Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups

JRC4558 myths...

Discussion in 'The Stomp Box' started by 11 Gauge, May 23, 2007.

  1. GUITARmole

    GUITARmole Tele-Afflicted

    Mar 13, 2005
    Portland, OR
    I think there's a subtle difference between the JRC and TI 4558's (FWIW I prefer the TI) but neither will change the general sound characteristics of a Tube Screamer significantly.

    Also, BOTH are "correct" for the TS-808 as either chip was used in vintage TScreamers.

    Other ICs can change the pedal for better or worse depending on your opinion...and are farther away from the "classic" TS-808 sound.

    IMO, the best bet is to socket the IC and try out different chips and let your own ears decide.

    Perhaps the biggest "Myth" is the TS-808 itself. I've never thought it was as great of a pedal as people seem to think it is and until recently I wouldn't even think of using one over a different OD or just plugging straight in and cranking the amp. I traded an original TS-808 for a script logo MXR Dist + back in the day as I thought the TS-808 sounded like **** through a Marshall. Now years later I sometimes run a TS-808 through my Deluxe Reverb or Silverfaced Champ and think it doesn't sound half bad.

  2. FrankB

    FrankB Tele-Holic

    Mar 21, 2006
    Havertown, PA. U.S.A.
    I have been down the modding road for a long time with regard to tube screamer style circuitry. And here is what I have learned.
    minimal effectiveness mods ae as follows.
    Resistor quality change.
    non polarized Capacitor quality change.
    Though in combination they do effect the sound of the respective pedal, whether or not it is better or worse depends on your ears preference.
    Dramatic effectiveness mods are as follows.
    Diode swap out. Remove existing diodes and install blue strip toshiba diodes. this makes the biggest different I have ever noticed, it's huge. earlier breakup with longer sustain without being overly distorted. seems to take the blanket off of the pedal so to speak.
    opamp swap. O.k. here's the big debate right? well, my experiences have led me to in some ways not change the opamp unless it is change to the malaysian 4558 chip. That seems to be the most SRV like chip from what I am experiencing. Other than that, they do all sound different the TA chips seem to allow more stuff to pass through, as the JRC chips seem to clean up the sound a little and that's fine if that's what you want.
    That's about it from what I have been hearing over the years. I have even seen really old ts808's with Ceramic Caps all over the inside which would normally seem to be a harsh tone, but they sounded quite great actually.

  3. Kungpow!

    Kungpow! TDPRI Member

    Jan 15, 2010
    Northern California
    I got my JRC 4558 and 2 carbon comp resistors from Small Bear. Total cost: IIRC, this is all I ordered, so I got charged couple bucks for shipping, much more than the parts LOL ( I was a noob then :))

    I simply read that the new 4558 were just as good as the NOS ones = Good nuff fer me, as it was a vast improvement

  4. guitarminator

    guitarminator Banned

    Jun 13, 2009
    warwick RI
    When I went into full TUBESCREAMER production last year I built 6 with the same components from the same vendors. My son and I swapped out JRC4558 and OP275's (my company makes these)

    We found that from each Tubescreamer we found differences in tonality and volume. I really liked the OP275 however for "vintage sound" the JRC4558's are the way to go. More interesting was that swapping the 4558 chip alone from unit to unit resulted in noticeable differences from unit to unit even though the circuits and components were the same. For example in 2 particular units swapping the 4558 resulted in a warmer tone in one and a thinner sound in the other. Hey I test DSP's for a living and much stranger things have happened !

    Personally I believe the biasing and filtering components have a greater impact on the overall sound.

  5. vjf1968

    vjf1968 Poster Extraordinaire

    Jan 9, 2008
    Didn't the guy who runs Visual Sound do a blind(?) hearing test using different chips in a TS?

  6. 11 Gauge

    11 Gauge Doctor of Teleocity

    Mar 21, 2003
    Near BWI Int'l
    Bingo! Along with differences in tolerances.

    It's so easy to forget that the TS circuit amputates everything below ~700Hz. If your HP filtering is off a bit, it will make one pedal seem a little brighter or tighter than another.

    It's also easy to forget about variations with potentiometer tolerances as well. You could line up 10 identical builds and end up having to futz with the dials to get them all to sound the same.

    But op amps themselves? Very consistent with gain ratings and performance specs. At least relative to many discrete circuits.

