DIY SUSTAINER...hear for yourself

[JimRayden]

It just flashed to me... what if I took a little speaker and attached it to the body of my guitar to make it vibrate. I guess there would be some problems with that, as the guitar is alot tougher to move than the cone and it would propably just cause lots of squeeky feedback.

Any thoughts on this?

-----
"One fun thing to do with it was using without an amp and just sitting there holding out notes forever."

Oh yes, imagine doing those long-sustaining solos on an acoustic. Creepy stuff

--------
Jimbo

[Bernardduur]

I once tried the same but than with the microphonic option of a pickup; mount a speaker under a pickup with the fed back signal makes a bit sustain.......

Took it off; it was too much of a hassle

[Doug_H]

That really sounds awesome!!!

I love the clean chords.

Doug

[Somicide]

I would so love to put on in my guitar, but alas... I have an EMG setup.  

and at $94/pop, I'm not pulling them out.

now, if I can get that 2nd guitar, you might have a deal...

PnL,

Jeff

[psw]

While it is a goody, the 386 is as old as the hills and there are lots of other little amp chips available these days with pop-less operation.

Remember that there are hundreds of chips that were introduced 20 years after the 386, which have already become obsolete.

Philips is one company to check with, TI is another.

Oh yea... when it comes to other chips out there, the fact that your driver is isolated from the signal ground allows you to use bridge configuration
outputs. That greatly expands the number of chips available. You might be able to get this whole thing to run at 3.6V in which case you could use a lithium polymer battery and reduce the size drastically while greatly increasing service life. The only gotcha is the need for a real Li-poly battery charger circuit, but there are zillions of those out there too. (see Maxim and Linear Technology to start)

That sounds great...can you suggest some actual chip number's or series to check out...I've looked a little into it, was thinking of D class amps...but I only know electronics from what I run into and use...it's a little limited...

The driver takes a fair amount of current to run, and I think that's where the real power consumption is happening, it may be unavoidable...

I've designed and tested the thing with rechargable 9v (8.?) batteries but they don't last too long on a charge compared to a normal battery...the cost of a charger is not really an issue compared to continuously having to change batteries... :wink:

So any info, or suggestions for further study would definitely be appreciated...

pete

[psw]

It just flashed to me... what if I took a little speaker and attached it to the body of my guitar to make it vibrate. I guess there would be some problems with that, as the guitar is alot tougher to move than the cone and it would propably just cause lots of squeeky feedback.

Any thoughts on this?

-----
"One fun thing to do with it was using without an amp and just sitting there holding out notes forever."

Oh yes, imagine doing those long-sustaining solos on an acoustic. Creepy stuff

--------
Jimbo

Well...while not suggesting anyone read the whole sustainer thread...it's so long cause it's open to all ideas regarding sustain and covered a lot of ground, Ansils synth like sustain generating box, ebows, gizmotrons...and of course the old vibrating guitar idea....

Here's a link we looked at and some ideas I really tried...
http://www.marksmart.net/gearhack/feedbackgen/feedbackgen.html
that's not me BTW...

An old trick in the studio has alway's been to jam your headstock against the speaker baffle of your amp to generate feedback sustain...Sustainiac's Model "C" acoustic sustainer is the same thing...a transducer fitted to the headstock...

I have to say, I didn't have a lot of luck...it does kinda work...but then again...nothing like the electromagnetic string driver idea, which is a lot more elegant...IMHO. Some reported having more luck by placing the speaker on the headstock...you certainly could put a lot more power into it as you're well away from the pickups and got a lot more flex and leverage on the strings...must look a bit weird...and it does make a bit of a racket, it's not silent...
---------------------------------------------------------------------------------

On the acoustic thing...yeah, it doesn't need to be plugged in to get sustain  :wink: . I don't have a electro acoustic but I imagine if you mounted one of these small drivers in the soundhole like a magnetic pickup sometimes is, you could probably drive it with the piezo output...Not been tried yet but there is a guy about to with some graphtec piezo bridge saddles on a fretless guitar.

I also have a project planned for a DIY piezo "buzzer" mounted to the bridge on this test strat...that's what the other knob is for on the test strat... :wink: . I'll do some tests to see if this output is ok to drive the sustainer circuitry...

So a sustainer/acoustic is a distinct possibility...it really would change the way you could compose for the instrument. It would take a lot of technique (a la Tuck Andress) but you realise that, like the ebow the sustainer can generate notes from nothing (no picking) they just swell up when a pitch is fretted, especially with the bass strings.

The track clean chords (thanks Doug H)hints at that...imagine developing a style where you play a walking bass line with a bowed sustained effect (sans picking) with a melody, chord or lead above it...on an acoustic, if you like...so many musical possibilities...

