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elmo7sharp9

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elmo7sharp9 last won the day on January 31 2016

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  1. Frank Zappa had this done to a Stratocaster. I tried it myself. Handling noise (Including the Pick Attack) swamps the string vibrations, You get artificial reverb off the Springs. You can "play" the lacquered body with the friction of your fingertips (And hear the friction of your clothing against the rear of the body). VERY unmusical, even if you're Avante-Garde, just UGLY. Still glad I tried it as now I *know*. Piezos need to see a higher impedance than a guitar amp input - FET preamps are normal - the "Treble-only" sound and low volume is a direct consequence of impedance mismatch. Prostheta is entirely correct about piezos needing to be under direct pressure from the source of the sound (Underneath a fixed Fender bridge is ideal) - the Gel Pack idea is a non-starter - filtering by electronics is cheap and easily repeatable.
  2. You'll not gain magical hum-reducing properties in this way. You'll sum the hums of the individual pickups. Expect to hear roughly as much hum as a single coil on its own.
  3. Beware... There's still some research required. Some synchronous logic chips clock on the Positive-going edge, others on the Negative. Ideally, you'll choose all chips in your system to share the same clock behaviour and it'll work like Clockwork.
  4. There's a clear representation of the system that Curtisa describes here: http://wilsonminesco.com/6502primer/potpourri.html Replace that 6522 VIA with a simple oscillator (Google "simple ttl oscillator" - there's endless choice) driving a decoded counter to drive the LOAD and CLOCK lines. Use the raw oscillator signal as your CLOCK line for the counter and for the CLOCK inputs of all the shift register chips. The counter circuit works like this: We ignore all counter outputs except for bit 6 (Weight=32) and bit 1 (Weight=1). We derive two signals from the counter: Use the Counter's bit 6 as the Load/Shift signal. Logically AND counter bits 1 and 6 to generate a counter reset pulse. THE SEQUENCE IS AS FOLLOWS... During states 0-31... Permit one-bit-per-state data transfer across during states 0-31 (That includes the 2 unused bits) On state 32... Handily, the counter outputs xx100000 - use the Counter's bit 6 as the Load/Shift signal. This will need inverted to drive the '165s, but can be applied directly to the '595s. This will simultaneously LOAD the Input State (Key-side '165s) AND transfer the JUST-FRESHLY-SHIFTED bits to the output pins of the '595s. On state 33... RESET the counter. The counter outputs xx100001, so logical AND counter bits 1 and 6 to generate a counter reset pulse on reaching state 33. This signal may need inverted, depending on the polarity of your counter's RESET line. With the counter reset to xx000000, the cycle starts again from state 0. The speed of the clock oscillator is up to you. To avoid logic-defying mystery faults... Use one 100n supply-decoupling capacitor for each chip, mounted physically close to each chip's positive supply pin.
  5. Now that *IS* interesting. Have anyone tried that here? Talk about feedback! That's feedback gone wild. Perhaps some filtering will tame that feedback. I wonder how well it behaves though, especially when playing clean with lightly played and long sustained notes (none of that in the video). That demo sounds like an uncontrollable mess, with lots of noise and some overpowering microphonic feedback. Look at the alignment of the magnets... the WEM Fifth Man sustains the side-to-side vibration of the strings, the Roland sustains the more usual up-and-down vibration. From memory, the Roland has a Common-Collector driver for each string with a different current-limiting resistor value for each channel (Presumably to achieve some balance across the strings - I don't see there being a significant variation in resistance-to-ground through different string gauges!). I tried it out on a piezo-equipped acoustic, using a variety of magnets at the neck - couldn't get sustain at all - tried different power amps, too. The usual "Too Many Variables To Account For" that DIY Sustainer enthusiasts know well.
