Max Normal

[size=4]I was reading a forum by a guy who designed the optical pickup and the physics of how it works. One of the questions was whether it would not work if it was placed on a node (part of a string that vibrates at a different frequency to the fundamental), and he replied that it worked anywhere due to the movement of the fundamental and of the harmonics along the string. I’m a bit too hungover to go out and do something useful, so I spent the afternoon researching the science of why our guitars sound the way they do, and why they all seem to sound different, and why wood matters when the pickup is basically just sensing the vibration of the string. This is what I came up with, and I think it raises some interesting questions.[/size] [size=4]Every now and then the same question pops up. We know that different tonewoods and bass guitar construction materials affect tone but some of us (including me until recently) do not know exactly how. Frustratingly, somebody just usually pipes up with a list of the tonal qualities of various tonewoods, and does not actually answer the question.[/size] [size=4]For those that don’t know, the answer is fairly simple if you think about it. Once plucked, the string vibrates in a wave pattern dependent on its length. The frequency of this wave pattern determines the pitch of the note and the fundamental note is released (the “main” note that you expect to hear).[/size] [size=4]This is not necessarily however a “standing wave”. The waves of vibration retain their frequency, but travel along the length of the string. This is illustrated brilliantly here:[/size] [url="http://www.youtube.com/watch?v=0AWTUN6RD1c&feature=related"]http://www.youtube.com/watch?v=0AWTUN6RD1c&feature=related[/url] [size=4]and here:[/size] [url="http://www.youtube.com/watch?v=_X72on6CSL0"]http://www.youtube.com/watch?v=_X72on6CSL0[/url] [size=4]When the string rebounds, the various partials called harmonics and overtones are released. Partials are vibrations that are integer multiples of the fundamental (i.e. higher pitched notes), and these also travel as waves along the string. When you hear the note, you are not just hearing the fundamental, you are also hearing all of the harmonics and overtones layered on top of it and adding to its tonal character (you might notice that some of the string waves being produced by the hairy guy with the acoustic bass are quite asymmetrical, showing the pattern of overtones on the string).[/size] [size=4]Naturally the sting is anchored at each end to the instrument, so when these vibrational waves reach the ends of the strings they continue to travel through the body and neck of the instrument. A vibrating string is a fairly pure and simple system, however a bass guitar is not. The body (including the neck) of a guitar can be thought of a filter for specific frequencies.[/size] [size=4]When the string vibrations return from the body material (in the case of wood, principally via the biopolymer lignin), certain harmonic frequencies will have been lost, while some will have been retained and are transferred back into the string to be collected by the pickup.[/size] [size=4]In its simplest form, this explains why a softer, less lignin-dense wood such as basswood gives a softer mellower tone than a wood with a tight lignin structure like maple, as the higher frequency partials have been absorbed by the wood (the individual fibres in the wood are less well connected can move more freely, and convert the vibration into heat rather than transferring it along between the fibres), and only the lower frequency partials are transferred back into the string. Conversely, more of the original partials are returned to the string in the case of maple, giving the appearance of a “brighter” tone.[/size] [size=4]But lignin itself has a different structure as well as density in different woods. There is not a simple sequential dampening of partials from high to low frequencies as the lignin density within the wood decreases, more that a range of specific partials are “selected” for transmittance back into the harmonic characteristics of the vibrating string, while the rest are absorbed by the body of the instrument and lost. Moreover, it’s not just the lignin density. Seasoned wood also contains cellulose and the lignin: cellulose ratios will vary between different types of wood, or even different cuts of the same wood.[/size] [size=4]Undoubtedly the grain of the wood also has an effect. Rosewood is a fairly dense and hard wood (which is why we can use it for fretboards), but has a far more open grain structure than maple or ebony. The open grain structure of rosewood can be thought of as a series of dampening chambers that filter out certain partials from the specific resonance of the string, again giving the tone a warmer, softer character. Wood sawing angles change the grain structure, and neck joints and joinery between multiple body pieces also act as dampeners of specific frequencies. [/size] [size=4]This is far from the end of the story though. After the body of the instrument has decided which partials it will transmit back to the string, certain remaining partials may cancel each other out as they travel along the string, or combine and create new, amplified partials, and this will all add to the overtone spectrum of each specific instrument.[/size] [size=4]Obviously the method in which the strings are anchored to the body of the guitar also makes a difference, a dense metal bridge and a metal nut transferring more high-frequency partials than softer materials, and perhaps selecting others, Dead skin particles stuck between the windings of your string, the type of winding, and overstretched un-elastic old strings will select for particular partials, all contributing towards the overall tone of the instrument.[/size] [size=4]I’m wondering how easy it would be to measure the relative partial/overtone profile of a really great sounding bass, and try and replicate it by predicting what the partial profile of a new bass would be. Also, it would be interesting to use this to see exactly relatively how much each component (bodywood, fingerboard material, badass bridge etc) contributes towards the tonal characteristics of a bass so we know which component to spend more of our lucre on. Also, is there a consensus partial profile for each instrument (i.e. is there one for “the perfect Jazz bass” or “the perfect Stingray”) that we can aspire to and maybe modify our instruments to achieve?[/size]

