phase 90 bypass pop with bypass buffer

[joelap]

hi all, just built a buffer board for my phase 90.  Typical JFET buffer, 1M gate resistors, 4k7 source resistor, 33uf cap off the source.  I cut the trace going from the switch to the output jack as seen here: http://www.erikhansen.net/diy/phase90_outputbuffer.jpg   The buffer works, i know the trace is fully cut (checked with meter).  Problem is, there is a loud pop coming in and out of bypass.  I put 1M pulldowns on the input and output jacks, still there.  I'm wondering if anyone else experienced this problem when making a buffer for their phase 90?  I understand this is caused by DC on the switch usually... anyone experience a similar issue?

Thanks,

Joe

[R.G.]

It's get out the DMM time. Pops when you switch are caused by switching between two different DC levels. Find out what those are and trace them back to where they come from.

[vanhansen]

Interesting.  I haven't noticed a pop with mine after putting the buffer in.

I need to update that pic or edit that one in Photoshop or something.  The +9v wire needs to go to a different spot or the buffer will not get power when using a DC adapter.  Wiring it up as seen makes it battery only.  I found this out the hard way.    I'll open my Phase 90 up tonight and make the changes to the pic.

[joelap]

Interesting.  I haven't noticed a pop with mine after putting the buffer in.

I need to update that pic or edit that one in Photoshop or something.  The +9v wire needs to go to a different spot or the buffer will not get power when using a DC adapter.  Wiring it up as seen makes it battery only.  I found this out the hard way.    I'll open my Phase 90 up tonight and make the changes to the pic.

Erik, my board actually has a different look than yours does, and things are slightly different (pinout on the 9V adaptor was different, for instance).  I was able to get everything to the right spots.  This pop is very substantial however, I just need to find the appropriate location for a/the 1M pulldown(s).

RG: I guess measuring DC on the switch would be the smart thing to do.  I'll get on that, see if something is a dead giveaway.

[vanhansen]

I wasn't aware that they changed the layout, unless that happened recently.

You could just put the 1M pulldown resistors across the jack lugs themselves.  They are PCB mounted but just soldered tip lug to sleeve lug on the PCB should do it.  Maybe even try 2.2M instead.

[joelap]

You could just put the 1M pulldown resistors across the jack lugs themselves.  They are PCB mounted but just soldered tip lug to sleeve lug on the PCB should do it.  Maybe even try 2.2M instead.

Did it.  Did Tip to Sleeve on both input and output jacks.  Maybe they are normalling jacks and are one half are disconnected, and I've got one and or both on the wrong side. 

[vanhansen]

You could just put the 1M pulldown resistors across the jack lugs themselves.  They are PCB mounted but just soldered tip lug to sleeve lug on the PCB should do it.  Maybe even try 2.2M instead.

Did it.  Did Tip to Sleeve on both input and output jacks.  Maybe they are normalling jacks and are one half are disconnected, and I've got one and or both on the wrong side. 

Quite possible.  Should be easy to find out with a DMM.

[joelap]

Just a follow up in case anyone does a search for this problem: I had DC on the switch because I had no capacitor coming from the switch to the gate of my JFET buffer.  Case closed, problem resolved.