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Post by fenderbender on Sept 18, 2012 13:14:31 GMT -5
I need some help determining if this switch exists or if there is something out there that can be wired to do the same. Essentially it is a simple bypass switch that in practice is not so simple since I can't seem to find one anywhere. I've asked JohnH with some help here but figured this might be worth knowing about to a larger audience. Below is the unicorn I seek: The bypass would be the center detent. Thanks - fb
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Post by long813 on Sept 18, 2012 13:24:04 GMT -5
An on-on-on toggle switch is all that you are asking right?. That does exist, example here: Search "on-on-on toggle switch" www.allparts.com/4-Pole-On-On-On-Toggle-Switch-p/EP-4362-000.htmI do hope they are not all that expensive though! Wiring the center position to bypass isn't really a mechanic on the switch, (its just another on position) but the means of which you wire to the output (ie, straight to it). Is this what you were looking for?
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Post by fenderbender on Sept 18, 2012 13:33:42 GMT -5
An on-on-on toggle switch is all that you are asking right?. That does exist, example here: Search "on-on-on toggle switch" www.allparts.com/4-Pole-On-On-On-Toggle-Switch-p/EP-4362-000.htmI do hope they are not all that expensive though! Wiring the center position to bypass isn't really a mechanic on the switch, (its just another on position) but the means of which you wire to the output (ie, straight to it). Is this what you were looking for? Yes to the second part. If the switch above is like any of the 4P3T found here then it's not as simple as it appears.
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Post by newey on Sept 18, 2012 14:22:45 GMT -5
fb-
ChrisK's diagram shows both the DPDT On-On-On and the 4PDT On-On-On. (There is also the Kent Armstrong variation on the 4P version, which mates a DPDT on-on-on with a DPDT on-off-on).
But, apart from custom-made switches, that's all that are commercially available.
Now, you diagram doesn't help clarify exactly what you want this switch to do. Rather than working backwards here, let's zero in on what functions you want the switch to perform- and then we'll see if such switching is possible.
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Post by fenderbender on Sept 18, 2012 14:45:20 GMT -5
Now, you diagram doesn't help clarify exactly what you want this switch to do. Rather than working backwards here, let's zero in on what functions you want the switch to perform- and then we'll see if such switching is possible. newey- Here's the best way for me to put it: This ties in with what you and I had discussed in the PM's to some extent. It's so I can use the switch to run different cap values in parallel with a third cap in the active part of the circuit. I do not want the active circuit on 100% of the time hence the boggle I'm in currently. John had suggested running the output from the active circuit into the switch initially until I realized the switch logic just wouldn't allow bypass that way. It was mis-communication between us and when I explained further he realized his suggestion would indeed not work. EDIT: Clarification - the active circuit is on with stereo jack wiring but not in the loop unless input from volume and one of the caps is selected on the toggle.
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Post by newey on Sept 18, 2012 20:19:45 GMT -5
That really doesn't clarify much for me. Let me see if I follow this.
There is an active circuit (which is not shown) that we want to be in parallel with one of the caps selected by this switch.
There is a stereo jack which connects/disconnects the 9V battery for this active circuit. Even with a plug inserted, however, the active circuit is only placed in the signal chain when the toggle switch selects Cap A or Cap B, but which is not in the signal chain when the switch is in the middle, "bypass" condition.
Am I reading this right?
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Post by sumgai on Sept 18, 2012 20:28:56 GMT -5
bendy, Let me see if I've got this right...... You want to connect a DP3T switch so that when it's up or down, one of the two caps is in the signal path, and when it's in the center position, both capacitors are out of the signal path - is that correct? And while we're at it, can you post an image of your diagram for the rest of your circuit, please? That bit about "in parallel with a third cap" peaks my interest...... sumgai
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Post by fenderbender on Sept 18, 2012 21:29:03 GMT -5
That bit about "in parallel with a third cap" peaks my interest...... Blame John for that! lol I didn't want to post an image since the originator (Tonefiend.com/Joe Gore) asked for it not to be reposted on his hand drawn image. However, his copyright thing is in there for the appropriate part (dashed box area) so I guess it will not be a complete sin if I show what I'm trying to accomplish. The active circuit is a Rangemaster pedal clone - more or less. That also was found at TF.com and here is a link to a demo with the PTB wired in the guitar. A link to the actual Rangemaster build guide PDF from TF.com is here. And last but not least is my crude rendering of said nightmare. May the force be with you. Edit: linked the wrong demo initially (however most of his demos are cool anyway).
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Post by sbgodofmetal on Sept 19, 2012 0:10:45 GMT -5
On-on-on switch? They're a dime a dozen at any radio shack inexpencive and most come in multipacks.
