cd4066

[cr_XD]

ok, i've been reading the article on geofex to make a bypass with a cd4053, but ansil recomended using cd4066. can i just replace it directly, i mean, minding the differences in pin layouts.

about the flip flop. can i replace it with just any d flip flop.

las question, why not use the last switch to control the led??

here's the link to the geofex

[Saber]

The 4066 contains 4 spst switches whereas the 4053 contains 3 dpdt (oops I meant spdt) switches so it depends on what you need to do with them. If you need only 2 dpdt (oops again this should be spdt) switches, then you could make that from 4 spst switches in the 4066 but you would need to add some inverters to control two of them. Or you could avoid the inverters and use the flip-flop's Q output for one side of the 4066's "improvised" spdt (well at least I correctly typed spdt here)switch and the -Q output to control the other side.

Edited June 12, 2004 by Saber

[cr_XD]

Or you could avoid the inverters and use the flip-flop's Q output for one side of the 4066's "improvised" spdt switch and the -Q output to control the other side

indeed i was thinking of using q to control both, what may be the difference?

[Saber]

-Q is just the opposite logic state of Q, so when Q is at a logic 1 (or 9V) -Q is at a logic 0 (or 0V) and vice versa. So in order to use 2 spst switches of the 4066 as a single spdt switch, one side of this spdt switch has to be ON while the other side is OFF, so you have to send a logic 1 to the side that has to be ON and a logic 0 to the side that has to be OFF.

[cr_XD]

one side of this spdt switch has to be ON while the other side is OFF

yeah, if you just place the wires in opposite order, you don´t need the not gate.

what about the d-flip flop can i just use any?? the signal level is always the same isn't it?

[Saber]

yeah, if you just place the wires in opposite order, you don´t need the not gate.

I don't see what you mean by "placing the wires in opposite order".

what about the d-flip flop can i just use any?? the signal level is always the same isn't it?

As long as you stay within the 4000 series CMOS chips, then you can use them with a 9V supply as the logic signal levels will be 0V and 9V. If you're thinking of using another type of logic chip like TTL for example, that won't work. Which D-flip-flop did you have in mind?

[lovekraft]

I'm not a logic expert, but isn't a single DPDT switch the best you could do with a CD4066? You've only got 4 SPST switches, so it would take all 4 for a DPDT, right? Unless that's incorrect, the CD4053 has three times the functionality for about the same price and size - why would you bother with the 4066? And couldn't you just run the LED from one of the flip-flop outputs (with a buffer if necessary) so you don't waste a switch? If I'm missing something obvious here, please let me know so I don't screw up the switching system I'm working on for a pedalboard. Thanks.

[Saber]

Maybe I should proof-read my own posts. Wherever I wrote dpdt, I meant spdt. Sorry if my carelessness caused any confusion.

[ansil]

hmm i think i remember this topic. the reason i recomended the 4066 is someone was doing similar project and said they were having problematic 4053's... not sure though.

[Saber]

If I remember correctly (and that was some time ago), Craig Anderton used the 4016 (which is pin-for-pin compatible with the 4066) because he could get it to do soft switching (no clicks or pops) by slowly ramping the control voltage of each analog switch.

[cr_XD]

the series wich i know i can get easily is all that start with 74, so i assume they won't work, i think the high level is 5v.

I don't see what you mean by "placing the wires in opposite order".

i don't really know if i can get across, but has something to do with the switch, it doesn't matter which pole is the input and wich the output, if you look at the original schematic from geofex you can see they don't u don't need the inverter and in the specs from the 4066 both poles of the switch are mentioned like in/out.

I'm not a logic expert, but isn't a single DPDT switch the best you could do with a CD4066? You've only got 4 SPST switches, so it would take all 4 for a DPDT, right? Unless that's incorrect, the CD4053 has three times the functionality for about the same price and size - why would you bother with the 4066? And couldn't you just run the LED from one of the flip-flop outputs (with a buffer if necessary) so you don't waste a switch? If I'm missing something obvious here, please let me know so I don't screw up the switching system I'm working on for a pedalboard. Thanks.

that is what i want to do too. but i wanted to have a wide view of all the posibilities. .

