Sustainer Ideas

[dibsmjf]

Well I put my circuit together over the past few nights, the 386 section (from column 13 onwards) works as laid out above, I did make it up slightly differently so might update it and repost it if anyone's interested, if there's demand I'll do a stripboard version too although I probably won't build it to test.

Not sure what happened with the Tillman, whenever I connected it up to the amp, I just got a horrible buzzing sound. However this may not matter, as I have had a different idea about how to go about this. I think I will split up the preamp and poweramp sections when they are installed in the guitar, with the poweramp going underneath the neck humbucker with short leads running up to the driver.

My big idea is with the preamp, instead of using a custom made circuit, I have an old Danelectro distortion pedal at home, which from memory is all SMD and has a very small circuit board. So the plan is to gut this pedal, and use it as a preamp ie with the gain turned all the way down, this also has an advantage of having a built in tone control, which may be useful for boosting the treble to get better drive with the higher strings.

As I was running over this in my head last night, I remembered Pete you were talking about implementing an electronic switching system so to use tiny SMD switches instead of toggles. Well, the Danelectro has electronic switching built in, so that effectively takes care of the preamp power, it also has an LED power indicator, which is switched on and off with the effect. Whilst this could be useful for indicating the power status of the sustainer, a possibly more important use is supplying power through the guitar to the remote poweramp section.

I'd imagine it has a current limiting resistor (almost certainly SMD) to drive the LED, if I could find this and bypass it I'd have a switchable 9V power output to run to the amp, and I could run a status LED from here. The switch from the pedal could be replaced with any type of SMD switch which could be mounted anywhere, which is important to me as I'd like to keep my guitar as standard looking as possible.

All of this is total theory at the moment, I was not at home last night when I came up with all of this so I couldn't check the pedal in question, but it seems to me like it might have some serious mileage in it. I did also have wild ideas of using a compressor pedal instead of a distortion as the donor for the circuit, which would give a form of AGC quite easily...

I also made a start on my new driver, using some 4mmx4mm rod cut into 60mm lengths, based on Pete's Blueteleful driver design, potted with a mixture of white glue and super glue at the end to hold everything in place. It's currently drying off, when I left it things seemed ok, apart from the sides of the coil coming away from the bar, ie forming an oval around the straight core-will these air gaps matter, should I try and stick the coil to the core?

I'll try and get some pics of my driver and amp up tonight, and hopefully some more progress on the distortion pedal circuit.

dibsmjf

[psw]

Thanks...well late, so a short note

dibsmjf...I used to use compressor type circuits and stuff...not sure about the distortion power switching. The electronic switching that ideally would be needed and is most likely the vertical black mystery board on the sustainer for instance operates the bypassing and selection as well as power and most likely delay and reverse delay in switching to avoid pops. This is not like the pop in an effect pedal...it is most likely a back lash of current in the driver coil that is released when grounded back when the sustainer is turned off. I have rarely if ever had switch on problems.

Also...distortion tends to badly affect performance and enhance the potential "fizz" problems...or worse in some cases. If the pedal can run clean...this might be effective...but probably not the bonus you may think. Compressors are good...but AGC is more of a limiting effect. As col pointed out, you really wnat (I think) a forward feed compressor...which is very rare...for this application.

Best is to make a standard basic circuit and mod from there when it operates. Switching on a multi pickup guitar will require at least 4pdt switching like on the telecaster...there is no way around it. Except...you could use the superswitch and if clever...perhaps a push pull that means that position 5 is bridge sustainer on or off for instance. So no bypassing...no ideal but would look kind of "stock".

Not sure what happened with the Tillman, whenever I connected it up to the amp, I just got a horrible buzzing sound. However this may not matter, as I have had a different idea about how to go about this. I think I will split up the preamp and poweramp sections when they are installed in the guitar, with the poweramp going underneath the neck humbucker with short leads running up to the driver.

Well...that doesn't sound good. I have to take back the recomendation for the above circuit and it's back to the Fetzer Ruby unless it is sorted. Obviously the tillman is very well tested, so I suspect a fault. As for 13 onwards...that was the bit I suggested from the LM386 datasheet...hehehe...so the only bit that works is the bit I suggested...sheeesh. I know...so why don't I just design a circuit, test it and post it as a standard circuit?

