Always On mod for Ibanez DL10 delay?

[Michael2]

Hi all,

For a TB mod on an Ibanez DL10 Delay, the effect needs to be in Always On mode. Can someone tell me how to do this? It has the JFet switching.

I cannot find a schematic of the DL10 but some claim that the DL5 is (almost?) identical:http://experimentalistsanonymous.com/diy/Schematics/Delay%20Echo%20and%20Samplers/Ibanez%20DL5%20Delay.gif

Someone advised me to place a jumper on the outer legs of Q1. Tried that but no luck, not  even with the transistor fully removed. It still needs the relay to switch on.

[reddesert]

The answer was almost right. Q1 is the switching JFET.  When the electronic switch is turned on, it puts the JFET into conduction and the drain and source of the JFET are connected with very low resistance. The rest of the schematic is drawn in a complex way that makes it hard to see, but that turns the effect on.

The drain and source are the top and bottom terminals as drawn on the schematic, but they are probably not the two outside legs on the physical device. You need to figure out which legs are the drain and source and jumper those together. You could find the pinout for the JFET if you can find a device code on it. Or if the switching is the same as the DL5, the drain and source are connected to 1 uf capacitors, while the gate is connected to a diode. Or, just do it by trial and error.

[Michael2]

Thank you Reddesert!

Jfet is a K118. I have checked the specs and drain and source are supposed to be the outer lugs.

While examining the board I noticed that next to Q1 is an identical K118 labeled Q2. That differs from the DL5 schematic as far as I can see. Now I'm starting to wonder if Q1 is one of the jFEts that's responsible for the switching feature on the DL10. It then could be for something else, right?

Secondly, I checked where the legs of Q1 are leading to. The source and gate lead to D1, a diode (in and out) and the drain to a 47k resistor.

Hmm....pretty confusing....

[Michael2]

On further inspection I noticed that Q2's outer legs are connected to two separated 1 uf caps and the gate to a diode...the two caps are being followed by 100K resistors: just as Q1 on the DL5 schematic. Too bad there is no DL10 schematic around, that would have made things a lot easier....But what do you think?...is this the one we are looking for? Can I just try it without frying something? And will placing a jumper from source to drain be enough or do I have to take out Q2?

Thanks!

[roseblood11]

The DL10 is almost a collectors item, I wouldn't mess with it. Is the bypass really so bad? Have you tried to place a buffer in front of the delay? That's what I do with my PDM1...

[Michael2]

I'm helping a friend out to rehouse this Delay in a larger enclosure. Besides a multiple speed switch, one of his wishes is a 3PDT switch and TB. Since he has more pedals on his board that contain buffers he thinks it will be overkill. And I have to say, although the buffer is pretty good, it makes the signal slightly muffled imo...

[reddesert]

It's very unlikely that jumpering the source and drain of a JFET would break anything, of course I can't guarantee it, but a JFET in the "on" state conducts between those pins anyway. And you don't have to take out the transistor, just solder a little piece of wire between source and drain. If you can get clip leads onto the legs, you can try it out temporarily.

[Michael2]

Thank you so much Reddesert! I tried it and it is working! Woah! You are the man!

For others who want to do this mod: The original led will not follow the status (irregular behavior). Taking the led out gives no problems.