  7. JDC

    JDC Tele-Holic

    May 9, 2003
    Las Vegas, Nevada
    "Didn't the guy who runs Visual Sound do a blind(?) hearing test using different chips in a TS?"


    Yes , indeed.

    I found the test to be very interesting. One pedal was used as a "control" wherein the chip remained the same throughout the test. The other pedal (an identical model) had its chip swapped out half a dozen different times. What caught my attention was, not only did the chips sound pretty much identical, but one of the replacement chips wasn't even an audio chip. It was a video chip.

  8. Impulse

    Impulse Tele-Meister

    May 19, 2010
    It's the clipping diodes alone where the distortion occurs, right? So why would it matter what kind of chip I use, as long as it amplifies the signal the way I need?

  9. Jakedog

    Jakedog Doctor of Teleocity Ad Free Member

    Mar 26, 2003
    The North Coast
    I was wanted to chime in and say I am really enjoying this discussion. I have no idea what 98% of it means, it's kind of making my head spin. BUT, I think it's really cool that you folks know so much about this stuff and put so much effort into what you do. It makes for a really interesting read, and I have learned a couple of things...

    For me though, I'm never gonna care what chip is in my pedal or how much it costs. When I buy a pedal, it goes like this-

    Is it well built? Because I'm gonna gig the crap out of it, and be mad if it's junk and breaks or falls apart. I want metal jacks, metal casings, heavy duty switches, etc. The exception is when it's a toy. I have bought some really cheap pedals just to play around with for fun. And if or when they go belly up I don't get upset.

    Does it look cool? Sounds stupid, but it matters to me.

    Does it sound like I want it to? I don't give a rats rump what chip is in there, whether or not it's true bypass, who built it, what kind of resistors it uses, nothing. I just don't care. I wouldn't understand it anyhow. All I care about is that when I step on it, it makes me smile. I have a set sound and behaviour pattern for OD pedals locked into my head. I know they all vary a little, but they basically fall into two categories- Worse than I am used to, or better than I am used to. If it's better, and I can afford it, I play it. Period. What is inside the box never gets much, if any thought from me.

    I just bought a used Keeley modded TS-9 for $100. It sounded pretty cool, and I could afford it. I couldn't tell you what was done to it, except for what the previous owner told me, which wasn't very technical, and truthfully, I don't care what's going on inside. I already had one guy locally here tell me that I wasted my money, and I should have gotten a different one because of such and such chips and resistors. Those guys crack me up.

    If I stumble onto a different one that sounds better and I can afford it, I'll buy it. But I don't need a data sheet. All that matters is listed above.

    So in answer to the original post in the thread- I haven't ponied up any silly money for mods. Because I wouldn't know what to ask for, or how it would turn out anyhow.:D

  10. klasaine

    klasaine Poster Extraordinaire

    Nov 28, 2006
    NELA, Ca
    I have an old TS7 that I've thought sounded really great. I guess that's why.

  11. telepath

    telepath Friend of Leo's

    Jun 26, 2009
    Wales, UK
    not to hijack the thread, but - out of interest- did the Boss SD-1 , which I gather has been around nearly as long, have the same sort of history - i.e. different chips at different stages - Japan / Taiwan etc?.

    Bizarre in a way that the SD-1 has so much less legend / mojo / myth attatched to it, when it is essentially the same as a TS-9 in so many ways and in quality of construction etc - aside from thje symetrical / asymetrical clipping.

    Or is it that SRV never used one, but .. ones nephew might well have one ("because it is a Boss, and they are 'the best - right? Uncle?" ... umm!) - thus the ubiquity devalues the Mojo factor.

    I understand the old Japanese SD-1's are sought after. Horsefeathers? - or for good reason due to the Mojo chips/opamps/etc ?

  12. JCSouthpawtele

    JCSouthpawtele Friend of Leo's

    Apr 28, 2009

    Your getting down to more than just chip differences. It could be like the old saying "never buy a car built on a monday or a friday". I myself have seen amps that cost alot of cash(Budda,Bogner,Mesa) with bad solder joints. So pedals with the closer tolerances inside such confined space on the board. When I started out working with Option5 my solder skills were scrutinized, and had to check my ego of how "good" I was with the Iron. The casual fix of electronics on my own time or fixing a bad cable out on a sound gig is a toltal different thing than sitting at a desk with 20 pedal "green" boards.

