Author Topic: Ibanez ES-2 Echo Shifter Bypass Circuit  (Read 122 times)

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Esabtech

Ibanez ES-2 Echo Shifter Bypass Circuit
« on: December 06, 2017, 08:06:23 AM »
I recently bought a non-working Ibanez Echo Shifter in hopes of getting it to work. Using an audio probe and pin out diagrams I can tell that the Cool Audio V3205's are working as well as the DSP chip. All LEDs work except for on/off. There is no audio signal at the output jack. The on/off switch does cause the tap tempo function to stop or start functioning. So, I believe just the bypass switching is not working.

Does anyone know what type of bypass circuit is used?

Plexi

Re: Ibanez ES-2 Echo Shifter Bypass Circuit
« Reply #1 on: December 06, 2017, 08:37:33 AM »
Post some photos!
To you, buffered bypass suck tone.
To me, it suck my balls.

Esabtech

Re: Ibanez ES-2 Echo Shifter Bypass Circuit
« Reply #2 on: December 06, 2017, 09:17:29 AM »



I'll take one of the front when I get home.

Esabtech

Re: Ibanez ES-2 Echo Shifter Bypass Circuit
« Reply #3 on: December 06, 2017, 06:23:47 PM »

















Esabtech

Re: Ibanez ES-2 Echo Shifter Bypass Circuit
« Reply #4 on: December 08, 2017, 11:04:47 AM »
Oh well, now it's spare parts! I must have shorted something with my audio probe, and now I'm not getting any signal from outputs of the DSP chip. But maybe this will help someone else out:

Before it went down I was able to figure out that the ADAU1701 DSP is used for bypassing the wet signal while the dry signal is always on. The last output channel - VOUT3 pin 43 of the DSP is the final delay signal and is switched off with the on/off footswitch. Also, the volume at pin 43 is controlled by adjusting the level pot. So, the bypass switching was actually working the whole time on my unit but the on/off LED had failed. I was able to replace the LED and keep probing. Still no wet or dry signal at the output jack. From what I can tell something is shorting the output jack tip to ground. Somewhere between after the point where the wet delay signal is mixed in with the dry signal and  the output jack. Could possibly be the dual inductor L7 or C35 that goes across L7. Both read 0 ohms to ground, on all four legs of the inductor and both sides of the cap. After that I hit something and now the tap Tempo and on/off LED's stay lit constantly and I can't hear any signal coming out of the DSP.

I have another used but working Echo Shifter coming so I can check to see if that is what it is. But, it really doesn't matter at this point. Now it just spare parts for the working one.