4066-4049 true bypass

[dj_death]

Hi from Greece, i wired today the bypass circuit with 4066 and 4049 at Laurier's Handy Dandy site. First of all there are two little mistakes at this pcb. Pins 8,4 of cd4066 should be connected, also VDD pins 14 of 4066 and 1 of 4049 should be connected as well. I tried to wire this little bypass circuit at my home made small stone (tonepad layout). It worked, but when i bypassed the circuit i could here some LFO sounds (oscillation problem i think). Of course the clicks during bypass was also audible. I added a 1.2M resistor to ground to the input of the circuit  (pin 1 of 4066) and the problem was disappeared, also the clicks are very very rare and almost inaudible now. I'm very satisfied right now, because there are no DPDT stomp switches anywhere in Greece and this cicrcuit costs just 2.5 Euro. The only think i worry is that the 4049 (cd4049ube)ic gets a little hot and i don't know if this is normal. I used my multimeter to measure the current the power supply feeds the hole circuit and it was about 75mA and i'm not very sure for this measurement. It is a little big value i think. Any experiences in this? Also is it normal to ground all the inputs and outputs of the inverters of the 4049 that are not used?
          I read in the forum that the fet bypass circuits used by boss and others are more reliable than the 4066/4053 circuits but these are very big and they will cost more than a DPDT Stomp switch. Imagine this as a true bypass circuit for a fuzz face, the bypass circuit will be much bigger than the main circuit and it will cost more. I don't doubt about your experiences with this ics but i think that they can be used in most cases.After a little tweaking of course.

[The Tone God]

The only think i worry is that the 4049 (cd4049ube)ic gets a little hot and i don't know if this is normal. I used my multimeter to measure the current the power supply feeds the hole circuit and it was about 75mA and i'm not very sure for this measurement. It is a little big value i think. Any experiences in this?

The ICs should be cool at all times unless you are putting too much voltage into it. 9v should be fine.

Also is it normal to ground all the inputs and outputs of the inverters of the 4049 that are not used?

All unused gate INPUTS should be brought to either logic low (ground) or high. Its good design practice. OUTPUTS should NOT be grounded. If you are grounding the outputs then maybe thats the cause of your overheating IC. Leave the outputs unconnected.

I read in the forum that the fet bypass circuits used by boss and others are more reliable than the 4066/4053 circuits but these are very big and they will cost more than a DPDT Stomp switch.

I don't know I would say its more reliable. ICs can be just as reliable as discrete parts.

There is an article about electronic switch bypassing called "Wicked Switches" here:

http://www.geocities.com/thetonegod/

Andrew

[dj_death]

You were right Andrew. I knew it, grounding the inputs and the outputs of unused inverters is a mistake. The pcb layout has many mistakes. I fixed it and i grounded the inputs of the unused inverters leaving the outputs floating. Know the ic is cold like ice and the current dissipation of the bypass circuit is a few uA. Thank you Andrew i checked the  bypass circuits at your site and now i think that i will use these bypasses for all my effects. Finally i have to note that the pcb layout of 4066/4049 bypass at Laurier's Handy Dandy site is mistaken. The unused outputs of the inverters should not be connected to ground. Of course the corrections i mentioned before should also be done.