Can you make a TS-9 automatically on ?

[Nuts]

Hello everyone !
I have a Boss SD-1 that when I plug it to the power supply- the pedal turns on automatically.
Is it possible to make an Ibanez TS-9 like that ? and if so, how ?

[Max999]

Yes you can. You need to unbalance the flip flop circuit. You can do this by making C40 and C41 unequal. Adding 10pF in parallel to one of them should make it come on in the same state. You will have to experiment which one gives you the "on at startup" behaviour.

This is a very good link that mentions the answer to your question http://www.geofex.com/Article_Folders/bosstech.pdf

[Nuts]

Thank you so much !

[Nuts]

Is this schematic correct ? I can't find any 100p capacitors (c40 and c41) in my tubescreamer or these 47k resistors that parallel to them

[Max999]

I used the same schematic when answering your question, it is unfortunate that it seems to be wrong.
I found another ts9 schematic:



The caps and resistors you are looking for are rather cryptically called "Cr1" and "Cr2". In the text below them they are called "Crf?1 and Cr2"  and are referred to as a "special cap and resistor in parallel", the cap is 56p and the resistor is 56K.

If you do find these, I would like to hear what is so special about them

[Nuts]

I can only assume that c40 and c41 are these:


but they say 102 on them, so i just tried to connect a 10pf cap in parallel anyway and after it didn't work, I tried it with any other suspicious capacitor and it still didn't work

[thermionix]

I would like to hear what is so special about them

Well they're in a single package, look like a funky ceramic cap.  Having only built true bypass Screamers, I never really paid attention to these parts.  I have a .pdf of the original TS808 service manual, and it gives no specs for CR1/CR2.  The reissues seem to have used discretes, shoved into the same hole.  Pics I have show 100k/1000pF, but could have been different in the originals.

[duck_arse]

I can only assume that c40 and c41 are these:


but they say 102 on them, so i just tried to connect a 10pf cap in parallel anyway and after it didn't work, I tried it with any other suspicious capacitor and it still didn't work

it's hard to tell in that foto, but it looks as tho the 1nF is perched atop a 1/8W resistor. if this is the case, try 100pF across one and the other, or 220pF, 330pF.

[Nuts]

it's hard to tell in that foto, but it looks as tho the 1nF is perched atop a 1/8W resistor. if this is the case, try 100pF across one and the other, or 220pF, 330pF.

Thanks
I tried 100pf ,220p and 2 220p in parallel (i don't have 330pf) but it doesn't want to turn on.
Should I try even bigger ones ?

[Max999]

You mean it doesnt turn on at all with added caps in parallel? If so, is the pedal still dead with the added cap removed?

A quick and dirty solution would be to swap the components on the two sides of the flip flop circuit I think 
Not the most scientific solution but if it gets you what you want ..

[thermionix]

You mean it doesnt turn on at all with added caps in parallel?

I think he means it doesn't turn on automatically when power is applied.  Not sure why this would be desirable.

[ElectricDruid]

You mean it doesnt turn on at all with added caps in parallel?

I think he means it doesn't turn on automatically when power is applied.  Not sure why this would be desirable.

It might be handy if you were using it in a switchable effects loop. Otherwise, I agree, I can't see much point. But that specific situation might be the OP's situation.

[Nuts]

It is in a true bypass looper, so if it was possible to mod it to turn on, I wouldn't have to turn it on myself every time I connect my power supply.
Just a 'laziness mod' 

[mth5044]

What if you pulled C11 and shorted the drain and source of Q2? Maybe too ham fisted

[PRR]

> wouldn't have to turn it on myself every time

If literally EVERY time, then just jumper-cut. Jump J2. Rip one leg of J4 out. Now no matter what the flop does, the output is always dirty.

[Nuts]

Thank you Paul, but I want to have the possibility to turn it off, just in case

[Nuts]

Does changing one of the parallel resistors make any difference ? they are 100k each and c40,c41 are 1nf (102)
I tried to replace one of these capacitors to a lower value capacitor, and it still didn't work.
Has anyone ever done a mod like this to a TS-9 successfully ?

[Max999]

I was thinking about why the capacitor trick did not work. These ceramic disk capacitors can have 20% tolerance. So when you are really lucky and one is 20% high and the other 20% low you need 400pF alone to balance the two existing capacitors. Lets say you want 10% inbalance, 100pf. Total pf needed extra would be 500pF.

The Geofex article is written by R.G. and he states he made it work.

[ElectricDruid]

I was thinking about why the capacitor trick did not work. These ceramic disk capacitors can have 20% tolerance. So when you are really lucky and one is 20% high and the other 20% low you need 400pF alone to balance the two existing capacitors. Lets say you want 10% inbalance, 100pf. Total pf needed extra would be 500pF.

The Geofex article is written by R.G. and he states he made it work.

If the capacitors were one 20% high and one 20% low, the pedal would probably always boot up in a consistent state already, wouldn't it? All you'd have to do would be swap them around if it was the wrong way about!

[Max999]

I am under the impression that the pedal now consistently boots up in one state ( off). I did suggest earlier to swap the components on the two sides of the flip flop circuit.