Thursday, 24 July 2014

HAO Rumble Mod

Request.  It's probably worth considering using 2 independent 500K log pots and separating the boost and drive sides.  It seems a little restrictive to have them as a dual pot rather than being able to set their gain individually and of course it may also be preferable to make the toggle a stomp so that you can change "channels" on the fly.  A little wide to fit in a 1590B horizontally, but will fit in mounted vertically no problem.

Info about the original:
The ultimate overdrive unit, the HAO Rumble MOD RM-1 uses hand-selected components to provide the purest, smoothest, thickest overdrive ever. The problem with most OD’s lies in mismatched input/output impedances that can make components work overtime. The Rumble’s input and output buffers provide proper impedance matching, allowing its circuitry to focus purely on generating the fattest overdrive possible. The Rumble’s two modes of operation – Clean Boost in Mode #1 and Overdrive in Mode #2 – allow for a variety of applications and tonal options. If you’ve been searching for that $10K amp sound but are several $K short of the mark, the HAO Rumble MOD is the economical answer to your tone quest.






25 comments:

  1. Does make sense a stomp spdt instead a toggle one (for rythm and lead)?

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    1. Yes some people may prefer it to be "stompable", then you could add a channel LED as well and still only need a DPDT stomp.

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    2. I also thought it would make sense to use two separate 500K log pots and separating drive and boost so you can set them independently. I've added a note about it to the main post.

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    3. Sounds great, i am really a noob, maybe it´s ask too much, but a v2 vero with the DPDT plus led, and the 2 drive pots, will be a must, after this one be verified.

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    4. It really doesn't need a new layout for that, when all it will be doing essentially is changing the labels on the wires to the drive pot, change the switch to a DPDT and add an LED to the new pole. Sometimes I'd prefer to encourage people to do a little thinking for themselves, then they'll learn more.

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    5. For sure..i will try it on a DPDT, i think i will use 2 lugs on left side for switch, and two right lugs for led (-) and ground wire. Two lugs will left, and that´s it.; Hope to be correct!

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    6. "Sometimes I'd prefer to encourage people to do a little thinking for themselves, then they'll learn more." Naturally this is true, but I think the truth is that for most of us noobs that is a little like saying, "I'd like to encourage people to start writing songs before they learn how to play guitar"

      It's pretty hard to be creative before you even know the basics. I am getting pretty good at "paint by numbers" (or follow the chords in the Fake Book) - but I think I am still pretty far off from getting overly creative with this stuff, beyond changing a cap here or there for a different tone, or trying different trannys.

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    7. No one is suggesting you should run before you can walk, boratto was asking for a new layout which would just add an extra pole for an LED to the switch. The gain pot wiring would have been exactly the same but connecting to two separate pots instead of a dual gang pot, so the only change there would have been in the notes. They're the sort of things I'm not going to be doing a new layout for. I would hope that everyone building these things would know how to swap a SPDT switch shown in the layout for a DPDT and add an LED and ground connection to the extra pole if that is a small mod he/she would like to do. If not then they really should because it will save us a lot of support time when things like that are understood.

      I'd suggest that everyone should learn the basics, that's what I did. My background is in electrical and control engineering and so I've no formal electronics training either (especially electronic amplifiers), but I read a lot and tried a lot of things, and learnt a lot on the way.

      There is nothing complex in any of these circuits. A collection of transistor or opamp amplifiers with a variety of filters which become easy to spot the more schematics you look at. Read about electronic amplifiers, passive and active filters and maybe a few Brian Wampler books, along with great books like "Small Signal Audio Design" and "The Art of Electronics" and even general electronics books like "Circuit Design - Know it all". Spend a lot of time looking at the schemtics as well as the layouts. The position of the Gain/Drive pots often shows you clearly when the variable gain amplifier is, and the various tone pots show you where at least some of the important high and/or low pass filters are.

      How far you want to delve in is up to the individual, but when something is very basic I would expect people to put a little effort in themselves so that they learn something clearly in their own minds rather than just being told. Remember we're talking about adding LED illumination to a switch here.

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    8. Second. My background has nothing to do with hardware level electronics. I'm not an engineer. Things like these (LED on a switch and many similar connections) can be figured out with little effort. All one needs to know is how the switch work. I believe i've posted this link a number of times: http://mirosol.kapsi.fi/varasto/boxes_other/pots_switches.png
      +m

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  2. Congratulations Mark and Miro on your 800th Layout

    They keep coming and we keep building

    Well done and a BIG BIG - - - - THANK YOU

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    1. Just noticed D1 and D2 are not identified - checked the schematic and notice they are the usual 1N4148s

      As these Si diodes can be a bit grizzly, in the interests of science ;-) I might give some alternatives a go.
      If I want to try Ge diodes (I assume there will be a volume drop) would it be possible to change the values for the second buffer to get the gain back?

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    2. That's weird because I definitely did that note. I must have overwritten it with the switch note without realising.

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    3. It's a buffer and so by it's nature unity gain. Just socket it and give it a try, there may be enough volume to easily accommodate Ge diodes

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    4. Thanks Mark. I must get those dual pots ordered with my next Tayda order. I know I can just use single pots which will mean that I could have different gains for the two switch positions :o)

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    5. Thank you very much for doing this layout (and the other 799), Mark. I hope that i will be able to build it soon.

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    6. Hey,

      I've built this one and it is working. But i have two issues. The drive pot in the Boost mode ist doing nothing and if the tone pot is complete ccw there is nearly any sound. I must admit, that i have two drive pots and 25k B tone pot. I have tripple checked everything, but without any luck.

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    7. I'm pretty sure it's right to the schematic which is this:
      http://oi59.tinypic.com/2s9ulo7.jpg
      25K linear for the tone pot should work fine even if the sweep isn't as intended.

      Are you sure all your connections around the gain pots are good?

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    8. Thank you for the quick reply. I can't find any mistakes around the drive pot. But I found a review on a german hompage (http://www.guitartest.de/HAO%20RUMBLE%20MOD.htm), it says, that in the boost mod the drive pot,or its range, is taken out off the signalpath. May be it should work that way. I don't know.
      I messed up the tone pot connections. I had to change the wires from lug 2 and 3 but now I get heavy oscillation in the drive mode when then tone pot is ccw and level and drive is nearly full cw. Thanks for your help

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  3. Hi, not sure but the 10nF between A1 and B2, should not be connected to B1 instead of A1?

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    1. It's connected from A1 to B2 in the schematic. The only thing connected to B1 is the 330K resistor. Note in the schematic posted above that lugs 2 and 3 of the pots is incorrect, the wiper is always 2 of course.

      http://oi59.tinypic.com/2s9ulo7.jpg

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  4. Another great layout, you ROCK..
    I am hoping someone can help, hopefully someone has come across this and has figured out why the boost pot does not do anything when the pedal is in boost mode?
    I have tripled checked everything and all the components as well as the solder joints and everything is exactly as the layout suggests. However the boost pot does nothing when the pedal is in boost mode just the volume pot and tone knobs work in boost mode. Is there a connection that is suppose to be there that maybe was accidentally left out, I have tried everything and can't get this to work? Please if anyone has a remedy I would appreciate it, thank you .

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  5. Still need help with the last question, would appreciate any help..
    Thank you

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    1. Hey P.o.B,

      it isn't an issue, the original Rumble Mod just works that way. There is a pdf manual in the internet which describes the functions.
      Do you have any squeeling in the drive mod, when the tonepot is fully ccw?

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