Ibanez SD9 Bypass issue

[nieh]

so I have an Ibanez SD9 which works great when turned on, but when its bypassed I get no clean sound. any ideas? switch is working and I checked the jacks and looked for any wires that came loose, but I'm not finding anything. could I add a 3pdt and just true bypass it?

[cherler]

I'm guessing it's a bypass buffer issue? One half of the op-amp should be used as a buffer when the effect is bypassed and maybe some connection there got messed up? That's my best guess at least, we have way more qualified people hiding here somewhere.

[crochambeau]

If you add true bypass (hijacking the input & output wires) you'll want to ensure that you set the flip flop to be always engaged (or hard wire a logic high on the effect switching FET so it can't close)

I'd probably go to the trouble of seeing if it could be fixed as stock. If the current footswitch engages and disengages the effect, it's reasonable to conclude the momentary switch and flip flop sections are both functioning. Which leaves the 4558D section in the bypass path, the 2SK30A-Y FET that should switch through the clean section (not to be confused with the 2SK30A-Y FET that switches through the engaged section), or the Vbias tap at the FET.

I would scrutinize the FET first, confirming you're getting the logic high from the flip flop section and signal at the 4558 output.

[Dr Satan]

Yep, most likely gonna be the JFET. I'd swap them both out personally.

[eatyourguitar]

Yep, most likely gonna be the JFET. I'd swap them both out personally.

I have the complete schematic here and I would %100 agree that it is the 2SK30A-Y. I have them in stock big bag. these go for $5 each on ebay. I will do it for less. PM me.

[eatyourguitar]

[nieh]

[eatyourguitar]

sent you an email. need your shipping address. you can paypal me same email address and price I emailed you.