  13. 11 Gauge

    11 Gauge Doctor of Teleocity

    Mar 21, 2003
    Near BWI Int'l
    SRV got his pedals at the pawn shop. A TS is what they had, so that's what he used.

    The SD-1 has basically remained the same since it's introduction - always had the 4558 chip. So did it's predecessor, the OD-1, which is basically the same thing w/o a tone control.

    The MIJ Boss pedals are generally a better deal, because those pedals were a little different - the DS-1 used different clipping diodes (people always chalked it up to the chip, which now is under speculation).

    The MIJ vs. MIX thing hasn't really been addressed unless you're talking to someone who's owned both, and can be objective about it. I know folks that prefer some of their MIJ stuff, some have better ones that were MIT, so they sold the MIJ.

  14. JoeNeri

    JoeNeri Friend of Leo's

    Mar 16, 2003
    Silver City, NM


  15. chrisgblues

    chrisgblues Tele-Afflicted

    May 31, 2010
    I've been trying out different OD's since the early 90's and even tried the Analogman TS-808 Brown mod on my Ibanez TS-9 reissue back when nobody in my town had heard of him (around 96 or 97 I think). The pedal, and the mod, and the cross-border shipping cost me well over $200

    I then sold my modded TS-9 about 3 years ago when I bought a Bad Monkey for $40.

    My current 3 favourite pedals all have SMC. Ask me if I care...they sound fantastic.

  16. 11 Gauge

    11 Gauge Doctor of Teleocity

    Mar 21, 2003
    Near BWI Int'l
    The interesting thing is that the most popular SMD chip by far (IME) is the 4580, which is just a modernized version of the 4558. All of the new Digitech pedals use it, the Dano Cool Cats use it (Drive may have a TL072, though), even the Surh Riot uses it, IIRC.

    As more stuff switches over to SMD, like the Red Witch stuff has, most of the Lovepedal stuff has, much of the WHE stuff has, it's going to be the chips that they can get for the C H E A P E S T prices.

  17. electricbody

    electricbody Tele-Afflicted

    Jan 19, 2007
    South Louisiana
    Yep, which is why I bought a TS7 when I was first starting out. It's still on my board. That doesn't mean I don't think there are other things going on in the pedal that affect the sound--lead dress, quality of other components, and values of other components.

  18. chrisgblues

    chrisgblues Tele-Afflicted

    May 31, 2010
    My Drivetrain has a surface mount 4558, although it confuses me because it also has the numbers 4834 on it, maybe it's some kind of date code.

    Regardless, they could have a lump of coal in there and it wouldn't matter to me. I'll leave the details to the professionals like 11 Gauge ;) and Analog Mike, and I'll just enjoy the sonic goodness that each pedal on the market has to offer without concerning myself whether or not they use "this" or "that" five cent chip...

    Good discussion though!

  19. kp8

    kp8 Friend of Leo's

    Aug 22, 2004
    Seoul, Korea
    My DOD FX69 has three 4558s in it.[​IMG]

    Does that make it 3x as nice?

    The DOD Grunge is like a fine wine, fruity overtones yet not precocious and with a clean finish.... so subtle and delicate


    & Does not require a poncho & bolero style hat.


  20. 11 Gauge

    11 Gauge Doctor of Teleocity

    Mar 21, 2003
    Near BWI Int'l
    There is almost no lead dress to speak of in the TS7. It uses a couple of ribbon cables to connect the different boards. It's a very smart and truly strain relief design that is not vulnerable to many of the ills of board mounted jacks that other pedals suffer from.

    ...As far as component quality, that is a touchy and subjective subject by itself. Considering that the handwired TS's use the same cheapo caps that are in the 808/9/etc., I don't think it's significant.

    ...The only one that really makes me wonder in the '7 is that they use a ceramic for the .1uF cap prior to the output buffer. I'd swap that one for a mylar/film type.

    I actually LIKE that the '7 doesn't use tantalums for the tone caps. I personally loathe tants in most dirt boxes. But it's so subjective that it's kind of stupid.

    The '7 is almost exclusively electros, just in strange sizes like some of the DS-1 caps. The input cap is the familiar .02uF film type.

    The '7 PCB is a little fragile, and it uses lead free solder that is not much fun to work with. Other than the .1uF ceramic cap, I'd leave it stock.

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