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Post by dannyhill on Dec 14, 2012 17:26:13 GMT -5
Hi all,
Here a question for you!
If for single coils pickups a high pass filter between them and the pot only works for 0.01uF downwards, what happens if one uses higher caps? No audible effect? Or do we start to cut in the mids and then treble range?
Cheers,
Danny
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Post by JohnH on Dec 14, 2012 23:08:46 GMT -5
Hi all, Here a question for you! If for single coils pickups a high pass filter between them and the pot only works for 0.01uF downwards, what happens if one uses higher caps? No audible effect? Or do we start to cut in the mids and then treble range? Cheers, Danny Danny, are you talking about using a cap to reduce bass? which is unusual but has been done. If so, it does indeed seem to need a very small cap in series with the pickups, just before the volume pot, and anything more than 0.01 doesnt do very much. So a bigger value lowers the frequency below which an which an audible reduction takes place, and above this frequency its almost unaffected. Smaller caps will raise this frequency, cutting mids and bass etc. J |
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Post by dannyhill on Dec 15, 2012 5:03:33 GMT -5
Hi John,
I'm trying to work out a way to maximise the number of controls on my guitars and sometimes space is premium, say between two pots on a tele control plate.
I was going to use DP3T toggles to allow two different cap values plus a direct no cap connection (e.g. wire) for high pass filter, low pass filter and series tamer functions.
If a very high cap value has no audible effect (for high pass/series tamer) I can use an SP3T where I get high cap/x/low cap to work where x=1(1/cap high +1/cap low)-
e.g.
0.047/0.0032/0.01
Right?
For no audible effect, where should I start?
0.022?
0.033?
0.047?
Higher?
Conversely, for a treble cut, how low does the cap need to be before I hear not bass cut, 0.001uF? 0.0005uF?
And can I swap caps for resistors on an equal basis?
D
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Post by JohnH on Dec 16, 2012 6:37:28 GMT -5
I think we need a diagram of your full circuit to see what values would be best
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Post by dannyhill on Dec 16, 2012 11:22:04 GMT -5
Hi John, Here you go:  The idea being to put three SP3T switches, one for each cap where they are located to switch between: Strangle cap - 0.022?/0.0038/0.0047? Series cap - 0.022?/0.0038/0.0047? 4th positon cap - 0.0047?/0.0008/0.001? (all uF) If I get no affect on tone for the first value of the first two and none for the second value of the third then I'm happy. Otherwise I will have to limit myself to 2 SP3T and 1DP3T or just the two current DP3T's I have between the two pots on the control plate. Danny |
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Post by ashcatlt on Dec 16, 2012 13:07:10 GMT -5
I don't have enough information to comment on the diagram itself. What is tha green wire? And where are the other ends of the pickups?
For the cap switching thing I'm afraid you're just not going to accomplish what you're looking for with any degree of satisfaction. To the extent that the "non-cap" is large enough to have no effect it will also be too big to affect the total parallel value to any appreciable degree. Just look at the numbers you've posted. .0008 is within tolerance of a 20% .001 cap. .0038 might be almost noticeably different from .0047, but I don't think it's enough to justify the switch itself.
Anyway, you can grab JohnH's GuitarFreak calculator thing from the Reference section. I don't think he's got a strangle cap in there. I think, though, that if you turn the T to 0 the frequencies which remain are pretty close to those which would be attenuated by a series cap - the graph will show the opposite of the bass-cut action, or close enough.
Or, go look at the input caps on some stompboxes maybe? Or, you know, grab some alligator clips and a handful of caps!
Don't have any idea what you mean about swapping resistors for capacitors, though it leads me to believe that you're thinking of an on-on-on switch with the caps in parallel. You're aware that the caps need to be in series to "add" the way you're thinking? You'll need center off switches for that.
*.01 and .047 cannot possibly be less than .005! In fact, this part of the problem to which I'm alluding. The total can never be greater than the smaller of the two, nor less than half of the smaller. The further apart the two values, the more the smaller value dominates.
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Post by dannyhill on Dec 16, 2012 15:50:08 GMT -5
Hi Ashcatlt,
The green should be the bridge ground lead.
The neck ground is directly attached to the upper right lug i.e. ground.
The 4th position cap acts as treble cut for the bridge pup and both are in parallel with the neck pup which is also in parallel with the series tamer cap.
The series tamer cap goes between the neck and the bridge pup.
I know in a separate build John was saying I could use resistors instead of caps in a bypass circuit. Was just wondering, anything with an RC value right?
Centre off is what I had in mind to use for all of these. I take your point on having two values so close together to allow a third 'non-cap' value, I may as well have just a dpdt and just use one cap and a wire?
