Couple op amps I've been swapping in/out of an EQD pedal in place of the stock & kinda bright LM833:

LM1458 - Much darker than the above. Pretty much what I was aiming for when I thought I knew what I wanted.
TL072 - Maybe sits somewhere in between the two others. Plays better with the MXR bass Rat running after it than the 1458. The unlikely winner?

Still tweaking but old gear that is new again is the best!


Has me thinking about all the LM308 nonsense weekend pedal dorks blabber on and on about with Rats and all the variants but even ProCo say it's a thing , so...

But buying into that game is too rich for me.


And thx to FM DR. Balls for the IShouldHaveKnownThat tech stuff.

I was looking to upgrade from the ancient (but reliable) 4-channel presonus interface that I use to track drums in my practice space so I could have some more input channels. I've been curious about RME stuff for a while based on the fanatical devotion of its user base and their track record for keeping 15yr old devices compatible with whatever apple throws at them. I did some reading, and by all accounts their latest driver software allows their older firewire units to work extremely well with M1-based macs. So, I made a lowball offer on a recently-serviced fireface 800 and after a few weeks with no other interest, he went for it.

Then, in a classic turn of gear events, I mentioned the buy to a pal who's losing his current studio space and consequently downsizing some stuff. He said "shit, I wish I'd known - I have one of those I was about to list." So... now I have two.

Finally got all the cables and dongles required to set everything up and based on a quick check it seems like everything is working great running both units in parallel into RME's totalmix FX software; and all three DAWs I use on the regular (audition, reaper, reason) seem to recognize the aggregate device in the system. So! For less than $1K CAD, I went from 4 analog inputs to 20, plus the option of 36 more via spdif and ADAT inputs should I ever need to mic terry bozzio's kit or w/e.

I only have 8 channels of external pres so I guess I'm going to have to pick up some more... for... reasons.

Anyway, I'm genuinely impressed that this shit works, and kudos to RME for keeping these boxes running well past any reasonable sell-by date for a computer peripheral.

LBx wrote: Fri Nov 04, 2022 4:59 pm Couple op amps I've been swapping in/out of an EQD pedal in place of the stock & kinda bright LM833:

LM1458 - Much darker than the above. Pretty much what I was aiming for when I thought I knew what I wanted.
TL072 - Maybe sits somewhere in between the two others. Plays better with the MXR bass Rat running after it than the 1458. The unlikely winner?

Still tweaking but old gear that is new again is the best!


Has me thinking about all the LM308 nonsense weekend pedal dorks blabber on and on about with Rats and all the variants but even ProCo say it's a thing , so...

But buying into that game is too rich for me.


And thx to FM DR. Balls for the IShouldHaveKnownThat tech stuff.

What EQD pedal?

Rats and LM308... I'm not sure. Been a while since I messed with it all. I still have a few LM308s (like two) from back when they weren't unaffordable. I've built and modded a few Rats. It's my favorite dirt pedal. Here's the thing, swapping between the LM308 and the OP07 now used by ProCo I recall telling a small difference. It's been too long to remember the details, but maybe a smidge more bass? Most of it can be compensated for by tweaking the knobs. I think a bigger difference happens between different particular rats. Rats have a part of the circuit that shapes the clipping and eq and is very sensitive to tweaks. It involves a few electrolytic caps, which have a pretty wide tolerance. Maybe that accounts for two Rats sounding different? I don't know. I just know one of my Rats sounds better than any I've played no matter which chip I put in it.

Woke up this morning from a dream about having a shootout between a bunch of vintage traynor solid state amps that don't exist. They all looked amazing, and sounded the same, but great. Culminated in "The one I've always had is still the best", which was also something that doesn't exist. I don't know why my brain does this to me.

