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How to rewire a Hofner violin bass control panel for more tones

Discussion in 'Pickups & Electronics [BG]' started by fermata, Dec 4, 2017.


  1. fermata

    fermata

    Nov 10, 2015
    Just to round out the thread, here are some diagrams and images of the stock control-plate wiring I've found. Note, on the Contemporary series, at least, the pots are 500K.

    circuit.png

    2676114_orig.png
    Source: Hofner Icon Bass 500/1 mods

    2670616_orig.png
     
    Jefenator, RomanS and DavesnothereCA like this.
  2. DavesnothereCA

    DavesnothereCA

    Aug 21, 2017
    Canada
    ~
    Hello again !

    I now have a Hofner bass (Ignition Club), and began to comment about it in the below-linked topic, when I noticed issues with the schematic presented in post #1206 (the same pic was posted by a different person, earlier in the thread as well).

    Hofner-(not just Beatle Basses)-Group Part 2

    My remarks about it received no replies.

    Then you added your most recent posts over here, including the one with the stock Hofner schematics & pictorial layouts, all of which I found to be both interesting and ironic, during my own evaluation of my new bass, and considering whether or not to mod it.

    These schematics & pics also served to induce me to revisit the other topic.

    Please, when you get a chance, would you follow my link to the other thread, examine the schematic in post #1206 and my posts about it, and then make a comment over there ?

    Thanks.
    ~
     
    Last edited: Nov 5, 2019
    fermata likes this.
  3. PawleeP

    PawleeP

    Oct 8, 2012
    East Coast
    Part of any perceived loading could be due to inherent phase cancellations too, i think! pp
     
    mikecd1 likes this.
  4. Rockbobmel

    Rockbobmel Supporting Member

    Is it just me, but these Hofner pups are extremely HOT. I have a CT 500/1.
     
    fermata likes this.
  5. mikecd1

    mikecd1 Supporting Member

    Mar 3, 2009
    New England
    I also have a Hofner CT and think the 500k pots can give that perception with extra highs you get. I switched to the 250k pots and its very tame and a warmer sound IMO.
     
  6. DavesnothereCA

    DavesnothereCA

    Aug 21, 2017
    Canada
    ~
    I have looked at various diagrams for these Hofners, including the ones which you just posted, while I decide whether and how to mod my Ignition Club bass.

    For the vast majority of the time, I do not use either of the two switches which disable the opposite pickup and switch in one or the other of the capacitors.

    I do however use the solo/rhythm switch and the volume controls, in a simplistic manner as follows :

    My main sound is both pickups working, both volumes at full, and the switch in the 'solo' position, for louder uptempo material, and my amp set as needed to match the stage and room.

    After establishing the above, my alternate sound is to back off the volume control for the bridge pickup somewhat to reduce the overall treble, and usually to move the switch to the 'rhythm' position, for slower quieter songs.

    That strategy, plus where I pluck along the strings, is about all that I have been doing, and one way or another, it mimics how I have used the controls of other basses in the past to get those same two general sonic profiles.

    That all said, I have only considered ONE wiring change so far, away from stock, and that might be to modify the wiring of the 'Treble On' switch, so that when it is engaged, it still inserts the series capacitor into the signal path of the bridge pickup, BUT, it would NOT remove the signal of the neck pickup from the mix.

    Then, I would run my other controls starting the same as I described just above for my uptempo sound, and expect to observe a mid scoop of some sort, like the stock wiring of a Ric 4001 is supposed to do (even though MY Ric has not been wired that way since at least 1985).

    That brings me to a question.

    You stated that the pots are not the same electrical value among some versions of Hofner basses.

    I have also noted a remark in the schematic which I quoted/linked in this post, where it indicates that the bracketed values of the capacitors are different, by a factor of 5, and that those values are only for the Icon series.

    This variance is quite significant.

    Having not opened my Ignition Club yet, I do not for certain know what values of caps are in it, but from listening to the sounds which I get when playing with the switches, I would guess that the caps are also the larger bracketed values used in Icon series Hofners.

