Donovan

Great information Donovan - especially the practicality of a brightness control. If guess if tri-colour LEDs were used, it would be feasible to have a pair of stacked colour blend pots....!

As an aside, my minor project at college was a multi-band spectrum analyser just a step up from the pickup/op-amp idea. I made several bandpass filtered/half-wave regulated/DC smoothed signals drive an array of bi-colour LEDs with a green "bar" and a red "peak", which was pretty cool and taught be the huge difference in linear representation of logarithmic values right there and then since I didn't do so in class much....absolutely enormous on breadboard, and somewhat difficult to cram into a guitar control cavity however....!

Thx Prostheta. My company is keen on training and part of my position there allows me to explore electronics during my downtime. It is a lot of fun as well as at times frustrating and perplexing.

It sounds like your college project was very similar. Opamps have a huge place in the scientific instrumenation world due to their ability to listen and magnify without affecting what their listening to.

I've not had a chance to mess with any tricolor LED's. I have played with the bi-directional, bi-color types, those are interesting, but your comment opens up even more opportunity for our friend djhollowman. It would increase the circuit by one set of wires per color, and add one selector switch, but... you could set it up to select the color of choice for mood. They type I just checkout out online just a second ago are four leaded, having an anode for each color and a common cathode. Is this what you meant or are the you you mentioned something else? I can see how multiple pots would handle color blend... and so let's consider takking it now WAY over the top for more "fun with bling".

Imagine this...

Opamp taps pickup signal and amplifies it to useable level to drive LED strings.

Amplified signal is split into 2 branches.

Branch 1 controls momentary on-off, giving the "varying brightness with attack"effect.

Branch 2 controls a series of JFETs in Ohmic mode (voltage controlled resistance), giving a "varying color with attack" effect.

Rotary switch controlling master brightness or mode control. Modes might include steady on, "attack" mode, a random (555 timer setup) blink mode... whatever can be imagined.

Your stacked "color blend" pots controlling color mix and/or 555 timer's drequency/duty cycle.

The point is that the limits are only what you can imagine. I'd love to try this, only my woodworking skills are sucka$$.

DJ... something tells me this is not the time for the KISS rule.... but rather a perfect opportunity to make something that is kind of a "been there, done that" novelty into a totally unique as can be, stage light-show machine!

What guitar and type of pups are you using it with?

I think your cap value is too small ie the cutoff freq. is too high and is perceived as a volume drop.

as cap value and/or pot value decreases cutoff freq. increases. ie halving the cap value doubles the freq. value.

G&L use a .022uF cap and 1meg pot, so their cutoff frequency would be 22x lower that yours ie more bass passes through.

If you want to find out (roughly) what the values are:

Cutoff freq.(Hz, cps)= 1/(2piRC)

where R= resistance, C=capacitance, pi=3.14159265.

So his cutoff frequency is about 168... very close to the standard 4th string, 2nd fret E. I'd be curious to know what the frequency turns out to be once you find something you like. I am also wondering if a guitar does produce any frequency below the 80'ish of standard low E. Intuitively, I'd guess it doesn't, except for induced noise from the outside world, which is useless anyway. If you get the chance, that might be an interesting and subtle point to starting testing for cutoff frequency. All you'd have to do is add another of the same cap in parallel with your current configuration.

I work with these types of LED circuits all the time at my employer and have a decent amount of knowledge regarding led circuits.

I think that your 2 strings of 5 setup looks good. I have a couple of ideas to add.

I think what you will find is you will probably not get much brightness benefit from running them at their full rated 30mA. Percieved brightness vs current is analogous to lagarithmic curve of a volume pot. Once they are bright, for a large current gain, there will be little brightness gain. While this is only somewhat pronounced if you look at the datasheets, the perceived effect will be much more evident. Consider this when you design for battery life.

Also, you may be doing yourself a favor to consider sucvh things as an external master brightness pot for on-the-fly control and a zener regulator so that peak brightness does not as noticeably change with battery wear.

A totally AWESOME feature (and easy to implement) would be an op amp tapping the pickup signal to make the LED's turn on and off with the attack of the player. If interested, I'd be willing to help with a design/schematic.

