Multi-capacitor tone control

Discussion in 'Pickups & Electronics [BG]' started by tonebrulee, Feb 4, 2011.


  1. tonebrulee

    tonebrulee

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    Been playing around with capacitor values for my recent P-Bass build and liked what I heard so much, I decided to install a mini switch (ON-ON-ON) that let's me choose between three caps. I had been curious about the Stellartone ToneStyler product and thought I'd check out how different cap values would change things. The result is the unit in the pictures which allows for switching between .047mF (traditional P-Bass value), .022mF (1/2 value) and .0047mF (1/10 value) caps. After trying about a dozen values, for my money these three values open up a world of possibilities. And, b/c the switch only changes the cap value used on the traditional tone pot, you still have a full tone control sweep across the chosen cap. This is different than the ToneStyler design which, if I understand correctly, gives you 16 fixed presets - i.e. the traditional variable tone pot is replaced with a 16-position switch that chooses between different fixed cap/resistance values. The home-brew switch here only has 3 cap values, but you retain the traditional ability to adjust the mix between the wet and dry signals. Two different approaches, depends on what you're looking for - YMMV.

    I'll try to get some sounds samples up this weekend, but in a nutshell, the .0047 cap produces this amazing open, woody tone that simply isn't available from the standard .047 cap. The .022 is a nice balance between the .047 and .0047 results - it basically allows you to dial some of that open woody-ness into the traditional .047 sound. It also allows for a unique and expanded range of more mid-focused sounds. Overall, the switch give a broad new palette to choose from. Total cost... like $7.50. Well worth a try if you can do the work.

    Oh yeah, for the switch, everyone and their brother wants to charge $12-$18 for an ON-ON-ON DPDT mini-switch, but I found one here for $3.75.

    [​IMG]

    [​IMG]
     
  2. HaMMerHeD

    HaMMerHeD

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    Radio Shack has those switches in most stores for about $4 or so. I've thought about doing this too, but with a 5-way rotary switch. But then I remember I don't have a passive bass.
     
  3. tonebrulee

    tonebrulee

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    Glad to hear it - my local RF had a decent selection of mini-toggles, but not an ON-ON-ON.

    I did a bunch of testing using a rotary switch, but once I narrowed it down to 3 caps, a mini-toggle takes up less space inside and has a pretty minimal visual impact outside.
     
  4. StevieMac

    StevieMac

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    Interesting. I'm really considering getting the Stellartone ToneStyler but this is an interesting option. Thanks for posting.
     
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  6. tonebrulee

    tonebrulee

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    No problem. Yeah, I was considering the ToneStyler too but figured I'd check out what's what on the cheap first. Glad I did b/c I feel that keeping the traditional wet/dry mix of the tone knob is very useful. Especially so when you are adding smaller value caps into the mix. There's a very interesting thing that happens when you roll a small cap all the way off. At the very end of the taper - with like 10% travel left - the tone rolloff seems to reverse direction and opens up rather than becoming muddier. But it's a different sound - i.e. if we call this point 90% (of cap invoked), it's not like 100% sounds the same as 80%. The 100% tone is almost as if the high mids get bumped and a bit of reverb is added. I know it's hard to believe, but it's for real - I'll demonstrate in the sound samples. Anyway - I'd be curious whether the ToneStyler puts 100% of the signal through their chosen cap value b/c this effect is very distinct - you might like it or not. In my case, I prefer being able to choose the 100% tone or not.

    BTW - I don't know whether my description would hold up if you try to explain it with actual measurements or looking at waveforms. I could imagine it wouldn't, but I'm not suggesting anything about the formal electronic measurements here - the proof is in the pudding and what I'm hearing and is very distinct.
     
  7. markanini

    markanini

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  8. tonebrulee

    tonebrulee

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    Similar, but the switch configuration on that thread doesn't let you choose the third cap since the middle position can only give you a combination of the two caps. Fine if you are OK with the .015 combined value, but in practice that value is very close to the .022 so I don't think you get as large a range of tones as when you use a DPDT ON-ON-ON switch and get to choose a lower value like the .0047. Also, I've gotta think while that combined .015 value might be correct in terms of total capacitance of the circuit, I'd bet it sounds different than a single .015 cap in this case b/c the caps are being used as band-pass filters and the combined scheme is effectively splitting the signal and puting it through two separate filters. Might be cool though - you'd have to wire it up and hear for yourself.

    The ToneStyler does seem a little pricey, though $100 isn't much in the bigger scheme of tone-chasing if you really dig what it gives you. But my guess is it gives you something different than the switch described here. Cheers!
     
  9. bassbenj

    bassbenj

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    Interesting. And I'm trying a slightly different variation of a multi-cap. I noticed that I tend to use the tone setting of full "off" a lot. In other words maximum brightness. And sometimes I like to switch to a more rolled off darker tone or vice versa. For this reason I decided to go with an on-off-on switch. That gives you one setting with the tone out of the circuit which gives you maximum brightness and then two cap choices. Obviously one of those ought to be an .o47mfd. for "normal" sounds. And then the other one something else. Someone in another thread thought .015 worked well for him. Probably some experiments are in order.

    The point is you can dial in a tone setting with a choice of either cap and then flip easily to "bright" and then back to "tone" as dialed in by the tone pot but without having to turn any knobs. At least that's my idea. I can't say how it works because the on-off-on switches have not yet arrived from Mouser. But it does seem to better fit how I use my tone control than just three different caps.