And really that's what's driving the sustainer project...the musical possibilities...someone is going to make some beautiful and amazing stuff with this kind of device...my role is to facilitate it by helping to make it as widely available as possible...

Meanwhile, us mortals with lesser technique can just have a whole lotta fun.... :lol:

pete(r)

Oh....Bernardduur...sounds like Ansil's Sustainer Mod...kind of works a bit different...it's a kind of inductive compression type of effect...poor Ansil's copped a bit of flak for that and moved on to better things...worth a go if you're into experimenting, and that's what it's about really....

[psw]

I would so love to put on in my guitar, but alas... I have an EMG setup.  
Jeff

You may still be in luck....

A PG member Tim/onelastgoodbye is...not only a fantstic graphic artist/designer (check out his amazing 3D realizations in the early 30pp pf the sustainer thread)...but is actively working on making drivers like mine, and plays an EMG equiped guitar.... :lol:

At the moment he's a bit busy designing the most amazing toaster (hi Tim :wink: ) but has made several drivers...you'll have to find his posts.

The driver does not have to sit on the pickup...everyone else is making independant drivers...here's a pic of a couple of mine...

The thin one is about 4mm thick and 10mm wide...it's identical to the one on the pickup used on those tracks. You can see on the bottom a few little Neodyminium magnets in an attempt to make it smaller...these could also be incorporated into the core of the coil (replacing the blade) which would make the wole thing very slim...possibly slim enough to fit under the strings without having to cut into the guitar (the wires could enter via the pickup route)...

Tim has experimented with the magnetic core thing too with success...his drivers (and circuit) are not quite the same (thicker wire, looser windings, etc) as mine and he's experienced a few problems (squeeling...) but these are not related to the EMG's...

So...the pickup driver...neat as it is...is only one way to install it, and EMG's don't necessarily restrict you...find a suitable place for the driver, now that may be a problem.... :wink:

Some nice replies....thanks...very encouraging and helpful...I hope my answers encourage and help you in return...

pete(r)

[psw]

While it is a goody, the 386 is as old as the hills and there are lots of other little amp chips available these days with pop-less operation.

OK...so I've done a search here...can't seem to find anything on class D amps or a suitable replacement for the LM386

So...I did a search...
so..many...c.h.i.p.s... :shock:

So...I'm back again....

found things like this...NCP2820

Features

Optimized PWM Output Stage: Filterless Capability
Efficiency up to 90% and Low 2.5mA Typical Quiescent Current
Large Output Power Capability: 1.4W with 8Ω Load and THD+N<1%
Wide Supply Voltage Range: 2.5-5.5V Operating Voltage
High Performance, THD+N of 0.03%@Vp=5V, RL=8Ω, Pout=100mW
Excellent PSRR (-65dB): No Need for Voltage Regulation
Surface Mounted Package 9-Pin Flip-Chip CSP (SnPb and Pb-Free)
Fully Differential Design. Eliminates Two Input Coupling Capacitors
Very Fast Turn On/Off Times with Advanced Rising and Falling Gain Technique
External Gain Configuration Capability
Internally Generated 250kHz Switching Frequency
Short Circuit Protection Circuitry
Pop & Click Noise Protection Circuitry

 Application  

Cellular Phone
Portable Electronic Devices
PDAs and Smart Phones
Portable Computer



The NCP2820 is a cost-effective mono Class-D audio power amplifier capable of delivering 2.65W of continuous average power to 4 Ohm Bridge Tied Load from a 5V supply. Under the same conditions, the output power stage can provide 1.4W to a 8 Ohm BTL load with less than 1% THD+N. For cellular handsets or PDAs, it offers sapce and cost savings because no output filter is required when using inductive transducers. With more than 90% efficiency and very low shutdown current it increases the lifetime of your battery and drastically lowers the junction temperature.
The NCP2820 processes analog inputs with a pulse width modulation technique that lowers output noise and THD when compared to a conventional sigma-delta modulator. The device allows independent gain while summing signals from various audio sources. Thus, in cellular handsets, the earpiece, the loudspeaker and even the melody ringer can be driven with a single NCP2820. Due to its low 42uV noise floor, A-weighted, a clean listening is guaranteed no matter the load sensitivity.

Sounds great...Ideal even...more than enough power...

Only seems to come in some 9 pin SMD package...very small...read: how'm I s'posed to solder the little bugger...

Probably a minimum order...definitely not radio shack...