Because...(insert any number of personal and health and legal issues here)...and I do this for free!

I also made a start on my new driver, using some 4mmx4mm rod cut into 60mm lengths, based on Pete's Blueteleful driver design, potted with a mixture of white glue and super glue at the end to hold everything in place. It's currently drying off, when I left it things seemed ok, apart from the sides of the coil coming away from the bar, ie forming an oval around the straight core-will these air gaps matter, should I try and stick the coil to the core?

I am not sure I am really following this...it doesn't sound like mine. The blueteleful driver is a 3mm coil with 3mm magnets under = 6mm total.

The air gaps probably do matter...tape the sides of the coil to hold it in place and clamp sticks to the sides to push them in tight and remove air gaps while glue dries. If there are gaps between poles...probably some putty in there might be an idea. You don't want any possible vibration of the coil or resonances. Just as it will be trying to vibrate the strings...so it will try and vibrate the windings...very bad and is why often the second go is significantly better for learning what went wrong the first time.

As always...maximum information (preferably with pics) = maximum support and less time wasted by all. Feel free to run things by me here before you do them to be sure...or just to show off! SOme good ideas though...so don't be deterred.

...

totoxic

I intend to make your pickup for the driver, i think that this is structurally the better.

Ok...I hope you see the bit where you need to block up the bottom of the pickup bobbin so there is only 3mm at the top to wind the coil on. It is probably the easiest and neatest way. Use wood glue and if it needs rewinding it will be easy to remove.

My problem is the circuit,if I follow the feltzer/ruby's schemathics, i have the datasheet but i don't understand where i put the preamp. Maybe there are two circuits, one for the amp(feltzer/ruby) and another one for the preamp, but I don't found the datasheet.

May be having a translation problem...and scribs was a long time ago so if you could post it or show me where it is I might recall. Obviously I didn't design nor make it and I don't recall how it worked out in the end. When you say data sheet do you mean schematic. Post up what you have so I can see it...or where I can find it with a link.

The fetzer is the preamp...the ruby is the poweramp/LM386 (like 13 onwards in the circuit above).

Someone mentioned that they had a preamp already in the guitar...I don't know if that was you?

Basically...a F/R is all that is needed as far as circuitry goes and has shown to work. Everytime I say "that looks good, as above, I get burned. The above circuit should work...but it has not been made exactly like that and what has been made did not work (probably a simple problem). With any of these circuits...I have not made them (other than the modded LM386 suggestions...a chip I know well now) so I don't like to say. As for layouts...even a simple circuit is very hard to check...making it is the only real test but it must be the same to be verified.

Ok...very tired so better go...

a bit frazzled at the moment...but you guys seem to be getting the idea. The DIY Layout creator software (I don't have the link handy) has another tutorial which uses a blocked up bobbin...so this might be worth a look too. I have linked it several times before. The telecaster does give reasonable pics, if not details. Sorry it is such a treasure hunt...it is enough work to reply than to "clean it up"...

pete

[mrjstudios]

Not sure what happened with the Tillman, whenever I connected it up to the amp, I just got a horrible buzzing sound. However this may not matter, as I have had a different idea about how to go about this. I think I will split up the preamp and poweramp sections when they are installed in the guitar, with the poweramp going underneath the neck humbucker with short leads running up to the driver.

Ok, this is a common preamp problem with the JFET preamps it seems. Ususally it is caused by not biasing the JFET properly, or just because the JFET likes to buzz

I hope you ordered at least 5 J201s -- you might want to leave your circuit untouched and just swap that 1 part and re-bias. Surprisingly, that can fix things.

Also, now that I take a look at your design, I think the JFET is in there all wrong. The pin you have connected to R2 and C1 is the pin you should have your bias pot running into... the way you have it now it is running at a fixed bias of who knows what.

Fetzer Valve

If I'm not mistaken, I think you have it in there backwards -- check out the link and see for yourself.

Edited September 18, 2008 by mrjstudios

[dibsmjf]

Thanks for having a look at it MRJ, now I look at it I see what you mean, I had the bias pot in the wrong place relative to the JFET-typical! I've ordered some new J201s along with a few other bits and pieces, so I'll come back to the preamp and hopefully get it sorted soon.

