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What Should I Do With My Peavey T-40? Mod?

Discussion in 'Basses [BG]' started by Roy Royerson, Aug 14, 2017.

  1. IMG_0310.JPG Well Talkbass, I need your help. I'm getting my old 1981 peavey t-40 back in good shape. It's just been waiting for new frets, a repair on the jack and was out of commission for a couple years now as I've been neglecting it. Anyway I'm going to take it in the shop and get all the work it needs. Also I'm thinking of getting it modified but I don't know anything technical about the logistics or possible repercussions of a mod. I'm thinking I want to be able to split both pickup's coils independently and change the stock phase switch into a pickup series/parallel switch. This way I have complete control of how the pickups operate. Then I'm thinking of just having a regular volume and tone for each pickup with the 4 knobs. I'm also thinking of refinishing it but I'm on the fence more on that one. I should say I don't care about hurting the resale value. I bought the bass for less than a hundred bucks and it came to be one of the best basses I've owned so I just want it to sound, play and function as well as it can. I should say ive never made significant changes to a bass. I pretty much play em stock but I feel like this will only make this bass better and more controllable. Here are a few questions if anybody has thoughts on any of them, please enlighten me.

    Do you have any other/better ideas or additions of how to modify it?

    If I refinish, what finish would you go with(I'm thinking a burst and still show the grain some)?

    Is there any reason that won't work or are there any hurdles and pitfalls I need to watch out for? Are there any drawbacks to the mod other than resale value I might be missing?

    Are the T-40 pickups good for my plan (I like their sound) or would you consider another set of pickups?

    If I go with the mod described about how much should I expect to pay a quality reputable luthier for the work?
    hombass likes this.
  2. Axstar

    Axstar Banned SUSPENDED

    Jul 8, 2016
    You're in a lucky position as you appear to have all the parts, with the exception of the pickup rings.

    I would perform only the mods that don't require any sort of invasive procedures such as drilling the pickguard out for additional switches.

    The wiring you outline could be pulled off quite simply, presuming that you want the series/parallel switch to act upon the relationship between the two pickups rather than the coils of each pickup itself? Your wiring will also delete the coil-split for the pickups, so you will always have them in humbucker mode. This is ok?
    Roy Royerson likes this.
  3. BassikLee

    BassikLee Commercial User

    Feb 13, 2004
    Deltona, FL
    Owner: Brevard Sound Systems
    If it were mine, I would take pictures of the stock wiring, then carefully desolder the pickups and remove and store the stock pickguard. Then, order a new, possibly undrilled pickguard. I like the series/single/parallel thing, so that's two mini switches. Maybe a pickup pan control, instead of two volumes. Master volume? Not for me, i'll just take a kill switch. Master tone? Ok.

    That, OR.... keep the two mini switches, and go for an Audere four band preamp. The two that I have both use three holes, as they are three stacked knobs. Volume/blend(active, buffered blend), Low mid/high mid, bass/treble. Sound great. You should be able to cram that and a battery in there without addition routing.
    Roy Royerson likes this.
  4. davedblyoo

    davedblyoo "All the mayhem and none of the sticky mess."

    Nov 15, 2012
    Augusta, GA
    Maybe you could leave it alone and save all of that modding for another bass in your arsenal. T-40's are a unique bird, enjoy it the way it is.
    KJMO, Ikkir, jukap and 4 others like this.
  5. Englishman


    Apr 26, 2017
    Yeah, the bare-ash T-40 body is pretty iconic, I wouldn't be painting over it if it was mine.

    But it's not, so you can do whatever you like of course.
    Roy Royerson likes this.
  6. Eilif

    Eilif Holding it down in K-Town. Supporting Member

    Oct 1, 2001
    I wouldn't mod the electronics for practical reasons. The original control configuration (check the link at my sig for more complete info and a schematic) is already incredibly versatile if you know how to use it.

    As for splitting, the stock T-40 wiring already allows you to switch the pickups to single coil mode at the 7 position on the tone knob.

    Regarding a series/paralel switch, I'm a huge fan of them in Jazz basses but I don't see any value for that in an instrument that has two splitable humbuckers already. Two humbuckers in series will be muddy (you can already get a nice mudbucker tone with the neck pup) and if you split both humbuckers and put it in series mode it probably won't sound much different from the bridge pup in humbucker mode.

    Looks like you'll need the shop to make you some pickup rings, but that shouldn't be too difficult with some wood or pickguard material. Here's a fellow selling some purpose built replacements that look similar enough to the originals that it probably wouldn't affect the instrument's value much.
    Peavey T40 pickup rings | eBay

    When it comes to refin, it will of course ruin your resale value. I know you said you don't care about that, but remember that T-40's are now going for $450-650 or more and they seem to be holding their value and pushing upward slowly. Even with the replacement rings and what look to possibly like non-original switches A good cleaning and maybe some polish from your local luthier could put in condition to be 400-500 bucks or so. Refin will cost you few hundred and knock the value down a couple hundred.

