Aaaaaaaahhhhh!!!!!! 4558's... there everywhere!!!

Must be the prosumer gear chip of choice. Just opened up my em auhdio bx8's (biamped studio monitors). There's 4 of em (4558's) in the amplifiers. One for the line in and 3 more for the eq. Also a TL072. Popped 5532's in their place in one speaker and compared the two with the same mono signal. Aside from the usual more detail with a swap like this, I also noticed that the 5532's were less splashy sounding on cymbals.

I thought it was the 4136 that led people to hate chips, however that doesnt explain why people pay so much for an LA4...

I think the 4136 sounds good in an LA4, but in a bad way.

dave

I thought that the "chips" in an La4 were transistor arrays . . . Love my cranky old La4 to bits( it survived both a studio fire(Easy Studios,London, and the chemical foam that the fire brigade sprayed! had to chip it off . . .) I think that later La4s were chips(?)

Maybe I'm wrong . . . .

Andy P[/list]

[quote author="buttachunk"]i now believe that TL0whatevers are the cause for people hating chips, and for the exorbitant price of vintage gear.

5532s are in alot of gear along-side TL0whatevers... that's probably why 5532s got such a bad rap,, being blamed for the TL0whatever sound.

TL0whatevers function well in sidechains, but not in signal paths. :wink:[/quote]

Actualy, I left that TL072 in for now because I didn't know if I could drop a 5532 in its place without any other mods. Can I?

Impossible to answer without knowing the circuit.

The TL0-series are FET input, the 5534 and 5532 are BJT input, and that's only the beginning of the differences. They are not nearly the same. As a general rule of thumb (with some exceptions, certainly) you cannot swap one for the other.

buttachunk made the following comment when I questioned an alternative to TL072:

"IMHO the OP2604 sounds MUCH better in Soundcrafts, Tridents, and DDAs.
or, if you want a softer, 'tubier' sound, try the opa134."

Regards,
Tom

Has anyone tried the OP249 in place of a TL072? AD bills it as an enhanced replacement. Here is the datasheet.

:thumb: :guinness:

Hi Seth,
That's some history you got there... :thumb:
http://sethglassman.com/
Regards,
Tom

seth never talks about the band he was in or his "stage name".

modest bastard.



haha

dave

> i now believe that TL0whatevers are the cause for people hating chips

> I thought it was the 4136 that led people to hate chips,

No, it was the 4558 and the 741. 4136 is better, but not better enough.

These ARE fine chips, up to gain of about 3 or maybe 10, peaks to a volt or two, and loads above 2K.

At gain of 10 you have less than 40dB of feedback at the top of the audio band, which is not enough to hide the flaws.

741/4558 won't slew fast enough to handle cymbal peaks above 1V or so. Put a triggered-sweep scope on the output, set to just display the loudest peakes, and see if you are exceeding 1V.

In lower level low-gain work, the 4558 revolutionized low-price audio. It really does sound better than the cheap alternatives, and is so easy to design with. But when used for more than a little gain or output, it can't keep up. This got a little notorious, "chip-sound", leading Jung to investigate and clarify slew rate needs.

Also don't starve them. I think the book says they work down to 10V total supply, but they are much happier with 20 or 30V total supply. (However, running from a 9V battery, gain and slew tend to not be problems because you have to keep signal level low to avoid clipping.)

4136 is a slightly improved 741 in a quad-pack with a pinout that did not catch on. Back in 1977, the 4136 was the best alternative to 4558s, but not wonderfully better. From today's perspective, they are the same kind of thing. (Unless you managed to blow-up a 4136: because of the odd pinout, nothing else plugs-in.)

The TL07x series has more slew and bandwidth, can handle 5V peaks and gains over 10. But it is not real happy about its 2K rated load, is much happier if it sees 5K or more. These do tolerate 10V supplies well.

Compared to 4558, the 5534/5532 has a LOT more input bias current, and in 741-like designs with large input resistors a 5532 will bias up all wrong. It also needs more supply current, and really needs a good bypass cap at each chip, whereas 741/4558 can get away with one per board. The 5534/5432 has plenty of GBW and slew for any sane audio need, and will drive 600Ω comfortably.

Good advice. Too bad so many seem intent on ignoring such "inconvenient" details since they don't fit in with the quick-and-easy-upgrade mentality.

Way back maybe 15 years ago I built some stuff with TL07x, and still like that stuff. It's more a matter of design than the chip, as others have said.

I've noticed that all of the stuff I hate has knobs. Therefore, I shall eliminate knobs from all future designs.

Man, you cut right to the heart of that logical fallacy, didn't you? :thumb: :thumb: :thumb:

Witht the TL07X there is an often overlooked design issue. They have P-Channel input FETs. When used in non-inverting mode the input capacitance varies with input voltage unless the impedances seen by both inverting and non-inverting inputs are reasonably matched. The capacitance modulation is one of the reasons of distortion in the input stage for these opamps. In inverting configuration this is not an issue.

I just want one or two knobs on my gear too...

[quote author="NewYorkDave"]Man, you cut right to the heart of that logical fallacy, didn't you? :thumb: :thumb: :thumb:[/quote]
Why do witches burn?
- cause they're made of wood!

Best regards,

Mikkel C. Simonsen

"All men are mortal. Socrates was mortal. Therefore, all men are Socrates."

-- Woody Allen

Perception is a funny thing, I guess. I listen to stuff pretty carefully too, and either my ears aren't that good or else there isn't that much of a difference. Or I'm a better skeptic than most. Regardless, I've often found myself much less fussy about some details, unable to hear any real difference. Granted I haven't done much in the way of mic preamp comparisons, but I've found that mics are still the biggest difference in a recording chain.

But I definitely wouldn't rule out other folks being able to hear differences.