Converting a Passive into Active - Newbie at electronics!

Discussion in 'Pickups & Electronics [BG]' started by michinho, Mar 5, 2014.


  1. michinho

    michinho Supporting Member

    Joined:
    Oct 11, 2013
    Location:
    London, UK
    Hi all,

    I've been playing bass for a while now but when it comes to electronics and modifications i'm pretty new.

    I want to modify a Fleabass. I'd like to make the bass active although i'm a little confused over a number of things :confused:

    Firstly i'm confused about the difference between an active e.q. circuit and an active pickup. I've heard/seen most people replace the stock pickup on these basses for an EMG 35DC. When looking at the EMG website for more info on these I see that the pickup set comes with a 9v battery clip. Is this just for the pickup? or would this be powering an e.q. circuit that is attached to the pickup? Are there any other users that have done a similar thing but used another type of pickup? I was reading up on SD Basslines and was wondering how they would compare to the EMG's? Would these pickups slot right into the bass or would I need to make the pickup hole in the body bigger?

    Also, if I was to leave the stock pickup in the bass can I just go about adding an active e.q. circuit? If so how is this possible? and what ultimately will this do to the bass? (i'm hoping adding an active circuit will make the bass more punchy . I also prefer an active e.q. circuit incase I have to go straight into the board while playing live in some last minute cases. That way I know I have all the sound and e.q. I need right there without an amp)

    Finally if I wasn't to add an active e.q. circuit, can I get an outboard one that won't colour my Tone? Just enhance it like an onboard one? Would having an outboard one be like the same as having an onboard one?

    Thanks,

    Mike
  2. bongomania

    bongomania Gold Supporting Member

    Joined:
    Oct 17, 2005
    Location:
    PDX, OR
    Disclosures:
    owner, OVNIFX and OVNILabs
    Outboard EQ is pretty much the same as onboard EQ. Any one specific EQ will have different specs and range of control than any one other EQ, but that's regardless of onboard or in a pedal.

    An "active bass" is 99% of the time passive pickups connected to an onboard preamp with active EQ included.

    Active pickups, like EMG is known for, have the preamp part in them, but do not always have EQ included.
  3. michinho

    michinho Supporting Member

    Joined:
    Oct 11, 2013
    Location:
    London, UK
    Hey Bongo, thanks for the reply.

    so what you are saying is that the 9v with the EMG would be powering the pickup? would the electronics that come with it just be attached to the existing circuit that is in the Fleabass? Or would that be completely removed? sorry if that seems like a stupid question to you. I'm a massive beginner when it comes to all this stuff.

    If I put an EMG 35DC in, would this be basically doing the same as my other active bass? (SGC NANYO SB320)
    or would it be different?

    Also, if I decided to keep the stock pickup (or swapped it for another passive pickup) would I be able to install an active circuit? Without drilling more holes in the bass?

    Finally, can you recommend some good outboard pre-amps if I decide to go down that road? That would simply enhance my tone as if the bass was active, not colour it.
    I've been reading up on the BB Bass RC Booster, the EWS Tri Logic and the Sadowsky. Would I be right in suggesting that for what i'm trying to achieve any one of these would be best placed first in my effects chain? (well, after my tuner) This would then go directly into my Diamond Bass Compressor. I'd like to keep the same amount of level with each bass going into the compressor. The 3 basses I will be using are my Fleabass, SGC Nanyo and Fender Jazz bass. Out of all of them currently only the SGC is Active so even if I decide to go down the modifying route with the Fleabass i'll still need an outboard for my Jazz. Would doing this with an outboard pre only switched on with my passive basses be like having 3 "active" basses?

    I hope that made sense, i'm just really confused about all this and not sure what the best path is to take! :confused:

    Thanks for the help though!

    p.s. sorry for the essays!
  4. bassgod0dmw

    bassgod0dmw Supporting Member

    Joined:
    Mar 1, 2007
    Location:
    White Plains
    The battery would be used to power the pickup, and if you decided to install an active preamp/EQ, it could power that as well. You would remove whatever electronics are currently in the bass.