As I mentioned above, I've changed my setup to a separate preamp and poweramp, which will hopefully make things easier to fit into my guitar and gives me the option to easily change/upgrade the preamp in the future. You're absolutely right (again!) Pete, my idea of using the distortion as a preamp was a bit of a bad one, the more I thought about it and your points the worse it became! It did work quite well as a clean boost but the circuit board was much bigger than I thought it was, so out with that idea. On the plus side just got my poweramp working well, based on the 386 suggested circuits but squished up loads so it will fit on an 8 by 9 perfboard as shown below:

And here's a pic of the finished board, along with my second driver effort:

Apologies for the terrible pic, I've only got my mobile to snap with at the mo. The driver is basically a 60x4x4 steel core wrapped with wire, onto the bottom of which I'll stick some magnets once I've tried a few, I think it's fairly close in design to psw's but I haven't described it very well.

I've been working on an idea for handling the switching with a strat-type guitar, which disconnects the output and ground of the 5way, re-routes the 2 outputs and ground of my bridge humbucker from the 5way and routes it to the preamp & volume pot and applies power to the pre and poweramps. When the switch is off, the preamp is disconnected from the rest of the guitar, which operates as normally.

This will require either 2 3PDTs or my prefered 6PDT open rotary which I've used before-a PITA to wire up, but more solid and reliable than a toggle in my opinion. The upshot of this switch is to disconnect the neck and middle pups and the 5way from the circuit entirely (ie signal & ground) which should cut down on interference I hope. If it all works like I have drawn it out, this offers the possibility of a fairly simple addition of a sustainer to most guitars, the only change to the guitar's wiring is tapping into the connection from the bridge pup to the 5way switch.

Any thoughts?

dibsmjf

[psw]

Thanks MRJ...my brains been hurting lately...

Reversing the transistor is a common mistake. See how easy it is to make a mistake in a simple layout like this and not spot it. One of the reasons I ahve not done something about making my circuit available is the risk of getting circuit boards or even the circuits made with a mistake in them...now that's expensive!

Rotary switches can work...there are options...a simple toggle is the easiest to use and actually do...and probably the cheapest.

The important thing is to make the driver and circuit and test it before getting too carried away with the details. Some have started the other way and mostly failed, finding out later that they did the coil badly or the circuit has noises in it...

Which reminds me...it is always best to connect a small speaker to the circuit in place of the driver to see what it sounds like and pickup up any faults.

That driver looks ok...I am amazed the you were able to wind it on like this and keep it that way with white glue? Did you user a top and bottom plate when winding or something? Where are the magenets...or is the core the magnet? Will it fit to the guitar? If mounting like my tele with wires under the scratchplate...leave the drivers long and use those to get to a pickup cavity before soldering real wires and avoid handling too much to avoild breaking...this lets the scratchplate sit pretty flat like mine did.

...

OK...so I hope people feel betterer than I do today...keep up the good work and thanks again MRJ

pete

[psw]

This pic from the tele thread shows the driver in testing...see I have no switches and the circuit is out of the guitar. I could put the driver under the strings because of the design, but holding it above the strings would have worked as well...I also had not connected the neck pickup to test it like this...so a complete bypass...testing up the neck avoids this too.

I almost lost the driver...see how I had those wires hanging out...the broke off, but I was able to attach new leads but it was tricky...especially with epoxy.

So...even I still test things and screw things up

pete

[mrjstudios]

Edit: The 3 red pads are where the volume pot connects to the board

Ok... lets have a look in a little more detail. First, leave the JFET where it is. But instead of having the top pin connected to R2 and C1, connect your bias pot (VR1) directly from the 9V+ to it in stead. Then you will have the JFET at least being fed voltage (I'm not sure what it does when it is connected like you originally had it...).

