Stomp 3pdt´s and dpdt´s..I´ve just had enough!!

[earthtonesaudio]

Sure, as long as the DC requirements are not disturbed by that arrangement (use capacitors on inputs and outputs).

[nexion777]

thanks earthtonesaudio, now I have understand. But... you said you have problems with noise switching with the 4053, what kind of control were implemented?

[Processaurus]

Hi, I sent the effect input to V 1/2 to save parts.  The idea of avoiding pops is to have the exact same DC level waiting on either side of the switches.  When the 4053 switch is on, the wire going to the input is held at 4.5v by R3, so if it were held at 0v (ground) when the 4053 is in its bypass state, from the point of view of the effect input, when it is switched on it would see a way huge transient of 4.5v that would make it through the input capacitor for an instant.   *POP*!

Like earthtones had mentioned, V1/2 is a very low impedance source for AC, so any noise that might be picked up from the effect output on its input when bypassed that would make it oscillate (common in high gain effects with a sensitive, high impedance input) is shunted to ground through the big cap in the V1/2 source (C1).

[nexion777]

I think I understood, you sent the fx input to Vref because in this way pin 14 need not be connected to Vref through another 1M resistor, but is sent all the same to ground throug the filtering capacitor on the voltage divider... Great!  A larger capacitor accompanied by a 0.1uF mkt can bring some benefits or is irrilevant?

[Processaurus]

Yes, my schematic just uses the cap in the Vref supply to hold the DC level of the pin at Vref, but at the same time shunt AC noise to ground.

A larger capacitor accompanied by a 0.1uF mkt can bring some benefits or is irrilevant?

It never hurts, but it is probably not necessary here. You see the .1's in parallel with the big electrolytics because they catch some high high frequencies that electrolytics can't.  High speed digital circuits need it, analog guitar pedals probably not.

[earthtonesaudio]

thanks earthtonesaudio, now I have understand. But... you said you have problems with noise switching with the 4053, what kind of control were implemented?

I did this on the breadboard, using a 555 (not CMOS) timer as the control circuit.  This is probably what caused the noise, and not the 4053.  Unfortunately, the project I was working on wasn't as cool as I'd hoped, so I scrapped it without figuring out the exact cause of the noise.

[nexion777]

hhmmmm....  I also thought of using 555 as a flip flop (to save space), but according to your experience then I think that will reconsider the 4013... the cd4049 seems unreliable because of its vulnerability to electrostatic charges. My idea is to make a board that includes the bypass by 4053 and a input opamp buffer.  Possibly (and space permitting) we could move on this board the main caps of power supply filtering (from pcb effect) and use the voltage divider to provide 1/2 Vcc also to the effect (when 1/2 Vcc is need).    

[Lurco]

the 4013 as well as the 4053 being cmos chips like the 4049, are as vulnerable electrostatically.

[nexion777]

Hi, Lurco. I know about cmos electrostatic vulnerability, but reading the datasheets, I seemed to understand that 4013 and 4053 have some internal protection (and are therefore less vulnerable) and the 4049 does not (more vulnerable?). But perhaps I am wrong, my experience is very limited 

[earthtonesaudio]

Many CMOS chips have internal protection for signals above and below their supply rails, the 4049/4050 in particular are only protected for signals greater than their supply, not less than ground.

Notice the use of the word "signals" and not "electrostatic discharge."  The internal protection works for a few extra volts, which is a far cry from the tens of thousands you get by walking across the carpet on a dry day.  So it's still good to take the standard precautions (store with pins inserted in something conductive, keep handling to a minimum and perhaps use one of those anti-static wrist bands).

[dschwartz]

i have never had issues blowing a 4049..just take the minimum considerations..and if they blow.. well they are cheap enough to not worry.

[JKowalski]

Sounds like you need some of these:



Airplane certified DPDT momentary pushbutton switches, up to $200 bucks a pop - custom made. 

Will probably last through 50,000,000,000 cycles  

They feel like standard pedal footswitches when clicked, they even make a nice sound. But they are momentaries, the clicking is just cosmetic. Too bad they are so long, but they will probably fit nicely in a extra deep hammond box... And don't be fooled by the shallowness of the button itself, it's actually quite long, most is obscured by the super thick front panel.



My dad (avionics engineer, designs %^&*pits) randomly brought them home one day, they didn't need this thing any more. Amazing how much money they waste - my dad also brought home a big package of various toggle switches, DPDT, SPDT, 3P3T, about 20 of them - they were all in a bin in the hanger to be thrown away!!!!