    If you do decide to refin, the grain on yours looks pretty nice so a trans color like red or blue would be lovely. With the thin satin finish that is present, you might get a nice look by sanding back the satin a bit, leaving the walnut grain-filler as-is and doing an open-pore, trans-satin finish to get an effect like this:
    Would also probably be alot cheaper than a traditional gloss-coat refin.
  7. Thanks for the advice so far guys. I'm leaning towards keeping the finish as it does look nice Englishman.

    I do have the pickup rings, but one is cracked so I do have everything. I noticed Axstar mentioned if I do the changes I described I will loose the coil splitting. Is it not possible to split each pickup independently or even split the coils on both with a switch? Honestly that's sort of the point of all this and the series/parallel switch is more of a bonus. If I can't split the coils and I get only humbuckers I probably will keep the original wiring.

    Bassiklee, I like the idea of a pan and a master volume. Then I could use the existing pickup selector and phase switch for other uses. That's right, isn't it?

    Davedbyloo, I can appreciate the advice and the magic of the T-40 wiring but if I can make the changes I want this will be an even better bass for me. I'm not sentimental about keeping anything original so it's hard to see a downside for my use.
    davedblyoo and BassikLee like this.
  8. I'd weigh in on the keep the electrics the way they are. I owned a T40 for years (lost it in a fire). I just approached it like a standard Gibson style instrument, as that is what it appears to be from the 4 knob layout. But later I read an article somewhere about how it works and it really opened up the way I got sounds out of it.

    If I was going to mod the wiring. I'd have a switch put in that let you put it back in stock mode.

    In fact of all the basses I've owned, that T40 with fresh SS round wounds is the one sound I probably miss the most. Eats a Stingray for breakfast.
    jukap likes this.
  9. Eilif

    Eilif Holding it down in K-Town. Supporting Member

    Oct 1, 2001
    As for the cracked pickup rings, Great to know you have the originals! I'm pretty sure they are made of polystyrene so a plastic solvent glue like Plastruct Plastic weld should get them back perfectly. You can also glue a bit of plastic to the inside to reinforce it if you would like. Thin rod styrene for this purpose can be found at your local hobby shop. If you can tell me the dimensions of what you need I might even be able to send you a couple appropriately sized pieces gratis.

    It is entirely possible do split coils independently with two switches or both together with one. However I still don't understand why would you want to do that when stock T-40 setup already has coil splitting in it via the tone knobs?

    I would strongly advise against a pan and master volume. Not the worst setup for two single coils (though I don't like it there either) but when dealing with two humbucker pickups that can both be split individually (as the original wiring allows) you will want to have full control over the volume of each pickup to compensate for the differences in output between single coil and humbucker. A simple sweep as provided by a blend knob is massively less flexible than two volume knobs.

    I don't want to beat you up too much here but it seems that except for series/parallel, the stock T-40 controls already do everything you need if you take the time to learn how to utilize them. The link in my sig will show you everything you need to know about stock T-40 controls.
  10. Great now I am gassing for a T40 again.
    Okay, but only if I can find one in white. One has to have limits on their pocketbook.
  11. PDGood

    PDGood Supporting Member

    Sep 19, 2010
    Nashville, TN
    It would be a shame to alter that beautiful T-40 body. Since they are pretty heavy, one possibility would be to make another body in that shape out of lighter wood. Then you can paint/drill as much as you like without damaging the original.
  12. bigtone23


    Dec 10, 2014
    Denver, CO
    Though I feel the original wiring is pretty great as is, I can see why and how some may want it to be tweaked for certain aspects of control. Being able to roll off the tone a bit in single coil mode is not possible stock. There is not series/parallel options when using both pickups.

    I guess it could be rewired without the pickup selector and VVTT (wired like a blendable stack pot Jazz). The tone pots are a special S taper to accommodate the spin a split when stock, but should work fine as a standard tone control. Repurpose the PU selector as a series/parallel switch for the pickups and repurpose the phase switch as a master coil split for both pickups.

    Perhaps it could be redone as VVTT with each switch location repurposed as a series/split/parallel for each pickup. You could probably get extra tricky with push/pull pots on the tone controls to control the phase of the pickup and allowing you to pick which coil is activated in split mode..?

    I would be tempted to wire it with a master volume, a no load style blend (so each pickup is fully gone when the blend is fully turned one way or the other), and passive bass/treble (G&L style). Make one switch the master coil split and the other series/parallel of the pickups.