VaticanShotglass wrote: Sat Nov 12, 2022 10:11 pm

LBx wrote: Fri Nov 04, 2022 4:59 pm Couple op amps I've been swapping in/out of an EQD pedal in place of the stock & kinda bright LM833:

LM1458 - Much darker than the above. Pretty much what I was aiming for when I thought I knew what I wanted.
TL072 - Maybe sits somewhere in between the two others. Plays better with the MXR bass Rat running after it than the 1458. The unlikely winner?

Still tweaking but old gear that is new again is the best!


Has me thinking about all the LM308 nonsense weekend pedal dorks blabber on and on about with Rats and all the variants but even ProCo say it's a thing , so...

But buying into that game is too rich for me.


And thx to FM DR. Balls for the IShouldHaveKnownThat tech stuff.

What EQD pedal?

Rats and LM308... I'm not sure. Been a while since I messed with it all. I still have a few LM308s (like two) from back when they weren't unaffordable. I've built and modded a few Rats. It's my favorite dirt pedal. Here's the thing, swapping between the LM308 and the OP07 now used by ProCo I recall telling a small difference. It's been too long to remember the details, but maybe a smidge more bass? Most of it can be compensated for by tweaking the knobs. I think a bigger difference happens between different particular rats. Rats have a part of the circuit that shapes the clipping and eq and is very sensitive to tweaks. It involves a few electrolytic caps, which have a pretty wide tolerance. Maybe that accounts for two Rats sounding different? I don't know. I just know one of my Rats sounds better than any I've played no matter which chip I put in it.

I made a rat clone a few years ago and socketed the opamp, I went through all the usual suspects (op07, LM308, LM208, the CAZ-whatever thing that JHS uses) and honestly I couldn't tell any meaningful difference between any of them, and they all sounded basically the same as my vintage one.

Last time I checked, the surplus electronics store not too far from me has a bin of LM308s for $9/ea and a bin of LM208s for $1/ea. Very weird.

mdc wrote: Sun Nov 13, 2022 1:47 pm

VaticanShotglass wrote: Sat Nov 12, 2022 10:11 pm

LBx wrote: Fri Nov 04, 2022 4:59 pm Couple op amps I've been swapping in/out of an EQD pedal in place of the stock & kinda bright LM833:

LM1458 - Much darker than the above. Pretty much what I was aiming for when I thought I knew what I wanted.
TL072 - Maybe sits somewhere in between the two others. Plays better with the MXR bass Rat running after it than the 1458. The unlikely winner?

Still tweaking but old gear that is new again is the best!


Has me thinking about all the LM308 nonsense weekend pedal dorks blabber on and on about with Rats and all the variants but even ProCo say it's a thing , so...

But buying into that game is too rich for me.


And thx to FM DR. Balls for the IShouldHaveKnownThat tech stuff.

What EQD pedal?

Rats and LM308... I'm not sure. Been a while since I messed with it all. I still have a few LM308s (like two) from back when they weren't unaffordable. I've built and modded a few Rats. It's my favorite dirt pedal. Here's the thing, swapping between the LM308 and the OP07 now used by ProCo I recall telling a small difference. It's been too long to remember the details, but maybe a smidge more bass? Most of it can be compensated for by tweaking the knobs. I think a bigger difference happens between different particular rats. Rats have a part of the circuit that shapes the clipping and eq and is very sensitive to tweaks. It involves a few electrolytic caps, which have a pretty wide tolerance. Maybe that accounts for two Rats sounding different? I don't know. I just know one of my Rats sounds better than any I've played no matter which chip I put in it.

I made a rat clone a few years ago and socketed the opamp, I went through all the usual suspects (op07, LM308, LM208, the CAZ-whatever thing that JHS uses) and honestly I couldn't tell any meaningful difference between any of them, and they all sounded basically the same as my vintage one.

Last time I checked, the surplus electronics store not too far from me has a bin of LM308s for $9/ea and a bin of LM208s for $1/ea. Very weird.

I concur - and for people on those other forums who spend thousands of hours replacing op amps, I would love to hear an explanation as to why they would sound so different, given what is actually inside an op amp, and how they are manufactured...