Like I said earlier, there's a half a second of charging period, where the zenor charges up to the voltage its set to. Zener diode will pull as much current it needs to charge to its break down point

No, I think you are confused on the zener's mode of operation. If you give a 5 volt zener 3 volts, you will get 3 volts max. I do not think there is a way to get 5 volts.

So...have you tried this only in a virtual world...or have you actually tried this?

I've only done this in virtual, but in theory it works, and when I measured the components the amperage maxes about 1mA

Next, anyone remember the ideal model of a zener diode? I kicked the two virtual zeners up to about 20v and dang it kicked the amps up to about 2mA and looking at the output it just blasted that thing to kingdom come

This project sounds wishy-washy at best and I'm not getting this part at all. Zeners regulate voltage down, not up, at least that's what I was taught.

Indeed... instead of those two resistors and the jumper switch I'll have a large value preset potentiometer. Y'know, the little blue ones you set with a screwdriver. My reasons for not having a single pre-amp are because I'm not confident in my ability to make such a good DIY piezo bridge so I can set up each string well, and also because I'd like to play around with hexaphonic pickups and stuff later on. But thank you for your advice.

Another concern is how I'm going to fit six of these circuits into my guitar, without effectively making it hollow...

You're going to have to spend a lot of time on the layout to accomplish what you want, unless you go with a surface mount build or buy a premade circuit.

Why not build a simple mixer, mix 6 down to 1 using the minipots you suggested, then preamp the output signal. You can then accomplish what you want with less components.

Check out the schematics on this page. This is how I'd do it.

Of course, this does mess with your idea of hex MIDI stuff later, but I don't think there is another way around the space thing for component count reasons.

Hi everybody,

There's a lot happening at the moment (simulations, hexaphonic pups, new schematics). I like to comment on some of the ideas proposed. But first I show you my sustainer.

I wouldn't advice people with less experience in electronics to build my sustainer. (No print available, need to do a bias setup - with oscilloscope-). Ofcourse I don't mean the hank mcspanks, zfrittz6, col and donovans of this world. Piece of cake for you guys

Steady Steed

The schematic

Info 1

Info 2

Cheers

Fresh Fizz

Actually, can't count me in that list... I consider my project a failure on hold at the moment. I burned myself out from messing with that circuit and probably won't try another sustainer circuit until I learn A LOT more than I know now. I've been reading this thread on a regular basis, hoping to get up to speed, but Col and Hank are getting into some unchartered waters. With any luck, they'll have it sorted before I break down and buy a Fernandes or Sustainiac system.

I put a set of Graph Tech Ghost piezo saddles (same thing you are looking at except minus the actual floyd tremolo) in my strat a few months ago. The install wasn't too bad and I love the sound. No complaints. The acoustiphonic preamp has 1 gain control that works across all 6 strings, BTW. There is a secondary preamp, called the hexaphonic preamp that you can get in addition that sends each string's individual signal through a 13-pin connector... I didn't feel the need to go that far though.

See the original thread here. There are souns samples as well.

I don't get it. Why would I need to carry a guitar when I am hunting. LOL. If you put it down would you ever find it again?

Of all the paint patterns one can do Camo is the lowest on my list, sorry. But I guess if I had to have one I like the black outlined version, stands out.

Now where did I put that shot gun

+ 1 on that.

If hunting or military is your bag, I can see why you might want to mix it with music for a personal guitar, but I don't think many would go for this idea.

re soldering pins that are only 0.65mm apart ....well, for a start if you've shaky hands, just flood all the pins with solder, then use copper braid to get the excess off thereby removing 'bridges' (the capillary action of the braid will lift the solder off...except the solder that's underneath the pins) - there are plenty of tutorial youtube videos about, you can get the idea here...

(from about 3m46sec in).

Another method is to buy some solder paste (eg http://cgi.ebay.co.uk/SOLDERPLUS-LEAD-FREE...A1%7C240%3A1318 - you normally need a syringe, but you could get away with dabbing a needle into the container & then dabbing it on to the pin pad) .. place a small amount on the pin pads, mount the chip (the paste holds it in position) & whack it in your oven (got to use the right temp!) - the paste morphs into solder - no bridges with this method.