    Although, now that I think about it, the 3way switch does have an advantage that you can just leave one of the caps off and you'd have the "on"-"Off" capability, PLUS the 3way switch lets you put "off" on any of the three positions whereas my switch always forces you to have "off" in the center position...Hmmmm. :meh:
     
  10. Arvin

    Arvin Underwound Supporting Member

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    Awesome. I've thought about doing something similar to this, but just haven't gotten around to it. I've got more motivation now. :)

    One way to get a fourth option is to use a no-load pot, which will take the tone control out of the circuit when it's turned all the way up. Anyone looking for that "no tone control" kind of sound may wish to try that. You can either purchase a no-load pot, or make your own. Here's a tutorial showing how.
     
  11. DTF

    DTF Supporting Member

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    thanks for the link I just ordered some switches, I bought 4 radio shack switches recently and 3 failed because of the heat from the solder ,couldve been my fault but it hasnt happened with other switches ive used in the past
     
  12. The Professor

    The Professor Supporting Member

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    Can you post a picture or diagram of the wiring schematic? I'm going to try to do this sometime soon! AWESOME!!! :bassist:
     
  13. scarekrow

    scarekrow

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    I love this post; it's right up my alley, directionally speaking. I have run 2 SCPB p'ups straight to dual volume pots for many years and have been completely satisfied 'wide open', but with a Delano split P waiting on a refinish to be installed on a traditional P bass, these options are definitely in order to widen the passive tone options. Thanks!
     
  14. tonebrulee

    tonebrulee

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    Sure Professor.

    Here's a link to a good diagram for a DPDT ON-ON-ON switch. Just scroll down a couple of pages to the 3rd section marked "DPDT" switch. They explain the difference between the ON-ON-ON switch and the more common "center-ON" switch. You want the ON-ON-ON which allows for a 3rd discreet connection. The center-ON is what you would use for the "2-cap + combined" scheme at guitarnuts discussed earlier.

    Looking at the 6 lugs on the switch, we'll number them 1 to 6 starting with 1 at the upper right and going clockwise. You would then connect the leads from one cap to lugs 1/6, one cap to lugs 3/4, and the the third to lugs 1/4. You should be able to see this clearly in the photo where I'm holding the switch. The big Orange Drop cap is the one across lugs 1/4, which is selected with the switch in the center position.

    With the caps soldered to the switch, then you wire lug 2 to ground and lug 5 to the center lug on the tone pot. That's it! Below is a link to the standard P-Bass wiring diagram at Seymour Duncan. What we are doing is replacing the green cap by connecting lugs 2/5 from the switch where to the points where the cap was.

    Seymour Duncan P-Bass wiring diagram

    Lemme know if that isn't clear and I'll try to clarify.
     
  15. seedokebass

    seedokebass Supporting Member

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    I was just thinking about this a week ago!

    Did you play around with different caps, or just decide to go with the .022 and .0047?
     
  16. SurferJoe46

    SurferJoe46

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    I did it this way:::

    My original drawing, but I kept the Tone pot, although it doesnt show on the other two drawings::

    [​IMG]

    I hybridized it and this next pair is for the switch info only::

    [​IMG]

    But I used a slightly different switch::

    [​IMG]

    It works, and you can install whatever uF caps you want - I ran the .047uF, a .020uF and a .100uF cap and the Tone Knob still has command of the caps.
     
  17. line6man

    line6man

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    [​IMG]

    This diagram shows two cap values and a bypass, but you can add a third cap to the unused terminal for 3 cap values.
     
  18. tonebrulee

    tonebrulee

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    Tried .001, .0022, .0047, .01, .015, .022, .033, .047, .068, .10 with some in a couple different cap types. Didn't really notice any difference in cap types with the exception of the .015 cap which was a boutique Jensen oil-and-paper cap which I didn't like b/c when the cap was dialed all the way in there was a distinct "phaser" quality to the tone. The caps I chose were a .0047 (generic ceramic disc), .022 (yellow Mallory 150, polyester-film) and .047 (100v Sprague Orange Drop, polypropylene-film). People talk about the Orange Drop as a tone "upgrade", but frankly I don't hear any difference between it and a cheap ceramic. But the OD is smaller and might be longer lasting in the long run. Pretty lookin' though, I'll give you that!
     
  19. tonebrulee

    tonebrulee

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    Here is the wiring diagram for how I set things up. I like this scheme b/c it is completely self contained on the switch and might be a little clearer to understand - i.e. you remove the standard cap on the tone pot and wire lugs 2/5 from the switch right to the same points.

    [​IMG]
     
  20. TomA1234

    TomA1234

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    This is an awesome idea. I have loads of spare caps. I am going to "borrow" it.:D
     
  21. SurferJoe46

    SurferJoe46

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    That's right. A cap is a cap and if the tolerances are good enough (NASA caps are the best!), you won't hear any differences at the minuscule voltages and signal values we get outta a passive system.

    Size-wise - I don't think an Orange cap is any smaller than this::

    [​IMG]

    (Radio Schlack - 3/99¢)


    As far as wearing out - 'tain't gonna happen. There's no moving parts, and unless you use an old paper/wax cap from a 1928 Crosley radio, you won't have any oil or grease leak out either.

    Orange caps are a rip off associated with boutique gear, when in reality they are vastly overpriced and even if their tolerances were tighter, we ain't talking space ships here.
     

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