rc4558p vs jrc4558d

[suncrush]

What is the difference between these op-amps?

I cannot figure it out for the life of me.

[GGBB]

What is the difference between these op-amps?

I cannot figure it out for the life of me.

Manufacturer.

RC is made by Texas Instruments

JRC is made by NRJ - New Japan Radio (formerly JRC - Japan Radio Corporation)

[electrosonic]

I guess that implies they will not be identical internally - so they will have similar, but not identical specs. Check the datasheets and see.

Which may or may not matter depending on your application.

Andrew.

[suncrush]

Alternatively, since they are 40 cents, order both and let the ears decide!   

[PRR]

RC was originally Raytheon. Who hasn't made anything small in decades. It figures that TI has bought-out that business.

4558 was always a "cheap" chip. It works, often very good. What you get inside depends on when it was made-- silicon technology has changed a LOT over the decades and while old products like '4558 don't get updated, they may have to be adapted when old machinery is retired.

'4558 can't be a big cash-cow for TI. It sure won't be made on their best process (anyway '4558 "needs" old-old processing), or get the best technologists. The TI part will for-sure meet all published specifications.

However in pedal-world we often use parts for "un-published" behavior. The published specs do not cover every aspect of "making sound", particularly the clipping mis-behavior.

JRC is historically a trailing-edge audio company (though they are much more now). Their main products for decades were improvements on the '741 ('4558 is a dual improved '741) which sounded good. Their '4558s will be for-sure good in low-price hi-fi. Since even that business has moved away from good old '4558, it is possible that JRC is aware that "crazy pedal builders" buy many of their '4558s, and has taken some pain to preserve the historic mis-behaviors too.

[Quackzed]

i liked the p, from my ts modding experiments, seemed a bit smoother... less grainy. i could have easily been hearing what i wanted tho... was not a scoped or even pseudo scientific analysis...
i think this one sounds smoother, i like it, it stays. was about the extent of it...

[LightSoundGeometry]

one is in a red snapper and the other in a tube screamer lol ..all I know

[R.G.]

Wanted to jump in and let you all know that I have authentic (NO China made products!) Texas Instruments RC4558P available here:

What else in the way of help to people learning to build pedals other than just advertising chips for sale do you have?

You have four posts, and they're all involved with advertising ICs for sale. This one is a response to a thread last added to back in May.

[Cjuried]

Hi R.G.,

What would you like to discuss. RC4558P characteristics? Common mode rejection ratio issues with operation amplifiers due to lack of properly balanced impedance ratios with a >10 Ohm differential. Johnson–Nyquist noise, Crosstalk, common-mode impedance coupling, capacitative and/or inductive parasitics...?

[wampcat1]

Hi R.G.,

What would you like to discuss. RC4558P characteristics? Common mode rejection ratio issues with operation amplifiers due to lack of properly balanced impedance ratios with a >10 Ohm differential. Johnson–Nyquist noise, Crosstalk, common-mode impedance coupling, capacitative and/or inductive parasitics...?

ahhh, sarcasm.

[R.G.]

What would you like to discuss. RC4558P characteristics? Common mode rejection ratio issues with operation amplifiers due to lack of properly balanced impedance ratios with a >10 Ohm differential. Johnson–Nyquist noise, Crosstalk, common-mode impedance coupling, capacitative and/or inductive parasitics...?

Actually, I'm pretty much at home with any of those, and if you need any questions answered there, I can probably do it or find you the info you need.

But the forum is pretty much entirely focused on how to build pedals and how the work, not on being an advertising medium.

So  - again - what else in the way of help to people learning to build pedals other than just advertising chips for sale do you have? Or is selling your wares all you have for the forum?

[Cjuried]

Hi R.G.,

I'm happy to contribute in any way beneficial to the group, respectfully.

[R.G.]

I'm happy to contribute in any way beneficial to the group, respectfully.

Good. What information do you have for the forum?

[Cjuried]

Reply posted in other thread.