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Post by fenderbender on Sept 19, 2012 0:34:26 GMT -5
On-on-on switch? They're a dime a dozen at any radio shack inexpencive and most come in multipacks. If switches worked like plumbing - no problem. They don't though. In fact I think most were designed by slightly anti-social deviants that think a bag of wet cats is orderly.
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Post by long813 on Sept 19, 2012 0:44:05 GMT -5
On-on-on switch? They're a dime a dozen at any radio shack inexpencive and most come in multipacks. If switches worked like plumbing - no problem. They don't though. In fact I think most were designed by slightly anti-social deviants that think a bag of wet cats is orderly. I feel a rotary switch may be your best bet. Took me a while to understand what you wanted (not your fault!) and a rotary will get it done.
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Post by fenderbender on Sept 19, 2012 1:13:17 GMT -5
I feel a rotary switch may be your best bet. Took me a while to understand what you wanted (not your fault!) and a rotary will get it done. Yeah I know. Rotary is not an option though. Guess I could eliminate one of the switching options for the caps and then I feel it would be relatively easy to implement.
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col
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Post by col on Sept 19, 2012 1:22:30 GMT -5
Hi,
If I understand you correctly, you wish to use a two-pole on-on-on switch to select one of two caps, with the centre position bypassing both caps.
Yes, it is possible to do this. You would shunt the caps rather than take them out of the circuit. It would require the type of on-on-on switch where the common terminal is connected to both outputs at the centre position.
Sorry, no diagram, but I can describe it.
A B C D E F
Wire the above terminals like this:
C = in D = out
C-cap1-B C-cap2-F
A-jumper-F E-jumper-B
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Post by sumgai on Sept 19, 2012 1:51:02 GMT -5
bendy, Let's ignore the dragon's lair for a moment, and concentrate on the text underneath that line.... "The two switchable caps are to replace(?) these." Now I'm really reaching for my meds! Are you contemplating replacing the pot, so that the lower cap is either "fully connected" or "fully disconnected" - or do you actually desire to switch other caps into the circuit at those points? I guess I'm still in the dark - exactly what to you wish to accomplish here? For Gawd's sake, spill it all out - we need all the details you can give us!! ;D sumgai
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col
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Post by col on Sept 19, 2012 2:05:41 GMT -5
Hi fenderbender,
Assuming that I did indeed understand correctly, it occurred to me that this possible with the more common dptt (on-on-on) switch, where the centre position results in one pole connected one way, and the second pole, the other.
For this type of on-on-on switch, the caps would be disconnected at the centre position.
Where position 1 results in terminals A-C & D-F connected; center position results in A-C & B-D; and position 3 results in C-E & D-F.
A B C D E F
Wire the above terminals like this:
C = in D = out
A-cap1-B E-cap2-F
A-jumper-F
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Post by JohnH on Sept 19, 2012 2:19:49 GMT -5
fb - are you still wanting to have the middle position with the active circuit bypassed? To do that, with the other settings using different caps, it can work with a 4pdt on-on-on, with a slight reconfiguarion required of the input circuitry. I will sketch it if that is still the plan J
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Post by fenderbender on Sept 19, 2012 2:31:55 GMT -5
sumgai,
Pretty much this: "Are you contemplating replacing the pot..."
Plus this: "desire to switch other caps into the circuit at those points"
Here's what John had mentioned in private discussion earlier:
"The cap switching is a good idea, to use an on-off-on you need 3 caps, one of which is permanently wired in and you switch one or the other in parallel to it to add overall cap value "
Although that was prior to me clearing up our snafu with mis-communication and my intent.
Ideally the 3 way should operate like this: UP (cap A + input into active) - CENTER bypass active circuit completely and normal tone controls- DOWN (cap B + input into active). When bypassed (center) neither cap feeding the active circuit will be involved at all. Likewise, when switching to one of the cap options, we do not want signal from the normal controls to head straight to the jack. Signal will be directed through the Rangemaster and then to output.
That help?
Edit: John - Yes, and thanks. I thought this would be nice to have in the forum in case this topic comes up at a later date.
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Post by JohnH on Sept 19, 2012 3:20:10 GMT -5
This is a rough version of what I think you want. Schematically, using a two pole three way switch to give fully bypassed in the middle position and through the active circuit via one of two caps in the outer positions. To make such an arrangement out of a 4pdt on on on toggle, wiring is shown. (numbers are arbitrary, just to relate the schamatic to the switch diagram) cheers John
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Post by sumgai on Sept 19, 2012 13:26:29 GMT -5
bender,
John's version above will work as you described your wish-list. ;D It adds a resistor, but that's small potatoes, considering the overall effect you'll derive.
Now, FWIW.... In my opinion, Joe's inclusion of a pot merits consideration. As he describes the circuit action (correctly), the lower-value cap limits the low-frequency range of the circuit. That implies a "treble-only" response, which is true. Increasing the cap's value lowers the frequency limit, thus allowing ever-lower frequencies to pass through to the output. Again, true.