If I remember correctly (and that was some time ago), Craig Anderton used the 4016 (which is pin-for-pin compatible with the 4066) because he could get it to do soft switching (no clicks or pops) by slowly ramping the control voltage of each analog switch.

mmm, that looks interesting, how slowly "slowly" is? enough to having a significant lag as you notice in some digital effects?

[lovekraft]

Seems to me if memory serves, unlike the 4066, the 4016 doesn't have an inverter on the control input, so it acts like a simple VCA, and you can use an RC ntwork to control switching speed. I vaguely remember someone ( I have no idea who) using them as faders in an old DIY mixer project years ago.

[Saber]

I don't see what you mean by "placing the wires in opposite order".

i don't really know if i can get across, but has something to do with the switch, it doesn't matter which pole is the input and wich the output, if you look at the original schematic from geofex you can see they don't u don't need the inverter and in the specs from the 4066 both poles of the switch are mentioned like in/out.

It's true that you can interchange the input/outputs of the analog switches but that doesn't change anything as far as determining whether they are ON or OFF. The Geofex schematic doesn't need inverters because it uses the 4053 which has spdt switches meaning that one side of the switch is ON when the other is OFF. The 4066 (and 4016) has four spst switches that are ON when the control voltages are 9V (assuming you're using a 9V supply) and OFF when the control voltages are 0V. In order to make a spdt out of two of these spst switches, you have to connect the two spst switches in series. That connection point would be the common of your new spdt switch. The first of these two spst switches would have to receive a control voltage of 9V while the second receives 0V. When the first receives 0V, the second would have to receive 9V. The two are always opposite. You need an inverted control signal between the two spst switches to do this whether it's from a 4049 hex inverter or from the -Q output of the D-type flip-flop. I hope this is clear because I don't know how to explain it any better.

If I remember correctly (and that was some time ago), Craig Anderton used the 4016 (which is pin-for-pin compatible with the 4066) because he could get it to do soft switching (no clicks or pops) by slowly ramping the control voltage of each analog switch.

mmm, that looks interesting, how slowly "slowly" is? enough to having a significant lag as you notice in some digital effects?

I found the old Guitar Player issue where Anderton mentions this. In the October 1981 issue, he says that it's Project #15 in Electronics Projects For Musicians. He says "it fades the signal in and out over a period of a few milliseconds. This delay is so small we don't hear it as a delay, but it does prevent any abrupt level shifts that might result in pops."

[cr_XD]

saber... you are damned right. sorry, i thought i was talking about the 66 when indeed i was thinking of the 53, then it all got mixed in the head..... a look to the specs again was needed. how can all you expirienced people be so patient??

[lovekraft]

Found it:

Audio Switch Notes

Between this and RG's pages you should become a switching expert!

[cr_XD]

slowly improving my electronics knowledge i came up with this idea reading your last linl lovecraft: i don't really know if it's already been done

if you feed a sine wave to the trigger of the 4016 that should make a tremolo, right?

i'm still looking into the sine wave generator, i think it could be done easily with a 555 and then placing an rc on the output, but haven't found a text that explains it yet.

[cr_XD]

found this sine wave generator, i more or less understand how it works, but could someone help me to move the signal to the levels i need??

i must move the signal so that the lowest level is 0 instead of a negative value to control the 4016 right?

[lovekraft]

Jsut to keep signal levels compatible, you could use a CMOS oscillator - take a look at this app note:

CMOS Oscillators.

With dual oscillator outputs with opposite phases, you've got a stereo tremelo/ panner with only two chips (well, three I guess, you'll probably need a dual opamp to buffer the whole thing). A triangle wave should be good enough for tremelo.

[cr_XD]

wow, i've read the sheet. i don't understand a word.

haha, see if tomorrow i can get some books and study about this.

[lovekraft]

Here's your simple tremelo oscillator - the output shouldn't need any serious scaling (try it as-is). Click on the pic for a bigger copy.