    The cap values NOT in the brackets are VERY different from the bracketed values, and the sonic difference noticed (if flipping those values back and forth in a bass) would far outweigh the expected difference in sound when comparing 250K to 500K pots.

    To get the desired mid scoop, I anticipate needing to reduce the value of the series capacitor somewhat, bearing in mind that in a Ric 4001, this cap is .0047 uF (I have confirmed this since the last time that I posted about it).

    My gut says to first try the .01 uF value which is outside of the brackets in that schematic (not as many mids as from using the Icon value of the cap), and change it from that starting point if necessary.

    Thoughts ?
    ~
     
    Last edited: Jan 29, 2020
  7. fermata

    fermata

    Nov 10, 2015
    Yep, I think that's the single best mod one can do to a Hofner. Try .01 uF for the bass cut cap first (that's likely what's already in your bass); if you want a more dramatic effect, go a bit smaller (.0047 uF, for instance).

    One of the bracketed capacitor values in the diagram you link to is clearly a typo--.047 uF would be quite ineffectual as a bass cut capacitor, so there's no way that's accurate. Apparently, though, some Hofners back in day had different treble cut (Bass On) cap values.

    As for Bass On, your bass probably has a .1 uF cap in series with an 8.2K Ohm resistor. If you still want a treble cut cap but find the stock one too bassy, try .047 uF or .033 uF. Without the series resistor you'll get a resonant peak that may or may not be pleasing to your ear; the resistor smooths out the sound by dampening the resonant peak.

    You can also decouple that switch from killing the bridge pickup, so the treble cut cap affects both pickups. But having both a treble cut cap and a bass cut cap on at the same time pretty well kills the bridge pickup output, so I'm not convinced by that particular mod.

    If you don't want a treble cut cap at all, you can turn that switch into a kill switch, which can be handy with two volume knobs. The easiest approach is to wire the kill switch to the output jack so that it shorts hot to ground in one position.
     
    Last edited: Jan 29, 2020
  8. DavesnothereCA

    DavesnothereCA

    Aug 21, 2017
    Canada
    ~
    Hi once again,

    I have edited my post after you quoted it (please refresh and reread), and noticed that you have edited yours as well.

    Anyway, I do not think that my Ignition Club has a .01 uF series cap, based upon what it sounds like when i engage the Treble On switch, but yes, .01 uF is what I would first try if I do my first mod.

    I agree with you that having a treble cut cap serves little purpose, as I already get that change by simply reducing the volume of my bridge pickup by using its pot, bearing in mind that the Hofner places the neck pickup much farther North on the body than I currently have the neck pup located on my FrankenRic, so reducing the treble and mids of the neck pickup on the Hofner seems moot, compared to what I might occasionally be inclined to do on the Ric.

    However, the KILL switch idea might be interesting, as it would be easier than wearing out my pots if I used them for the same purpose, and for maintaining a non-full setting, if I had been using one.
    ~
     
    Last edited: Jan 29, 2020
  9. DavesnothereCA

    DavesnothereCA

    Aug 21, 2017
    Canada
    ~
    I agree that .047 uF would let too many mids thru for a useful scoop (with both pickups on), and that is why (along with knowing how .0047 uF sounds in a Ric) I would initially try .01 uF.

    The only time that .047 uF might be useful in series with the bridge pup is if a person was going to use the bridge pickup alone, and coincidentally, that is what happens with a stock wired Hofner when engaging the Treble On switch.

    IF the designers changed the series cap value to .047 uF at some point, that may well be a plausible reason for doing so, and from the sound of mine, I think that they did.

    I will sometime later post what the current series cap value is in my Ignition Club (both caps, hey why not ?), when I eventually get around to opening the bass.

