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Converting SR800 AFR to passive, need some pickup help

Discussion in 'Pickups & Electronics [BG]' started by ScorchMountain, Jan 15, 2019.

  1. ScorchMountain


    Jan 15, 2019
    Hello. I did search this question, for days and days over weeks and weeks. I read what felt like dozens upon dozens of conversations about this but never found reliable, practical info. So maybe this will not only help me, but anyone who follows in the future.

    I've got a 1992 MIJ Ibanez SR800 (4 string) with the AFR active P/J pickups. I like the body and neck but really dislike the sound. (Lots of threads about that.) I've adjusted pickup height, changed the battery, adjusted the tone, got new strings, etc, but in the end I thought it would be a fun project to turn it into a passive bass (like my other bass). The problem has been finding pickups to fit in the cavities. I guess I was naive to think that "any P/J set" would fit the vast majority of P/J basses without significant modification.

    I play heavy music, fingerstyle, mostly doom, sludge, and black metal. I like that full low end, growl, aggressive, and I'm tuned BEAD. (ha ha, I like passive aggressive.) I'm not fond of the more modern metal sound that can be very thin and a lot of upper register, and I'm not fond of trying to dial in a tone on the guitar using active pickups. I'd rather dime the Volume and Tone, Blend 50/50, and be done.

    After researching which passive pickups might have the sound I want, I decided that the hotter (as opposed to vintage) pickups probably seemed right, and it seemed like Alinco 5 was often recommended. I ended up buying the Seymour Duncan Quarter Pound P/J set. If you can already guess what happened, please keep reading, you are exactly who I need help from. (If you think I'm choosing the wrong pickups for that kind of sound, please let me know that as well.) Of course I also bought a new Volume/Blend/Tone passive harness, from Best Bass Gear.

    It turns out the Quarter Pound pickups are the tiniest bit too large for the pickup cavities! Like maybe 1/32" too large (although the screw holes seem to line up). They simply will not fit in the cavities, period. I've read many threads where apparently people are swapping their SR-X00 pickups with QPs, and they're not saying anything about having to enlarge cavities or hammer them in with a mallet. I did not expect there to be a problem. So now I don't understand if the cavity size has changed over the years, if my SR800 is somehow unusual or out of spec, or why exactly I haven't found a single thread that said the QP's are too large for the SR800.

    The best measuring device I have is a cheap guitar-setup ruler, the kind you use to set string height and pickup height, etc... the kind of accuracy you can get for $9. So probably not all that accurate. When I measure the QPs and compare my findings to their published dimensions, they seem to match, so I feel like it's accurate "enough". Yet I can't seem to find new passive pickups that match the measurements I'm getting of my old AFR pickups. (My measurements will be posted at the end.) It would be far better of course if I could find actual factory dimensions of the AFR P/Js, but I can't find that info anywhere.

    So there is my dilemma, I want to turn this active SR800 into a passive P/J bass with a full heavy aggressive metal tone, without having to resort to active.

    Some things that might help me...
    #1 - Does anyone know the factory spec measurements of the 1992 AFR P/J pickups, so I can compare those with other manufacturers without relying on my amateur measurements?

    #2 - Did anyone else have trouble putting QP's in their SR800? Or I guess, did anyone have no problem at all? Why is mine not fitting? I can't find any threads that said the QPs won't fit in the SR800.

    #3 - Anyone know of a chart (for example) where you could look for your bass and its year, then go across the columns to see a bunch of pickups that are designed to fit correctly? (Or, for lack of a better term, is there a "size" of P/J that will fit, so I can search based on that?)

    #4 - Are any of you connoisseurs of the 1990s SR800s and the replacement pickup possibilities that might work, who might read this and think "this guy needs to get pickup set XYZ, they'll fit perfectly and have tons of full metal tone"?