So...anyway, might need a little more advice on this one...sure the LM386 is old but what's it's typical replacement...?? In all the projects here and elsewhere (typically practice amps), I haven't yet seen anything...they all seem to use LM386's

So has anyone got any suggestions, seen anything on the forum or elsewhere that could set me on the right track...?

pete

[Somicide]

so then, if i were able to find a way to seat it (low action, its an ibanez rg170, think I have maybe 5mm)) I could put it somewhere unobtrusive, and hmm.  

it doesn't actually go to the putput, does it? It just keeps the strings vibrating?

PnL,

Jeff

[psw]

that's right! :lol:

[PCS]

Is there any reason you couldn't put a secondary winding on a regular pickup, or just rewind a regular pickup?

[psw]

Not sure what you mean PCS...

My Pickup/Driver combo is just that, a secondary winding on top of a regular pickup...

If you mean winding a driver coil over the top of the pickup windings...no I don't think that's a goer...too far from the core

If you mean winding an inner driver coil...quite possibly...want to have a go...it does mean a total rewind, not everybodies cup of tea...

As for rewinding a pickup as a driver...plenty of people have done this with success...I'm told! I tried it with limited success...possibly too thin winding wire to carry enough current....so not really conclusive.

It will work...again you're sacrificing a pickup to do it...most of the guy's doing this do seem to be using pickup mags and such. The blade design is pretty important if you want to bend strings. I did make a very good one out of a super cheap pickup now that I think of it and is pictured next to the slim driver earlier, worked very well but was a slimish pickup bobbin to begin with...

For various reasons the slim design has proven to be most successful. When people ask "is it really that simple...is that all there is to it", well you could check out the sustainiac circuit from the patent which runs to about 4 pages of schematic with AGC, phase correction, etc, etc,...but they are trying to address problems with the system inheirent in their driver designs...I believe...otherwise it's BS.

Lovekraft very early on suggested that I work on the driver design, not the circuitry, so that's what I've done...the solution may seem simple but the results from very basic circuitry is great...so either I'm on to something with the driver formula or I'm just lucky, but the super slim driver has performed better for everyone who's tried it, so what can I say...go figure...

pete

[psw]

Excited...You Bet....

Ok...it's only 10 mins old but I couldn't wait to show it to you all...

Here it is...the new...portable, psw guitar sustainer test kit....



Modeled here on my black beauty, lounging on the couch...there's a black box plugged into the guitar (with a battery clipped to it's side, and red LED)...an amp lead so you can hear the thing, from the box...a driver attached to the neck pickup of the guitar (blade pole), lowered to accomodate it, and simply by the power of the pickup's magnet...

So, already it's shown that with a guitar like this (PAF style humbuckers) the sustain is insane....   :twisted:  

This setup duplicates what's in the low powered strat, same driver (sans pickup) same circuit but on this guitar...only the tiniest amount of power is required...on a control from 1-10...about 0.5...!!!!

Lp=big fat sustain...LP with sustainer=big fat sustain, forever...!!!

Who knows how long a battery'd last with this amount of power going to it.... :lol:

Anyway...couldn't wait to let it be known...even the "pop" is less, and only on turn on!!! I didn't even need to disconnect the neck pickup, just used the selector to turn it off...go figure...!!!!

pete

[Somicide]

so will you be releasing a PDF or something on building this baby?  It'd be killer on a particular song of mine!

-PnL,

Jeff

[psw]

Here's another pic showing some mods to it...I've added two trim pots for preamp and poweramp gain...seems as if I need to calm the thing down...

The important thing to see is the size of the driver...that's where the magic lies. It's 3.5mm deep (slim), 12mm wide and the core is 3mm steel.

As for the amp...still open to suggestions...I'm sure it could be better and certainly smaller...

For info on some of the stuff I've been trying...check out the sustainer thread for a really long post....

oh...Somicide...since you seem keen...I recall you have EMG's as my friend Tim (on the other side of the world) does...I asked a couple of questions about EMG's that you could look into over there too...I could have some ideas for you... :idea:

EMG's are really just preamped conventional pickups (so I believe) in which case, if the magnetic field is comparitable to other pickups, this kind of "driver top" may just as easily work for you...as they're already preamped, there's no loading from the poweramp, so it may be possible to dramatically shrink and simplify the circuitrt, and of course, you've already got at least one battery on board...could be you've got the perfect set up for this thing...give me some clues and we'll see what we can do...!!!

enjoy, and good night...

psw

[Peter Snowberg]

Congratulations!

Fantastic work!

I've never played with class D amps, but they look interesting enough for the efficiency.

