New (broken) pedal day!

[Pepe]

I don't know if that helps, but in the KORG KFL-301 Flanger is a pair of tantalum capacitors connected in reverse. They aren't connected to the ground, though.

[laurie]

A pair of electrolytic capacitors in this configuration electrically mimic a non-polar capacitor half the size of each individual capacitor.

Very common in low-speed oscillator circuits.

[Pepe]

I already suspected something like this, but I didn't know that it results in half of the µF-value. Interesting!

[Pepe]

I found a picture of another Ibanez CS9 that seems to have the tantal capacitor soldered in in the way that I suspect is the correct one: with "+" at the "+" marking, thus the cathode going to the negative ground.

I am going to order parts soon and I will buy a new tantal for the CS9. And I'm going to put it in in this way, except someone has a really good idea why the anode is going to the negative ground in the schematics (which does even make less sense to me after reading a bit about tantal capacitors).

Ibanez_CS9_Tantal.jpg (435.46 KiB) Viewed 7677 times

[Pepe]

Today I examined the Ibanez CS9. I soldered a new tantal capacitor in the direction that I see as the correct one. I also found a few bad looking cold solder joints. After putting everything together the Stereo Chorus finally sounds as it should.

One of my two bosses at the closed music shop had the Ibanez UE 305 Multi Effects pedal that contains the Analog Delay, the Compressor and the Stereo Chorus of the Ibanez 9-series. My CS9 does now sound as I remember the sound of the chorus in that big unit.

I don't know if the tantal (that is still working due to the multi tester) in the "wrong" (factory!) direction was the culprit or if one of the cold solder joints caused the waveform to sound odd, but now it produces a much more symmetric sound.

[laurie]

Nice!! Congrats on another save.

[The_Doc]

Excellent work, as always, Pepe

[Pepe]

Will just chime in here that while the CS9 is one of my favorite chorus pedals of all time, the vintage ones often have a lot of weird LFO noise (that the reissues do not suffer from).

The CS9 does indeed produce a distinct noise floor. A lot more than the vintage CE-2 units that I have had.

[laurie]

PS-2 in need of some TLC arrived today. Many thanks to pepe for pointing me at this deal!
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PS-2_pic1.jpg (54.88 KiB) Viewed 6087 times

[Pepe]

Hopefully a very easy job for you!