  6. "I guess it's the same for the GK3. Are the low pass filters not bypassable? " On the GK-2A, It's the simplest single pole RC filter, between the pickup and an op-amp input. Snip the capacitor's ground leg and the filter is defeated. "Are there schematics (or at least block diagrams) available?" http://www.vguitarforums.com/smf/index.php?topic=73.0 There's a GK3 diagram as well. "Do you know what the cutoff frequencies are?" I have never calculated them. I see that on the GK3 diagram, each of the 6 channels is identical. My memory of per-string values comes from earlier dedicated Roland guitars (G303, G505 and the G707). Prior to the GK-series, Roland's dedicated synth guitars had similar onboard filtering. When used with the GR-100 (No synth - just Polyphonic Chorus and Compression), the signal was crisp and clear- no ill effects from the rolloff. Interestingly, the earliest Roland guitar synth had POLYPHONIC SUSTAIN. The GR-500 guitar had strings that were isolated from Ground at the bridge. The strings were grounded at the nut and, when Sustain was switched on, each string carried a 15 volt sine wave of its detected fundamental pitch. The strings passed over a broad permanent magnet, located where the Rhythm pickup is on a Les Paul. http://en.wikipedia.org/wiki/Roland_GR-500 It's an unusual configuration for a sustainer, but not unique... Watkins Electric Music made an ultra-rare guitar, called the Fifth Man, around 1967. It featured a similar arrangement, but with opposing permanent magnets mounted at each side of the neck joint. The guitar was self-contained and the circuit was powered by a heavy-duty (and heavy!) rectangular torch battery in a cavity on the rear of the guitar. http://www.youtube.com/watch?v=NqBaW1qMs4w
  7. "it's easy to chop an envelope to achieve the muted banjo like effect." I keep forgetting the Polyphonic scope - the ability to treat each string separately... The Vo muting, then, is a rather "moot" science-demonstration of the power of the system. Oh, if only there was some way of using the edge of my hand to tame the string vibration . Regarding previous comments about using a Roland hex pickup as a source: I have done this, in combination with a monophonic power amp and driver coil, in order to achieve a more consistent response across the strings (Fully polyphonic sustain was beyond my grasp - I used trimmers in a summing amplifier to achieve balance). The GK2A, that I used, is not PASSIVE... It has active buffering for each micro-humbucker on board, with different low-pass filtering for each string (to aid Fundamental Detection). The GK2A takes a +7v/GND/-7v supply in normal use - it DOES work with a 9v battery and a resistive divider to provide the GND tap. Regarding the possibilities of stimulating a string with samples etc... We can only stimulate the harmonic series that is physically present in the string. This usually results in the string sustaining a close-to-sine tone - a musically uninteresting result, once the novelty wears off. I have had freak occurrences of a string sustaining BOTH the Fundamental and the Octave-plus-a-Fifth harmonic - a musically interesting result that can surely be made repeatable by controlling the proportions of each harmonic in the stimulus signal. It would be interesting to have a slowly-shifting transition through the harmonic series as a note sustains. This is already achievable, using an E-Bow, by pinging a "weak" harmonic and observing the string vibration "morph" to a pitch that has a stronger resonance - but the effect is a one-shot, one-way and monophonic. The effect would be far more impressive on a Polyphonically Sustained chord - a Tamboura-like drone of incredibly complex texture. Naturally, I'm imagining different rates of change on each string... It's a just a short step away from what you've achieved already... I look forward to future developments.
  8. Steel-wrapped (versus Nickel) strings made my AGC-less Bass Sustainer spring into life - it's a significant step up in efficiency. But it really shouldn't be a requirement. For 6-string guitar, Nickel-wrapped strings are all that's available in most stores now. I'm guessing that a nickel 9-42 set, in regular tuning, is what most potential users will have on their guitar, and want to continue using. I'm impressed with Cycfi's "synthesised excitation signal" approach and must ask - have you tried to replicate Moog's "mute" response?
  9. 100k is the standard value. During a period of "try all known mods", I tried 470k - no discernable difference in sound or operation.