    If someone opens up an Ignition Club or Violin bass and beats me to posting the info, I will defer to their observations, and prob'ly will procrastinate opening mine for a bit longer. ;)

    It still works pretty well as it is, AND, my most recent change was to remove the DR roundwounds from it and install LaBella Low Tension Short Scale Flats (42-56-75-100, IIRC), and yes, they do fit scalewise, as I not long ago posted along with more details in the main Hofner thread.
    ~
     
    Last edited: Jan 29, 2020
  10. Dan_reeves

    Dan_reeves

    Jun 14, 2013
    Sorry to resurrect this post - I am considering some wiring changes on my Jay Turser beatle bass that shares the same wiring schematic as a Horner Icon from what I can tell.

    Is it possible to wire these VV with the switches being tone capacitors but the middle switch being a series/parallel switch? I basically run mine full on all the time - I assume the pickups are in parallel when on full? Being able to switch to series might be interesting.
     
  11. DavesnothereCA

    DavesnothereCA

    Aug 21, 2017
    Canada
    ~
    I expect that you would encounter grounding issues if you try wiring the two pickups in series, as IIRC they do not have a separate coil return wire and ground wire coming out of each pickup.

    VV[T] would be possible, and the Epiphone Viola bass is apparently wired that way, all in parallel like a Fender Jazz.
    ~
     
  12. Dan_reeves

    Dan_reeves

    Jun 14, 2013
    I should mention that I swapped out the stock pickups with different mini humbuckers, both of which have the four wire set up. And I don't want an individual pickup wired series/parallel - I meant the humbuckers in relation to each other. Just a clarification there...
     
  13. DavesnothereCA

    DavesnothereCA

    Aug 21, 2017
    Canada
    ~
    I WAS clear on what you wanted to do, which was why I answered as I did.

    However, now that you've spilled about your alternate pickups, that changes everything !

    So that's four wires PLUS a ground they each have ?

    If so, then it opens the door to doing what you wanted to do, as well as what you didn't, plus other things.

    The only limitation is what mods you choose to make, and whether or not you are OK with physical changes from mounting other electronics, if that becomes necessary to support those choices.

    And let me ask you - what humbuckers did you get, and did you have to make changes/cuts to the body of the bass ?

    I may want some of those pickups too, but not necessarily for the same reasons.

    BTW, mine is a Hofner Ignition Club bass.
    ~
     
    Last edited: Mar 30, 2021
    Dan_reeves likes this.
  14. Dan_reeves

    Dan_reeves

    Jun 14, 2013
    Sure!

    I actually purchased mini humbuckers from Lace - they dropped right in with no mods. I got these:

    https://lacemusic.com/products/nitr...MI5tODqI3Z7wIVljizAB31mQEwEAQYAyABEgIw5PD_BwE

    I was really unhappy with the output and tone of my set. I tend to like really aggressive sounding pickups, use flatwounds and getting my sound through technique. They were actually slightly smaller than stock...just barely. These pickups are typically for Firebird guitars. They sound really good. Better than what was in there. They are also louder, with more midrange than stock.
     
    DavesnothereCA likes this.
  15. Dan_reeves

    Dan_reeves

    Jun 14, 2013
    I should admit that I love the beatle bass look but usually want a rock sound that roars so that is the foundation for my choice.
     
    ctmullins likes this.
  16. Dan_reeves

    Dan_reeves

    Jun 14, 2013
    And lastly, the sound I like best is solo neck off bridge off which I think is typically just everything on right? I hate the idea of switching to rhythm...I have knobs and a volume pedal for less volume and I would never play that way. Just my own personal choice, I am certain purists would scoff at my choices and that’s cool.
     
    erksin likes this.
  17. I recently had my '86 Greco VB50 converted to the MASTER VOL / BLEND / MASTER TONE arrangement. This not only sounds a TON better getting rid of all those extra switches, it makes every control way more useful - the TONE control especially so - even with it all the way off I can still get punch, note definition, and fullness. The RHYTHM switch on the old stock Hofner-style set-up just made everything dull and thuddy by comparison. And having the ability to blend in just a bit of neck to the bridge to fatten it up a little, or some bridge to the neck for some more attack is pure win. I don’t know why Hofner doesn’t do this out of the gate!

    GRECO MOD.jpeg
     
    BigAndyA and Dan_reeves like this.
  18. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    May 15, 2021

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