Replacement preamp for a Godin piezo bass?

Discussion in 'Pickups & Electronics [BG]' started by Jim C, Nov 30, 2012.


  1. Jim C

    Jim C Supporting Member

    Joined:
    Nov 29, 2008
  2. khutch

    khutch Praise Harp Supporting Member

    Joined:
    Aug 20, 2011
    Location:
    suburban Chicago
    I'm guessing the answer is yes even though I don't know which ones. I would try emailing some piezo companies to get their opinions. If you don't already know who made the pickup and preamp I would ask Godin. They have always been good about replying to my questions even though I don't own one. Perhaps the company that made the piezo system on this bass is still in business and they should be able to tell you what will work best with it.

    Ken
  3. Jim C

    Jim C Supporting Member

    Joined:
    Nov 29, 2008
    I emailed Godin and am very disappointed in their reply:

    Hi Jim,

    That model was discontinued in the late 80's, and we unfortunately no longer have replacement parts. My guess is that the problem is caused by the battery connector. Make sure it's properly soldered, and also change the battery.

    Regards,

    Michel Belanger
    Support Clients / Customer Support
    Guitares Godin / Godin Guitars

    I would have thought that any pro company that no longer supports their products would at least offer advice or the schematic for repair.
    Also think that the smart a$$ answer about the battery is disrespectful as I explained that this bass was a gift to one of there earlier dealers that owned a repair shop.
  4. khutch

    khutch Praise Harp Supporting Member

    Joined:
    Aug 20, 2011
    Location:
    suburban Chicago
    He did offer you some advice and I see no disrespect in it. Some companies have schematics for equipment that old, many do not. I asked the same person several questions about an old Acoustibass I see for sale in a local shop and he gave me the information on who to contact about a preamp and replacement parts. The company that made the preamp was really no more helpful than Godin was since they don't make that model anymore but they were willing to sell me a new preamp and pickup system if I ever needed one! I think that if Michel had any more information to offer he would have offered it. Godin typically relies on third parties for piezo pickup systems and if they have no spare parts or support neither does Godin. So Godin is a dead end on this project and a little sleuthing says that Zeta has gone out of business. Your only options are to find an electronics tech who can look for simple things like Michel suggested (and possibly even reverse engineer the preamp which often is not difficult for gear of that vintage) or start talking to other piezo pickup makers who may know those pickups well enough to suggest suitable replacements.

    Ken
  5. Guey

    Guey

    Joined:
    Sep 12, 2011
    I used to have one of those basses. I am fairly certain it can be repaired. Mine had very shoddy wiring inside the electronics cavity.
    This drawing may help.
    Good Luck -
    Dan

    Attached Files:

  6. RustyMetal

    RustyMetal

    Joined:
    Jul 30, 2011
    I have one of these basses. The connections to the preamp are with these 'insulator slice through' connectors. You push the wire insulator and all into the connector and it slices through the insulation to make contact. The problem is that sometimes they don't make good contact or they become oxidized and the contact degrades. One solution is to actually solder the wires to the preamp board.
  7. Grissle

    Grissle Supporting Member

    Joined:
    May 17, 2009
    Bartolini, Ghost and Fishman all come to mind. Probably find something that blows away the original. The old setups could be brittle and thin compared to the new gear.
  8. JustForSport

    JustForSport

    Joined:
    Nov 17, 2011
    Recently purchased an EMG preamp buffer that may work- but haven't installed it yet.
    Check EMG's site for info.
    It's inexpensive, worth a try- cheap on the 'bay.
    Bartolini makes a small buffer, also, costs a little more.
    The Fishman preamp that is in another bass sounds really good, no 'thin and brittle' about it.
    All three of those are designed to be able to be connected to magnetic pickups if desired.
    BTW- Godin was very helpful when I've contacted them:
    you may have gotten the answer to your problem there.
    No cost, just go over the connections well.
  9. Davo-London

    Davo-London

    Joined:
    Sep 17, 2007
    Location:
    London, England
    Try a replacement K&K pure transducer. You can use an external preamp, which gives you more choice. That's what I did on my Godin A4 fretless!

    Davo
  10. jeffbonny

    jeffbonny _____________ Gold Supporting Member

    Joined:
    Nov 20, 2000
    Location:
    Vancouver, BC
    Maybe in the hands of a competent tech it can be fixed.

    Chances are good the pickup itself is fine. Quick check is to bypass the preamp and wire straight into the jack. It might sound a little thin if there's an impedance mismatch but if it's even across all the strings it's working. If it is then replacing the preamp will solve the issue.