  10. "...maybe distorting the signal being fed through the strings might result in a similar "raspy" "zingy" tone..." Sadly, this is not achievable by simple electronics - to achieve "buzziness", interference with the string envelope is necessary and electromagnetic interference with the string envelope (The Moog Guitar, for instance) is a lot harder to arrange than physical interference.... My own experience with DIY Sustainers suggests that 1) You can only excite a string with a signal that is coherent with one of the natural, physical harmonic series of that string's current condition. 2) In the regular Sustainer feedback loop, the string will settle to a sine wave that is related to the drive signal - the physical resonances of the mechanical system (including the physical location of the drive transducer along the string length) largely determine whether you get a Fundamental or Harmonic out of the string. 3) Using a square wave drive signal is just a less power-efficient way of supplying the string with the sine wave that would get the same result - if the string rings at the Fundamental, all the energy you're supplying in the Square Wave's harmonics is wasted (and similarly for the string ringing at a harmonic - you'd be more efficient just supplying a sine wave drive signal at the frequency of that harmonic). The Electromagnetic Harp could easily utilise a per-string drive signal that fades between sinusoids of the the harmonic series. Incidentally... Having said all of the above, I have had - with both fixed sustainer and e-bow - freak occurences of single strings sustaining two frequencies at once - usually a natural Fifth interval (which is logical, when you consider the relative energy levels of each harmonic within a ringing string). There are too many variables to make it an easily repeatable event - I'm just happy when the magic happens...
  11. The closest, in the electric guitar world, is the bridge on a Coral/Danelctro Electric Sitar guitar. You'd need some means of fine-tuning the bridge's interference with the the string's vibrational envelope. I have Rockinger Sitar saddles installed on a cheap Telecaster copy (I can't believe I spent £35 to make a cheap guitar sound buzzy ) and the correct angle for buzziness is a very fine adjustment and is no match for an actual Sitar bridge. There's an entire ancient craft - called "Jawari" - pertaining to the science of shaping Sitar bridges to produce the best buzzy drone. An on/off system for a Sitar bridge could operate like the adjustable mutes in this Fender patent: http://www.google.com/patents/US3427916?printsec=drawing#v=onepage&q&f=false ...set to buzz only when engaged.
  12. I have followed the Electromagnetic Harp since its first appearance on Project Guitar. It's a great technical achievement and looks fantastic. The actual music in this clip reminded me of Robert Fripp's Frippertronics music - specifically the "Let The Power Fall" album. The slow attacks and the looping nature of the piece were similar -though Fripp used 2 Revoxes, a volume pedal and a Les Paul, the end result is a select pallette of notes, overlapping in time. It'd sound great with a Sitar bridge...
  13. My Ibanez RG doesn`t have my favourite Fender tones as stock. I didn`t want to drill any holes in the only guitar I possess that has any resale value, so I used this variation on the Peavey Tone Control Coiltap. The guitar acts as normal with tone set anywhere between 0 and 9. With the tone at 10: Position 1 is Neck North Coil for Jimi-style warm leads Positions 2, 3 & 4 are SILENT, for killswitching Position 5 is Bridge South Coil for Fender-style sparkle. Using this diagram http://img13.imageshack.us/img13/6495/rg470.jpg Just add a wire from the unused lug on the tone control to the unused lug on the pickup selector switch. Easy to do and undo...
  14. I have read the Brosnac book (and have had it since the 1980s !). It's a bit simplistic and the information in it is (nowadays) freely available on the web. I recommend http://www.scribd.com/doc/64028088/Electronics-for-Guitarists which starts with an exploration of the effect of component values in passive circuits within guitars, proceeds through how classic effects pedals work and ends with how valve amps are designed. There are example schematics for the effects and amps.
  15. If you can source a 13-pin DIN socket, you might be better off starting from scratch, rather than cannabilising a gk2a (especially one with "issues"). I reinforced my gk2a with epoxy at the weak spot you mentioned (the tiny retaining screw had chewed the thread in the casing), and it has lasted over 15 years. I built a "13-pin to 1/4" sockets" breakout box to pan the strings in stereo (which was boring, because of the sterile sound) sum the pickups through a mixer to be able to vary the string balance in the drive signal to a sustainer (with, sadly, results roughly equal to using a conventional pickup). recreate the hex fuzz of earlier Roland guitar synths (which I STILL haven't got around to doing). I rarely use my Roland GR-50 guitar synth, as its Linear Arithmetic synth engine sounds "dated" to me and nowadays, freeware VST plugins do a faster job of note-following (not surprising, considering the comparative processor power)
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