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MERCYFULFATE
Copper Member
USA
45 Posts |
 Posted - 06/24/2005 : 23:35:33
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the jrc "japan radio company" chips are pretty famous in the older ibanez pedals but they are also used in several other brands as well.
what are your thoughts on this infamous and legendary chip?
i have several pedals with this chip. i have some with 4 of them. |
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boss freak
Gold Member
USA
663 Posts |
Posted - 06/25/2005 : 02:08:21
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| This chip was also used in several Boss pedals, including the OD1 and the SD1. I have four or five OD1s with the 4558 (some JRC, some Panasonic) and two SD1s with the 4558. I have a few other brands' OD pedals with 4558s as well, including of course some Tube Screamers. A few people consider the 4558 to be more hype than anything else, but I think that it's been proven (by it's popularity) that it's more than just hype. How can millions of ears be wrong? |
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MERCYFULFATE
Copper Member
USA
45 Posts |
Posted - 06/25/2005 : 02:37:30
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| correct! millions of ears can not be wrong, i knew they used them in some boss pedals. i have some also. the perfect overdrive chip. keeley uses the TI "texas instruments 4558p chip as opposed to the jrc 4558d chip. either or they both kill in terms of clarity and resonance. |
Edited by - MERCYFULFATE on 06/25/2005 02:39:02 |
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pawnshop_trash
Gold Member
USA
603 Posts |
Posted - 06/25/2005 : 06:23:29
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does anyone know the true difference between the JRC 4558D and 4558DD chips? (the short answer is one "D", but what does that mean!??) I've heard that the single D is a lower-noise version, but it would be nice to verify that.
my stock MIJ SD-1 has a 4558DD chip, as does my presumably stock CE-2. Analog Man installs a 4558D in his modded SD-1s (alas, I didn't peek under the hood to see what kind of chip a recent stock MIT SD-1 uses).... |
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boss freak
Gold Member
USA
663 Posts |
Posted - 06/25/2005 : 07:00:16
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4558D = Single Shielded
4558DD = Double Shielded = lower noise |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 06/25/2005 : 11:38:41
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Boss has used almost every brand of 4558. JRC, Nec, Texas, Matsushita etc. Not sure if JRC's version is superior or if the others are just as good.
Have you noticed any difference between different makes of 4558 chips? I'm not sure who initially owned the patent. Did JRC make the first version or did they copy someone elses design?
I have 4 chips here with the text "4558 Portugal". Who made those? I was going to use them for a project that never ever got started  |
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boss freak
Gold Member
USA
663 Posts |
Posted - 06/25/2005 : 12:09:18
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| I'm not sure which company developed the 4558 chip, or which company made them first. There seems to be a majority of people that prefer the JRC4558D, but there seems to be a small percentage lately that prefer the RC4458P. Allegedly the 4558P is a little better from a sonic standpoint, but I'm sure my ears wouldn't hear the difference. |
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Pedalhead
Silver Member
USA
245 Posts |
Posted - 06/26/2005 : 01:48:41
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| Ok so here is my deal with the JCR chip. I have had an OD1, SD1, and one '80s TS9 Tubescreamer, all with the chip, They all sounded very bla. My friend has had both TS9 and SD1 that sounded amazing. I did not realize that there was a difference in chips(D vs DD). But this might explain the differences I heard. Otherwise my DS1(metal screw,serial#0100) blew the JCR pedals I had away so I sold them. But now I am looking for another SD1(Japan of course). Who knew. |
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MERCYFULFATE
Copper Member
USA
45 Posts |
Posted - 06/26/2005 : 16:02:03
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imo the jrc is the most famous and possibly the best.the jrc was used in most of the maxon and ibanez/maxon pedals.
of course im still a litttle unclear of the differences in the 4558??? chips. |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 06/27/2005 : 09:57:59
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Just noticed that Texas Instruments 4558 datasheet says that each of the two opamps on the chip are identical to the very common uA741. It also says that it is designed to be compatible with Raytheon RC4558. I guess that means Raytheon made the first version of the op amp then.
datasheet: wwww.ges.cz/sheet/r/rc4558.pdf
Edit: The URL above doesn't work correctly. It's a known problem with the forum software. It will always look for www to identify a URL and fails when there's 4 w's. Copy/paste the url into a browser to make it work. |
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Pedalhead
Silver Member
USA
245 Posts |
Posted - 06/27/2005 : 19:58:55
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| I just heard of a JCR4558DX IC? Is this the same chip as the JCR4558D? |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 06/28/2005 : 09:56:38
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| I'm quite sure it is compatible but it probably isn't exactly the same chip. Where did you hear about it? We would probably need the datasheet to find out what is different. |
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Pedalhead
Silver Member
USA
245 Posts |
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walrus121
Silver Member
USA
187 Posts |
Posted - 09/30/2005 : 22:59:53
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Read http://www.geofex.com/ and his "Technology of the Tube Screamer" article for more info. Basically the JRC chip was only sounding good for a limited period of time, so true officianados buy the NOS chips ($4-$5 a pop last time I saw them). There are many other op amps that can be substituted for the original JRC 4558D that have the same operating characteristic that makes them sound good in overdrives. I like the LM 833N, it's a low-noise op amp. I substituted the JRC 4558D in my GE-7 for that reason (it's not an overdrive, so nobody should have any qualms except I destroyed the JRC chip in the process  . |
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walrus121
Silver Member
USA
187 Posts |
Posted - 10/16/2005 : 20:52:05
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| Update from R. G. Keen at Geofex, side by side tests prove that JRC4558Ds made before the NJM name change sound exactly the same as JRC4558Ds made after the NJM name change. Discount my previous post. |
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Topic |
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the infamous jrc op amp chip