[nexion777]

oh, damn.. I hoped that they ad a more robust kind of protection! Fortunately, as Dschwartz said, CD4xxx are very cheap ICs. I have almost completed a preliminary layout based on the processaurus schematic with the addition of a tl071-based input buffer. If Processaurus is in agreement I could post it here, in the case it is interesting for someone.

@ JKowalski: I have no words ...       

[earthtonesaudio]

For ultimate reliability, maybe consider optical or other radiation-based switches.  Good enough for smoke alarms...

[nexion777]

Well, I think I have managed to draw all the connections and tracks properly. I only have one last question: to avoid any distortion in bypass mode (using the pedal alone or in a pedalboard) which signal path is better (and if you can explain why).

1.   input jack --> input buffer (tl071) --> CD4053 --> unbuffered fx input --> buffered fx output --> CD4053 --> output jack
2.   input jack --> input buffer (tl071) --> CD4053 --> unbuffered fx input --> buffered fx output --> CD4053 --> buffer (another tl071) --> output jack
3.   input jack --> CD4053 --> buffered fx input --> unbuffered fx output --> buffer (tl071) -->CD4053 --> output jack
4.   somewhat better (which?)

I am very scared for the possibility of distortion after reading geofex's article on the 4053, but I did not understand under what conditions this occurs.. maybe using Hi-Z pickups? For this I thought it was better a buffer before the CD4053, but in reality I am somewhat confused.. 

[tempus]

1.   input jack --> input buffer (tl071) --> CD4053 --> unbuffered fx input --> buffered fx output --> CD4053 --> output jack

I would think that

input jack --> input buffer (tl071) --> CD4053 -->fx input -->fx output --> CD4053 --> output jack
   
would be sufficient - the buffer serves to lower the impedance of the signal. The ouput impedance of a TL071 would be in the order of a few hundred ohms, which is plenty low enough. So you'll have a low impedance signal driving the fx input, and the fx output should also be fairly low impedance (as always depending on the effect, but I would think this would be the case for most modern effects).

When in doubt, breadboard the different combinations and see if hyou notice any difference.

[nexion777]

Thanks tempus, I thought something similar but I was not so sure...  I would also like to hear the opinion of R.G., since he uses  the 4053 successfully in his pedals.

[blacKtearZ]

I recently put a danelectro pedal in a hammond box to make room for some mods, and kept the CMOS switching (momentary switch clocking a 4013 driving a 4053), just like the GEOFEX article on electronic switching),

Sorry for resurrecting a long buried thread.
I have just converted my mini dano pastrami to a Guvnor(minus the EQ). I am still using the Dano 4013+4053 switching board for bypass.

To my understanding the wires coming in from the switching board are as follows;

Blue - Effect input
Green - Vcc 9V
Yellow - Gnd
Orange - 1/2 Vcc 4.5V
Red - Effect Output
Brown - feeds gnd to Led

I have used them with the same understanding for the Guvnor circuit and it works. Only poblem is i am getting  pops when the Guvnor is switched in and out. The bypass was fine with the Pastrami circuit so i assume its a problem while interfacing with the Guvnor.
Has anyone here used the dano bypass module for other effects and had the same issues?
All ideas are welcome. Thanks

[danielzink]

Just for kicks - have you tried a 1m resistor from input to ground ? see if that helps w/ the popping.

Dan

I recently put a danelectro pedal in a hammond box to make room for some mods, and kept the CMOS switching (momentary switch clocking a 4013 driving a 4053), just like the GEOFEX article on electronic switching),

Sorry for resurrecting a long buried thread.
I have just converted my mini dano pastrami to a Guvnor(minus the EQ). I am still using the Dano 4013+4053 switching board for bypass.

To my understanding the wires coming in from the switching board are as follows;

Blue - Effect input
Green - Vcc 9V
Yellow - Gnd
Orange - 1/2 Vcc 4.5V
Red - Effect Output
Brown - feeds gnd to Led

I have used them with the same understanding for the Guvnor circuit and it works. Only poblem is i am getting  pops when the Guvnor is switched in and out. The bypass was fine with the Pastrami circuit so i assume its a problem while interfacing with the Guvnor.
Has anyone here used the dano bypass module for other effects and had the same issues?
All ideas are welcome. Thanks

[Processaurus]

Treat the 4053 like 3 mechanical spdt switches, and look for a DC difference between the two throws and the common on each switch, by using the DC volts setting on the meter and putting one probe on the common and the other on a throw.  Each throw should be within a couple millivolts of the common

Something in the mod  might have gotten rid of bias on one of the places in the circuit the 4053 is hooked to.

That rehoused fab metal clicks a little bit when it turns on (but not off), I think because the sudden inrush of current to the big LED I used.