[2470] Fake LM308

Date: December 13th, 2018 | Comments : [2] | Categories: DIY.

Fake LM308 in a Mooer pedal… well, not an original National Semiconductor chip anyway.

So, is it a fake if you mark a plain cheap op-amp that meets or exceeds the specs of the original LM308 with that part number but the internal circuit is not the same?

It will work in circuits designed for the LM308 and perform well. It does the job. But at the fringes and limits of the electrical characteristics where many fx pedals operate, it will not be the same as an IC with the internal circuit design of a real original NatSemi LM308. Is that a fake or just a poor substitute?


2 Responses to “Fake LM308”

[786098] dMac Says: 2:44 pm, December 13th, 2018

I just know I’m going to cop some stick for this… I’m a realist, but also a tiny bit educated (thanks to you, Jack!)

Firstly, just because it’s a substitute doesn’t make it a poor substitute- only results will determine that…

Did it say on the box “contains genuine NS LM308”, or did you have to go looking?

If it is passed off as a genuine NS chip, I have issues. Without any statement on the box or advertising, Mooer put out an order for chips, and the ones they got were so marked. If it’s in a $30 pedal, etc, I know it’s not a NS, and the people lining up to buy it who aren’t going to take off the base plate aren’t going to expect one either- or care. And if it had a spot of back nail polish on it- would I be typing this?

But if I was paying $500 for it and it was so advertised, it had better be original.

I’m going to be controversial. What is the end result difference between the two? People may say you can hear the difference between them by A/B-ing or scoping them. That may be true- but if you need to A/B or scope them, then that difference isn’t that great, and (for my purposes) the audience on the floor isn’t going to care.

As always- thanks, Jack (please don’t be mad with me!)

[786101] admin Says: 7:15 am, December 14th, 2018

David, I agree with you. Mooer doesn’t know or care if the chips are originals as long as they have the right part number.

Did a chipmaker duplicate the original Rubylith masks for the original LM308? Not very likely.

If the alternate source LM308 chip meets the minimum specifications for an LM308, then it is a valid substitute… EXCEPT for pedal gearheads that assign special properties to the vintage LM308. (BTW, with the right test equipment, you can tell the difference in LM308 chips and the fakes.)

Lastly, the OP-07D used in the Rat2 is close to the LM308 is specs and the Proco guys did a good job of picking a substitute chip when they had to make the switch. If I got them labeled as LM308, practically no one would be able to tell the difference (without a lot of test gear).

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