However, by using a pot to control how much of the higher-value cap is in the circuit, we are effectively blending in the lower frequency limit, thereby seemingly acting as if it were a Bass control. Compare this to your intended "all or nothing" arrangement, and determine what your needs might be.
Of course, if you don't like/need/want Plan A, you can always go back and institute Plan B. ;D
Also, be aware that even though you've taken the amplifier out of the signal path with your Bypass Switch, it'll still be drawing power. I might suggest that if you are 'bypassing' the amp a good deal of the time, then you should consider the idea of using a switch pole to turn the power on or off as needed. This would of course require the use of a DP3T at the minimum, but it's yet another way to ensure longer battery life.
HTH
sumgai
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Post by fenderbender on Sept 19, 2012 14:54:41 GMT -5
John - Thank you so much. SG - I thought about that a lot but I have some constraints I'm trying to build to. Four knobs max, and two switches. Some of that is due to the physical limitations of the guitar and some aesthetically. Also I wanted this to be as simple as possible for combinations. After building the HBD circuit it quickly became apparent that it was too much. Heinous words around here but that thing was not very intuitive at all - for me. Hopefully this design will prove less daunting to maneuver around with only two switches to slap around and some knobs to twirl. The physical limitation I mentioned is the thickness of the guitar. 1.25" at its deepest tapering down to less than one inch at the edges in some spots. Just finding parts that fit in some of the tight spots has proven a challenge. Before you ask about the megaswitch - flipped on its side and mounted with a bracket. New 90 degree actuator made to attach to arm and poked through the top. Laid on its side it is one of the thinnest really functional pickup selectors around. Anyway, if it turns out that all or nothing isn't working like I want then I may have to break down and add that fifth knob. There's one stacked concentric audio taper pot I found that may work in place of the PBT - tone controls and still fit if it comes to that. We'll see when the time comes. Thanks everyone for your comments and help.
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Post by JohnH on Sept 19, 2012 15:32:04 GMT -5
fb - You'll be bread-boarding this first, so it will be a good idea to try different cap values, and the extra pot too. Then, if you find two good settings that you would like to build in, you could adapt my sketch with a couple more (small cheap) fixed components to replicate those two sounds, and still avoid having the pot if you prefer. Presets are another option for this, accessible through a small hole with a screwdriver, so you can still tweak when you feel the urge.
sg - the 'power-off' pole in a bypass switch would be great, but I've found it very difficult to achieve in active circuits without a massive thump. Bleed resistors to ground and power supply caps only go so far to fix it. There's no problem with the 'switch off' thump - an electrolytic across the supply fixes that, but the switch on just has to make a big change of all the voltages in the active circuit and it does not sound pretty. So I think it is better to let all that happen as you first insert the jack plug, then let the power run steadily after that. This circuit will draw less than a mA so its not too bad. That being said, it must be possible to fix this issue but it needs more complication.
I suspect that it may be for this reason that there are no commercial stomp boxes or active guitar circuits that I know of that incorporate a power control on the same switch as an active/passive bypass.
cheers
John
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Post by fenderbender on Sept 19, 2012 22:11:52 GMT -5
OK, I think I may have translated John's sketch into something here. Click for image.Any comments welcome and appreciated. fb
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Post by JohnH on Sept 19, 2012 22:50:51 GMT -5
Yes, that should work. You can delete either the green or the yellow, since they connect the same things.
John
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Post by fenderbender on Sept 19, 2012 23:05:10 GMT -5
Excellent! Thanks, John and everyone else.
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Post by sumgai on Sept 20, 2012 12:34:14 GMT -5
John, The solution to the power-on thump is nearly the same as for the power-off..... simply insert into the signal path a 22µfd electrolytic cap. Place the Positive lead towards the pre-amp's output, and the Negative lead goes to the output jack's Hot terminal - Presto! you're all done. ;D The cap's voltage rating should be at least 16wvDC,* but larger won't hurt, provided there's physical room for it.** The net effect here is that the cap will need about 8 to 10 milliseconds to charge up and start allowing the signal to pass through. That's long enough to thwart 99% the power-on thump, but quick enough to seemingly be "instant on", when desired. 22µfd should handle frequencies all the way down to sub-20Hz with ease, regardless of the cord's capacitance value or the amplifier's input impedance value. 10µfd might do the job, but I suspect that it will charge up a bit too quickly, and allow more than a tiny bit of thump. However, if my suggested value is not immediately at hand, then some experimentation is highly recommended. This is one of the few cases where Your Mileage Shouldn't Vary, at least not by much. HTH sumgai * wvDC stands for "working volts Direct Current". These days, you often see it without the first "w". ** Note to other Nutz/lurkers - if you're using a dual-battery supply (18vDC) for your project, and you think this tip might be of use to you, be advised that the minimum voltage rating for this cap should be 25wvDC.
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