I would find something in a larger package. :lol: That's a flip-chip which the size of the actual semiconductor die. It's only 0.057" square. BGAs like that flip-chip are the only things I have not been able to solder with a regular iron. Most tiny SMDs are really easy and take only a fraction of the time it takes to install DIPs.

I picked out a bunch of amp chips in my surfing, but I had different selection criteria so my list is somewhat useless unless you want a list of what's second best for your project.

You want something with pop-less power up, BTL output, externally selectable gain, and a package like SOIC-8 or even SSOP-8. Class D is an option if you're adventurous but AB is just fine.

For batteries, check out Spark Fun. If you can get operation down to 3.6V or so you can use a lithium-polymer battery. Option 2 would be a pair or trio of NiMH AA cells. The energy density of both of these options is huge in comparison to a 9V.... well at least if you don't use 9V lithium cells.

For SMD soldering, look at Spark Fun's article about their "reflow skillet".

For getting chips, use http://www.digikey.com . I just went there, searched for "audio amp", looked in "Amplifiers - Audio(528 items)" in the ICs section, and then filtered by case style for SOIC-8.... that brought it down to 102 items in 5 pages. I've never used it, but take a look at the TI TPA701 series. Th shutdown input reduces drain to 1.5 NANOAMPS which is so far below the self-discharge of the battery that you could consider it "off".

[psw]

Thanks Peter...

I checked out a few things...again, so many chips.... :?

Anyway...looked at the TPA721...looks pretty promising...

One problem has been preamplification with the circuit designs. A raw LM386 really loads the signal down...while my preamp is fine, it's almost twice the size of the LM386 section...

So...looking at the TPA721...will this require a preamp do you think...

I'm not sure if this is the relavant bit of the .pdf, but...

Given that the TPA721 is a MOS amp, the input impedance is high...recommended effective impedance seen by the inverting node of the amp be set between 5kohm-20kohm...

If not...are there any amps that can drive speaker loads and accept a guitar's input without loading, or have their own preamp built in???

BTW...this is to anyone...not just Peter

pete

Oh...here's one...what about a TDA7052...looks good, low external parts and DIL pack for DIY'ers but same questions apply re: pre-amp...any thoughts...?

[guitarmonky55]

would there be any negative effects if i wired up this circuit to a regular single coil pickup? i have a few epiphone coils from some old humbuckers, each coil is about 6k with individual poles and i have the alnico magnets to match.  maybe ill give it a try.

[psw]

Um...I'm not sure quite what you mean...a bit tired lately, sorry...

By the way, I think I saw your nic' over at PG...if your new over there, welcome and join in on the discussion on the sustainer thread there...

So...you've got some old pickups...humbuckers, yeah...and you want to do what...Hook them up??

Now...if you wanted to strip the wire off the bobbin (if that's what you mean) yes you could... However, I'd suggest blocking up the bottom half or more of the bobbin to create a slim coil at the top...see how slim my driver is above...like that... You could use the other coil as a single coil...

However, you'll be destroying a perfectly good pickup. You could simply make a driver coil like mine above, and stick it to the top of the pickup and install it, or (as I'm now working on) just stick it on your guitars existing neck pickup...

Remember the guitar must be wired so that when the sustainer is on, only the bridge pickup is on. You cant drive it from the other coil of the humbucker (too close) or the coil the driver's installed on...

Anyway...have I got the question right..? Oh and the blade style is kind of necessary if you do a lot of string bending (more important than with a pickup)...

This brings up something I wanted to mention...It doesn't seem to be the circuitry that's daunting to most (even those who've never been burnt by an 'iron) it's the coil winding...

Really this is a shame, for about A$7 (US$5) you'll pickup a coil of choke winding wire (0.2mm), enough to make a whole bunch of coils. This stuff is thin but not that thin that it will break when hand winding (about 200 turns) or soldering...it's really quite strong...not at all like pickup winding wire that's hair thin (0.063mm) and very fragile...

So my message is...it's not as bad as you might think to do, and cheap...plus if you stuff it up...you've got more to practice or experiment with...so the message is, don't be put off by the winding part...

Anyway...feel free to join in over at the Sustainer Thread and I'll return here as replies come up or developments occur...thanks for all your help guys and keep it up...

There may be some new sounds coming too with the new toy on another guitar...so stay tuned...

psw / pete

[PCS]

would there be any negative effects if i wired up this circuit to a regular single coil pickup? i have a few epiphone coils from some old humbuckers, each coil is about 6k with individual poles and i have the alnico magnets to match.  maybe ill give it a try.

If I understand correctly, the reason you can't do this is that with a 6k pickup, you'd have an almost 7000:1 impedance mismatch to your 8Ohm LM386 chip, which might give you some SME faults. :shock: