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I pulled apart an old dead radio shack receiver someone gave me and found a card with 3 each JRC 4558 DX chips on it. I have some current production JRC 4558's that I use for TS clones, but I'm wondering if there is anything magic about the "DX" suffix on these to make it worth the trouble of removing from the board. Couldn't find anything on the net saying so.
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They are dual op-amps, plain and simple. Regardless of what advertising copy or forum threads you have read, thee is nothing special about JRC op-amps, whether old or new. Some folks find they like the tone of them in a Tube Screamer, while others find that completely different chips deliver up the tone they hear in their mind. Most folks find they generaly do not like the tone of an op-amp that was harmed by heat during its removal from a board (wink, wink, nudge nudge).
I regularly cannibalize stuff from old projects, TVs, stereos, computer peripherals, etc., so I have nothing in principle against scavenging parts from things left at the end of the driveway. It's good that we recycle as much on the planet as we possibly can. That being said, there is nothing about those 3 chips you could not replicate for about $1.20, and there is no reason to want to try and remove them if it involves too much effort or risks damaging them in the process. -
I totally agree with Mark H.
On the other hand you COULD cash in on the frenzied hype by selling them on ebay...
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especially with xtreem postage & handling for each of the 3...
(sorry: just joking)Comment
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The last thing I had with a DX suffix that was supposed to be special was a 486DX CPU. Turned out to be nothing special.
4558 Dual op-amps are a decent utilitarian chip for a lot of different purposes. That's why so many pedals have them. I feel pretty confident is saying that not very many classic pedals employed op-amps that were "taste-tested" (i.e., swap chips in the socket until you find one that sounds good). They just used what worked, was available and was cheap enough. The JRC4558 was one of those and remains so.Comment
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The 'X' means it was selected for a particular noise performance.Originally posted by casey73 View Post
http://www.njr.com/pdf/appnotes/LowNoiseAmp.pdf
'X' is screened for lower noise than 'D' if I remember correctly.
--johnComment
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I tend to agree with you Mark. I've built TS clones in the past and several recently. I always use sockets. I've listened to a wide variety of the popular dual op amps in A/B set ups and am hard pressed to hear a significant difference between most of them. My hearing isn't what it used to be, but I do think some of claims out their regarding certain op amps border on urban legend. But, if I'm selling them, and I do sell a few, some musicians are sold on the JRC 4558 as being essential to the original sound. They are cheap and readily available so I use them. I just wanted to know if the DX was more "special" than the regular JRC4558
And, I've just getting back into pedals after years of focusing mostly on tube amps, so I'm not real up to date on all the latest trends in pedal building.
On a tangent, but somewhat related, I think that guitar players with little technical background sometimes get caught up in certain beliefs that I personally find odd, and I'm being kind saying that. Two examples are Eric Johnson and Carlos Santana. I like both of them and acknowledge their playing skills. However I remember reading somewhere that Eric Johnson said some pedal he used (fuzz face or TS?) sounded better if he placed a rubber band on the battery, or something like that. The details are sketchy but the idea was pretty bizzare. Carlos Santana said recently that his main Boogie started giving him less than good tone after he added a Dumble to his collection of amps. According to Carlos, the Boogie was jealous. I could believe it if he was talking about his yellow lab (mine barks when I kiss my wife) but an amp? Maybe Carlos is into shamanism?Comment
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JRC 4558 revisited
In an earlier post I'd said I had a difficult time distinguishing between JRC 4558 and other dual op amps in a tube screamer circuit. But, I'd read many opine on the virtures or pitfalls of a wide variety of op amps that can be dropped in. So I did my own A/B testing using identical TS clones I recently built.
Doing side by side comparrisons with identical pedals set the same way provided a clear difference between the popular JRC 4558 and other op amps. I even switched the op amps between the pedals to insure that variations in values because of 5-10% component tolerances in the components didn't have a major effect on the tone.
I went through several popular op amps, but the one I personally prefer is the LM833. The JRC 4558 sounds muddier compared to the LM833. The LM833 provides a cleaner distortion. I suppose that might be an oxymoron? There was a little less residual fuzziness with the LM833. The tube screamer isn't an over the top distortion device and I kinda like the idea of a higher fi chip to clean it up a little. Purists may disagree.
I went a step further, and listened to them through headphones on a small solid state amp, and heard a bit less hiss from the LM833 at full gain, and an apparent increase in sustain of a single note. Now, this is all very unscientific, and it is possible I unconciously plucked harder when using the LM833 pedal, giving it an unfair advantage, but I tried to be objective as I really had nothing to gain from the experiment other than to satisfy my own curiousity.
I gave these two pedals to a friend and asked him to give them a listen over the weekend and report back. This guy owns several original screamers, so I'll be interested in hearing what he has to say.
Mark commented that the JRC 4558 was available and cheap at the time some of the early screamers were made by Ibanez and little thought went into tone produced by them. This is no doubt true. As for the original JRC 4558 DX chips I asked about, they are still on the board waiting for a spare few minutes to be pulled out and resold as an esoteric, super secret and rare item on Ebay
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That's pretty funny Casey and more power to you bud. Get all you can ! FWIW I had a real old Tube screamer (still have it) it had a 7558 chip originally in it. After changing them so many times I finally gave up so what's in it now is what was the last thing I tried. Some type of 4558 it may even be a NTE which I still can't seem to tell a difference from the JRC. Once you start getting to clean they will start sounding like glass breaking so there is a limit.KBComment
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"x-treeem postage"
I hear ya on the postage thing. It amazes me how some people pad their profits by bucking up the shipping fees on stuff. I do some selling on Ebay, and charge my postage costs, since I get my priority mail boxes delivered to my house free. On a large item where I've had to purchase some packing material I may charge for that, but some of these Ebay sellers are making more money on shipping than the actual items they sell.Comment
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