dori2o Posted August 26, 2008 Report Share Posted August 26, 2008 (edited) As the title suggests I need help with the piezo pickup for my homebuild semi-hollow acoustic. I want to add volume/tone controls. can anyone advise how I can do this, provide a schematic, wiring diagram etc? Do I have to make a circuit? or can I put the volume/tone pots into the circuit without one? Will it need a power source? 9v battery? Is it cheaper to but a preamp and gut it? any and all help appreciated, build is on hold until I can figure this out as I need to know what pockets/channels need routing out of the body. Many thanks in advance to anyone who can help. Edited August 26, 2008 by dori2o Quote Link to comment Share on other sites More sharing options...
psw Posted August 27, 2008 Report Share Posted August 27, 2008 Welcome dori2o... As the title suggests I need help with the piezo pickup for my homebuild semi-hollow acoustic. I want to add volume/tone controls. can anyone advise how I can do this, provide a schematic, wiring diagram etc? If you search here you will find a variety of circuits and ways of doing a DIY piezo things... There are a number of things that are unclear... How much experience with electronics you have...have you ever built circuits before? What do you expect from the piezo? Is it the only pickup, or is it to augment a magnetic pickup? Do you already have ideas of how you intend to mount the thing (under the bridge for instance)? What do you intend to use as a piezo...a buzzer element is a common DIY approach for instance? Where in the world are you? It is hard to recommend things if you don't have access to the resources (for instance, I am in Australia) Do I have to make a circuit? or can I put the volume/tone pots into the circuit without one? Generally yes, it is a matter of impedance. You can literally take a piezo element and plug it into a guitar amp and it will make a sound, it will not sound very good and will not mix with magnetic pickups due to "loading". Volume and tones will not be very effective without a preamp. Will it need a power source? 9v battery? Yes...if there is a preamp, you will need a battery! Is it cheaper to but a preamp and gut it? Quite possible, although some are more difficult than others...again it depends a lot on the application. You can get some acoustic piezo undersaddle and preamps as you would find on the side of an acoustic guitar for a reasonable price, cheaper than something similar the DIY...pulling things apart often requires some ingenuity and experience, a lot of these small preamps have slider controls that are physically mounted to the actual circuit board. I have a couple of these such things and it is an area I have done a little work on and looking to explore a little more in a number of ways... Hope this helps for a start, more details of the project and your ideas, resources and experience would help...also do a bit of a search around and see what else has been done. I seem to recall a strat with piezo bridge and modified preamp built into it, there are various buzzer ideas and a bunch of circuit ideas. pete Ps...if you have some electronic experience but not a lot, a preamp kit and buzzer idea can work out ok. The response of the piezo or even multiple ones can be greatly affected by where it is place...it is possible even to put one inside the neck socket for instance. Be aware also that piezos work by vibration, so it will pickup handling noise and such unlike magnetic pickups. Quote Link to comment Share on other sites More sharing options...
dori2o Posted August 27, 2008 Author Report Share Posted August 27, 2008 (edited) Thanks that is a start. I'm in the UK by the way. I have some knowledge of electronics, but it was some time ago when I did my appenticeship in engineering, and I can read a schematic quite competently, so wiring/soldering etc isn't a problem. The guitar itself is essentially solid piece of ash cut into the guitar shape, with sound pockets and wiring channels routed out, covered with an Oak veneer on the front (to cover the sound pockets and routed channels for the wiring), and a clear varnish or whatever on the back. 12 string neck and headstock handmade from maple stock. I do like the slider pre amps, but they are too big for the body of the guitar, hence why I was thinking of gutting one. I don't really want to go down the route of using coil pickups cause I want the guitar to look like an acoustic, I dont want pickups on show. Unless someone has an idea on how I could use a hidden single coil/humbucker pickup? I was hoping to make an under saddle pickup from piezo cable, not really sure if an under bridge piezo disk would work as the veneer is approx 6mm thick. Regards dori2o Edited August 27, 2008 by dori2o Quote Link to comment Share on other sites More sharing options...
