mrjstudios

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.

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.

There are a lot of beautiful guitars in this month's GOTM. However, one really does stick out to me, even thought it is designed not to particularly stick out at all. Pete's Telecaster is the culmination of years of work in guitar electronics, and most importantly, it is the culmination of Pete's pioneering research and development into a relatively untouched field of guitar electronics; the 'sustainer'. Yes, Kramer, Sustainiac, and Fernandez have already ventured into this field, but only one of them still makes the 'perfected' unit, and even that one has many flaws, not to mention being extremely expensive and large. Putting one of those units in your guitar often means permanently destroying that guitar's character and desirable features, all to make it be a 'sustainer' guitar. Moog has also just released a guitar which demonstrates this theory of "sustainer = 1 trick guitar". However, Pete not only ventured out to find a better functioning sustainer, he also made it cheaper and most importantly, smaller. With his unit, you can install one on your guitar, and still retain everything you liked about your guitar in the first place, and still enjoy the benefits of kicking in the sustainer. He has single-handedly done something that no large, or small guitar company has been able to do. The best part is, Pete has shared his knowledge along the way, allowing countless others like myself to build our own sustainer's based on his research. For the developmental aspect alone, I think the Blue Telecaster might go down in history as a very important guitar, much like the first HB equiped guitar, or the first Floyd Rose equiped guitar, or the first active electronics guitar. Therefore, my vote goes to the Blue Telecaster!

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. 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 .

oops... doublepost

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

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.

Hey -- I've been checking the site, I have just been majorly sidelined in my own sustainer project... I still don't have the parts I need, and I have been mostly working on a custom amp which has never quite had the bugs worked out of it... and now my backup 5150 is down... some previous owner did a BAD bias mod, etc, etc.... I can't tell if the powertubes are happy or about to catch on fire So now I am modding that amp and the custom one... Anyway, I hope to totally rebuild the F/R circuit soon with ALL mods, and maybe 1 or 2 more. I know my driver is good -- it works really well even with a gritty sounding, (JFET not biased right, etc.) F/R circuit. (It follows the generally accepted 'optimum' size too -- 3mm x 3mm cross section.) I hope with a better and cleaner driver circuit, it will really perform to its potential.

Email resent... Don't worry, when I was talking about eliminating the JFET, I was considering maybe using another 386 or similar IC chip as a preamp stage in stead. I know there is not enough initial gain from the guitar to drive the circuit. But that is only something to consider if the mods are not sufficient.. we'll see.

I did get your email PSW -- but did you get my reply back? My email has been weird lately... I think after class gets out Thursday I should have some time over the weekend to tweak my current circuit. I'm gonna add the ZN and a 10K pot right before the 386 -- as the data sheet shows. I will keep it to that for now, and see how the resulting circuit works. If it is not optimum, then I'll try some of the other stuff (like maybe eliminating the JFET all together to clean up the signal a little...)

Hehe, yes I do! I know that... I'm not running it at full -- only about at half actually. I just thought though, that there should be some more headroom in the F / R design, but now that I go back over it, there isn't really. It is meant to sound like a dirty tube... but it is capable of pretty nice cleans as long as you keep it limited. That is what I had originally in mind, until you mentioned the trim pot.... I think I will go with the pre-chip gain. Somehow I think it might lend me a little more control, but who knows until I test it. Yes, I know this too from months of failing and inefficient circuits previously constructed . Once I get rid of the oscillation or whatever in my circuit, I think it will operate fine at about 40-50% power, from what I can tell. It may even become a lot more effiecient once the distortion in gone too, so who knows -- perhaps 20-30% will do the trick. I will add the parts to the circuit when I have some time...

Oops. I totally forgot that it would stop circuit oscillation. I thought somehow it was only a guard against speaker/driver oscillation. I'll have to hunt down some more parts and add one! Okay, if you mean the cap in series between the Chips + out and the speaker/driver, then I should be good. I have a 220uF cap there. Hmm... I figured that the F / R design would allow you to run at full blast, but maybe not. This certainly could be the problem; I just assumed that the original designers did it right hehehe. I might try adding a pot there then. Before or after the 10uf cap though? Or does it really matter... Should I use a circuit mounted trim pot, or do I need to be able to access this control on the fly? It is working -- it may 'dirty' the signal a little, but who knows what effect and to what extent that will really have. I mean, it can't be too bad, since I've got the thing sustaining fine in fundamental mode even WITH that horrible feedback going on. I even got some harmonic mode action.

