LM308 & OP07 IC Comparison in ProCo™ Rat™ Replica

[miguelangelobc]

Man, you just proved that there's no difference between lm308 and op07!!! I listened to ths video several times and didn't notice any difference! Now I believe that the difference between the old Rat and the new Rat that is shown in other videos doesn't occurs due to the op amp that's being used... that warm sound lies on another thing... maybe a capacitor, maybe a resistor, or even a pot!... who knows? any clue? greetings from brazil!

[matthewcjenkins]

But who uses a rat at low gain?

[jwyatt4]

@matthewcjenkins: Lol, good point.

[matthewcjenkins]

@jwyatt4 I've watched the video again and decided they both sound better. :) Just added an OP07 to my Mouser order.

[youzektube]

Honestly?.. don't heard any difference on my pc speakers!

[hithisishal]

I'm surprised that you would get a rolloff from the trebs in the LM308. There is plenty of feedback...I bet the amp could handle it. I don't mean to criticize your methods, but did you use tight tolerance parts in your pedals? I feel like a +/- 10% capacitor somewhere in the feedback circuit is more likely to influence tone, but I could be wrong about that.

I wonder what an older, "worse" opamp would sound like...something like a 741.

Thanks for posting!

[jfrizzlle]

not big enough of a difference to justify saying the lm308 is better

[DarkAngelEU]

it's barely there, but yeah I can hear a difference.. I can choose to buy a new RAT2 or a vintage one (with the LM308 in it), guess I'm gonna go with the vintage one ;)

[askwho69]

Op07 is a little bit compress rather than LM308 ! but its a tiny winny can hear it if your not focusing on it

[taigkyo]

Great & useful demo, thanks for posting this!

[jwyatt4]

@taigkyo Thanks for tuning in.

[AngrySemite]

Thanks. Useful info. We're really in cork sniffing territory here. I can get way more tonal variation from my picking hand. Interesting, because I found an LM308 in my friend's basement, swapped it into a turbo rat and completely transformed it into a super pedal. Never liked the stock Turbo, but it blows away my original RevB now. The combo of the LM and the diode is nice. Dumb luck. I am a tube guy and had never heard of the LM308 mod.

[jwyatt4]

@AngrySemite Yeah... playing style is definitely a variable that heavily influences tone. Also glad to hear the swap transformed the Turbo into a better sounding pedal. That is awesome and (I suppose) why some of us have become cork-sniffing geeks.

[ChickenRapist]

Actually, the largest difference in the two chips can be heard at low gain. The OD07DP will penetrate the soundscape easily at higher gain with its harsher treble content while the LM308 sounds smoother at lower gain.

[jwyatt4]

@ChickenRapist Yep

[widepass]

Have you measured the potentiometers and resistors actual resistance and tappers + the caps actual capacitance?

The tolerances on these are never the same!

[jwyatt4]

@widepass Very true indeed. But this experiment has less to do with volume or amount of gain than it does bite vs. warmth of tone which I can hear (though barely).

[Schpudd]

i genuinely couldn't hear any different until i clicked 480p... make sure you've done that if you haven't guys

[gullywoots]

Subtle! I built mine with an LM308 just in case, but I won't be afraid to go for the op07 on the next one.

[ThisIsNotHappyDays]

The 308 sounds slightly brighter, the 07 slightly darker to me but... inconsistantly,only at certain frequencies while at full distortion. It was much more pronounced at half.

[OverblazeBand]

hi, i ordered this kit, is this truebypass?

[jwyatt4]

@OverblazeBand Thanks for asking. Yes. All GGG pedals are wired for true mechanical bypass. When the switch is clicked off, the signal goes straight to the output.

[vecinto]

308 sounds slightly richer; 07 sounds a bit more aggressive

[jwyatt4]

@vecinto Yes, I agree, but in my mind, there really isn't a "better" one just a little difference. I've used both of the pedals in the demo in live situations and when the music is kicking, I couldn't discern one from the other. Under an audio microscope, there are audible differences for sure but not, in my opinion, to the degree that would or should necessarily make or break building or buying one of these with or without a 308 in it.

