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, depending on the mod, because the Tube Screamer circuit produces a smoother gain and the RC4558P has a little more high end grit than a JRC4558D.
JRC4558DD – Made by Japan Radio Corporation (JRC). This is a Higher Gain & Smoother in the Highs version of the JRC4558D (notice one has one “D” and the other two “DD”s). The JRC4558DD 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 am now stocking these and you can order them directly from me.
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.
LF353 – 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 – Originally Made by Burr Brown (Now Made by Texas Instruments). This is the most expensive opamp 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 and DS-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.
LM1458 or MC1458 – These are essentially the same chip and to me sound identical. I will supply which ever one is available at the time you place the order. Some of these chips are getting increasingly harder to find. The 1458 is a Dual Opamp Version of the famed LM741. This is the chip that was originally used in the Famous DOD Gray 250. I use either a LM1458 or MC1458 in my DOD 250/YJM308 Mod. These chips sound great in the reissue DOD 250/YJM308 pedals.
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 struture.
WARNING! — The OPA2134PA opamp, of which are included in many of my kits, is currently extremely hard to find. Mouser and Digikey are currently out of stock with none expected until 2023. I have hundreds in stock. BE CAREFUL BUYING THE OPA2134PA ON EBAY. THE MAJORITY ARE FAKE! Manufacturers in China are rebranding cheaper opamps and selling them as OPA2134PA opamps. I test all my OPA2134PA opamps I buy. You can easily test whether a OPA2134PA has been rebranded. Do this, take some Acetone on a Q-tip and rub across the lettering of the opamp. If it is Fake the ink used to print the labeling will dissolve into the Q-tip.