    Some of this has already been mentioned but off the top of my head Graphtech, EMG and Bartolini make onboard units. LR Baggs might too. You could also gut something like a HPF-Pre or any other smaller 9v battery unit from K&K or Fishman or whoever and install it onboard.

    Going with an outboard preamp will widen your choices a whole bunch. The HPF-Pre is a high pass filter originally designed for piezos and the double bass but has found a home with many electric players too. Killer device. Fishman makes several preamps (I've never cared for them but they work well for lots of people), the Headway EDB-2 is good, LR Baggs makes several tried and true units, K&K has some lower priced stuff, the Radial PZ units work well, the D-TAR Solstice is good, a Raven Labs PMB if you can find one.....and that's just off the top of my head. Check out Gollihur Music for details on most of this stuff. Searching over on the double bass side will net you lots of info on outboard preamps some of which like I say you could gut and install onboard if that was important to you.

    Hope this helps.
  11. Jim C

    Jim C Supporting Member

    Joined:
    Nov 29, 2008
    Thanks to all.
    Does a piezo require a special type of preamp or will a standard magnetic pre work?
    I was under the idea that they had specific requirements and were not compatible with a magnetic pre.
    Meanwhile I will go through the connections again.
  12. jeffbonny

    jeffbonny _____________ Gold Supporting Member

    Joined:
    Nov 20, 2000
    Location:
    Vancouver, BC
    The issue is what's commonly referred to as impedance matching. The output impedance of a piezo is higher than the designed input impedance on a lot of the preamps built for the bass guitar (including the one built into your amplifier) can effectively deal with so you get loss of certain frequencies. A preamp with a high input impedance corrects this mismatch. A lot of amps these days (EA, Genz Benz, Acoustic Image and lots more) have an input impedance that will deal with the ultra high impedance of piezo pickups without signal loss. You need to check specs.

    In most cases you want something designed specifically designed for a piezo. The key is looking at the input impedance specs of the preamp. Look at the specs of the Boss GEB-7 stompbox EQ. With an input impedance of 1 M ohms it will in theory match a piezo to to a bass amp. The bottom line though is how does it sound? Correct specs don't keep something from sounding like ass with your particular instrument. It's really easy to spend a lot of money trying different preamps for piezos. My recommendation would be start with outboard units purchased from places with good return policies. It's really hard to rely on anyone's personal opinion here.
  13. agedhorse

    agedhorse Development Engineer-Mesa, Product Support-Genz Supporting Member

    Joined:
    Feb 12, 2006
    Before jumping to the conclusion that it's easy to replace the electronics, it should be noted that Zeta used a fairly unique pickup system with fairly small crystals in cantalever bending stress configuration. Each crystal is brought out to a separate input and I'm pretty sure they are separately buffered and summed with gain matching adjustments (maybe internal). A standard set of preamp electronics will not work.

    I wouldn't fault Godin either. It's unlikely that they ever had access to the schematic as it wasn't theirs to use or share. It belongs to Zeta, but Zeta is nothing but long long gone. I agree that your best bet is to find a very good tech (not a ham fisted, glorified wannabe) that might be able to get this sorted out for you.
  14. Grissle

    Grissle Supporting Member

    Joined:
    May 17, 2009
    Yes they are special. I believe these are piezo preamps that have the ability to run a magnetic pickup in conjunction with the piezo that have been mentioned.
  15. Jim C

    Jim C Supporting Member

    Joined:
    Nov 29, 2008
    Wow
    As usual, great high tech advice from an engineer with a massive amount of MI expertise!
    Thank you and I look forward to your posts in the future in the amp section.
  16. agedhorse

    agedhorse Development Engineer-Mesa, Product Support-Genz Supporting Member

    Joined:
    Feb 12, 2006
    In another life I designed piezo pickups. ;)
  17. JustForSport

    JustForSport

    Joined:
    Nov 17, 2011
    I recently picked up bass with a Fishman piezo bridge containing a separate crystal and wire in each saddle.
    Because the bridge was bent, I bought another identical bridge without the saddle crystals/ wires.
    Since the individual crystal wires were combined into one on a strip under the bridge, all I had to do was de-solder each wire, then swap saddles and re-solder them to the 'combiner' strip which went to the preamp/buffer.
    If the Zeta wires could be combined, then fed as a single feed wire to a preamp/buffer like EMG and Bartolini make...
    That would work?

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