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Help identifying bass + diagram

Discussion in 'Pickups & Electronics [BG]' started by thislooks, May 5, 2010.

  1. thislooks


    Apr 21, 2009
    I know I'm going to be flamed for this, but this bass needs a lot of TLC. I just asked the same questions in another thread, hoping I will get some help with the tunning pegs; now I'm posting it here to see if anybody can help me with the wiring...
    I'm doing the exact same post just to be consistent.

    Hi all!
    A friend's wife just found this bass while doing some late spring cleaning in her mother's house; it belonged to her brother who passed away more than 15 years ago.

    There's no information on it as what the make or model is, only the word 'Japan' is stamped on the plate holding the neck. Looking around the 'net I found out that it seems to be a Univox bass, but again, not even a serial number.

    I plugged it in and although there's a lot of false contacts, there was some sound coming out from the pickups, although they seemed to be way too microphonic, amplifying every little tap on the wood --it was so bad I started singing through one of the pickups and it was working! The downside is that the strings hardly registered, and it sounded very, very hollow.

    I looked at the controls and it struck me as funny that one of them --volume I think-- has a switch that is actuated when you turn it all the way CCW, (it is disconnected, anyhow). Then I saw the connections and could see there were a lot of bad solder joints, and then I reaized that the volume control -the one with the switch- was only 10Kohms! The other one which I think is tone is 500Kohms. I drew the schematic diagram and it doesn't make any sense (I drew the DPDT switches as single pole, since they are bridged, and single throw on those that are not connected all the way.) Somebody tried fixing it, but I'm not sure what they were looking for...

    The tunning pegs have been messed with; three of them are missing the ferrules and one of them is missing the whole peg where the string wraps around.

    What I'm asking is for someone to help me get the wiring diagram for this bass (I think I'll have to replace the 10Kohm pot), and I feel there are too many caps, but that's just me. Also, I've been away too long from electronics and don't remember how to read the cap values, so I'm not even sure what their value is.

    It would be nice to know the make just to have as reference; it was so badly neglected that I don't think we would be able to sell it at a good price, and I don't feel it is really special in any way, although I could take it to some gigs now and then... it looks so cool!

    I would appreciate if someone could tell me about the 'microphonics' --I think that is the correct term-- of the pickups, why it is happening and how to solve it.

    I would like to know where I can get the replacement tunning keys and ferrules; we might start replacing the missing ferrules and the broken key, and maybe later change the other ones, if it warrants it.

    I'm attaching the pictures of the bass, the headstock, pickups, controls as well as the schematic diagram I drew so that you can have an idea of the bass and help me get on my way to bringing this baby back to life.

    Any information will be greately appreciated.




    Tunning pegs



    Components and diagram

  2. Hey,

    I can't really help you with the electronics or identifying the bass but what a great bass you have come across. It would be awful to leave it to rot, so good on you for wanting to fix it up.

    If you don't really want to sell it, why don't you do some simple mods to it, like some new Tuning pegs, pickups, pots, capacitors etc. It might cost more but it would probably be worth it in the end.

    Check out some Pawn shops or eBay for replacement tuners that might fit.

    Anyway, I'm sure a bunch of TB'ers might have some info on this great bass!

    All the best, MC
  3. GlennW


    Sep 6, 2006
    I'm digging the COSMOS pots.

    Look around univox.org for pics. It appears to have been rewired. The pickup are probably single coils. For parts look to ebay.
  4. thislooks


    Apr 21, 2009
    Thanks for your repliles and your nice comments!

    I forgot to mention that I took off the pickguard (not really a pickguard, but something like it that is suspended over the body in the bottom half of the front of the bass, which has a finger rest --I guess for strumming the strings with your thumb) in order to clean and polish it; you wouldn't recognize it if you saw how it was when they found it.

    I had looked around univox.org and found out it looks very much like the 'Lectra bass, but the hardware didn't match and was concerned that there was no sign of ever having any brand name on it. And, this friend used a search engine looking for images of Japanese-made basses that looked like the 'Beatles' bass, and he found out one that is very similar under the brand name "Fresher"... any ideas?
    The link to that bass is http://www.wutzdog-guitars.de/inventory/inventory-details/article/1980-fresher-violin-bass/

    I'm sure this one has been rewired, and possibly the volume pot replaced with the wrong one, that's why I would like to check that first; I'm sure the microphonics will go away (or so I hope). I might talk to a friend tomorrow who has a Hofner that looks just like this one; maybe he'll let me open it and take a look at the guts, and I'll let you all know.