    For refins, do what you like. The grain is nice, a stain would look best.
  13. Vinnie Boombatz

    Vinnie Boombatz Banned

    May 26, 2010
    Since you're asking for opinions, if it was my bass Id just have it repaired, get it a killer set up (and a fret level, crown and polish if needed) and keep it stock. For the money you'd spend on refinishing it, modding it, etc., you could probably buy another nice used bass. Not that these are worth much used, but any mods will most likely make it worth even less, so now you have a bass that you sunk a small chunk of money into, and if it doesn't turn out the way you expect and you want to sell it, you'll most likely get less than what you would have if it was original. If it's a nostalgic bass and you've had it for a while, do it justice and just bring it back to life, and don't try to turn it into something it's not.
  14. T-40 mods ???

    I've one humbuckers only,stuck a preamp in and strung it tapes :D
    Ok it came in pieces and after 1 messed up re-wire I couldn't be bothered so a handy preamp it got.

    For another it was junk the saddles for 5 single saddles and drill a hole for a 5th tuner,stick a set of La Bella Jamerson flats. Rejoice in a T-40-5.Slightly more involed than that but my good brother @mech talked me through it.
    Extra tuner hole had been drilled by the time it got to me so it was swap the neck or finish the job.
  15. Mirrormt4


    Aug 18, 2012
    Nor Cal
    I have a black '81 T-40. Owned it since 81. Don't play it much now, but I agree with everyone who says leave it alone. Do the frets, get a nice setup from a good shop / Luth, and play the crap out of it for the next 30 years. There are so many good Asian made basses under $1k that have all the bells and whistles. Or go with a Gekko and custom wire that.
    Also - the reason I don't play this much any more is my 56 year old back. My Czecktor Rebop weighs less in the case than my mahogany body T-40 by itself...
  16. Mirrormt4


    Aug 18, 2012
    Nor Cal
    BTW - Really appreciate all the comments and advice! Love this bass and good to know others love it too...
  17. hombass


    Jul 5, 2012
    Probably the most common upgrade to any bass is better pickups, but to be honest im very fond of the tone from seymour duncans ceramic magnet musicman pickups played passive. But as i recall from my T40 the pickups were very good. Id leave the ash clear its just really nice wood. Probably also the best stock bridge ive ever seen on a production bass. I made the bridge plates for my two basses from 3/8 inch thick brass i beam stock. So as a builder and player and owner of a T40 i dont think you can fault the stock instrument. Maybe playing with circuitry is a good way to go though i would look at a wiring diagram because i think there may already be some tricks in the original. The only other thing i can say about bass circuitry is i one of the basses i have built has no circuityr at all and is just straight pipes no knobs just a jack. Everything goes right down the wire to the amp and the subtlety and viopence achieveable is my preference. I reccomend .090 crownX .110 width fretwire, its strong and if pressed in will resist deformation even to the point of needing NO dressing. This wire is Stewart McDonalds largest.
  18. Jazz Ad

    Jazz Ad Mi la ré sol

    I love T-40s. Their electronics are very cleverly designed, I wouldn't cahnge them one bit.
    However, if I was to have one as a keeper, I'd find a way to hollow out that anchor of a body.
  19. Thanks guys. It seems like most people think keep it stock. I'm still on the fence, but I'm going to go talk to the shop/luthier in the next week when I have a day off and see what they think. A place near me in San Francisco is supposed to be really good. Good reputation and I've had friends tell me they are very good. I won't be changing much if it won't fit because I'm realizing there's not much room in the original cavity. I'm not gonna remove any, or much material from the body. So I'm on the fence between two options at this point.

    1. Leave it stock and get it as close to back to its original glory as possible.

    2. I'll mod it something like this if possible. Add one switch (if there's room in the existing compartment) that will be a neck pickup coil split. Use the existing phase switch as a bridge pickup coil split. I'm thinking of three way switches to access both singles independently and humbucker. Then have it set up as two volume and tone knobs. And keep the three way selector for the pickups as is.

    As for the finish. For now I'm gonna leave it natural. I just see pictures of the old ones with the burst and rosewood fretboard and I really like the look.

    I know this wiring change seems silly to a lot of you. I appreciate the innovative and clever wiring of the original. I would be happy to not have changes and leave it be but I feel like I could make it even better for me. I always wished I could split the coils more directly and in any combination. As in Inner/outer/both control for each pickup. I like that my MM Stingray HH does both inner single coils and both outer single coils. Sometimes I wish I had more control of the coil splitting on that bass but that's a story for a differant thread. Then more than anything I was occasionally frustrated when trying to dial in the right tone level with the stock setup.

    I'm not really a sentimental guy but the bass has been one of my favorites so I don't see why I would ever sell it. I'm looking to enhance the playing expieriance and tonal possibilities of this bass if I can. I'm not worried about value or cost.
    Englishman likes this.
  20. Killatine


    May 20, 2013
    Hollywood, FL
    I have to say, if I ever found one that wasn't original, or that needed a ton of work, I always thought about steampunking it! The hardware and the natural body just screamed steampunk to me! now that's all just aesthetics and not much in the way of actual mods, but that was gonna be dependent on what condition I got it. I know, no help with your question, but I had to put in my 2 cents!

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