madbeanpedals::forum

Projects => Tech Help - Projects Page => Topic started by: eniacmike on January 05, 2011, 10:46:57 PM

Title: lm308n vs lm308an
Post by: eniacmike on January 05, 2011, 10:46:57 PM
I built up a slow loris and it wasn't passing a signal at all.. the sound probe only made it to pin3 voltage seemed to be really low on the pins so I built a second one up and I had the same problem. Then I realized I had some lm308an chips instead of the lm308n chips. I swapped the chips and the problem went away.

I ordered these chips from pedal parts plus. in the picture it shows LM308's but the description says LM308AN. i'm kind of bummed because they were $4 a chip... is there any tweaks to get the AN chips to work?
Title: Re: lm308n vs lm308an
Post by: stecykmi on January 06, 2011, 02:34:43 AM
looking at two data sheets... i can't find any difference between the two... maybe you got some bad chips?
Title: Re: lm308n vs lm308an
Post by: jkokura on January 06, 2011, 03:28:09 AM
This datasheet says literally, "Although the circuit is interchangeable with and uses the same compensation as the LM101A, an alternate compensation scheme can be used to make it particularly insensitive to power supply noise and to make supply bypass capacitors unnecessary."

http://pdf1.alldatasheet.com/datasheet-pdf/view/8592/NSC/LM308N.html (http://pdf1.alldatasheet.com/datasheet-pdf/view/8592/NSC/LM308N.html)

Mike, ya gotta look at the datasheets before you go poking the answer the question people! You should know better! You can google just as easy as me I'm sure.

Jacob
Title: Re: lm308n vs lm308an
Post by: eniacmike on January 06, 2011, 08:08:14 AM
yeah unfortunately I looked at the datasheets and they don't mean anything to me. I was especially looking for different pinouts and they both had the same pinout diagrams.

Besides all that I get NO signal with the lm308an chips and everything works great with the lm308n chips. pretty weird. I think I may have bum chips though. I am pretty bummed that I spent $4 a chip for these from pedal parts plus, I will probably try to get a refund. I have bought lm308n's from small bear and from mammoth before and never had a problem.