I've been in electronics manufacture for the last 10+ years and currently function as electornic assembly technical expert and trainer. Flooding and wicking might get the job done, but I would advise against it and use the paste and hot air technique or look into getting a tip designed for drag soldering (it holds liquid solder in a reservoir that dispenses a small amount of solder upon contact to each pin) as every time you heat the component and the solder joint, reliability of both component and PCB are reduced. One, because you increase the thickness of the intermatallic layer (junction of the solder joint and the PCB land) which means embrittlement that leads to fracturing and two because you're applying another round of extreme heat.

Once you start using some of these more elaborate devices, you guys should also start considering an ESD-safe workstation to minimize the chance of rendering your devices nonfunctional due to electrostatic discharge. The basic setup would consist of a dissipative mat with a path to ground which is also common to any tools being used and the individual via a bracelt and ground strap.

In general, the device datasheets should indicate an ESD sensitivity level. If it references ANY level, you should take heed in order to not waste your devices. The industry spends a lot of money on protection from electrostatic discharge prevention and this increases avery year as devices get smaller and more complex (weaker with regard to static shock). Nothing worse than trying to troubleshoot something that comes down to internal device failure due to an ESD.

Checkout www.esda.org and give S20.20 a read if interested. I can also recommend very cheap ways of setting up the workstation for this.

Assuming the rear of the nut slot is still intact the job is an easy one. My templates show about 1 1/2" from the first fret to the rear of the nut slot or more precisely 1.533". A fret calc and adding .125 would be even more accurate. Assume if the distance is a hair over 1 1/2" you are original.

Not to sound a dumba$$, but is the headstock end or the bridge end the "rear"?

Hey Spoke, it's a pain, but I think an oportunity too. Donovan could use that extra space and compensate the nut. So it will look intentional.

Now that is really a good idea. I've never played one of these... supposed to make intonation more "correct", right?

One thing I should also mention, the slot may not be rxactly where it should be. I've always had a hard time getting the low E string to intonate properly. As a result, I've clipped the spring on its saddle to half length to get a little more distance out of it, so I guess this means that perhaps the new nut needs to be slightly further from the bridge.

I appreciate the comments on this. Thanks to all.

What did you expect me to do read the PDF too??

You are right, I just glanced at the picture who knew the artist draws backward, LOL I'm bad.

Man if you cant build using pictures what good are the instructions. Seems like Mr D should consult a professional. Oh wait that would be the people on this forum??? You still there Mr D????????????

Cutting a shelf 3/32" in a nut is a bit of a pain if you dont have something like a mill. Hopefully the rear of the original slot is still intact. Install a fender nut and just fill in the fingerboard seems the easiest thing to do.

If Mr D needs a custom nut, I sell nuts and have a mill, easy enough to make up a custom nut for you.

Yes, I am still here.

To be honest, it was so long ago (ten + years) that I don't know what is left of the original slot. I don't recall which direcion I widened the slot in, but I know I did follow directions, I just didn't do it neatly or with the correct tools.

I am interested in a custom nut. What are the possibilities and how would we handle this? Would I ship the guitar or neck to you or would I have to have the slot re-routed/cleaned up? I am looking for a "one-stop" solution.

What we need is a good cruise control! (AGC).

Hello gentlemen.

I've recently been doing some reading about pulse width modulation using 555 timers as a means of more efficiently controlling electrical motors. The duty cycle is modulated, rather than pushing 100% of the time, it pulses power in the form of a square wave at a (for the most part) undetectable frequency.

Just a shot in the dark, but could the analogy of the cruise control be realized as an AGC through the application of PWM to the output stage's power supply (or somewhere else in the signal chain) through a low frequency, say under 20Hz, with the signal amplitude modulating the duty cycle?

That's pretty much the path I'm taking by using a PIC in my sustainer circuit.

The PIC 'monitors' the sustainer's preamp output level & ultimately adjusts the duty cycle of its own PWM output stream to suit - if you feed this PWM stream into a low pass filter, you end up with a DC level - this DC level is applied to a 'gain control' JFET in the preamp (which adjusts the gain applied to the incoming signal to ensure a constant predefined output into the power amp)

Thank you for that excellent explanation. I feel like I just learned something important and I'm glad that what I suggested had some merit, even if it's not an original idea!