Then, in place of where VR1 originally was, put your input and 3M resistor in parallel with the input to ground from there. You might want a buffer resistor too in there -- one that your signal input runs DIRECTLY through before it hits the JFET. This is how most tube amps are designed, and there are very good reasons that they are there. The J201 is designed to work the same way as a 12AX7 tube, so I would assume the same type of undesirable effects would happen if you left out an input resistor. You could go anywhere from 4K - 68K. But NOT having one at all can cause: oscillation, it can help you pick up radio stations, and it just plain sounds bad and distorts faster, and clips undesireably (which is REALLY bad for this since we want clean power.) Just as a reference, most classic Marshalls have a 34K input resistance on their 'High' input. I think the same goes for vintage fender bassmans too...

Then the middle pin of your JFET should be sent to the + end of a 22uF or so capacitor (see the Fetzer valve) and then that should go to ground.

Just fix what is mentioned above with your JFET, and your circuit might otherwise work. Just correct the design, and try building it -- that is the only way to know, and work out the less obvious errors. Good luck

[dibsmjf]

Yea the driver was a tricky to do, I had two bits of card white glued to the top and bottom of the core to keep everything in place. It's a bit of a mess to be honest, but it was only intended to be a test piece. The core is not magnetised, I have a selection of small magnets to fit to the bottom of it, I'll give it a test with the amp over the weekend.

I've been using a speaker to test the amps as I've been working along, and I've use the stereo outputs of my GT-8 to test the amp and driver that I previously made, I haven't even been inside the guitar yet.

Many thanks for the help MRJ, I think I understand now how the preamp needs to go together and more importantly why. I'll work through your hints over the weekend and see how I get on.

EDIT:

Just been having a go at this preamp, using MRJ's instructions and referring to the Fetzer Revisited on ROG. Below is what I've come up with so far, and the original Fetzer layout from ROG:

Ok so the input flows through the 34K input resistor which I assume attenuates the signal slightly and the 3M resistor to ground is what generate the high input impedance so as not to load the pickups. The input then goes to the gate of the J201.

Meanwhile, the 9V power flows through the 100K trimpot to the drain of the J201, the trimpot is then adjusted to give 4.5V between the drain pin and I assume ground-is that right? The output is taken from between the timpot and the drain, the 22nF capacitor is to remove DC current from the output.

Finally, the source of the J201 is connected to ground via a 22uF capacitor. This is the bit I'm not sure about, what function does this cap serve? Also, the Fetzer has a 1.5K resistor in parallel with the cap, what does this do?

As I understand it, by applying a current to the gate the transistor then allows a larger current to flow through it in proportion to the input current. When the transistor is biased to 4.5V this becomes sort of the base voltage for the transistor, so when we feed in an input, this causes the voltage to change up and down from 4.5V. The output cap removes the steady 4.5V because it blocks DC, leaving only the amplified AC. Does this make any sort of sense?

dibsmjf

Edited September 19, 2008 by dibsmjf

[psw]

Yes...thanks MRJ...much appreciated...it gets a little lonely being Mr Know-it-all...I'd rather be rocky...but more likely bullwinkle

Yea the driver was a tricky to do, I had two bits of card white glued to the top and bottom of the core to keep everything in place. It's a bit of a mess to be honest, but it was only intended to be a test piece.

The photo doesn't show a lot (needs more light...a lot of my pics till recently were with a camera phone)...but I am amazed the wire even stays on there. Anticipating making a second driver is a good idea...MRJ knows this...and the second is often a vast improvement.

Honestly...the tele driver was a first go at that design, but I had been playing with epoxy coils for a while and it took a day to workout and set up the thing...and a machine...to make the thing. I am surprised it worked out so well...and then I almost broke it when the wires snapped...doh!

The above is a selection of mostly failures and rejects...the box on the right are failed epoxy coils. Some failed while testing epoxy types to find one that would work...some were just bad.

This will give you some idea of the frustrations I have had to endure and what motivates me to help others avoid them...if my mistakes or insights help you prevent them, I don't feel so bad about this box of errors!

MRJ also has an old video on youtube showing the testing of one of his earlier examples that shows how that is done and has learned from his own mistakes and so...an expert like me! If anything should happen to me...I am sure he will thus be qualified to help out along the way and even now is working on his own solutions.