    Yes. As for drilling holes or not, that entirely depends on what you want to install. If the new preamp has the same amount of components that are currently installed you wouldn't need to drill holes.

    Essentially
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  6. Bingo

    Bingo Banned

    Joined:
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    Location:
    South by Southwest
    This guy is spot on. However, there are some options using stacked pots that would allow you to put two knobs in the place of one. Some preamps are offered this way, or are that flexible to work with, and some are not.
  7. michinho

    michinho Supporting Member

    Joined:
    Oct 11, 2013
    Location:
    London, UK
    So the current electronics would be removed even if I just installed the EMG 35DC? How would that work?
  8. JustForSport

    JustForSport

    Joined:
    Nov 17, 2011
    EMG (not EMGhz) pickups are active, requiring a battery whether or not an active EQ is added.
    EMG pickups require 25k or 50k pots as well- EMGhz (passive) use 250k to 500k pots.
    With EMG's preamp setup, these pots are before the preamp in the circuit.
    Some preamps that have the pots after the preamp in the circuit use 50k pots.
  9. JustForSport

    JustForSport

    Joined:
    Nov 17, 2011
    Also, you may need a 'stereo' output jack to enable the battery to be connected/disconnected when the cord is plugged in/ removed.
  10. JustForSport

    JustForSport

    Joined:
    Nov 17, 2011
    You can wire the pickup(s) to the pots and battery, then to the jack. Or add EQ between pots and jack.
  11. JustForSport

    JustForSport

    Joined:
    Nov 17, 2011
  12. vaesto

    vaesto

    Joined:
    Jun 21, 2010
    Simply. If you get EMG 35DC you'll recieve: pickup itself, pre-wired volume and tone control pots, input jack and all the wires. You'll need to take all of fleabass electronics out. Put everything EMG provides and connect it. Find a place for battery somethere behind the backplate. As far as I know EMG made all the stuff solderless...

    Don't bother with onboard preamp. You'll need way more skills and knowledge to do it properly. And the price of all the parts and work would be beyond reason with that bass.
  13. JustForSport

    JustForSport

    Joined:
    Nov 17, 2011
    +1 ^^,
    however, if the EMG 35DC is purchased used, it may not come with all the 'factory' stuff.
  14. michinho

    michinho Supporting Member

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    Oct 11, 2013
    Location:
    London, UK
    I wouldn't be doing this myself it would be a guitar tech. What if I got an EMG 35Hz (the passive one) and installed an EMG onboard Preamp? Is there one that I could use that would mean I wouldn't have to have another hole drilled?
  15. michinho

    michinho Supporting Member

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    Oct 11, 2013
    Location:
    London, UK
    Also what would be better for that Punchy Modulus/Stingray Flea type tone... EMG's or Seymour Duncan Basslines?
  16. bassgod0dmw

    bassgod0dmw Supporting Member

    Joined:
    Mar 1, 2007
    Location:
    White Plains
    Active pickups require different components than passive pickups. Different pots and a different output jack. Last I knew EMG supplied the bare essentials with their pickups, or you could grab one of their wiring kits. You will need to check on that should you decide to go this route.

    Not really. Just as you mentioned above...active EMG's will require different pots than a passive setup, so those would need to be replaced. The output jack would need to be a stereo pot rather than the mono in a passive setup so that would need to be replaced as well.
  17. JustForSport

    JustForSport

    Joined:
    Nov 17, 2011
    bassgod0dmw-
    "Not really. Just as you mentioned above...active EMG's will require different pots than a passive setup, so those would need to be replaced. The output jack would need to be a stereo pot rather than the mono in a passive setup so that would need to be replaced as well."

    ref'd that in posts #7 and #8- on-going discussion.
  18. bassgod0dmw

    bassgod0dmw Supporting Member

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    Hence the reason why I said "Just as you mentioned..."