    Thanks again!
  5. There is definitely something wrong with the wiring. The switch and cap on the right don't do anything. Looks like a wire may have been severed on the middle lug of the rightmost switch.

    Even if it went to ground, the switch wiring in conjunction with the pots doesn't make much sense to me. Was this supposed to be volume/tone or two volumes?

    Any idea what the switches were supposed to do?
  6. thislooks


    Apr 21, 2009
    Yes I like the COSMOS pot too (the other one does not have any marks on it, other than 'Japan' and the 10K value.)

    The diagram is exactly how the controls are set, that's why I'm confused. If I remember correclty from how a Hofner works, the switch closer to the volume knob is for the bridge pickup, the middle switch is for the neck pickup, and the other switch is for some sort of 'solo' setting, increasing the volume when in the 'ON' position related to the other two switches.

    Now, remember, I'm trying to figure it out since the bass is not mine, it was abandoned for some years, and its previous owner passed away more than a decade ago... so as to what the switches and pots are supposed to do, your guess is as good as mine.

    When I connected the bass there was some sound coming from the pickups, regardless of the position of the switches; now I understand why this happened, since the bridge pickup is always connected to the output (which shouldn't be that way). According to the diagram, the neck pickup would come into action when the two switches are ON (I'm not even considering the one which has the middle tap disconnected, this one is always out of the circuit, along with the .001 cap.)

    I thought the 500K pot was for tone, but looking at the diagram there's no change in how much the capacitors --either one of them-- have in the signal.

    As for the switches, when I was playing my friend's Hofner at first I thought the 'solo' switch put the pickups in series, thus increasing the output, but in this bass the switches are bridged from DPDT to be SPDT, so there's no way of having that parallel-series combination as it is.

    I'll keep looking, and thanks again!
  7. thislooks


    Apr 21, 2009
    I think I got it!
    The diagram part, at least.
    Looking at the parts placement I figured out the output should be taken from somewhere else; we already
    know that the center of the two leftmost switches are paralleled... and then it goes to the bottom part
    of the other switch which is using a cap as a jumper to the other position, leaving the center free!

    Thus, instead of the right pot, the output should be taken from here.
    The connections should be like this:


    The resulting diagram would be like this:


    To keep hum to a minimum it is recommended to use a 'star' grounding method, like this:


    I just realized this way would have no tone control... or could it be that last switch giving us two tone
    settings, 'bright' and 'dull'?

    I'm also concerned about that 10K pot... I wonder how it will sound once it is going. I'm still looking
    for a *real* diagram for this bass!
  8. toul62


    Jan 25, 2010
    I thought I was the only one that had come across one of these! I have the exact same guitar as you with the same control panel with one exception. Instead of a 10K I have 2 of the 500's. Infact with the same lettering and such as you have. I also have the 3 caps installed as you do but one of mine is round verses all 3 square. I figure as long as they have the correct values it should work.

    I was able to clean mine up, change strings, install new machine heads and actually get a good tuning which from what I have heard is somewhat difficult to maintain on this type of bass. My problem was a grounding problem which also messed with my pickups working properly. I finally took apart the control panel and due to the age I'm going to just replace all the components to be on the safe side. Lot of work to put it all back together and find somethng else wrong.

    let me know how yours turned out! :)
  9. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    It's a pickguard, so you don't scratch the bass when playing with a pick. Like Paul McCartney does. ;) You can also rest your fingers there when playing with a pick. Lots of people play bass with a pick, especially back then. That's also why Fender had a chrome hand rest over the pickup, and had the finger rest under the strings. For playing with a pick. ;)

    I wouldn't leave that 10k pot for the bridge pickup. That's way too low a value. Obviously someone replaced the original pot, since that one has a switch on it, and it's not connected to anything. The soldering also looks different.

    That's a cool bass though. I had a Norma, or some such brand violin bass back when I first started playing.

    You can put some nicer machine heads on that and clean up the wiring.

    Do the pickup's work? If you need new ones you can get them here:

    Chrome Pickup for Hofner Style Bass | Allparts.com

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