From another time zone...

pete

[Leppard84]

Greetings all! I haven't read over all of the threads, but I just sucessfully built a Little Gem amp using this MPF102 buffer which is similar to the Tillman Circuit. MPF102 FET Preamp. Might be easier to get a hold of an MPF102 than a J201 (atleast in Toledo, OH). Dropped this preamp infront of a Little Gem (LM386) and it works quite well. I replaced the 220k pulldown output resistor with a 500k audio pot, to control the volume. I have a 10uf capacitor between pins 1 and 8 of the LM386 and the distortion is downright thick and muddy (almost to the point of becoming unpleasing, so be warned. Might work better without the electrolytic cap and just have a 1k gain pot. Hope this helps some of us! ToNy

[mrjstudios]

oops... doublepost

Edited September 19, 2008 by mrjstudios

[mrjstudios]

Just been having a go at this preamp, using MRJ's instructions and referring to the Fetzer Revisited on ROG. Below is what I've come up with so far, and the original Fetzer layout from ROG:

Ok so the input flows through the 34K input resistor which I assume attenuates the signal slightly and the 3M resistor to ground is what generate the high input impedance so as not to load the pickups. The input then goes to the gate of the J201.

Meanwhile, the 9V power flows through the 100K trimpot to the drain of the J201, the trimpot is then adjusted to give 4.5V between the drain pin and I assume ground-is that right? The output is taken from between the timpot and the drain, the 22nF capacitor is to remove DC current from the output.

Finally, the source of the J201 is connected to ground via a 22uF capacitor. This is the bit I'm not sure about, what function does this cap serve? Also, the Fetzer has a 1.5K resistor in parallel with the cap, what does this do?

As I understand it, by applying a current to the gate the transistor then allows a larger current to flow through it in proportion to the input current. When the transistor is biased to 4.5V this becomes sort of the base voltage for the transistor, so when we feed in an input, this causes the voltage to change up and down from 4.5V. The output cap removes the steady 4.5V because it blocks DC, leaving only the amplified AC. Does this make any sort of sense?

Ok, the input resistor is just a "safety", but also functions to shape tone A LOT. It does slightly attenuate the signal. You are also right about the 3M resistor to ground. By the way, almost every tube amp ever made uses a 1M in that spot to ground, so you may want to try that if your preamp isn't acting ideally once it is done.

You can test the 4.5V drain between where it is input into the JFET from the bias pot and ground. Just use that bias knob, and a new 9V that actaully reads close to 9V, and bias it to as close to 4.5 as possible.

The function of the 22uF capacitor going to ground from the 'source' is just like a tube amp again. The 'source' is like a 12AX7's cathode, which is always tied to ground using usually a capacitor and resistor in parallel. The function is for tone shaping, so the different resistor and capacitor values you use will cause different frequencies to be bled of, etc. The fetzer uses those particular values to mimic an early standard fender input stage.

I think you are right, but I'm not sure about that last bit.

MRJ also has an old video on youtube showing the testing of one of his earlier examples that shows how that is done and has learned from his own mistakes and so...an expert like me! If anything should happen to me...I am sure he will thus be qualified to help out along the way and even now is working on his own solutions.

Yes, you can google 'sustainer video' and mine will come up pretty high, if not first on the list. It was a crappy sustainer, but it did work, and the video shows how you can go about testing your unit before finalizing it and installing it.

And by the way, thanks Pete .

[psw]

Welcome Leppard84

The J201 can be substituted with the MPF102 or other Jfets...need to watch out for different leg outs and orientation when substituting. You can't get J201's in Oz for some reason...another reason I had to go it alone and what I might have suggested might be hard to get over there (wherever you are!)

This page from that interesting link to the MPF102 in the tillman shows some concerns for this application that is confirmed by your results I suspect...

the distortion is downright thick and muddy

Not actually what we want in this project ideally. Remember we want to amplify the signal to move the strings not for tone qualities like pleasing or even any distortion. You should not in fact "hear" the sustainer at all ideally...just the guitar sustaining away...distortion you can add to the signal to taste.

A distorted signal or fuzz is typically a squared wave...not a smooth sine wave and full of harmonics. Now consider the strings movement...not squared at all...so the more efficient and better drive signal will be a clean signal most resembling the actual string signal.