    Thanks for any help. I'm pretty frustrated right now. For what it is worth, my amateur measurements of the 1992 AFR pickups, to the nearest 1/32nd of an inch, are as follows...
    Neck PUs = 2 & 3/16 x 1 & 1/16 (body), with 2 & 3/8 between the screw holes
    Bridge PU = 3 & 11/16 x 11/16 (body), too complicated to describe the holes, LOL
    I have no doubt that the factory specs would certainly be more precise, probably decimals that do not correspond to 1/32nd of an inch, and for all I know they're metric. But that's what I get using my little ruler.
    Last edited: Jan 15, 2019
  2. K-2


    Nov 30, 2016
    Vilnius, Lithuania
    I wont be of much help, sorry.
    What I wanted to say is that QP pups are awesome. They have a slight low boos and mid cut, as well they are pretty hot.
    If it was me, I would search for a local guy who works with wood. Not specifically a bass luthier, but maybe someone who atleast has a hobby working with wood.
    For someone with experience and tools it shouldn't be hard to make pup cavity a tad bit bigger.
    In my book it would be much more cost effective, as you already have QP.
    I wish you best luck in your search if you go that route, and hopefully there are some replacement pups out there!
    ScorchMountain likes this.
  3. I believe the pups in some ibanez are an off size. check aguilar and bartolini for pickup dimensions. please take a picture of your bass and pickups for us to see.
  4. ScorchMountain


    Jan 15, 2019
    I don't know if there's much to show in photos, but maybe this will help. There's one of the cavities with the AFR pickups removed, there's one with the cover of the Quarter Pounder sitting on the cavity but it won't go in because it's a bit too big, and there is one of the original AFR pickups. 20190116_091626. 20190116_091655. 20190116_091814.
  5. ScorchMountain


    Jan 15, 2019
    they're so ridiculously close to the same size that it's hard to capture the difference in photos, but in these two pics, perhaps you can see that the QP is just about 1/32" to 1/16" larger than the original AFRs. It's tempting to say that such a small difference should not prevent the pickups from squeezing in, but the neck (P) pickups just won't. I can CRAM with bridge (J) pickup cover into the cavity by distorting the plastic under pressure, but that seems like not the greatest idea, and the P pickups won't be coaxed in anyway. Purely from a practical point of view, I had thought if the cavities had square corners instead of slightly rounded, they would fit, but it turns out that's not the case... the cavity is still too short (left to right). There is definitely a small but measurable difference in the pickup sizes. The AFR P pickups are about 2 & 3/16" in length, while the QP covers are about 2 & 1/4" long (almost 1/16" longer). The AFR is about 1 & 1/16th in the other direction (high, wide?) whereas the QP cover is 1 & 3/32" (about 1/32" more). ARGG... so close! 20190116_092916. 20190116_093019.
    Last edited: Jan 16, 2019
  6. ScorchMountain


    Jan 15, 2019
    I had looked into the dimensions of various brands, most are within a couple one-hundredths of an inch of their competitors, so while Brand X might be spec'd as shorter than Brand Y and might possibly fit, it's also wider in the other dimension and probably won't. I guess I was hoping that there was a "whole size" down that I was not aware of. The techs at sweetwater think that my bass just happens to have unusually small cavities, just big enough for their AFR pickups, and although they are extremely close to "standard", the tolerances are too tight, and if I want to put in any after-market pickups I'll probably need to enlarge the cavities. I see that StewMac (and probably others) sell templates, so I guess that's going to be my best solution if I want to do it myself, or maybe I'll search for someone who could do it inexpensively. Fortunately the finish on this bass is already crap.
    Last edited: Jan 17, 2019
    ctmullins and K-2 like this.
  7. The plus side is that once the cavities are the right size, other pups will drop right in.
  8. ScorchMountain


    Jan 15, 2019
    yeah, it's looking like that's going to be the solution. I can't say enough nice things about the people at Best Bass Gear. Frankie knew precisely what I was talking about, made me feel sane again, and is really going out of his way to help me out. I suppose I'll keep this updated, maybe it'll save someone a lot of frustration in the future.
    Last edited: Jan 17, 2019
    ctmullins likes this.

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