Depending on how they're used/circuit topology I could see some of the claims given, but in a single chip distortion pedal, I can't wrap my head around the drastic differences given the printed specs

TylerDeadPine wrote: Sun Nov 13, 2022 2:03 pm I concur - and for people on those other forums who spend thousands of hours replacing op amps, I would love to hear an explanation as to why they would sound so different, given what is actually inside an op amp, and how they are manufactured...

Depending on how they're used/circuit topology I could see some of the claims given, but in a single chip distortion pedal, I can't wrap my head around the drastic differences given the printed specs

Yep. What reasoning they do offer still doesn't account for a difference when using the OP07, which is supposed to be very close to the LM308 in the relevant respects.

Again, I think any difference between chips can be accounted for by tweaking a couple of resistors and caps. I once built a Rat for the sake of experimentation. I had a switch to flick between the factory resistors and a daughterboard with trim pots, more or less working like the extra knobs on the Fuzzrocious Cat Tail. You could tweak the eq and distortion character a little doing so. I found I preferred the stock values. The more recent ProCo Fat Rat has a little resistor switch to tweak the bass. I assume it is one of the resistors I swapped for a trim pot.

Still not sure why my Dirty Rat sounds so much better than others. I did mod it to toggle between the factory schottky diodes and the traditional silicon ones as well as socket the the opamp. I think it wound up with a LM308, but I might have put the original chip back in.

VaticanShotglass wrote: Sat Nov 12, 2022 10:11 pm

LBx wrote: Fri Nov 04, 2022 4:59 pm Couple op amps I've been swapping in/out of an EQD pedal in place of the stock & kinda bright LM833:

LM1458 - Much darker than the above. Pretty much what I was aiming for when I thought I knew what I wanted.
TL072 - Maybe sits somewhere in between the two others. Plays better with the MXR bass Rat running after it than the 1458. The unlikely winner?

Still tweaking but old gear that is new again is the best!


Has me thinking about all the LM308 nonsense weekend pedal dorks blabber on and on about with Rats and all the variants but even ProCo say it's a thing , so...

But buying into that game is too rich for me.


And thx to FM DR. Balls for the IShouldHaveKnownThat tech stuff.

What EQD pedal?

Rats and LM308... I'm not sure. Been a while since I messed with it all. I still have a few LM308s (like two) from back when they weren't unaffordable. I've built and modded a few Rats. It's my favorite dirt pedal. Here's the thing, swapping between the LM308 and the OP07 now used by ProCo I recall telling a small difference. It's been too long to remember the details, but maybe a smidge more bass? Most of it can be compensated for by tweaking the knobs. I think a bigger difference happens between different particular rats. Rats have a part of the circuit that shapes the clipping and eq and is very sensitive to tweaks. It involves a few electrolytic caps, which have a pretty wide tolerance. Maybe that accounts for two Rats sounding different? I don't know. I just know one of my Rats sounds better than any I've played no matter which chip I put in it.

It's a White Light. Swapped an older Hoof for it.

I think the measurable difference is meant to be the amount of sag with the volume up a certain amount. To me that's a desirable thing to play around with but not for everyone for sure. I assume some of the newer doom-y Rat knock-offs get there a variety of ways.

MD421 3rd party mic clip replacement

Well I mean it's fine. It doesn't feel super solid or anything and very obviously this is something out of a 3d printer.

But the price is completely reasonable and it works. I did not expect it to grip well w/out some sort of rubber or something grippy in there but I've left it pointing straight face down at a pillow for an entire day and it hasn't budged so, yeah, seems to be fine. I could put a small piece of gaffer tape on there if I really wanted to be double certain.

And also, it's black, not the blue shown in the default photo.

uglysound wrote: Mon Nov 14, 2022 1:29 pm If I recall correctly, the audible difference between opamps in distortion pedals comes from the slew rate. I think 208/308 chips have a slower slew rate which will sort of round off the corners of the signal, giving a darker sound.

That could make sense