But for example, if I use:
0.0047 and 0.0068 for the series tamer with an on off on, the first surely cuts no bass (?), the second will reduce the bass a little, the cap value in between is 0.028, close to the regular (cf jag) strangle cap value.
The same could be used for the strangle cap.
For the '4th position cap', so called as it only comes into play in that position I thought of using:
0.0047 and 0.001. The first would cut some treble, the second less, the cap value in between would be 0.0008 surely no treble cut?
?
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Post by JohnH on Dec 16, 2012 17:41:56 GMT -5
Danny – what I’m after, is to see how this stuff is wired into the whole guitar, and what values for pots, types of pickups etc, because it’s all interactive and which values are best, or have no effect will depend on the whole set up.
John
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Post by dannyhill on Dec 16, 2012 18:20:48 GMT -5
Sorry John:
Pots:
250KOhm Log volume pot
TBX tone pot 1Meg open, 220KOhm at notch, 0 fully closed.
Pickups:
Tele neck (approx 7kOhm)
Tele Bridge(approx 8KOhm)
Tone cap: OD 225P 0.033uF
Cheers,
Danny
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Post by dannyhill on Dec 17, 2012 17:40:27 GMT -5
Need more info :-)
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Post by ashcatlt on Dec 17, 2012 20:46:30 GMT -5
0.047 and 0.0068 for the series tamer with an on off on, the first surely cuts no bass (?), the second will reduce the bass a little, the cap value in between is 0.028, close to the regular (cf jag) strangle cap value. Nope. 0.028 > 0.0068. Cant happen. I think your decimal slipped! Is it possible that you're just getting too fancy here? Will parallel caps, or just discrete caps get you what you want more easily? Suppose it might need different switches... |
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Post by JohnH on Dec 18, 2012 3:08:59 GMT -5
Danny - I dont think Ive really understood why you want a cap with no effect. If you have SP3T switches, why not a piece of wire for no effect and two caps?
Your part circuit explains partly what you are doing. Is it the idea to add capacitors in series with pickups to cut bass? The type of values that start to have an effect will depend on where in the circuit they are, particularly are they before or after the tone control. If before, theny the loading of the tone control after the cap nwill add a bit to the bass cut.
Somewhere in the range say 10 to 30nF with your pot values, I reckon you will start to get some bass cut, but its too hard to guess and even a calculation will noyt tell you how it sounds. If you want to decide what you think is best the only good way is to rig it up with flying leads and experiment
The effect of resistors and capacitors in such circuits is different.
Caps in parallel with pickups are quite a different arrangement, even down to 1nF or less you can hear a difference.
Not sure any of that helps and not sure If it addresses what you are doing.
John
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Post by dannyhill on Dec 18, 2012 4:12:32 GMT -5
ashcatlt: I slipped on the 0.0047 to 0.047. Now corrected. ashcatlt and JohnH: I want a cap with no effect so I can use several sp3t (i.e. on off on). I don't have room for more than 2 DP3T on on on's, but I can fit 3-4 SP3Ts. JohnH: "Your part circuit explains partly what you are doing. Is it the idea to add capacitors in series with pickups to cut bass? The type of values that start to have an effect will depend on where in the circuit they are, particularly are they before or after the tone control. If before, theny the loading of the tone control after the cap nwill add a bit to the bass cut." They are all before the volume pot. One cuts bass going into the volume pot, another cuts bass between each pup when connected in series in the 5th position. The other only works in the 4th position, cutting treble going into the bridge pup. "Somewhere in the range say 10 to 30nF with your pot values, I reckon you will start to get some bass cut, but its too hard to guess and even a calculation will noyt tell you how it sounds. If you want to decide what you think is best the only good way is to rig it up with flying leads and experiment" Fair enough. Whilst I don't have time at the moment at home to try this I though maybe try some 'thought experiments'. So somewhere from 10-30 up to 100 works? What about the treble cut cap? "The effect of resistors and capacitors in such circuits is different. Caps in parallel with pickups are quite a different arrangement, even down to 1nF or less you can hear a difference." Now that is interesting, as in the 4th position the cap which is the 'series cap' in the 5th position goes into parallel with both pups. Not sure any of that helps and not sure If it addresses what you are doing. It does. Many thanks, D
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Post by JohnH on Dec 18, 2012 4:25:01 GMT -5
If you want to have a tool for your thought experiments, 5spice is what I use, and its a free download, plus its user friendly.
You can see in some of my posts how you can model a guitar circuit. No need to do the switches, but you could add the caps etc and see what they do. If you try it, Ill help and its a great learning tool.
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