Lm318 for Parentheses

Diynot

Active member
Has anybody tried an LM318 in a Parentheses build? Kicking myself for sending my only 308 off with a JHS modded Rat. Understand that the 318 is maybe more “hi-fi” and goes against all that the 308 offers to a Rat pedal, but the pin out is the same and I’m always up for an experiment.
 

Boba7

Active member
Nope but if I remember correctly I used a LM301 a while ago with excellent results! They’re easier to find than LM308
 

Diynot

Active member
Thanks Boba! Yeah, I have an order queueing at smallbear with a few different IC options, a 301 included. I was just looking for a few more flavors to try out
 

thewintersoldier

Well-known member
I know everyone wants mojo but when I didn't have any lm308s I used the OP07 that is often looked down on and it was to my ears exactly the same sounding. I would use it in a heartbeat if I were out of 308s!
 

JamieJ

Well-known member
Mojo is such a psychological thing. The internet has had a massive part to play in immortalising certain diodes and ICs. If they are available and you have the cash go for it but those “special” parts often don’t even make an audible difference.
 

mdc

Well-known member
I've A/B'd all the popular alternatives of rat opamps against a vintage LM308N model and there's absolutely no difference to my ears between any of them.
 

benny_profane

Well-known member
It’s always important to consider the source when evaluating component choices. Someone justifying an expensive purchase or trying to show off cred will always hear a difference.

That being said, the LM318 is a high speed op amp (slew rate = 70V/us). Compare that to the LM308 (0.3V/us). I wouldn’t recommend that part. A TL071 (13V/us) is a common part we can use for comparison here. The OP07 has a slew rate of 0.3V/us and does not require external compensation like the LM308.

Note that you can use a cap to adjust the slew rate.

Edit: the classic 741 (slew rate = 0.5V/is) is another chip that you could work with. It’s old and slow and you can further adjust the slew rate with the offset pins and a cap.
 
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mdc

Well-known member
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Diynot

Active member
Thanks for the input gang. I am not a “cork sniffer” as far as parts/tones go, being equally happy to produce classic sounds but also to electronically mangIe my guitar signal. I really just want my builds to work as intended, with maybe the option to switch things up. I did include a 741 in my order based upon the recommendation of the build docs. I do have a 318 in there too and let you all know if it is just plain shite
 

Boba7

Active member
I know everyone wants mojo but when I didn't have any lm308s I used the OP07 that is often looked down on and it was to my ears exactly the same sounding. I would use it in a heartbeat if I were out of 308s!

Totally agree. But when I sell Rat based pedals, customers usually prefer to get a LM308 instead of a OP07 in it... To my ears, it doesn't make any difference, and I tested the two chips quite extensively!
But I really like the LM301 too. Might have to build another Rat with an LM301 soon :)
 

Diynot

Active member
You just switch the chip add a diode switch and call it BOOOTIQUE! Has more mids, transparency, and unicorn tears!
 

Coda

Well-known member
I put a 308 in my Rat, and found it a bit too dark sounding. Popped in an OP07, and it cleared up a bit. I really liked to with a TL071…though it is internal compensation, and I didnt socket the compensation cap so it’s in there too, and I don’t know what that means. Not quite that classic Rat sound, but very musical…
 
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