Treble bleed caps(or whatever they are called)

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by Laroosco!, Nov 2, 2005.

  1. PanamaCZ

    PanamaCZ Member

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    Have you tried putting in a very large resistance for the bleed resistor?

    Regarding the condenser and resistance in series, the formulas on the "Calc" sheet would need to be revised to change the present relationship of the condenser in parallel on the volume pot to series. I did this but have no way to post it, but other than the higher volume pot settings, the frequency response doesn't look desireable.

    If Clorenzo sees this, perhaps he can help you with this.

    The Les Paul option simply exchanges the tone control circuit with 2nd half of the volume pot resistance, which doesn't help you model the circuit you're describing.

    Regarding cable capacitance, I think John Philips advice is very good and I agree with your conclusion.

    Regarding the pedalboard, you have the cable to the pedalboard and from the pedalboard to the amp. And you also have the pedalboard circuit as well. As the pedalboard has active electronics, modeling the pedalboard may be more work that it is worth.

    Mike
     
  2. Clorenzo

    Clorenzo Member

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    What I mean by "LP style", as explained in the Intro sheet, is a reversed volume pot, with the pu connected to the wiper lug and the output taken from what usually is the input lug. It's not that all LP's are wired this way, in fact most aren't, but it's an arrangement that you see in some LP-type guitars (and in most Jazz-type basses). When both pu's are selected, this arrangement allows the vol. pots to work independently, so you can turn one of the pickups all the way down without muting the other one, as is the case with the standard arrangement. The problem with it is that the loss of treble is much more noticeable and impossible to correct fully with a bleed circuit. The best you can do is use no resistor (give it a very large value, say 1000000) and a large cap, up to 1000 pF or so. This will help somewhat but won't correct the problem completely, especially at low vol. settings.

    As for the series bleed circuit (with the R and C connected in series), which is indeed used sometimes, I think I have a modified version of the spreadsheet with this option somewhere, I'll try to dig it up. What I'll do is create a new version where this can be selected with a checkbox. I think I'll also add some clarification about the "LP style" thing and maybe rename it to something less confusing like "Reverse", and while I'm at it I'll probably also add the option of placing the tone circuit after the volume pot (the well known LP 50's wiring mod). I'm busy with other stuff now but should have it ready in a few days.

    Re. pedals, most have a high input impedance similar to that of an amp (1M or so). Then the pedal output is usually low impedance and therefore not noticeably affected by the capacitance of the next cable. This means that what you should include in the spreadsheet is just the C of the cable from the guitar to the pedal and the input impedance of the pedal.
     
  3. SpanishCastle

    SpanishCastle Member

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    hi,
    many thanks guys, finally we are getting somewhere.
    i tried some different circuits in my les paul and indeed my les paul isn't wired that way. i got some good results as well so i already thought i couldn't have that kind of wiring.

    then for the series connection. i would love to have a spreadsheat where i could see some graphs of it. thus far i found my cable capacitance pf/ft.
    for the main cable i use a 6m monster rock it is 1050pf and i could some george L cables on my pedal board maybe 100pf totally. i was shocked about the high capacitance but i actually like some highs rolled of. i like it more than a long george L cable with lower capacitance.
    at this moment i have a series treble bleed of 1200pf with a XK resistor (have got to check it) and it works the best i tried so far. i tried parrallel bleed as well. they work fine, but i don't like the change of the taper of the pot so therefor im really interested in the series connection.
    so if you can send it to me or post it here. many thanks.

    at this moment i need a pedal that's not true bypass so i have an active buffer in my pedalboard. don't know which pedal i use yet. is a boss type of buffer good enough? i'd like a sd-1 as booster maybe.

    greetings,
    rene
     
  4. leofenderbender

    leofenderbender Supporting Member

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    I am extremely grateful to have people with the knowledge and practical experience of CLORENZO on this forum. What a great resource.

    Thanks Clorenzo!
     
  5. SpanishCastle

    SpanishCastle Member

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    indeed :) most people are worrying about sounding like somebody and talking about a list of pedals. but only a few do have knowledge about this little tool that's worth more than all my pedals really :).
     
  6. Clorenzo

    Clorenzo Member

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    Thanks for the kind words, guys, glad to be of help!​

    Rene, I've found the version of the spreadsheet with the series bleed circuit and e-mailed it to you. I'm not going to make it public since I'd rather produce a tidier version as I mentioned above. I'll report back when that one's ready.​
     
  7. SpanishCastle

    SpanishCastle Member

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    many thanks,
    i've already checked it out. conclusions:
    while the treble will be there and maintained, you see the response of the pickup changing much more than with the parrallel connection. however the taper of the pot is almost not affected.

    i checked the results also with what i use now. the response of the pickup gets more affected when turned down heavy. indeed when my volume is on 3 to 5 i hear a different response. but it's not darkening or brightning much.

    so... it's actually a difficult question. i think most will like the parrallel connection more. now i see the graphs i think i better try some parrallel circuits as well :X. perhaps i will get used to the new taper of the pot. it's worth a try anyway.
    greetings
     
  8. PanamaCZ

    PanamaCZ Member

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    Location:
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    Carlos,

    Recognizing that the question of tone relative to pot resistance and the other variables occurs frequently on this board, I wonder if the moderators would host a program on the TGP server that all could access.

    Following this thinking, what would be great is to have a "drag and drop" GUI that enabled a user to model a passive guitar circuit including series/parallel pickups, split coils, output cable and amp input impedance, etc. I imagine this would be quite a bit of work, but something like this may even suggest a business opportunity.

    Just thought I'd pass my thoughts along.

    Mike
     

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