Hello everyone. You may remember me from way back in the thread. I apologize for not continuing my research here, but other things got in the way. I was simply too busy to do any more sustainer tinkering. I am getting back into it again though, and I hope I am able to offer a lot more help than I was able to before. Since I was last here, I have learned a ton about electronics and circuits. I completed an entire all-tube 50 Watt amp from scratch, and have been learning and experimenting with (tube) circuit design. When I read back over my old material and looked at the sustainer ciruit schematics, I was amazed at how easy to understand they are -- and I was amazed that just a few short years earlier, I had no idea what the components in even the simplest circuit were actually doing! I have also completed 10+ custom guitars over the time I have been away, and have modified countless others, so I hope I may also be able to help with research or questions in that aspect. I re-read my old material on sustainers (most of it from this thread) and I was able to build an entire driver and circuit system in 2 days! This is the same exact stuff that I had spent months on before, and never fully succeeded. The system is installed in a guitar with a single bridge HB (wanted to keep it simple) and it works, but there are some small problems I thought I would post. I used the old Fetzer / Ruby (sorry PSW hehe) with the mod discussed previously here. It has a +10uF cap inbetween pins 1 and 8 on the 386 chip. The circuit works at low volumes, but when turned up it feeds back or internally oscillates. It is NOT my driver oscillating -- it is the circuit. I have tested that, so don't worry. The only thing I can think of that might be making the circuit a little weird is that I am running about 3.8 volts on the J201 bias (which is supposed to be 4.5 volts), and I did not add the zoebel network of a 10 ohm resistor in series with a .1uF cap which is supposed to be added across the output. Any obvious things stick out? Thanks guys, it's good to be back here.

jamforthelamb- I am also in the US.... I got some of my wire from ebay -- most US dealers that sell there sell 100meter rolls (yes, even the US dealers use Meter measurements -- even though they also use AWG instead of mm!!) of magnet wire, for around US$14. I had to buy 1 roll from some dealer's website though -- I think it was the .2mm (32AWG) coil. Sometimes there aren't all gauges on sale at any given time on ebay. newfuturevintage- That driver looks really good -- especially the coil. You should see mine (total mess, though they usually work...). However, Col is right about the welding bar. I actually used that same type of barstock (3mm thick) as the CORE of my driver -- but using it like you did might block some power coming from the magnets. Try it anyway though, like it is, because it might still be powerful enough to work just fine. Also, the brass 'cover' also bothers me... I remember a large discussion a while back about using shielding, and I'm pretty sure it was discovered that any conductive material near the driver would mess with the electromagnetic functions of it. Plus, if your coil's insulation rubs off in 2 spots, the brass could short it where the plastic would not. Being a trumpet player too (yes, there is more to life than guitar ), I like the look of the brass though! Good work. -MRJ

Hello newfuturevintage; It's good to see some other Americans getting into this! Actually, I can't believe this great thread isn't much more popular in the US..... it should be.... Yes.... it is... I wish I would have known that when I started; my first trip to radio shack did not produce any magnet wire (I think they were out of stock) and so I sourced some 30 AWG (by the way, since this is an international forum, we have to convert everything to mm.) 30 AWG = .25mm 32 AWG = .20mm Anyway, since then I have also sourced some 32 AWG / .20mm wire, and that is the best stuff so far. However, my first driver (single blade style) used .25mm wire, and it worked VERY well, so don't be discouraged at all by the .25mm wire from radio shack. If you build the circuit/driver combo well enough with .25mm, it WILL work. For what you are doing, the difference between those 2 wire sizes will not make your driver work or not; it will only affect performance, etc. You really have made quick progress compared to most of the rest of us. Good work. -MRJ

Nice job PSW!!!! I thought that stuff was epoxy..... definitely use black or something really dark though. You can kind of see through the white, and makes it look like it had an accidental fall into paint That switch also looks like it will be very usable as a 'controller' -- which is something I was worried about when I found out that you were putting all controls (that used to be 3 pots and 2 switches!!) into one unit. So I am confident that this thing will work in my guitar in the future. Also, my sustainer guitar is ready to be painted (and this one is going out to a real artist, unlike my last one which was subjected to my spray painting [the red one]), so it will probably be ready to test out your unit by the time you send them out/sell them. Good work, -MRJ

