Other Equipment

playing in the kitchen of overdrive w/ opamp swaps

1

As a lover of both the TIM/Timmy pedals and the Barber Burn Unit/ Small Fry/Tone pump pedals I often like to fool around with a smorgasbord of op-amp chips I have collected over time.

folks go round and round about what chip sounds better in tubescreamer variety overdrives but most of these pedals are not made very well and dont even have an op amp socket in them so one can readily fool with the gain textures of their favorite pedal...

in anycase my pedals I mentioned above DO have opamp chip sockets and are much fun to "chip swap".. if you have lazy turkey weekend time you should start experimenting in your tone kitchen. Whats in your cupboards?? If you are a geargeek/audiophile type you might enjoy this descriptive list of various chips swap options I find helpful.

CHIP DESCRIPTIONS

JRC4558D – Made by Japan Radio Corporation (JRC). Used in the original TS808s and TS9s. Ibanez later changed the chip used in their pedals. The JRC4558D is actually a very inexpensive chip that’s not considered Hi-Fi and was chosen because of its inexpensive cost and not for the tone it produced. It just happened to sound great when used with the Tube Screamers original circuitry. This chip has a little bit smoother gain than the RC4558P which is considered a more Hi-fi chip. I like the JRC4558D in the SD-1, it's smoother gain in the top end helps to offset the extra hair in the SD-1's gain. I prefer the RC4558P in a Tube Screamer because the Tube Screamer circuit produces a smoother gain and the RC4558P has a little more high end grit than a JRC4558D. Currently installed inOD-3

JRC4558DD – Made by Japan Radio Corporation (JRC). This is a Higher Gain & Smoother version of the JRC4558D (notice one has one "D" and the other two "DD"s). It's less Hi-Fi and has a smoother gain structure with a slight rounding off in the highs. This "DD" chip sounds surprisingly good in an SD-1. This is the stock chip you'll find in most SD-1s and TS7s. This is a good match for my SD-808. Try it and I think you'll agree. My SD-808 has clearer top end and more hair. The JRC4558DD tames the SD-808 a bit in the highs. Depending on your amp you might like this chip better. I have a few of these. Contact me if you want one, I don't have these listed for sale on my pedal mods page because most people write them off as being a bad chip. But, who cares what others say, the proof is in the tone and I say they sound great with some SD-1 setups. Of course, YMMV.

RC4558P – Made by Texas Instruments. Also used in the original TS808s and TS9s. Ibanez later changed the chip used in their pedals. The RC4558P is also a very inexpensive chip but considered to be a bit more Hi-Fi than the JRC4558D. It just happened to sound great when used in a Tube Screamer circuit. These are still very popular today and are a great sounding chip. Very similar tone-wise to the JRC4558D, has a little more high end grit.

RC4559P – Made by Texas Instruments. This is a more Hi-Fi lower noise chip than it's brother the RC4558P. The EQ and gain structure is a bit different than the RC4558P. I like this chip because of it's lower noise when used in a GE-7. I also like this chip in a SD-1 and Tube Screamer circuits. This chip changes the EQ of the gain and helps tame the mids in a Tube Screamer. LP353 - Made by Texas Instruments. Very similar tone-wise to the JRC4558D and RC4558P. Maybe a little less gain but an excellent sounding chip. Subtle differences. This chip sounds excellent in a Tube Screamer, Daddy-O or SD-1. This is a very popular chip with pedal modders.

NE5532 - Made by Texas Instruments. Very similar tone-wise to the JRC4558D and RC4558P. This is a more Hi-Fi, lower noise chip than both the JRC4558D and the RC4558P. I really like the tone and gain of this chip. In some ways I like it better than a JRC4558D or RC4558P. Rich, smooth gain with nice overtones. This is a very popular chip with pedal modders.

TL072 - Made by Texas Instruments. Very similar tone-wise to the JRC4558D and RC4558P. This chip has a very interesting tone. A little more complex than any of the other chips I sell. Very defined harmonics, especially at higher volume. This chip is very Hi-Fi with low noise and a great sounding gain structure.

