IC 5534DD - Is there a better replacement ?

[solarplexus]

Is there?

It's in my Ibanez Fat Cat (FC10), which sounds awesome but I'm wondering if the IC could be improved.

Any suggestions?

[Sir H C]

Depends on the circuit.  The 5534 can drive very low loads (~600 ohms) reliably so if they used that feature it can't easily be replaced. 

[Mark Hammer]

You're saying that's the stock chip? or is it what YOU put in?

Note that the 5534 delivers better noise performance than bi-Fet chips when the resistors around it (input, feedback) are low.

[solarplexus]

hey Mark,

yeah the 5534DD is the stock chip in the Ibanez FC10 (Fat Cat).  I was wondering if there is a better replacement for lower noise or better sound.  I like the sound of the pedal as-is, but if there is an improvement possible, it would be worth it.

[Mark Hammer]

I think you can safely stick with what you've got, then.

From the looks of the schematic ( http://www.fortunecity.com/tinpan/humperdinck/223/ibanes.gif ), the surrounding resistors are in the appropriate zone for decent noise specs.  My sense as well is that the choice of a 1M bias resistor (tied to the noninverting input) may be particular to that op-amp, such that whatever advantage might exist in changing op-amps would also require you to know what that resistor ought to be for other op-amps.

Assuming the schem that Stellan has posted is accurate (though the posted one obviously omits the FET switching), the unit is VERY close to a Proco Rat, which may be why Ibanez opted for an animal name that rhymes with it.

The amount of gain in the unit is pretty high (>1500 for content above 900hz or so) so, in which case the noise you need to worry about is perhaps more whatever is coming into the unit than what might be generated BY the unit.  hat's another reason why you're probably wise not the change what's in there.  I'm not saying others might not result in a tone which could be more to your liking, but if you've got something in there that likely delivers as good a noise performance as you're likely to get under the cicumstances, why change it?

[solarplexus]

Hey Mark,

thanks for the help.  I'll stick with the 5534DD.  The schematic link isn't working though.  Is there something I could do to give more range to the Filter knob? 

Thanks,

Matt

[Mark Hammer]

Specify what you mean by "more range" and I'll tell you what you can do.

[solarplexus]

Well, the filter (or tone) knob is very limited to what range it can have in high/low frequencies.  The highs are sometimes not enough, the lows are sometimes too much.  I guess I wish there was more highs and mids in the filter to give it more presence or that it could sweep more precisely, because the lows are very prominent, but are really great sounding.  I don't know if you get this ?

[solarplexus]

I guess not 

[Jered]

  I like how quiet Burr-Brown chips are. Which one would be best for your situation? I couldn't tell you.
  Jered