Obviously with tiny little battery amps with low headroom a 200X amplification or more with a preamp stage...there is going to be more distortion than we would like. There have to be compromises. A higher wattage, cleaner amp might be considered...but then it is limited by the battery power which will likely clip it too. You might solve this limitation with some clever remote power...has it's own problems though...but more power often results in more EMI... It's all a balancing act.

My problem with the Fetzer and similar JFET preamps in this application is exactly the reason they are so popular for what they are designed to do...distort like a valve stage!

Op-amps vs JFets

My problem with the Ruby has always been that for some reason ROG on many of their designs have removed components specifically there to stabalize and keep the LM386 happy at high gains...

LM386 Data and Application Sheet...see page 5, application 2...LM386 with 200X amplification. In addition, add a 100uF power smoothing cap as per C2 in the above tillman/ruby proposal and a 1K trim between with the 10uF cap and pins 1 & 8 and the bypass 10uF cap at pin 7 for good measure.

These are the "MODS" I suggested and use and while tempted to call them my own...and is used in the CHamp circuit kits...it is simply what the amp wants to prevent internal oscilation...again, I have no idea why ROG would seek to leave them out, but in this project, you want to keep the circuit happy.

As for preamps...all of these if built properly and biased correctly for performance should work. The main purpose of a preamp is to prevent loading...an LM386 is not designed to take the high impedance guitar signal nor will it be happy splitting it between this circuit and the guitar amp...and neither will the guitar amp. Similarly with things designed for "line" signals like computer speaker amps...these receive a signal preamped in the sound card and not designed for guitar signals resulting in loading. The result may give some hope...but not be working properly at all.

...

Far too much is made of the circuit...it is important to have a working circuit for sure but the key is the driver.

I do fully intend and have for some time (when things blow over, or not, on the home front) to provide most likely a prebuilt circuit like the one in the tele picture above. Small, some AGC, LED power, remote and different drive control and tested. This is my own design and guarded but the problem is time, cost effectiveness (I still don't know what you guys would pay for such a thing) and the logistics of getting parts and stuff.

Splitting the preamp and poweramp sections has been around for a while and I was keen on the idea...sometimes I come back to it...but in truth it makes it more complex, bigger, more wires (many that can pickup up noise) and perhaps not ideal. In the tele the circuit is under the bridge pickup. I used to want to put it under the driver...or even build it into it...but now I wonder if this isn't inviting trouble. The driver is putting out a lot of electromagnetic energy, having the circuit under it may cause EMI directly into the circuit resulting in ill effects like internal oscillation. Just a thought). The bulk of wires going back and forth takes up even more room...so for most not the ideal thing and more room for error and complexity. Also...as a rule, wires should be as short as possible...nothing can be shorter than a good compact single board layout.

...

The last time I tried to address the problem with a circuit of my own...I made a lot of mistakes and posted before testing it (not a good idea). The result, like the circuits recently and before is that the thread is littered with unverified or non functioning circuit proposals...and a reason it gets so big!

This is the main reason reading the whole thread is not a good idea...there is a lot of misleading information along the way.

In response to this, I went away and spent weeks refining and making circuits in an attempt to make my own circuit to solve the problem as best I could. I have given a lot away and support, but I really had to keep this one to myself as I can not really justify this level of commitment for this long for no reward and many times this whole thread or the ideas have been sought to be used for financial gain by others. Posting my circuit would only encourage a ROG clone or similar to slightly modify it and call it their own. There comes a point where you have to ask...what's in it for me...

...

Ok...more than enough from me...keep working the design...build them and get them working as clean as possible and when you find the solution (the fF/R will work if you build it right with the correct bias and stuff) post the verified version clearly. No problem in sharing proposals...but it is frustrating to find so many proposals and not the final solutions. I will then...or you can...transfer the result to the tutorial section for easier access...how about that!

pete

[psw]

Hi there...hope all is going well with the projects...

I have also had a few messages and mails from others who will be attempting this in the near future...one from GN2 which should be interesting and could add to the knowledge base. He thinks he may have a switching solution...we will see....here is his thread over there...

For those who don't know the Guitar Nutz forum, they are like a PG just for wiring schemes with a great bunch of guys who come up with some very creative wiring solutions. I know it is where I go when I need help. Also, a while back I started a thread on there which is a lot shorter and may be of interest...GN2 ~ sustainer thread

...

