Tubescreamer "Always On" Mod?

[JesperB]

Hello

I have a Ibanez TS9 AnalogMan Silvermod, which I've installed in a rack drawer and use it with a switching system (so the input/output and power is always connected).

I have a little annoying problem, you guys might be able to solve.

Whenever I power up my rig, the TS9 starts up in off position, so I have to slide out the rack pedal shelf and press it on manually first.

Is it possible to make it "always on" and start up in the on position?

Yes, it's a very small problem, but it really annoys me

Thanks,
JesperB

[dolhop]

If you want it "always on" you simply have to hardwire the two mosfet switches...the fet on the clean path off and the fet in the wet path on.

[JesperB]

Thanks for your reply

Do you have any pictures/schematics of what you mean?

[dolhop]

An excellent breakdown of the tubescreamer can be found here:

http://www.geofex.com/Article_Folders/TStech/tsxfram.htm

Here is a link to the full TS9 schematic:  

http://tremolo.elektroda.net/Efekty/Ibanez%20Tube%20Screamer.gif

So, if you look at the switching section, you'll see that the clean fet gate needs to be tied to 0V and the wet fet gate tied to 4.5V.  In both cases I sugges you do this through a resistor - probably where the CR meets the 1M resistor.

Double check my statements though......it's too early for me to be thinking clearly.

[bwanasonic]

I find that strange, as my TS stays in what ever state I left it when I power up/down the outlet strip my FX are plugged into.

Kerry M

[JesperB]

Mine doesnt

dolhop - I will try to make some sense out of the schematic (I have no idea what it means, though)

[dolhop]

Sorry, reading your post with the modded TS9 and switching rack I figured that you were experienced with the electronics part of it all.

What is your experience level?  Are you able to identify the components on the circuit board?  If you're not comfortable with a soldering iron, then this might not be for you to do - I'd hate to see you mess up your pedal.

What you need to do is find the two CR compnents on the circuit board.....they should be labelled on the board as CR1 and CR2.  From there you'll need to find the lead that traces to the 1M resistor.  From each of these traces (CR1 and CR2) you'll need to run wires....from the wet side (I think it's CR1) you need to a wire run to a 4.5V node.  From the dry side (CR2 I think) you'll need to run a wire to a 0V spot.  I just noticed on the schematic that those 1M resistors might not be 1M, they could be 22k or 10k.....

I hope this helps....if you need more detailed help, I'll try.

[fatoldsun]

i use a bradshaw switching system with cornish controller. when ever my rack is turned on/off all the pedals remain in what state they are in. ts808 included. are you leaving the all the cables plugged in (using power supply) or are you using batteries?

[JesperB]

dolhop - ok, thanks for the detailed instruction, I think I can do it myself now. Otherwise, I'll take it to my local tech to do it for me

fatoldsun - Hmmm, weird, I wonder why mine doesnt do that

[JesperB]

Analogman told me this:
"If you pull out one leg or R125 it should start up in ON mode."

What is "one leg or R125"?

Do you have some pictures?

[JesperB]

Man, this is hard

[JesperB]

What is your experience level?  Are you able to identify the components on the circuit board?  If you're not comfortable with a soldering iron, then this might not be for you to do - I'd hate to see you mess up your pedal.

I'm a newbie and can't identify the components on the circuit board. But I can use a soldering iron

[dolhop]

Unfortunately, the TS9 schematic doesn't have component labelling.  If the part names are the same as the ibanez metal screamer schematic I traced then R25 is the 1M resistor I mentioned on the dry path.  Yes, if you lift one end of it then the dry path will always be off.  Not sure if the wet path will always be on, but it's worth a try.  If that doesn't work then you can wire up R18 (the 1M for the wet path) to be always on.  

Have a look at the PC board - it should have labels on it.  When desoldering, make sure you use a solder sucker or some desoldering  braid.

A 1M resistor should have the colours black-brown-green-gold.  But it may not be 1M....look for R25.

[mikeb]

Look here ... it's a document done by JPL Audio that covers what you need to do.....
http://prophecysound.com/temphost/alwayson.pdf

HTH....

Mike

[dolhop]

Removing a transistor seems to be overkill to me.  And using scotch tape?  Semiconductors should be placed into static bags if anything.

[jplaudio]

[R.G.]

Guys, it ain't that hard.

The on/off is controlled by that discrete-transistor flipflop.

All's you gotta do to make it always on is to tie the base of the "off" transistor to ground.  In this case, it's the one whose collector is connected to two 1M resistors, not one. Find that base, and bridge a wire across the 56K to ground from its base. Always on.