Dating a JRC4558DD in a Boss sd-1

[AgentDouble]

Hello folks, forgive me if i post in the wrong section

I have bought a beat up Boss sd-1 and i would like to date it, but the bottom sticker is missing
The other sticker is "use boss ACA only" so i assume it is pre-1997
I looked inside and there is a JRC4558DD stamped 0301B
Can you help me to decode the date of manufacture of the IC ?

Thanks for help
Best regards

[Les Turnbull]

Not shure on the chip date but the capacitors are often dated .

[ElectricDruid]

I can't say for certain about the chip you're talking about, but chip date codes are often "year, week number" or vice versa. So, for example 8732 is the 32nd week of 1987. If that was the case for the one you've got, it'd either be the end of January 2001, or the beginning of January 2003.
There are other systems however, and not all chips are date coded…YMMV.

HTH,
Tom
 

[AgentDouble]

Thanks, but as i said, the pedal wears the ACA sticker, so it is obvious that the pedal is pre-1997. In fact, i did extensive research and with little info gathered, i assume that the first digit is the year code. In that case 0 wouls mean 1990, wich is very plausible. The last three digits along with the letter is batch number. It's a pity that the 4558 is such common IC and so little documented.

[Ice-9]

Thanks, but as i said, the pedal wears the ACA sticker, so it is obvious that the pedal is pre-1997. In fact, i did extensive research and with little info gathered, i assume that the first digit is the year code. In that case 0 wouls mean 1990, wich is very plausible. The last three digits along with the letter is batch number. It's a pity that the 4558 is such common IC and so little documented.

The 4558 is just a cheap as chips vanilla op amp, there is no mojo involved in dating the IC other than dating interest. You seem to have successfully(ish) dated the pedal due to the ACA psu requirement. 

[Vivek]

Dating an IC chip is fun if you are into legs !

[duck_arse]

short legs. and a dimple.

[Ben N]

Flowers, dinner and a movie.