Also. it is time to vote in the GOTM competition...looking very exciting. Obviously my sustainer tele is in there but it is already close and interesting...GOTM Link...that acoustic for instance looks like stealing the show...but the more that vote, the more interesting the results.

pete

[psw]

Also. it is time to vote in the GOTM competition...looking very exciting. Obviously my sustainer tele is in there but it is already close and interesting...GOTM Link...that acoustic for instance looks like stealing the show...but the more that vote, the more interesting the results.

^ voting is still going...but it is hard to compete with an acoustic guitar and a metal monster

An update of the GN2 project...here is a link to the new thread...GN2 Warmstrat complex rewire +kill switch and sustainer

Already some interesting ideas emerging from a different bunch of people putting their minds to it...

A bit quiet here...I hope that means people are happy and busy or things are going well...

pete

[Ripthorn]

Well, I am getting closer to actually being able to start my sustainer. I am setting up an order for the parts, but before I do so, i wanted to ask a question. I am going to be using a single pickup setup and I want to be able to switch the amplifier off and have the option for normal and harmonic modes. I am thinking that an on-off-on dpdt should be able to do this, with one on being normal and the other on wired in reverse. I was just wondering if this is correct thinking. Also, to wire for harmonic mode, do I simply swap the positive and negative wires going to the amplifier (or is it the driver) or am I way off base? Thanks.

[psw]

Hello...

I am not sure if you could wire a dpdt on-off-on in this way...or that it would be advisable to.

You need a dpdt to reverse the driver wires (although the signal in could also be switched...but not with multiple pickups so since it is the same thing, the driver is more usual). It is simply a phase switch (characteristic X wiring) to reverse the driver wires...so you have the idea.

In a guitar with more than one pickup...the harmonic mode on the signal/pickup would operate as a phase switch when the sustainer is off, causing the neck and bridge to be out of phase and cancelling.

As the -ve 9v, guitar signal and the driver all share the same ground...reversing the ground could cause problems with switching with a switch like this...also not all on-off-on switches work the same...so you may need to check that out... I can't think of a way to do it with a dpdt on-off-on off the top of my head!

One problem you might have is some switching noise. If so, it is generally only when switching the thing off so in a scheme with and on-off-switch there is the potential for noise when switching modes which would be bad!

The easiest way in use is to have two toggle switches one to turn it on and off, the other to turn decide the mode. A pair of dpdt will do that although the on-off could be a simple spdt if you wanted. You could also use dpdt push pots for both on off and mode if you wanted to get fancy...a bit more difficult to use though while playing. A rotary control could also be rigged up (I think col did this) but this too can be tricky to use unless you have a chicken head knob or something on it!

When ordering parts...it might be worth getting a pair or the transistors and look to see the parts suggested in recent versions that include my modifications. The output cap is often specified as 220uF which will give a good fundumental drive, but I have found that 100uF to be more useful and ensure better high string response and low string bloom...perhaps get both IC sockets and even transistor socket strips can be a good idea as well...this allows you to press fit the IC and tranny in so that if the transistor or IC ends up around the wrong way you won't destroy it and it can be reused. Transistors can be adversely affected by heat, handling static and misuse...so having a socket and a spare avoids that and gives you a fail safe for only a couple of bucks...better than paying to ship one on it's own or being caught with a minimum order or something. This stuff isn't expensive, but I have heard that people can get caught by a minimum order thing in which case you might consider adding parts like guitar pots or tone caps as they could end up essentially free...that is something you will need to explore with the supplier.

Hope that helps...

pete

[mrjstudios]

Ok... I've got a circuit all drawn up which is a modded version of the Fetzer / Ruby. I took all of the info I could find here and on the 386 datasheet, and put it into a redone design. I have decided to withhold the layout and schematic though until I fully test it -- I don't want to add any more confusion to the thread.

Hopefully I will have it done in a week or two.

Edited September 29, 2008 by mrjstudios

[Ripthorn]

If I just wanted to have an on off switch for the amplifier, is there a reason why it couldn't be an spst? Wouldn't it simply function to allow the battery's voltage to flow into the circuit when in the on position and block it in the off? Of course, I don't claim to have the best functional knowledge of the inner workings of switches and the like. Thanks.

