Ibanez EQ - filter cap upgrade (schematic attached)

[guitaristz]

For filtering, I have some 47uF at 25 Volt caps. Will these work ok in place of C2 and C31?
Also C21, I might reduce to extend some higher frequencies.

thanks.

[blackieNYC]

Why do you want to replace those two in particular? The RC filter that input belongs to will go lower but that's probabaly of no consequence. The other filters noise off the DC voltage and can be increased.
C21- probably yes (?)

[guitaristz]

The main reason is the pedal is somewhat noisy. I figured due to aging electrolytics.

As per that C21 I hope that a bit more brightness for my cleans.

[thermionix]

The schematic you posted is for an Ibanez.  Thread title mentions a Yamaha.  Are they the same thing?

[guitaristz]

Opps and corrected. Yes the same!

thanks.

[DIY Bass]

Just bought the same one as a Maxon pedal.  It's broken and needs repairing, so I will be watching with interest

[guitaristz]

You may want to try and resolver the Master level slider connections as this was all mine needed to get it working.

Now to focus on making it quieter....!

[amptramp]

The 4558 is good for noise (<10 NV/(Hz)^0.5 but not the best.  Maybe a different op amp would be a good idea.  You have a lot of op amps connected as gyrators and they all add noise.

[PRR]

> the pedal is somewhat noisy.

Hiss? Or buzz?

There's hardly-any buzz-filtering in the power section. Cap will help some, but not a heap.

Hiss is something else. Is the hiss intrusive when all sliders are centered?

[DIY Bass]

Had a chance to look at mine today.  Audio probe showed it getting very distorted and horrible after the first electro cap in the signal chain.  Not surprising really given that it an older pedal.  I've ordered replacements for all the electros on the board and will replace the lot.  There is no signal getting to the output, which I think is a second cap, but I haven't checked that as carefully yet.

[guitaristz]

Glad you're getting to the issue. I was just hoping to add a couple parts (values) that I had around but might just order a bunch and blitz through the pedal. The chips are the long type versus 4x4 ICs.

These stupid captions aren't helping the vitality of this forum.

[DIY Bass]

I do have DIP ICs.  I had caps of the correct value in stock, but they are all 50V. The originals are all 16V, and are small enough that I don't think the ones I have would physically fit.  That's why I need new ones.