, while AC128 (at least the ones from musikding) are E-B-C, emitter being the one with the lid.

      I finished Hornby Skewes boost today, and your symptoms sound a lot like mine with that. Once i noticed the pinout, it started to work right.

      And i think you shouldn't worry about having AC128s in stock :) Those are good transistors, and you can build yourself FF or Rangemaster or any other classic with those.
      +m

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    4. yep, twisted the legs to match the pinout, It almost sounds like a grounding issue but I've been over it many times and re soldered all points etc.

      Some just aren't meant to be I suppose.

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    5. I hear you. I've been there too. It's a bit frustrating when everything seems to be in order, but it just won't work. In a few of my problem cases it has been something really stupid that i've missed, but some cases just won't solve.

      This is relatively small and simple board, so how about a rebuild? And if Mark has time he could check the layout over just to be sure... Although his layouts are the greatest thing since man invented wheel, he's only human too :) I could try to check the schematic against the layout, if today is not that busy at work..
      +m

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    6. Yes I will probably have another go in a few days... I think Mark said he found another scheme that did things slightly differently so he's looking into it. I'm going to do a BOSS SD1 in the meantime, I read that Pepper Keenan used it to boost his amp on the Nola album.

      And yes Marks layouts are THE best! I owe him so many pints ;o)

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    7. This is the schematic I did it from:

      http://i76.photobucket.com/albums/j6/IvIark_2006/Layouts/Schematics/Java-Boost-Schematic.jpg

      But the other one I found uses the 100K trimmer between base and ground (with a 220K resistor from base to 9V) not base to 9V with a 470K to ground like with this schematic, so I'm really not sure which is correct.

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    8. I'll leave this one then Mark... thanks anyway ;o)

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    9. I think Torchy has a verified layout, so I'll see if I can dig it out to see which schematic he used. That will at least give us a better idea.

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  4. Is this fully working layout now ?

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    1. Someone on another forum verified it

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  5. anyone legitimatee verify this? this is the 2nd simple circuit i've built that hasnt worked and has been 'verified by someone on another forum'... no offense to you at all mark. This is such a simple circuit. I know everything is correct and working (even measured capacitors!)... only thing i can think of is maybe i killed a transistor in the process of powering it up. doubtful

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  6. i suppose the trim pots could also be causing this not to work- but ive tried adjusting them and one just makes the hiss louder. the tone control does make the hiss higher pitched, but it seems my volume control is not making the hiss louder

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  7. This is where I got the verification from. He said it was working fine and was just asking for advice on biasing it correctly:

    http://forum.musikding.de/vb/showthread.php?32089-Keeley-Java-Boost-Bias-einstellen

    Like you said it's a pretty simple circuit so if it's not working there's a good chance you have a faulty component somewhere in the build. Measure the voltages at the transistor pins and see if that offers any clues.

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  8. The trimmers are just for biasing the transistor, correct? So if I already know the values needed to bias my oc44, I can save a little space and omit the trimmers?

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  9. I've built this layout twice, now. Both builds have VERY low output signal.. Tried an oc 44 and an af105, both biased to 7 volts. I don't get it.....

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  10. I feel like an idiot. I thought it was a positive ground circuit. Working now. Sounds great. Thanks for another great layout.

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  11. I have actually some issues with mine, is it normal to notice current between B/e b/c c/e ? And R=0 between all the pins?
    I had sound, and then I changed the jack (without removing the Mullard OC44)
    Can it be burned out?
    I've tried then with an AC122 and I didn't get any sound anymore.

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    1. I've rebuilt for the third time the layout, and it works, but it has a really low sound, and it sound only when the level pot is at its maximum..
      So I think i've made a mistake at this level..

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  12. Make sure you have negative ground power supply. Mine did the same thing, until i figured out that this is, unlike other rangemaster circuits, negative ground.

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    1. I used a classic 9v battery

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    2. @ch1naski thanks for your help, actually, I think the layout is ok, because i've done it three times...Maybe I'm really stupid (I can esaily assume that) , does it need Ac Power supply instead Dc power supply? And is there a trick for using a classic 9v battery on it?

      Kind Regards
      David

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    3. A battery is fine. What I meant was, did you wire the battery for PNP or NPN transistor? you have red lead from battery going to 9v on the board? And you've checked the pinouts on the transistors? because the layout is funky on this one, with the base and emmiter switched around.

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    4. It needs a standard daisy-chainable negative ground supply, and so + to 9V, - to ground.