That is brilliant, the running it through a low pass filter portion. Am I correct in assuing this gives a nice smoothing effect, so the AGC doesn't act as choppy? Is this post-filtering a common technique and if so, what is it called or what other applications might I find it mentioned?

What we need is a good cruise control! (AGC).

Hello gentlemen.

I've recently been doing some reading about pulse width modulation using 555 timers as a means of more efficiently controlling electrical motors. The duty cycle is modulated, rather than pushing 100% of the time, it pulses power in the form of a square wave at a (for the most part) undetectable frequency.

Just a shot in the dark, but could the analogy of the cruise control be realized as an AGC through the application of PWM to the output stage's power supply (or somewhere else in the signal chain) through a low frequency, say under 20Hz, with the signal amplitude modulating the duty cycle?

Forgive me if this is a daft idea for reasons beyond my knowledge level... just came to me when I read that quote. If the power amp stage would be too difficult, the signal could be sent to ground using PWM, but again, modulated, not a 100% shot at some threshold as has been recently discussed and tossed out. I do realize this is something like the "shunting to ground" that has been talked about already on this page, but was just thinking this would be a more translucent effect, in theory, or at least intuitively within the confines of my flawed psychi.

I have this 98 American Std strat that I bought new back when I was a "kid" or at least when I cared less about my gear than I do now. I installed the LSR roller nut shortly after the purchase. I did not use the proper tools, but rather went to town with a simple woodworking file. The result is jagged, rough edges. Although I do feel I get a tuning benefit from the nut (and I'd never remove it from my main guitar which came with it OEM installed, I also have a suspicion that the the LSR roller nut kills off some sustain.

As you know if you've ever had one of these, the LSR roller nut requires widening the nut slot. I'm not sure of the exact width of the new slot, but I'd say it is somewhere between 2X and 3X the width of a stock nut.

Lately, I've been wanting to return this guitar to a more classic look and functionality, reversing many of the things (abuse) I've subjected it to in the past. The biggest eyesore for me is the shoddy installation job I've done on the LSR nut.

So, my question is, before I go calling around, is it reasonable to think that a decent luthier could fashion a new nut made of bone (or some other material, suggestions)? Again, the slot is 2X to 3X wider than "normal". I would expect the slot to be "cleaned up", preferably by machine, as well, further oversizing it.

Thanks for your help.

That's a shame, I was looking forward to having someone with a more scientific approach to share ideas and results with.

well, good luck anyway

Col

Please don't be discouraged. I appreciate what you're doing. Though it's slightly over my head I read regularly and enthusiastically. I look forward to reading more of your results with this new circuit and seeing a preliminary dwg when you're ready. I've been keeping quiet here (as I am sure many others are as well) as I "learn" some more basics and tinker.

Im no expert either but you could just get a SPDT or DPDT on/on and just put it in line with the active going to the jack. Connect the wire "in" to the switch on the middle pin and continue the wire from either side of the switch (it doesn't matter). That way its just a break in the active wire. Hope this helps.

Breaking the signal alone is not enough in a lot of cases. Shorting the signal to ground is a better approach then just opening the circuit, in my limited experience.

It is interesting he is using op amps where I have used a mechanical relay. The op amp design is a bit more complex. Not to sway anyone toward my design or away from anyone else's, it's just that honestly, I did not know one could do this an op amp, so I'll be studying that drawing more closely. However, my use of a mechanical relay in place of his semiconductor switching does mean the pedal will click as the relay opens/closes. I was not able to get the semiconductor version to be "click-free" and so went to the micro-relay. This clicking that is present now is NOT part of the signal, but at very low volumes, you may hear it from inside the pedal.

The PG main site also has a nice tutorial article on it that explains the cap and resistor in both series and parallel configurations.

thats the tone cap not the treble bleed cap...

Oops... sorry, my bad. I confused the question with SwedishLuthier's comment about the tone cap.

It says 0, 022, 10% right on it.

I really like the matching curves of that headstock with respect to the SG-style body. Nice pick.

That is a BEAUTIFUL finish on the top!!! Is that the natural grain of the Brazilian Mahogany? It looks like a reptilian skin in some of those shots... amazing. Seems like the 2 years was worth the wait for you.

Nice job! The front is very cool.