[vecinto]

@jwyatt4 I agree. Furthermore, the differences are so subtle that I don't think most people would even be able to tell, much less in a band soundscape. I could even go as far to say that it is absurd how picky guitarists can be about these things, but I suppose in the end if it makes one feel more connected to one's instrument, then the nitpicking has served its purpose.

Thanks for making these videos, by the way. I've enjoyed watching them and they've been very helpful.

[jwyatt4]

@vecinto Thanks, much appreciated.

[twoxOxtwo]

Wow, I'm listening with good headphones and i can barely hear any difference...

If i close my eyes i can't even tell when you're switching from the on to the other...

so much fuss about ... ?!?!?

[jwyatt4]

@twoxOxtwo Yeah...kind of the point of the demo. Thought there is a subtle difference, the point is that you don't have to search high and low or pay out the nose for a replica pedal with a 308 (or refuse to buy one without the 308) in it because the difference isn't world changing.

[andy92811]

308 sounds less harsh

[RNRDOLL]

The 308 is a bit more airy and warm slightly, but the OP7 is more cutting, which would be more useful live. I dont think a distortion should be 'sweet' like an OD, it should be aggressive, but not shrill. As far as vintage chips are concerned I favor the ones they used to put in the Ibanez pedals in the early-mid 80's like the SM9 or SD9. I've got an '84 SM9 with the JRC4558D chip, that thing is insane!

[jwyatt4]

Agreed. The RAT is a dirty distortion and not intended to be a smooth overdrive and cutting through the live mix is key.

[twoxOxtwo]

@RNRDOLL

[GriffinEffects]

Nice demo. I can barely hear a difference but that can be due to my computer and/or 20+ years of stage volume :)

There could also be a difference in sound due to parts tolerances along with how the knobs fit on. Unless you measure each component to match them, they will never be truly the same to compare but that would be ridiculous to do. Good job. I have a Rat2 with the op07 in it and I don't think I would swap it out for the LM308. At least I wouldn't be in a hurry to do it.

[jwyatt4]

Thanks.

Yeah. Subtle for sure. It's easier to hear in the room but the fuss many make over it I think is a bit over blown. I sense a little more warmth with the 308 but like I've said, when a band is blaring full blast, the difference will be unnoticeable to the inarticulate ear of the public.

[GriffinEffects]

I really like the TL070 in it. You can use a larger compensation cap to lower the slew rate down where the 308 is and it's much quieter. This you can hear :)

[throbgod13]

i like the 308..

[krettere]

Seeing how the clipping is mostly from the diodes and NOT the opamp, it makes sense that the sound is very similar.

[jwyatt4]

True...but I think certain opamps can provide an element of warmth. In a live situation, however, when everything is cranked, the mild differences aren't all that apparent.

[bruninhochorao]

LM308 sounds like Van Hallen

That's true Rat!

[Rbuzz73]

nice comparison. I think that the two are very close indeed. There seems to be a richer more "airy" sound to the upper hamonics from the 308 chip equipped 'rodent'. I have a vodka-modded model of a late 80's rat that I'm about to purchase some chips for swapping. The 308 is on the list. Thanks for the extra data.

[jwyatt4]

Thank you and you are welcome. Have fun experimenting...

[Rambo29]

Dude you have a huge foot

[jwyatt4]

Funny...

[dnpqkc]

I never want to admit things like this make a huge difference, but I think the 308 sounds a little nicer. That being said, it's not the end of the world if you had to go with the OPO7.

[jwyatt4]

Agreed on all accounts.

[Mural]

sorry i meant to click thumb up but i hit down and it won't let me change it :(

agree totally.

[jwyatt4]

Bummer. Thanks for tuning in though.

[jwyatt4]

Thanks. The LM308 seems a little fuller sounding. The trouble is the availability. However the OP07 seems a worthy alternative when the 308s are scarce. A cool thing about this kit is it comes with a socket allowing for quick change-out of op-amps for those who like to experiment.

[kaisersteev]

This is a good comparison, keeping switching enough to compare, and really side by side instantly... that being said i like the lm308