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  13. What do you mean by the base and emmiter switched around?
    I checked the red dot which correspond to the collector,
    I switch the center pinan and the emitter because the base was on the center,
    this is the third time I did the layout, maybe the 3 positions switch which is dead?
    I don't understand why it doesn"t work, because it worked shortly...and then I changed a ground wire and nothing...
    Thanks for your precious help

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    1. You don't have to worry about the collector and emitter swapping round, I've already taken care of that in the layout so it should work as it is shown. All I was explaining is that you can use a PNP transistor with a negative ground by reversing where you would usually expect to find the collector and emitter, ie the emitter is linked to the supply instead of ground, the collector is linked to ground instead of the supply. But like I said, that side has already been dealt with and it needs the pins going in the locations shown in the layout.

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  14. I think everything was at the right place concerning the pins of the pnp transistor and the components, i've made 3 times the layout, is it possible to plug the input, directly in sw2 zone on the layout to test ismy selector is not broken?

    Kind Regards
    David

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    1. You shouldn't need to because the Input and Sw2 wires make a physical connection irrespective of the switch. Then the other positions just put other caps in parallel with the main input cap to act as a switchable tone control.

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    2. I know, but I don't know how to debug my Treble booster, I think everything is well soldered, It worked one time, I changed a ground wire because it was too short to fit in the enclosure, and then, nothing at all when I turn on the effect..I've just a bzzz when I turn the level pot..which is not the expected effect ^^

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    3. thank for your Help Mark whatever, really appreciated !

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  15. dudave, you may want to make an audio probe out of a guitar cable, then you can work your way from the input jack, through the rest of the circuit. that will tell you where your issue lies. i dont know if mark has a guide, but here is one example:
    http://www.diystompboxes.com/smfforum/index.php?topic=79707.0

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  16. Is good to use nkt-275? I have just bought one , but it looks that has a lot of distortion.

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    1. That transistor should be just fine. If you're getting lots of distortion, then your bias must be off. The trimmers are used to tune the bias of the transistor. If your trimmers do nothing, then there has to be something else wrong with your build...
      +m

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  17. I'm building this pedal, and have a couple questions.
    I bought my OC44 from smallbear, and it came with bias resistors, which I gather would replace the trimpots. The bias for the trim pots on the Keeley are supposed to be -7.2v (from this manual: http://www.docstoc.com/docs/4932378/Java-Boost-Instructions-and-Schematic), and the resistors that came with my OC44 are supposed to be from -6.6v to -7.2v. So I think these resistors will work in place of the trimpots. To actually replace them, would I just put one leg where the middle lug is, and the other leg goes...? Would I still need to make the cuts in between the left and right lug?

    My other question is about reading the layout. On the axial electrolytic, there's what looks like a minus sign, as in the negative goes to ground, but I'm not sure if that's what it means. I guess it would make sense that the negative goes to ground, but I'm not certain. Guess I'm looking for 'verification' on this.

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  18. Hey! Just made this but having some problems.. It turns on and led comes on. sound comes through only when the pedal is off and it makes a loud popping noise when turned on/off. ive tried adjusting the trimmers, and have checked everything with a multimeter...

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  19. Hi! I just finished the building of this boost, everything seems to be correct but I have a really low output. I suspect that is something related to the biasing of the oc44. I set it at -7,2v measuring between collector leg and +9v on the dc jack and moving the 100k trimmer.
    Is this the correct procedure? Thanks
    Luca

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  20. Can I use a bc109c for this or bc108 I some of those. Thanks.

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  21. This comment has been removed by the author.

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  22. Hi everybody !
    this fucking low noise ! just for the power supply !
    I don't kwon why, but when i change the power i's work fine very fine !!!
    3 hours for nothing
    if some body know about it please tel me what is the difference…
    Franck

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  23. The tone control isnt very effective. It just dulls it down when turned far counter cw on my build. Anyone try different values or tapers? Also wondering if i can replace the trimots with fixed resistors (got a oc44 from small bear with biasing resistors) but it looks like the 100k trimpot has all its legs connected. Like its being used as a potentiometer and not a variable resistor. Any ideas will be greatly appreciated!

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  24. I cant find an error in the build but nothing is working ...done at least 5-6 of them with all 20 or so trannies I have from oc44 to oc71 to russinas

    http://s15.postimg.org/6u48316e3/Full_Size_Render_11.jpg

    http://s15.postimg.org/97hkgavff/Full_Size_Render_12.jpg

    http://s15.postimg.org/nfbuioxi3/Full_Size_Render_10.jpg

    http://s28.postimg.org/mouu33aml/Full_Size_Render_13.jpg

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