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KeithHowell

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Everything posted by KeithHowell

  1. KeithHowell
    It depends entirely on the circuit design. For example a tone control circuit in an amplifier could use both pot values along with a variety of capacitors and resistors to give a suitable tone adjustment. There is no 'benefit' of using 1M or 250K or whatever. It depends entirely on the ear of the listener and what the designer is trying to achieve. Potentiometers are purely resistive components ie they do not have a frequency dependent component (not at audio frequencies at least) In order to use them as a tone control, as in a guitar, they have to be coupled with a suitable capacitor to form a variable filter. Capacitors have an impedance determined by their value X = 1/(2 * pi * f) ie the higher the frequency (f) the lower the impedance. Keith
  2. KeithHowell
    Use the tang of a suitable file as detailed in Irving Sloanes "Steel String Guitar Construction" Polish it to give it some good edges. Works great! Keith
  3. KeithHowell
    A burnt out resistor would be indicative, to me, of something else wrong which caused the wattage rating on the resistor to be exceeded hence burning it out. I would suggest you check the voltage across the resistor once it has been replaced and see if it is within spec. Keith
  4. KeithHowell
    +1 on plug and redrill, provided of course if you have access to a drill press. Keith
  5. KeithHowell
    Am I missing something? If the string was touching the fretboard with no neck angle why would you want to add an angle? This would only make the problem worse. Raising the bridge slightly would alleviate the issue. Lowering the neck would also work as long as the angle was not changed. Keith
  6. KeithHowell
    It is not even a different calculation! It is the same one just expressed differently. The mathematics is as follows: Scale Length (SL) / 21/12 = Fret to bridge distance (F2B) The Twelfth Root of 2 is 1.0594630943 to 10 decimal places Therefore SL/1.0594630943 = F2B or SL * 0.943874312 = F2B (taking the inverse of twelfth root) therefore SL *(1 - 0.943874312) = Fret Distance(FD) or SL * 0.05612256 = FD or SL /17.81715374 =FD (Taking the inverse of 0.05612256) Which is the same as SL * 5.612256/100 = FD if you want to express it in terms of a percentage. So yes we have all used it. Keith
  7. KeithHowell
    All the "magic" numbers are calculated, or should be, from the twelfth route of 2 anyway. So if you do your mathematics correctly with this fundamental principle you will get the correct spacings. Keith
  8. KeithHowell
    Yes similar idea. Baseball is derived from cricket via a game called Rounders. The accent is largely Indian
  9. KeithHowell
    Willow, to me has a very nice ring. Listen to a good quality cricket bat every time the batsman plays a stroke. It can take a huge pounding as well without noticeable damage. (Fighting of the unhappy audience in dodgy pubs??) I have spent many an hour knocking in cricket bats. (Bashing them with a round headed mallet to mimic a cricket ball and compress and strengthen the playing surface, doesn't always work though. One bat my father used, after weeks of preparation, lasted one ball and split in half from handle to toe) I have always loved the sound of a good piece of willow. Keith
  10. KeithHowell
    I would suggest cyano. (the thinest type) It will penetrate the crack more easily. With a little light sanding while it is still wet you will get an almost invisible mend.