OPA2134PA – Made by Burr Brown. This is the most expensive op-amp chip I sell. This is a very popular chip with audiophiles. It’s low noise and excellent sound properties make it a popular choice with pedal modders. I especially like this chip in a Boss SD-1. It has a little more edge than a JRC4558D or RC4558P and is a tad cleaner with a flatter EQ which makes it a great chip to tame the mids of a Tube Screamer or SD-1. Very rich and defined gain with excellent harmonics and note detail. You can’t go wrong with this chip. Highly recommended.

LM308N – Made by National Semiconductor. If you want that Vintage RAT tone that made the RAT one of the most popular distortion pedals of all time then you'll need to replace the stock raspy sounding OPO7DP. The LM308N will give the circuit a very warm and smooth fat gain structure.

2

Hey Man, You maybe one of the coolest cats on here. Every I read What you right I want to buy something Else! And the stuff you make makes me drool. I don't own andy of it YET because I am Broke But One day I will. And i a primarily a Bass Player. But I have played With REDROCKER on here and He digs your Brain seltzer. I was wondering Have you ever thought about trying to Make a ONE STOP Rockabilly pedal? Ya know Like a Dynobrain On the front end and then like some Vibrato into some analog Delay? All in one pedal. I think if you could do that. Some folks Would really dig it. I know they would be like 500 a pedal But when you consider the cost of three pedals it would be worth it. I think it would just cut down on failure point. Like patch cables and power supplies. i don't know maybe I am Crazy. But no one makes Stuff specific to Rockabilly or maybe a High gain version for PSYCHOBILLY

3

I've got a LM308N laying around somewhere for my rat, I should really get around to putting it in.

4

Decomposed2006

I was wondering Have you ever thought about trying to Make a ONE STOP Rockabilly pedal? Ya know Like a Dynobrain On the front end and then like some Vibrato into some analog Delay? All in one pedal. I think if you could do that. Some folks Would really dig it. I know they would be like 500 a pedal But when you consider the cost of three pedals it would be worth it. I think it would just cut down on failure point. Like patch cables and power supplies. i don't know maybe I am Crazy. But no one makes Stuff specific to Rockabilly or maybe a High gain version for PSYCHOBILLY

Gotta point there, but then if you have an with one of the effects, you have to take the whole enchilada out of your loop, leaving you with nothing...

5

Much of the tone depends on the first component in the chip that receives the guitar tone first; some have a jfet and others have a transistor. You could mod around with the resistor ratio that determines the gain; it could change noise amounts and how tight the distortion is. Or throw in a pot with the diodes to get asymetric waves.

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guys.. I have made the higher gain version to cover jazz, country, rockabilly and beyond.. but remember I make preamps.. this one happens to be a Monstrosity.. an ATOMIC BRAIN!! play in "Abby" mode the entire time and get your Psycho on.

7

Eek! I like it!

What would happen if you'd use the Noc's vintage opamp in a screamer or was it on the list you mentioned?

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the opamp in my preamp uses a different pin-out than the dual opamp variety tubescreamer type overdrive pedal

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Something for the future then; mini board to make a duo with Noc opamps and connect them to a screamer. It starts to come back now, some weird vertical pin layout...

10

I love my old RAT and R2DU with the LM chips.

Tavo did you get your info from HERE?

11

nope, it was on a discussion on a pedal building/gear forum, forget if it was diy stomps or gear sluts.. I wonder if he "borrowed that info" :)

Its kind of been circulation in various forms since Jack Zucker was laying all this stuff out for us "experimenter" types back in the mid 90s.

This is one site I've loved for some time but links are disappearing: http://www.geofex.com/

Aaron Nelson's page was good too and amz http://www.muzique.com/news/

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Man I had not checked into geofex in a long time. That is a good site. Thanks for the links and info.

BTW I'm using my Brain Seltzer in front of my ART SGE with great results.

13

I thought I was old school with my Zoom Studio rack. You have an ART SGE!! wow :)

14

If you need any of the disappeared links, tell me. I might be able to dig them up. Ssssshh!

15

80's Strat loaded with Duncan hot stacks -> Nocturne -> R2DU rack -> ART SGE => two deluxe style heads (6L6 & 6V6), one sittin on a 412 univox(2-12" loaded) and the other 1-15" ampeg portaflex cab.

16

Tavo, do you know what they use in a Route 66?


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