JRC4558 AND JRC4558D

[Manolo Dudes]

What does the "JRC4558" above look like and what package does it come in?

I think i've got one of those in my parts box. I seem to recall it's an old one with shiny-sharp-edged package and one big vertical white line on the left side. I'll take a photo if it's still there.

[Manolo Dudes]

Rats!!!... I cannot edit my last post  :evil:

I only want to add that it's a regular 8-pin DIP package.

P.S. Is the "delete post" option disabled?

[smoguzbenjamin]

Follow these simple instructions:


Scroll down and right all the way
Look at the bottom right of your window

Now you know

[Ansil]

lol OH DEAR GOD....   i can't even finsish reading this....  i got one jrc4558 left.. not a new one, but an old one laying around for somethine. do you want it..  send me an address and i will give it to you.

[Manolo Dudes]

Scroll down and right all the way
Look at the bottom right of your window

:oops:

[Dai H.]

What does the "JRC4558" above look like and what package does it come in?

I think i've got one of those in my parts box. I seem to recall it's an old one with shiny-sharp-edged package and one big vertical white line on the left side. I'll take a photo if it's still there.

Well, I suppose that could've been called a "D", but just not marked as such, or maybe it was just "4558". I've seen the ones you're talking about on ebay before. Somebody was trying to unload a whole bunch of them, as I recall.

Dai

[Jay Doyle]

I agree with Dai, it must not have been stamped that way, but it had to have been ordered that way. I don't think I have ever seen a 4558 in a metal can package (I can't imagine what that would fetch on ebay) but it must have had package options.

Here is what Walter Jung says about it it The IC Op Amp Cookbook:

   The RC4558 (Raytheon, 1974) is also a popular device. Although the RC4558 is not a "true" 741 in the sense that it uses nonidentical circuit topology, it nevertheless is considered functionally so by many. It is a dual unit, offered in the same pinout as the MC1458 (this 8-pin dual-amplifier pinout has become standard.

  ...the major difference from a 741 circuit is use of pnp input transistors, as opposed to the npn's in the 741. This, of course, reverses the direction of the bias current in the source resistance(s), which may affect the performance of some circuits. It is for this reason that the 4558 (and relate units) cannot be termed a "true" 741, but equals or betters the performance of the 741 in other regards.

  The RC4558 features improved performance over a standard 741 in terms of noise, slew rate, and bandwidth. A great many other op amps are patterned after the pnp-type input topology, and it appears in quad form as the RC4136. The RC4136 was the first quad op amp to appear on the market, and it enjoys wide popularity and multiple sourcing, as does the 4558.

[/i][/color]


Random facts about a little chip for your Friday...


Jay Doyle

[Doug H]

Chip type (not package) DOES matter quite a lot, and my testing indicates that thre's MUCH more variation from manufacturer to manufacturer than from chip to chip (of a given type).

Chip type does make a difference, I've tested JRC's vs. TI's and they sound slightly different.

But the original question was about package type, not chip type.

Doug

[Doug H]

I have a bunch of JRC4558D's.  I was just wondering if i made a clone if it would be authentic.

And what does "authentic" mean to you? Do you possess an Ibanez design specification for the 808? Doubtful. "Authentic" in what way?

Seeing as how they changed chip types throughout the evolution of this product, I'm curious as to what anyone would define as "authentic" wrt this product.

Doug

[Dai H.]

Thanks for that tidbit Jay. The 4558 doesn't seem bad for audio, IME.

I agree with Dai, it must not have been stamped that way, but it had to have been ordered that way.

I've got the data sheet, and it does mention the suffix/package. Perhaps, the earliest ones didn't, but you'd have to see it to confirm that.

I don't think I have ever seen a 4558 in a metal can package (I can't imagine what that would fetch on ebay) but it must have had package options.

I have another one. Motorola, I think it was. Some of the ones in efx. do (or did) come in cans. 741, 308.

If anyone notices a difference with some of the caps, I'd be interested in your observations. I'm talking about the input .02, .047 near fdbk. lp., and the .1uF towards the output. What I mean to say is, if after trying an original type chip and not getting a cloned 808 sound, maybe try the caps. Or in modded reissues.

Dai

[Jay Doyle]

I have another one. Motorola, I think it was. Some of the ones in efx. do (or did) come in cans. 741, 308.

I knew about those, I assume that the 702 and 709 did as well as they were the first ones, I also know that the 3080 OTA came in a can as well, some of the early dynacomps had them in a can. Are you saying that you have a Motorola 4558 in a can? interesting...

[Gus]

The ouput buffer is mounted on the output jack board in the TS7.  People the vox valve tone had the rc 4558 stock,  The two 808 I have seen inside had jrc4558s.

 The new and older jrc 4558 don't sound different to me the letters at the end might just be grades for noise.  That said damaged chips might sound bad.  The input diff pairs can be hurt by heat and static and current surges.  This will change the overload recovery and noise.

 John Greene did alot of work finding info on the jrc4558.  Don't forget that people that have a bunch of one type to sell might state thing on boards alot of people don't test the statements and if the statement get repeated enought it seem to become a fact.

I have been in many TS and have modded  them in different ways.  I have two VVTs three ts7s,1 ts5. all modded  I have modded over 10 TSs for friends.  IMO the magic of the ts808 is the tant caps.  The closest I got was with a type of film.  The orginal 808s tants seem to have just the right amount of "grit".  IMO the VVT tants come the closest.


Don't get hung up with the chip.  chips are cheap try them.  I don't hear much difference with different chips untill tyhe petal gets a large signal and/or the gain and tone pot is up all the way. This is with upgraded caps.

When someone want a TS mod I place all my ts type petals(6) in a room and have the person bring there own amp and guitar.  The petals are not marked.  I leave the room so they can't see me and don't talk and let them pick the petal they like I them put that mod in there petal.

 Most of the time stock gain the 4558 is ok:however at higher gain I like other chips.

I have posted alot in the past about chips I like.


Gus

[Ed Rembold]

This thread is getting long-
maybe someone said this already-

JRC4558DD-

The 2nd "D"  stands for "selected low noise"
And it really does have less "hiss" at max gain.

This info from John Greene-  back in the early days of Ampage/Arons forums.
Ed R.

[Ansil]

This thread is getting long-
maybe someone said this already-

JRC4558DD-

The 2nd "D"  stands for "selected low noise"
And it really does have less "hiss" at max gain.

This info from John Greene-  back in the early days of Ampage/Arons forums.
Ed R.

woo hoo     those are the ones i have...

[Dai H.]

I have another one. Motorola, I think it was. Some of the ones in efx. do (or did) come in cans. 741, 308.

I knew about those, I assume that the 702 and 709 did as well as they were the first ones, I also know that the 3080 OTA came in a can as well, some of the early dynacomps had them in a can. Are you saying that you have a Motorola 4558 in a can? interesting...

Yeah, I bought it because it looked unusual.

The new and older jrc 4558 don't sound different to me the letters at the end might just be grades for noise. That said damaged chips might sound bad. The input diff pairs can be hurt by heat and static and current surges. This will change the overload recovery and noise.

I guess that could explain it when some people hear a diff. even with the same jrc4558, I suppose.

Dai