  11. KeithHowell
    In the old days of crystal radio sets this effect was used to form the diode in the receiver. The "crystal" was a lump of something, can't remember the details now, with some impurities mixed into it. You scratched on the lump with a piece of wire,called a cats whisker, until you found a spot which gave you reception. When valves/tubes were invented diodes became available and the need for the crystal and cats whisker fell away. This is not first hand knowledge, I'm not that old, but we learnt a bit about the history of radio in Radio 101 at Technikon. Keith
  12. KeithHowell
    Make sure there are no "dry" solder joints. See my comment above in the "killing pots" thread. Dry joints can have a diode effect and demodulate AM stations. Keith
  13. KeithHowell
    Cold solder joints and especially those that have bit of flux still in them can act like a semi-conducter and give a diode effect. Causing untold problems most often noise but can demodulate radio stations. Often the reason you get this in effects pedals or badly built amplifiers. When I worked in the telecoms industry the analogue equipment was very prone to bad soldering especially the older tube/valve stuff. Keith
  14. KeithHowell
    I've got a sealed bass tunerGotoh Tuner I would like to make a small mod on. Any tips for taking it apart and putting back together without damage? Keith
  15. KeithHowell
    If the wiper to track goes open circuit the resistance will go to infinity (theoretically) This could be a bad thing depending on circuit design. For example in radio type circuits you now have an antennae waiting to pick up noise. If the one end is connected the highest possible value will be whatever the track is and no (or minimal) possibility of an open circuit. Keith
  16. KeithHowell
    The main problem is mains 50 or 60 hertz hum which has a huge wavelength, far greater than any gap you could have on a guitar. It is only when you are getting radiation in the Giga Hertz range (microwaves) will the wavelength be down to centimetres and will get through the "gaps". But yes a good shielded wiring job is better anyway. Keith
  17. KeithHowell
    Bore it out to fit your saw. If you need to use it in a saw with a smaller spindle you can get an insert to put into the 25mm hole. I have an old 5/8" spindle De Walt radial arm saw but my blade has a 20mm hole in which I use an insert in to adapt it from Metric to Imperial. The blade was made up for me by my sharpening service for around $25USD a lot cheaper than Stew-Mac. I sure whoever bores it out for you can most probably make an adapter if you need it. Keith
  18. KeithHowell
    Transformers only work for AC. You would have to use an inverter circuit not what you want in a guitar! Have a look here:Variable regulators Should do what you want. You can also get the lower current versions of the regulator IC's I think they are 7805L, or 7809L if my memory serves me correctly. They are much smaller, around the size of a plastic transistor or FET and will handle the currents required for preamps. Keith
  19. KeithHowell
    It's not such a great idea to put batteries in parallel without interposing some diodes berween them. What happens is the "stronger" battery, and one will be, will try to "charge" the weaker one and probably dropping the resultant voltage, hence the worse sounding result mentioned above. Of course putting diodes in will have a voltage drop of 0.7v giving a nominal 8.3v but they should last longer. Parallel batteries wont give you anymore voltage "head room" only more current. Keith
  20. KeithHowell
    The formula for series capacitors is 1/c1 + 1/c2 + .... 1/cn = 1/C where c1 to n are the individual capacitors and C is the resultant value. Parallel is simply c1 + c2 + ..... Cn = C Keith
  21. KeithHowell
    Here's some inspiration for you. This is an original EVH that we swopped with Eddie for one of our Afri-Can Guitars
  22. KeithHowell
    Yes quite correct. He did say he had removed the fretboard though so I presumed reference was being made from the string and fretboard side. If there is indeed a concave fillet applied from the fretboard side this would most definitely be "made wrong" Keith
  23. KeithHowell
    It depends on the design of the rod. The Fender/Gibson design requires a curved channel, the lowest part of the curve (ie furthest from the fretboard) being about 6mm (1/4 inch) more than the ends. The rod is then covered by a curved fillet which pushes it into the shape of the curve. The stew-mac hotrod and similar designs as well as the double rod designs ( the rod is bent in half and the adjstment nut acts against the rod not the wood of the neck) require a flat channel. I have seen a design, by Yamaha I think, where the rod (Fender/Gibson style) is put into a straight channel, however the nut end is shallower than the body end. Ie the rod is the hypotenuse of a triangle with respect to the strings and gives a counterforce on the neck when tightened. Hope that helps. Keith
  24. KeithHowell
    NO! there should be a CONVEX piece of wood over the truss rod forcing it into a curve with the centre of the neck lower than the two ends. Thus when you tighten the nut, the rod attempts to straighten and puts upward force in the middle of the neck counteracting the force of the strings. What is happening now is that longitudinal force is being applied just under the fretboard , like an extra string! Keith
  25. KeithHowell
    What design of single action truss rod? If it is a Gibson/Fender style you have to have a fillet or it wont work. Keith
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