    Unless you're referring to something else in post #9 , telling OP he can just wire in an active EMG into his existing electronics isn't accurate info.
  19. Rob22315

    Rob22315

    Joined:
    Oct 23, 2010
    Location:
    Alexandria Virginia
    I just finished upgrading the electronics on two of my active basses and put a DIY buffer into a third to convert it from passive to active. None of it's hard if you're willing to do a little learning and asking questions. The big benefit to something internal to the bass is that you avoid having the cable capacitance impact your tone. If your cable run is reasonably short, something external will be fine and give you a lot more control if you don't mind spending some $$.

    If you might be interested in DIY, then read on, otherwise, TL;DR!

    The simplest way to convert to active is to install a buffer/booster circuit. These can be small, cheap ($$15 before shipping) and are available in kit form from BYOC or GeneralGuitarGadgets or you can build a simple one like the Tillman JFET buffer circuit. The Tillman circuit was about the size of a postage stamp (leaving lots of room for the battery), used the existing passive controls, and added noticeable but not outrageous boost to the output. The buffer/booster kits were cheap and easy to build and not much larger than the one I built. I still have them but never installed either of them.

    The next step up would be a preamp with the normal Vol/Bal/Tone controls. These can be DIY or fully assembled. The fully assembled pre's are nice because everything assembled other than the connections to the bass. I've only used a Bartolini NTMB which is nice and not outrageously expensive. Bestbassgear has a nice selection of good onboard preamps. As said before, get one that matches the current configuration of your bass or be prepared to drill some holes. Also make sure there's enough room in the existing cavity for a preamp plus the battery. Cheaper preamps can be had on ebay. I've never used one but the basstone preamps have gotten some reviews here on TB if you do a search. I don't think I've seen DIY kits for an onboard preamp but I find it hard to believe none exist.

    If you're into learning some circuit design principles, you can design your own or copy designs off the web or here on TB. You'll see some debate about obscure topics like opamps vs individual transistors or 'tone capacitors'. The biggest issue here is having to custom wire the circuit or use vero board unless you get a pre-printed circuit board kit. I had to relearn a little amplifier theory to complete the JFET Tillman buffer but really liked it when I was done. Parts can be bought at Mouser, for a preamp with equalization expect to pay about $20 not including pots.

    Regarding the installation - it's mostly knowing how to solder. The buffer kits are easy to assemble if you know how to solder. Folks here on TB can walk you through the final hookup if you need help. Preamps usually come with good wiring instructions as well although the Bartolini directions can be a little difficult to sort through. On the last swap, I used some tape and a sharpie to label each wire so I could sort through how it all needed to be connected. Having the manufacturer's wiring diagrams for both the bass and the preamp really helps too.

    You should also get familiar with heat shrink tubing to really do a nice job with installing circuits in your bass and avoid electrical problems down the road.

    Note, I have an EE degree so I don't find circuits intimidating. I also did mechanical assembly and soldering for an small electronics firm way back in the summer of 1983 so I am also comfortable with doing this kind of work. YMMV.

    Good luck with whatever you decide.
  20. JustForSport

    JustForSport

    Joined:
    Nov 17, 2011
    Posts #7- #10, AIO:
    "EMG (not EMGhz) pickups are active, requiring a battery whether or not an active EQ is added.
    EMG pickups require 25k or 50k pots as well- EMGhz (passive) use 250k to 500k pots.
    With EMG's preamp setup, these pots are before the preamp in the circuit.
    Some preamps that have the pots after the preamp in the circuit use 50k pots."
    "Also, you may need a 'stereo' output jack to enable the battery to be connected/disconnected when the cord is plugged in/ removed."
    "You can wire the pickup(s) to the pots and battery, then to the jack. Or add EQ between pots and jack."
    "EMG wiring:
    http://www.bestbassgear.com/bass-wir...agrams.htm#emg
    "
    (just for clarity).
  21. michinho

    michinho Supporting Member

    Joined:
    Oct 11, 2013
    Location:
    London, UK
    What would be the difference in having an EMG DC35 or an EMGhz 35 with an active e.q?

    Could someone recommend a good replacement pickup (e.g. EMG) and active e.q. circuit pairing that would go well together (The bass has 2 holes for controls and an input)

    Thanks,

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