Yes, now I can see that "supermicrophony" is the problem! If the driver is too strong, the strings will rise in volume to a point, and then go out of control and "distort" -- for lack of a better word. I think PSW or Col had this problem at one point, ask them about that. If the sustained volume is level now, but not too quiet or 'slow' to react, then I would say that your level is about perfect! As I understand it, {{{30AWG is .25mm wire}}} {{{32AWG is .20mm wire}}} I used .25mm wire on my single driver (in the youtube video) but I am remaking that one with .20mm wire. PSW and others on this forum have established (and now I have confirmed) that the .20mm is just better for single 8ohm driver coils. I am working on rebuilding my single coil driver right now, so we'll see how it works with the PSW circuit later on. -MRJ

Uhmmm.... I think you may have a way overpowered driver, or maybe just a super-microphonic driver here. You shouldn't be able to hear any sound from the driver.... Plus, the fact that you can't get it anywhere near installation distance from the pickups without squeeling would indicate to me that it is overpowered. But good job anyway so far. Your circuit looks really simple and clean. And at least you have a working driver period at the moment.... (I managed to screw up both my circuit and drivers now....) -MRJ

Ooooo, pretty driver coil.... That kind of smoothed-looking precision is something I appreciate, having made some very horrible looking driver coils myself. By the way, I checked the original measurements I made a while back of my pickups -- they are perfectly accurate, so you can use them as a reference for most strat copy/cheap electronics strat guitars. -MRJ

Sorry-- haven't been responding lately. I am very busy with school and my new 5150 Combo (something in the tubes got damaged during shipping.... but wow is that amp a beast!) But I just wanted to let you all know that I have been keeping up with the reading. And that I am looking forward to pics in the near future, and a PSW S***** Kit guitar in the somewhat far future! -MRJ

I think even the 1.5mm depth that you were talking about earlier will satisfy about 95% of your customers anyway. It just really isn't a big setback when you consider the advantages of the 'system' and new options in playing that come out of it. Plus, for the other 5% of the people who just HAVE to have it flush-mounted, they could take a dremel tool mounted like a drill press, pre-set its depth, and have at it with the inside of their pickup cover! (Although I wouldn't advise thinning out your cover that much...) The best (and coolest looking) option right now, in terms of selling a pre-packaged unit that eliminates the 1mm cover offset, would be to make some sort of blade-over-pole system that would stick onto the top of the pickup cover magnetically, and completely hide the poles. You could even put 1 sharp tack-like prong on each side, coming out from the bottom of the blade, that would add extra stability when they poked into your plastic pickup cover. However, I really don't think that the looks of this device are super important right now, (if ever), so don't worry about it! -MRJ

Ya-- we are on at the same time -- weird. Oh, hey PSW, I also do video editing/mastering (much better than I do electronics building/soldering, unfortunately) in addition to the audio recording/mastering/etc., that I mentioned before -- If you need video or audio stuff like that in presentation form on a CD, just let me know.

Score #2 For Col! Wow. Hey, just an idea.... As I understand it, you will be modeling PSW's driver in FEMM right? If you get that model/scripting working, try making another model file with a solid 'blade' core in stead of 6 poles, but with otherwise the exact same specs. I will beta test PSW's system in its original "stock" state -- but I am also going to try a blade that replaces the center poles in a standard SC pickup. If it works better with the blade, I'll show how to 'mod' PSW's kit, or in other words, the standard SC pickup, or maybe even he will want to offer a 'conversion-to-blade' kit if it works really well. Who knows. But it would be interesting to see what FEMM says about it... -MRJ

Nice work Col. That "cage" design is what I was trying to do with my shielding project a ways back in the thread. I figured that there was a way to use magnetic (Steel) 'fins' to channel the magnetic field, but I just couldn't figure out how to apply my theory. You seem to have figured it all out perfectly! I did try some channeling on my single coil design and got some improvement in response, etc., but I had no way to really tell what it was that I was doing that was actually helping. Now I think I will have to get out the angle iron that I was using before and cut some new fins to stick on my dummy pickup / PSW kit driver "unit"...... -MRJ

65.57mm Well, lucky for you all outside the USA, my digital micrometer has a mm setting accurate to the 000.00 decimal so my measurements are VERY accurate. Hmm, well I know mine are NOT tele pickups, and all 3 of them on that same guitar were exactly the same size. -MRJ