This is a simple bare bones guide to provide direction not address specific issues. It’s the approach I used and requires no particular skill or technical knowledge per se‘, just common sense and a general knowledge of how things come apart and go together. This Mod Guide is a compliment to the Trouble-Shooting Guide in FAQ (and to a lesser degree the Bass Tone Glossary). Hopefully repetition has been kept minimal but reading both will be complimentary and should help fill some gaps. There are also numerous links in a FAQ to threads on caps, switching, shielding, reviews, and more. No doubt some changes/corrections in days to come but basically this is it. CONTENTS Post 1 What bass is worth modifying? Cost Pre-planning: How I Choose Pickups/Preamps Post 2 Routing Parts Pickups passive active piezo location string relation to poles Capacitors (caps) Jacks Harness (pots/switches/jack and wires associated) passive (cut only) active preamps (boost or boost/cut) & battery supply active/Passive Compatibility Issues What Bass Is Worth Modifying? To me any bass that is comfortable, plays well, has desirable acoustic properties, and has no higher value of consequence as original is a candidate. Original value is not of consequence if mods are not permanent and kept reversible. Cheap basses in particular make for good lab rats cause of the low investment. Thanks to computer technology and the global market, quality control on the cheapest stuff is no doubt better than on the 60’s Fenders. The down side of cheap basses is the truss-rods are often junk. Another factor of consequence is the size of the control bay - since you are constrained (less routing) by it‘s volume limitations as to what you can put in it. A control bay can’t be too big but it can be too small. Another consideration is the neck. You want a bass with a truss-rod that is not buttered up and will at least set the neck flat with strings up to tension. I prefer bolt-on necks for lots of reasons but it boils down to I prefer their tone, their replaceable, and exchangeable to the same model bass. In my experience the acoustic tone of a bass is in the neck - swap necks and the tone will follow: http://www.talkbass.com/forum/showthread.php?t=152427&highlight=tone+neck. That reason alone is enough. If you think a neck will transfer to the same make different model bass, remote at best. Cost In general, modifying a bass will cost you nothing but your time and energy - if you buy used at fair market value (less shipping), market demand for the items remains constant, and you make modifications reversible. You need nothing more than ebay to do so. A good used preamp and set of pups will cost about $150. If you buy new it will be about double that and anything you pay beyond fair used market value is guaranteed loss, as is any shipping cost. Another way to look at it is you could mod two basses for the cost of one buying used instead of new. I’ve picked up plenty of used gear I couldn’t tell from new appearance wise and it sounds the same regardless. If you don't know the way to ebay read ALL of this first: http://www.talkbass.com/forum/showthread.php?t=200008 cause them waters is shark infested - Power sellers and online music dealers in particular cause they know the ropes. *Note: Upgraded basses rarely sell for more than the same stock bass in excellent condition. Most guys want a bass they have some idea of what it sounds like not some bass someone’s jacked with and probably screwed up. You’ll come out better returning the bass to stock and selling it and the upgrades separate. So keep the stock components cause they‘re basically worth as much as your upgrades - if you make mods reversible. Pre-Planning Assume there are holes in your plans and include alternative plans for what if's Keep It Simple - choose your projects in accord with your experience/skills Make all projects non-permanent/reversible if possible (To many reasons to list) Think beyond your current goals for the bass FWIW (For What It’s Worth), the more useful and practical bass is typically one that generates one or two quality tones that work well to a broad variety of music styles. In as much, fairly simple electronically. Such a bass is easier to plan, construct, alter, usually cheaper; and once completed easier to find and return to tone (important live and recording), more reliable, less difficult to trouble-shoot, easier to recuperate costs, and provides a solid base for getting more variety in tone elsewhere in the signal chain where it‘s plug/unplug and play - not have a seat and unsolder/solder. A bass with lots of control and tone options is just the opposite. Almost invariably in a short time one or two of the tones are used and the rest go untouched - that is if you manage to get it together and functioning as planned. That said, doing so can be useful to determine the tones you use (since you couldn't know otherwise) then stripping electronics down to that at some point. Of course you'll probably have some useless holes to deal with. Another thing about a bass with lots of controls is they tend to cancel each other, like too many colors mixed, too many spices in a dish, etc. This thread is a perfect example: http://www.talkbass.com/forum/showthread.php?t=283760. That harness was obviously put together by someone who knew their stuff, yet the owner can't get a tone. That's not an uncommon result of a bass that looks like that even though the guy who did the work probably is in the top 5% of his class. I myself started out with a wall of basses with pre’s and every knob and switch I could cram into a bass. Now my bass of preference has one pickup wired straight to the jack with NO onboard controls. *Note 1: I buy everything used (which includes new at used price - not that uncommon on ebay). *Note 2: I have wired everything conceivable wrong more than once in a bass and never damaged a single component. In my experience there’s just not enough current in onboard electronics to do damage. How I Choose Pickups/Preamps Choice is typically narrowed by routings and what‘s available as replacement. I’ve gone by shape and/or measure the pups then go to the various pup sites of interest and check their dimensions - and/or go to harmonycentral.com user reviews for a given bass and see what guys have replaced in them and their satisfaction with the results. Once you have some idea of options available, in addition to what’s on TB, there are plenty of pup reviews on the net from a google search - extended range pups are just longer versions of their equivalent 4 strings. Research will typically yield a couple three pups with potential and from there it’s buy one and see, you won’t know what it sounds like till it’s installed no matter what you choose. What I find most useful as a determination in selecting a pickup is a lot of reviews (say 10 or more) with an overwhelming degree of satisfaction. This translates into real world application where quite a few players have tried the pup through different gear, different settings, different music, different (you get the idea), yet are still satisfied with the results. Sound clips I personally find no value in for selecting pickups (too many reasons to list). Okay for a piece of the puzzle but I wouldn’t get hung up on it or use it as a determining factor. If you’re confined by routings, a J bass is the way to go to maximize tone options. There have been more different J pups made than other pups combined, they come in a myriad of coil configurations, and they all sound different. PJ is a good second but quality PJ sets often sell used for twice the equivalent J set, show less frequently, and often sell separately. J sets however are more frequently being sold separately as well. Choosing preamps is basically the same process. The current popular Bartolini, Aguilar, and EMG preamps to me do nothing of consequence beyond boost and cut of the signal so choice is more dependent on other factors: size, wiring options, availability, etc. There are some pre’s that do more and with few exceptions you will pay more in accord.