Just got my powerbrick from Samuel, no problems and great comms and honesty. Cheers!

I'm an experienced tutor in Woodingdean, Brighton. I have a dedicated music room/studio full of pro gear and basses in my house, can record, and will supply you with all the sound clips, click tracks, drum machines and software you need as well. I'm happy to teach technique etc to beginners onwards, I specialise in improvisation, building grooves and writing original lines. I teach basic to advanced finger and plectrum style and basic to intermediate slap. I teach Rock, metal blues and funk, music theory and bassline deconstructing so you can really learn how lines work. I also assemble, setup and wire my own custom basses, so I can teach you how to do that too. I have a driving, powerful, fluid groovy style learned from many years continuous playing and performance experience. Currently I play for a Foo Fighters tribute, but I have played in everything from function bands to metal and blues bands, including performing and recording with some notable musicans. price is £20.00 p/h Ta! Mark =0)

I might, all you can seem to get around Brighton is Upduck.

[quote name='henry norton' timestamp='1327253664' post='1508398'] I've heard allot of good things about the Ampmaker kits although beware, most mains electronics and especially valve amps are also very dangerous [u]after[/u] you've unplugged them, what with high voltage capacitors et al. If you want to build an amp just for fun then I'd go for one of the Ampmaker kits but if you want to build a 300 Watt dedicated valve bass head you'll find it's a fair bit cheaper, easier and rather less dangerous to just go out and buy a new SVT. Edit; Basschat's umph has been working on some bass amp stuff for a while now, maybe he can point you in the right direction [/quote] Um, yeah, that was kind of my point. Perhaps I should have said you can finish the wiring before you EVER plug them in (or learn how to discharge your capacitors) . Thing is, anyone with half a brain can do this. I work with very high voltage DC power sources and carcinogenic chemicals every day while teaching it to students. They are all fine, never had a problem, people are not stupid if they are properly aware of the risks, and I must say that I hate the kind of elitism that says "I can do this but you shouldn't even try". If you don't intelligently approach some risks in your life and learn to control them, you'll never progress in some directions. Still, I totally agree with the point about buying a new SVT if you want something useable, if nothing else you have said. However, in agreement, If you are a committed total and utter f***wit and know it, just get two cocoa tins and some string and try not to strangle youself on the string.

Some of these amps do actually have a difficulty level recommended for first-time builders, from what I can tell, most amp builders start with valves as they are so much more simple to build, but I doubt even first-time builders are usually strangers to a soldering iron (and I was assuming nor was the OP) I guess you'd be foolish to try and build one without fully understanding the dangers and how to deal with them, so yeah, up to you, I'd do it no problem, but i'm quite confident (or "reckless" ) They are not dangerous until you plug them in, and you can test them with a multi-meter for dangerous shorts and you could always get you local knowlegeable valve-amp geek to check your first lot of work (find them in real ale pubs with Tuesday night blues jam sessions ). There are a few good, cheap, safe transistor based-project kits here that might be good practice for soldering (as well as some amp simulators, project boxes, parts and some stomp-boxes), Theres a link for amp kits, but they don't seem to have any in stock at the moment. http://uk-electronic.de/onlineshop/index.php/cPath/105_248?osCsid=5468feae0040e870c19056e3985da69d The kit instructions are in Jarman, but nothing google translate can't handle.

