Hello.  I'm new to the group.  I'm just a casual player but like to do my own guitar setups and improvements.  I'm working on a Fender electric acoustic 400CE which has a Fishman Isys III under saddle pickup/transducer.  As I like to improve cheap guitars for myself I'm wanting to change the stock saddle to an unbleached bone.  I'm also changing the stock tuners to Shaller GrandTunes, going to slot the bridge for the strings, perhaps a zero fret, etc.  Questions:  I've done a lot of reading on saddle to bridge coupling when I was upgrading a non-electric acoustic that I have and employed what I learned when putting in a new saddle on it.  Real believer of good saddle/bridge/string coupling to bring out the best sound.  Seems to me that an under saddle pickup if one wants to play in an 'unplugged' mode is contradictory to good sonic coupling at the bridge.  I'll probably experiment with a sacrificial saddle with the UST removed to see if I'm crazy or not.  Before I switch to a bone saddle to get rid of the plastic one, I'd like some opinions about bridge coupling with a UST.  From what I can tell, to get the best of both worlds (plugged in/unplugged) it would be better to use a different type transducer perhaps mounted under the bridge plate but I'd like to use the original preamp.  Thoughts?   

Tags: UST and Bridge Coupling Delema

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I think those UST's have a DC bias applied to them to make them work , and so a standard UST piezo won't work with that preamp . I could be wrong , but thats my memory of it . I think as long as your slot is deep enough and reasonable break angle over saddle , you won't hear much change , bone is better than plastic of course .

Thanks for the reply Len.  Certainly agree with the bone - nothing manmade like it.  I'm assuming that when you said "standard UST piezo" that you meant an alternative under bridge plate type.  On the DC bias I'm guessing polarity.  I'll try and get info from the preamp makers an see if I can get some data.  Regarding the saddle coupling and break angle.  I would sort of agree with the Epiphone as the saddle is snug in the slot still allowing good seating on the UST, the UST doesn't have much of a 'pillow' feel, and the and the break angle is good (even better after I string slotted and slightly ramped the bridge).  The coupling then would be the front/back of the saddle and the good string connection to the bridge/bridge plate.  However, the Fender original saddle is loose enough to where the only way to have saddle to bridge coupling would be by a lean towards front or back.  The Fender break angle is good from factory (I haven't string slotted the bridge pin holes yet but intend to for at least the reasons of having better string ball fitting) but the kicker for me is the UST feels like a sponge under the saddle to the extent with the strings removed the UST is almost like a spring when you try and place the saddle in the slot.  Doesn't make sense.  Perhaps it is as simple as replacing well fitted bone saddles and leave the rest alone but curiosity has the cat and I'll probably experiment.  FYI - I have worked with MacNichols Guitars for a bone saddle source and would recommend.  Retail bone saddle is 15 bucks and will polish for an extra 4 dollars.  I asked him about the saddles for the guitars discussed and he will make them with a custom radius at no extra charge.  Don't mean to be dis-respectful to luthiers who make their own.  There is also a very good discussion on the acoustic guitar forum on the UST theory topic.  Greg 

Hi Greg,

Providing the saddle is a snug sliding fit and well seated on whatever is under it you are immediately into using recorded A/B comparison information to determine what if any difference is noticeable.   The very act of thinking about what differences are expected coupled with the time between changing the components is enough to nullify any meaningful ears only comparisons.  Particularly with a relatively low performance acoustic guitar.   Overarching that is that the senior 50 year old guys with lots of experience don't have the hearing response of a 20 year old and what they don't or can't hear can only be accounted for by A/B comparison and standardization measures.    Consequently, a lot of discussions and verbiage are not valid from the point of view that the writer has a different hearing response to the reader.

Changing out the plastic bridge and nut to bone or a quality synthetic will no doubt provide variance but in this case with the sloppy fit plastic job, just sizing up and snug fitting the replacement is likely to make a more significant difference than the material chosen or what its clamped onto.   

I don't consider bone to possess any magical voodoo qualities over engineered equivalents, Frequency response and density is not an exclusive property of cow skeletons and apart from  the traditional craft origins just gets too much attention from endless regurgitations on endless forums by people who should know better.   Unless you are going to machine your saddle slot base dead flat under simulated string tension its a trivial discussion on coupling anyway.  If anything a flexible UST and or saddle with a bit of give will do more to match and conform to a bad saddle slot base than its inherit difference in density (whatever that may be) changes the tone.   A dead flat piece of bone will not give and will decouple the bridge from the soundboard/bridge more than a dodgy piece of plastic if the saddle slot base does not match up with bridge saddle.

There is more, and my fellow associates on this forum know it, maybe someone else can pick up this a bit so this messenger has less risk of being shot.



My apologies Len.  Duh on the polarity.  Yea - Fishman may use a DC Bias voltage which the signal rides on.  I'll see what I can find.  Fishman did tell me their input impedance specs (1M Ohm to 10M Ohm).  The Esonic has an input impedance spec of 4.7K Ohm with no bias voltage discussed.  As discussed in some other replies, I'm maybe looking at a JJB Electronics SBT (1M Ohm advertised happy impedance).  We'll see what happens. 