psw Posted August 27, 2008 Report Share Posted August 27, 2008 Ok...thanks The UK still has access to electronics so that is possible ...I will try in the next day or so to dig around here as I think I have a few different ones around that are complete systems of the kind you would need and have the under bridge cable thing (I wouldn't know where you would get them otherwise). The preamps are typically fairly small and have a few eq and volume sliders...I will post some pics...often they are built into a metal sheilding box and have a face plate that allows for the side curve of the guitar, additionally, some are built with a battery box under it that makes them very deep, but not all and this could be modified. I know some get fairly elaborate, I think I even have one with an on board chromatic tuner and balanced output option that is pretty big... Will I look about, perhaps you could do a measure of the maximum allowable depth you have to work with, and perhaps a measure of the side width in case it is possible to mount it on the upper bout as is typical on an acoustic. pete. Quote Link to comment Share on other sites More sharing options...
dori2o Posted August 31, 2008 Author Report Share Posted August 31, 2008 I'm looking for some piezo cable in the UK, and the only thing I can find is this Coax cable Would this be suitable to make the under saddle piezo? Quote Link to comment Share on other sites More sharing options...
psw Posted August 31, 2008 Report Share Posted August 31, 2008 I am not following you here...this is not in fact a piezo but simply a shielded cable...fine for connecting the piezo to the preamp...but is not a piezo.... Perhaps if you provide a bit more detail of exactly what you have or are intending to do. A preamp/piezo setup will already come with shielded cable for instance...you have to consider the piezo element as well. Many people have got OK sounds from the buzzer thing with a general purpose mono preamp... details of exactly what you intend to do and perhaps a pic of the guitar itself might help spark the imagination and enthusiasm... pete Quote Link to comment Share on other sites More sharing options...
dori2o Posted August 31, 2008 Author Report Share Posted August 31, 2008 It's not a piezo disk/buzzer, it's an under saddle pickup. Like this Under Saddle Transducer This wire was suggested to me on another forum but I'm not sure if it's correct as the instructions talk about pvdf piezo coax cable? Quote Link to comment Share on other sites More sharing options...
psw Posted August 31, 2008 Report Share Posted August 31, 2008 Ahhh...well, you have your instruction there...however... The link to coax cable is not itself a piezo, it is suitable for the audio cable from the piezo to the preamp however...as per... Approximately 18” of high Z, shielded, single conductor microphone cable, 0.125” or less in diameter. (Mogami 2368 or equivalent). I don't know where you get the pizio stuff described, let us know when you find some! pete Quote Link to comment Share on other sites More sharing options...
dori2o Posted September 2, 2008 Author Report Share Posted September 2, 2008 Well then, here in the UK I've been unable to source any piezo cable, or Piezo film tabs to be able to make an under saddle transducer. So plan B. The guitar I'm making is a semi hollow body acoustic, it is topped with a 6mm veneer top glued to the body on which the bridge will sit. The strings are being passed through the body via string ferrules. So if I was to rout out beneath the bridge approx 3 or 4 mm rourhly the size and shape of the piezo disk and attach a piezo disk to the veneer beneath the bridge, would this be sufficient to pickup the sound? This would then be fed to the onboard preamp, jack etc. Quote Link to comment Share on other sites More sharing options...
psw Posted September 2, 2008 Report Share Posted September 2, 2008 What stage is the guitar at...has the top been put on...are there f-holes or similar to get inside? What kind of bridge...any chance of a pic? pete Quote Link to comment Share on other sites More sharing options...
dori2o Posted September 2, 2008 Author Report Share Posted September 2, 2008 What stage is the guitar at...has the top been put on...are there f-holes or similar to get inside? What kind of bridge...any chance of a pic? pete The guitar is not yet whole, i.e. the top is not yet on it. The bridge is a standard 12 string bridge as below Quote Link to comment Share on other sites More sharing options...
psw Posted September 2, 2008 Report Share Posted September 2, 2008 What kind of budget are you looking at for the pickup system. Remember that this guitar is essentially a solid body so the entire sound of the guitar is going to have to rely on the electronics. Further, unlike a lot of electric guitars, it is no easy matter to replace the electronics further down the track if it isn't suitable. I found a bunch of different preamps and undersaddle piezos here but have not had time to take pics...but this is really the kind of thing you will need. I suspect that it would benefit greatly from a preamp with eq as well. As such guitars are essentially electric guitars, they are typically designed around the pickup system. pete Quote Link to comment Share on other sites More sharing options...
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