You could try these: Vintage valve amps. I guess they are guitar amps, but I think in the olden days there was not much difference, and a lot of bassists used guitar amps anyway. They look like a real community of enthusiasts, so they could probably recommend modifications to make it a bona fide bass amp, or put you in touch with the right people if you asked them. Dunno about more modern stuff, but of course valves sound better if you like that sort of thing, and are easier to build as no PCBs. (Also enhanced chance of frazzling youself due to high-voltage circuits, or developing a penchance for tweed jackets with leather elbow patches and a pipe). From what I read when I was looking to do the same thing, these are very loud but low wattage, High wattage valve amps are not so easy or cheap to build apparently. Might want to pair it up with a separate poweramp if you went down this route? [url="http://www.ampmaker.com/store/home.php"]http://www.ampmaker.com/store/home.php[/url] Ps, sorry Rubis, was not checking out your profile, was trying to get a close up on your Avatar!

Sent me a loaded alder p-bass body at a great price, refused payment until I had received it. This chap is what Basschat is all about, thanks Gerry!

This guy not only manufactures guitar paint, but he has some really great blogs, pictures and videos that show you how to do various different paintjobs (including doing sunbursts) on his site. Really nice chap too if you email him. [url="http://www.manchesterguitartech.co.uk/"]http://www.manchesterguitartech.co.uk/[/url] http://www.manchesterguitartech.co.uk/2011/04/11/creating-a-sunburst-finish-with-aerosols/

No idea to the quality of these at all, but I have seen them on ebay. The way I look at it, if you put it together yourself, you'll be less squeamish about upgrading it or chopping/customising it up into something else. Looks like a solid piece of wood, maybe some decent pickups and hardware or a custom wiring job and/or active electronics and you could have a very nice bass on your hands. It could evolve as the years go by. If it is crap, well you'll certainly learn to set it up as best as you can. I was looking for a headless bridge/tuner for a homeade travel bass, and to be honest I couldn't find anything as cheap as this whole kit. Looks like a great way to learn the basics (and not much different to what I did with my EPJ) so I say go for it! And let us know how you get on, If nothing else, it aint made of plywood and it will be put together with real love and care, more than you expect from a lot of far eastern basses with a similar price tag. Good luck!

Lol! Too expensive to bugger it up as the missus sounds like starting a new build will [i]not[/i] be in the near future, that's why I spent so many hours hassling you lot on the forums! Might get a cheap s/h alder body for it just to see how different it sounds from the ash though. On the downside, my guitarist now wants me to install a phase switch in his Hagstrom and another mate made me install pickups into his Strat, so learning how to do wiring might not have been such a good idea....... PS, wish I could learn to do proper wood stuff like you but I can't even cut straight maybe one day I'll do one of those residential luthering courses that Shuker run, but in the meantime I can dream.

Good call, it weighs a f*ckn tonne! My band always ask why I sometimes spontaneously sit on the floor during rehearsals. I notice you are in Brighton, if you ever want to pop up and have a bong on it to see what I mean, you'd be welcome!