Russell, no shooting from me so no fear. I value your input as well as others from your associates. I can weigh all the inputs and come up with the best 'truth' Very good point on the saddle slot in the bridge. Not really sure how one would check that other than with a micrometer depth gauge and even then the measure from point has to be truly flat which a bridge top isn't. Easy enough to verify saddle bottom flatness. I also get the point about with a low performance instrument to begin with but it is what I have and can afford for now. Besides as I improve my skills I'd rather do it on something moderately inexpensive and leave any destruction at that. Potentially another valid statement is about the UST maybe providing an 'engineering slop' filler. I could agree with that if the sensor was reasonably thin and uniform as is the case on one of the guitars but I disagree where the "filler" is ridiculous. The only reason I really choose unbleached bone is (1) I have good experience with it not only from a sound perspective but also just as importantly for me it wears minimally, and (2) I have a good source for it (quality and cost). The only synthetics that I have experience with is plastic or plastic derivative like NuBone both wear quickly. Welcome synthetic material suggestions that parallel the tone/wear balance of hard unbleached bone. As I said before, the best practical answer to all this may be a decent saddle material properly fit but seems like there is an awful lot of very qualified sources saying that solid direct contact formed by the string to saddle/supporting break angle, then saddle base to bridge slot to form the couple is the optimum and in some cases the only satisfactory way to go. I could perhaps be swayed to compromise in saying that a well front/back saddle sides to bride slot fit is next best.

In humor, I'll take what you said "The very act of thinking about what differences are expected coupled with the time between changing the components is enough to nullify any meaningful ears only comparisons. Particularly with a relatively low performance acoustic guitar. Overarching that is that the senior 50 year old guys with lots of experience don't have the hearing response of a 20 year old and what they don't or can't hear..." as an attempt to humble me. I'm 60, still work for the Navy 37 years, and am certainly not humble.

Hi Greg I'm 64 and worked Air Force for 30 years,  I'm a professional luthier and run a full time repair and maintenance service and we are heading into our 20th year of operation.   We measure stuff and concentrate on knowing what makes a difference and what doesn't so as to provide good advice to our customers and not waste their (and our) time and money.   Consequently, I spend a lot of my time having to talk customers down from a frenzy of web induced paranoia or misinformation.  I do not think that this overstates the case and I don't enjoy the process.   Opinion and reality often collide and I don't like being at the scene of the collision.  

I agree that all the bits need to fit together in the drive train for optimal results but as I said, if the basics aren't present or the instrument isn't capable of responding because of its limitations the rest is all a bit academic.   I also reiterate;  if doing what we are doing reaps no appreciable or readily discernible results then I would sooner spend the time (which is, in my case, money) doing something which makes a real improvement.   

Synthetics like Tusq (Nubone is the cheaper down market version) wear out faster than bone:  so what?  We replace strings, saddles nuts and frets  when they wear out and enjoy the improvement that a new replacement unit makes - That your two biggest acoustic makers use synthetics on just about everything is validation enough.  Don't fall for the argument that they don't use bone because it is too expensive - a cnc machined bone saddle or nut is a couple of bucks different in bulk and installs just the same.   Consistent performance and predictable sonic qualities are one reason we use synthetics although we will cut a custom bone component if the customer insists (and we get to  buy craft beer instead of tap at the end of the week).  

Regards, Rusty.

Well Rusty, small world.  After active duty Navy servicing S-3 carrier aircraft as an avionics tech I got into aircraft software life cycle support and now am the software release manager for the V-22 Osprey program.  In addition to the USMC birds I also handle the AFSOC variants.  My interest in guitars has sort of resurfaced post mid-life whatever both playing and doing much of my own setup/repair work.  I already have a good skill set with tools and hands.  The working on the instruments is highly rewarding to me enough where the skills and the craft kind of naturally come together.  I've given thought to going to school on the craft perhaps doing some work for others if I ever retire.   Don't really want a full time second career but no lazy boy for me cause those guys are the first to go.  Anyway, I sincerely appreciate the feedback.  Actually sat down last night and just played partly to evaluate whether  doing anything is worth it (except changing the really crappy stock tuners) then my G string broke at the nut (darn it - new set of strings too).  I looked at that and because the particular guitar headstock is a little big and where the tuners are fitted, there is a significant break angle from the nut to/from the tuners.  Probably a little rounding of the string slot edges at the break is in order.  Life goes on.  Greg

Hi Greg, I retired 20 years ago and fell straight into a second career which as it turned out was as rewarding and much more challenging than my first (Nav/Sensor Op P3C Orion). Started life as a Scientific Instrument Maker/Fitter (your Aviation Tech equivalent) and went back to school to get into flight school - which has bought me full circle.   Currently studying valve amplification as a "hobby" to distract me from the guitars. Running a business well is the hardest and most stressful part of the gig, but it's also a source of much pleasure when it works.  Recommend this as a good second career choice.  Take it easy and look forward to hearing from you on forum,


I might suggest looking at Schatten HFN pickup? You could hook it to your existing preamp and it mounts easily in the guitar on the bridge plate. I use them in all my own instruments and can’t discern any effect on acoustic tone. Upside is plugged in there is less UST piezo tone, picks up a bit more body I think?


I looked up the Schatten HFN options and thanks.  While I'm still determining what I want to do (if anything) the is a JJB Electronics offering I think for about 22 bucks and change.  It is a dual 20mm SBT rig and comes with a 2.5mm plug which would work with one of my guitar preamps.  At least for an easy inexpensive test.  I did read on the Shatten site discussion about the HFN having a single transducers and their views on the positives on it.  Interesting point they made about mechanical conflict of multiple sensors on the bridge plate.  Heck, I guess I can test that too.

Well Rusty I didn't know we gave the USAF P-3s. Even smaller world as S-3s and P-3s were out of the same Navy program office (PMA-290). Someday we'll have to share sea stories.

HI Greg,

Royal Australian Air Force, (A)P3C Update 2.5. Best way to get to a party I know!  


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