relay bypass pops for the first one minute then stops ! why? r.g. ?

[domenico]

hi I've built a relay bypass circuit using the first part of this (cd4027 and cd 4011)  http://www.ee.washington.edu/circuit_archive/circuits/bypass.gif to drive a relay driver (a bc549 with a 10k resisitor on base ) and so a relay
the circuit pops louds for the first one minute so it stops popping and it works good , how can I avoid it ?
thanks !
domenico

[domenico]

This is the complete circuit : dual a/b with relays , a 3pdt which bypass a firts boost (microamp) ,  a 3pdt for a/b between 2loops , a 3pdt to bypass a send boost , even 3pdt make loud pops in the first minute ,
I get pops only on clean channel of my laney lc30
please help me
domenico

[Transmogrifox]

It sounds to me like you have stray DC voltages floating around on your signal line from a different source.  It is possible that a capacitor somewhere begins to charge at power-up, and induces DC current on the signal line (thus the pops).  Then when it is discharged, the line has been adequately pulled to ground and it doesn't pop any more.  Do you use pull-down resistors on the input and outputs of your circuit?  What is on the input of your pedal?  A schematic of the entire rig would be more useful since I doubt that the problem has much to do with the electronic flip-flop circuit schematic you linked.  It's most likely somewhere in the relay configuration and input/outputs, etc.

A trick that is used in my Peavey Duel 212 is that a JFET is connected to the signal path on a relay output, used to mute the circuit for a brief moment during switching.  It has pretty siltent channel switching.  It wouldn't surprise me if your Laney does something similar.

[domenico]

thanks for the answer
this is the signal path : guitar>ggg buffer>a/b with relay(for tuner)(with 3pdt) > microamp(truebypass with 3pdt)>loop 1/2> loop 3 on/off (with relay)> lpb1(truebypass with 3pdt) > ggg buffer > out
all the signal path above is in a single aluminium box
I use pulldown resistor for every circuit and using a digital multimeter I can read 0,06 mA on the output

[Transmogrifox]

... even 3pdt make loud pops in the first minute ,
I get pops only on clean channel of my laney lc30
please help me
domenico

This makes me think it's not your bypass  relay circuit.  Do you have a headphone amp?  If so, connect this mess up to your head phone amplifier and see if you get pops that way. 

Is your guitar passive or active?  If it's active, it may be a source of charge on the signal path.

Have you measured voltage from signal path to ground in bypassed and unbypassed states?  If you have a DMM or a VOM you can find out where it comes from.

[domenico]

I've connected the box to pc speakers ad connected an hedphone to them , it click but very little
my guitar is passive
the first switch (relays) when sending the signal to tuner make the general output to groud to avoid noise while tuning , in this case the dmm mesaure 0,00 mA
when the signal goes to the rest of the chain the general outup measur 0,06 or 0,08 (when loop 3 is on)
how can I use dmm to understand where It came from ?

[domenico]

I've disconnected all booster's in and out and I've connect them one a time to a 3pdt switch , the pop is there for both the booster , is it a problem of power supply ? I use a stabilized one
ah is it possible to use 12 volt relay with 9volt supply ?
thanks

[Transmogrifox]

Most relays rated at 12V do actually trip over at lower voltages, so it may work for some 12V relay types to use a 9V supply.

Your most useful measurement will be voltage on a mV scale.  Make a test point that connects to the signal path somewhere, and one to ground.  Set up your DMM to the mV range and measure the voltage with the pedal turned off, then turn it on, and measure the voltage.

Measure at both the input and output of the pedals, and do it all with your guitar plugged in so everything is connected the way you normally have it when you're playing guitar.

If you measure a DC voltage when the pedals are bypassed, there is something else causing the problem. 

If you measure a DC voltage when the pedals are activated, then it is a problem with your pedals.  If you are using large input/output caps, you may be having this problem as the power supply charges them to the steady state voltages in the boosters that are supposedly being blocked by the caps.  Since you don't need a time constant that low for guitar, you could make the caps a little smaller (particularly on the output) to reduce charging time on power-up.

If you measure DC voltages no matter what, you have both external and internal problems.

[domenico]

the pop came from the second buffer , the output buffer .
I've built in and out buffer(ggg buffer) using a dual op amp , now I' divided it into 2 single op amp buffer and ...no pops ! yeahh!!!
...why???