chirping tubescreamer ! ?

[bluedreamin]

Yes , I'm a newbie but very much enjoy the forum ! Hopefully someone can help me figure out my TS5 ...It chirps when I hit the switch , engaging it or disengaging it , does it every time ! It is very irritating , I did find and install a new switch but it did not help ...any ideas ? Thanks !

[Paul Perry (Frostwave)]

Maybe as the switch acts, it momentarily causes the unit to oscillate because the gain goes high?? Perhaps shielded wiring to the switch would help.

[bluedreamin]

The switch is mounted directly on the board , no wires ! It is an electronic chirp heard thru the amp ....capacitor problem ! ? Anybody ?

[Paul Perry (Frostwave)]

Does it do it both with battery, and with external power supply?

[bluedreamin]

Just battery , I don't have a power supply . Are you thinking the 9volt path may have a problem ?

[Sgt_Rutters]

On analogman.com, Mike reports about a chirping TS10 after 808 mods when the controls are up all the way.  Although he doesn't say what causes it, only that he has a solution for it.  Not sure if yours is modded or how close to the switching a TS10 and TS5 are though....

[jimbob]

Worst case - keep replacing parts with higher quality parts until the problem goes away.

[Gus]

there is a cap used in the switching section that sets the time delay for the transistion try a little bigger in value.  I would need to go to my notes for the number.

link a schematic for more help.

[bluedreamin]

Hey Gus , do you know which cap this may be ...electrolytic or ?

[gez]

do you know which cap this may be ...electrolytic or ?

If you look at bypass in schematics of commercial pedals you'll see RC combos coming off the outputs of a flipflop.  The junctions usually connect to the gates of the switching FETs via a reverse-bias diode.  Look for the diodes conncected to the FETs to find these caps and try making them bigger.  They're usually in the 10-47n range and not electrolytic.

Someone else had a similar problem with a home build recently.  Turned out to be gate capacitance causing the problem, and replacing the FET cured it if I recall.  Try the caps first though.

[bluedreamin]

Thanks Gez , there are a couple of 473 caps and a 104 in that area , are there suitable replacements for the fets that are readily available or will any jfet work ? Thanks again !

[gez]

there are a couple of 473 caps and a 104 in that area

Most likely to be the two 47n caps.  Make sure they connect to the diodes, you don't want to start changing values of caps that have nothing to do with the switching.

are there suitable replacements for the fets that are readily available or will any jfet work ?

I'll see if I can find the relevant threads.  Back soon!

[gez]

Last but one in this thread (one of his problems sounds like yours):

http://diystompboxes.com/sboxforum/viewtopic.php?t=35924

Four & five down in this one:

http://diystompboxes.com/sboxforum/viewtopic.php?p=254196&highlight=#254196

[gez]

PS  If you do end up replacing the FETs make sure the pinout is the same as the old ones if you can't find direct replacements.

[bluedreamin]

Well , the caps did nothing , the chirp/pop is still there ! Must be the fets which I don't have any of !

[bluedreamin]

Update ...I hooked up with a friend who also has a ts5 and he let me use the FET's out of his pedal , so, I have those in there and have doubled the value of the 2 .047 caps using .1 caps and I STILL get that chirp / pop noise ! Although I did notice if I turn down the volume to 3 oclock , with the drive in any position ,it is not audible ! ? I'm at a total loss here ...what could possibly be going on ? I really appreciate your help and patience guys ! Thanks

[gez]

...what could possibly be going on ?

Without a schematic, and an idea as to how they've done the layout, it's difficult to say unfortunately.  Perhaps someone here has had some experience of fixing this problem?

[gez]

! Although I did notice if I turn down the volume to 3 oclock , with the drive in any position ,it is not audible ! ?

Hmmm, sounds like Paul was onto something.  Might be oscillating.

[bluedreamin]

Any remedy for oscillating if that is what is going on ?

[analogmike]

Hi,

Sorry I dont have time to look it up exactly but changing resistor values in the mirror image FET switching circuitry to TS9 values helped the TS10. Maybe this info can help someone with more time tell you what to try.