Finally finished my homebuild. Had lots of help from fellow basschatters on this one, so thanks a lot chaps, particularly Ou7shined who chose my pickups and advised on the wiring! The concept was originally to use the natural tone of each pickup type and its string position to determine the tone of the bass. Each pickup was to have its own volume and tone control so that they could be infinitely mixed. The idea was also so that i could learn passive bass guitar wiring, which is another reason i chose such a wacky scheme. It seems that for technical reasons, unfortunately that when you have multiple tone controls, they influence each other too much and it never really works very well (which is why many multiple tone control guitars have pickup selector switches) . For this reason, I plumped for a VVV(VT) configuration, with a master volume stacked with the tone knob. I still get the tonal characteristics of each individual pickup with infinite mixing, and I tend to have to only use the tone control for small trim adjustments. To produce the "bass" part of the tone, I used a Dimarzio Model One, orginially designed for Gibson EB basses as a direct replacement (hence the E in E-P-J). To produce the "middle" I used a Seymour Duncan Quarterpounder and for the bridge "treble/clarity" component, I used a Dimarzio Ultra J. The compatibility of the pickups was checked by Ou7shined, who told me to check the impedance of each pickup was similar and report back to him. This is why such powerful overwound P and J pickups had to be used, as the Model One is a monster! Some people reckoned that this was going to be a dark sounding and thumpy beast, so I wired both the Model One and the Ultra J with push/pull coil phase switching, and I added series/parallel switching between the P and the J pickups. I have uploaded the wiring diagram in case anyone is interested. [attachment=96403:wiring.jpg] I found the single pickup routed unfinished precision body on ebay, it's solid ash and it cost me £27.00 as nobody else bid on it. I have no idea who the manufacturer is, but when I first gave it a tap, it had a nice ring to it suggesting it might be a quite resonant piece of wood. The neck is a WD Fender Jazz bass replacement. Because the wood was so resonant, i didn't want to dampen it by putting a great lump of metal of a bridge like a badass on it (I reason that these maybe work better with denser woods like maple and mahogany?), so I got a Babicz "full contact bridge", which is really light weight so allows the body to resonate, but the saddles touch the base plate along its length and use cams to adjust string height, so resonance is supposedly transferred between the body and strings with minimal damping of the wood. The routing and scratchplate modifications were done in the workshop at the university where i work. We used a milling machine instead of a router which worked really nicely and easily. In a final measure to attempt to keep the bass as resonant as possible, the neck is attached to the body using an inlaid metal ferrule neck fixing kit. [attachment=96404:Angle.jpg] [attachment=96405:back.jpg] [attachment=96406:Top down.jpg] I finished the neck and body with TruOil which was nice and easy and brought the character of the wood out, and lemon oil on the rosewood fretboard. In use, any fear of this being a dark sounding bass were confounded. I guess Model One pickups must sound different in a mahogany Gibson, because it gives a very powerful, punchy fat rounded sound. When you dial in the Ultra J at the bridge, you get a nice clear top end, and you can add some P-bass growl with the Quarter pounder in the middle. The best thing i can compare it with is a very powerful punchy active bass, but with the warmer tones of passive pickups. Its great for rock and blues and surprisingly, absolutely amazing for slap with the Model one and Ultra J together dealing with the punch and top end. Obviously, if you dial out the Model One, you get classic P and J tones, but phase switching the coils in the Model One gives a surprising woody, almost acoustic tone, which paired with the Ultra J gives a jazzier, tighter tone, dare i say it, it almost sounds like a jazz bass.......(I'll get me coat). To be honest, I was half expecting this project to be a bit of a useless experiment, but this bass tonally blows any of my other basses away and i would recommend this mod to anyone. The only things I would not bother with are the phase switch on the jazz pickup and the series/parallel switching between the P and J pickups, which I never use. Cheers for looking =0) Mark

[quote name='SidVicious1978' post='1228220' date='May 11 2011, 11:08 PM']hey i am looking for a preamp for active/passive bass i found out MM preamp has two 250K pot master volumes and two 100K for bass and treble so i can turn the two 250K into stack volumes and have a blend with a stack bass/treble plus a on/on mini switch for active/passive Sid anyone see a problem please tell me Thanks[/quote] Yup, that would work. Might struggle to get the pots. Can get the 250k/250k from Allparts on backorder, but you might have to order the 100k from the states. Try here if you can't find them in the UK: [url="http://www.darrenriley.com/shop/cart.php?m=product_detail&p=1104"]http://www.darrenriley.com/shop/cart.php?m...tail&p=1104[/url]

This does have different mounting holes to my bridge (seems to have two rows of screws), but the baseplate and saddles look identical, even down to the massively oversized saddles with the horizontal casting marks on them (which I have not seen on any other bridge), I guess these can be pre-drilled to fit a range of different guitars? I certainly had problems with these type of saddles on my bass (on a bridge was supposedly made for my bass), and my bass plays like a dream with the original saddles (also note the cast baseplate which is much thicker than a sheet metal one, pushing the available adjustment up). It would seem to me that if the trussrod adjustment was so painfully far out that the action could not be lowered any futher, the neck would have a hideously obvious bow to it? You can check that easily with a straight edge (I use a metal ruler edge on). I was assuming that the OP would have been concerned about that first, not the bridge. Of course if could be a combination of both bridge and trussrod, seems doubtful it's trussrod alone to me. anyway I hope he sorts it, I would be more than happy to be wrong if it gets it fixed quick. I (and obviously you Wil) am more than happy to adjust a truss rod when it needs doing and an easy fix is always good, but I am of the opinion that unless the trussrod is definately wrong, don't touch it as they can take a long time to settle in, so not checking everything, including whether the bridge is any good, before you take a wrench to the neck is bad advice. Also, I'm just saying I have had and remedied exactly the same problem as this with an almost identical bridge (whether the blah blah mounting holes etc) with identical oversized saddles.