[mrjstudios]

If I just wanted to have an on off switch for the amplifier, is there a reason why it couldn't be an spst? Wouldn't it simply function to allow the battery's voltage to flow into the circuit when in the on position and block it in the off? Of course, I don't claim to have the best functional knowledge of the inner workings of switches and the like. Thanks.

That would work. Just stick it between the 9v+ on your battery and the 9v+ input on your amp and you will have an on off switch.

You will need a DPDT switch for the lead switching between the circuit's output and the driver coil.

[psw]

Yes a SPST switch will work fine...you are right, you need only turn the power on...in fact on a single pickup guitar a momentary push button could be used potentially in addition to the on off which would be kind of fun.

The guys at GN2 had some interesting ideas about switching and if you have room inside...the extra dpdt switch might be useful...but not strictly necessary.

...

Good luck with that MRJ...and thanks for the great GOTM comment ...

It does get confusing on this thread and I tend to avoid it myself as I have previously posted some clunkers. Generally, I try to repost what seems to have worked in the tutorial thread once I have been convinced that the thing works. It can help a lot to have someone else go over it...time and again we have seen simple layout errors...but the only way to "verify" something is to build it, you are right. Banika from DIY layout and the stompbox forum use the same protocol...they only say a circuit of layout is right if someone has actually built it exactly as shown and it works, so even there you need to beware!

pete

[dibsmjf]

Hello again,

Not had much time recently to work on my sustainer, bit of a family disaster taking up most of my time recently. On the plus side, I did a pickup swap job for a friend last week, not expecting any payment, but to my surprise he gave me his old Epiphone SG to play with! It was in a bit of a sorry state, so spent the weekend removing the bits of finish still on it and gave it a simple danish oil finish. Ordered a new set of electronics, keeping the original pickups for now but everything else is new. Going to put together another coil tonight and then get back to the circuit whilst that dries out. I've drawn up a wiring diagram for the guitar based on the 4PDT switch from the Guitarnuts post so we'll see how it goes. I'm away over the weekend so hopefully I'll report back with updates next week.

[megadog]

Hi I am new here mainly because of the amazing information that is available and job that you guys have done with the sustain system. I am very envious. I am kind of looking at building one myself but I can't find any wiring diagrams and how to implement it into a previous system. I may just be missing the point or some key post somewhere and i may not be making any sense but i figured there would be no harm in asking. Thanks and great work you guys have done.

Edited October 1, 2008 by megadog

[psw]

Welcome Megadog...and thanks...

OK...so this thread is a place that has ended up collecting all the questions ideas and suggestions...not a good idea to try and read it it started 5 years ago!

For starters, look at the tutorials and pictoreials and check out my new sustainer tele project (not to late for a vote )...they are linked to the bottom of this post.

The link in the recent post to GN2 as I posted the wiring for the tele switch...

There are various circuits been suggested, the design I have proposed is designed to be used with a simple preamplifier/amplifier... There are various designs, but some that have been posted are not quite right so...hmmm

I know MRJ is working on something at the moment that might do the trick...but a little while back I added a few mods to the fetzer/ruby design that most have used successfully...

Anyway...check out some of those far shorter threads, maybe look at the last few pages of this thread and feel free to get back to me with any questions...

pete

[megadog]

Thanks for that i found out some useful information. But is it alright if i pose a question concerned with a specific wiring setup. I am in the process of designing a guitar and I really want to include a sustain system similar to the one you used in your blueteleful guitar. I am some what lost as I can't figure out how to incorporate you design into an existing system.

I was going to use one humbucker for the bridge pickup and a single coil for the neck with either 2 vol and 2 tone or 1 of each and a three way selector switch. I was also hoping to be able to turn the sustain on and off with the same effect as your design (turning the neck pickup off and the bridge one on).

The research I have done has provided me with some wiring diagrams for both options (minus the sustain system) but as I lack the expertise in the electronics area I fail to see how to combine the sustain into the equation.

I know its a big ask but is their some way you could post a diagram of your wiring setup here. Sorry if this is me just being rude.

Thanks

Edited October 1, 2008 by megadog