Which OEMs Actually Use The OPA627 / Other Uber-High Slew Rate OAs?

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ricardo said:
Dunno whether its true today but certainly for LN, cleanliness is everything.  It's all about sh*t in the chip.

The same Mullard Southampton factory made the Mullard BFW11, my old favourite FET for condensor mikes.  No other maker's BFW11 was anywhere near its LN performance.  Today, no BFW11 is a LN device.
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We may be talking about the same thing. Wafer purity matters the smaller the feature size used for the tiny components inside the IC. Over the decades time span that we are talking about for this one part the number of small transistors that IC makers can fit on a single digital chip has increased exponentially. So acceptable surface impurities from decades ago would stop modern chips from working at all.

So I would not be surprised if old masks run on modern IC lines were slightly quieter. This might impact a THD+N measurement if  the noise component is lower.

JR
 
I'd like to put a vote in for the JRC5532. I've used New Japan Radio's version in a circuit before and it consistently measured a bit better than the parts I had from TI and Signetics/Philips. It's not a huge difference, but the distortion spectrum seemed to have fewer high harmonics, never a bad thing.
 
yes, they are the same.

JRC = Japan Radio Corp ("JRC (number)" is marked on their op amps (and very old big transmitting type vacuum tubes IIRC).

NJM (not 100% certain, (and bit of a weird Japanese/English hodge podge but) this appears to stand for) = New Japan Musen ("musen" = ("mu" = absent, "sen" = wire) = wireless = radio)

and sometimes NJR (appears to stand for) = New Japan Radio

http://www.njr.com/corporate/history.html
 
So this thread went off the topic, discussing opamps and cables and THD and latching...
Let's get back to the original question!
Which OEMs are actually using modern high performance opamps?

Obviously, we are talking about audio equipment manufacturers, video and other higher bandwidth applications by nature require something better than TL072.
 
jackies said:
So this thread went off the topic, discussing opamps and cables and THD and latching...
Let's get back to the original question!
Which OEMs are actually using modern high performance opamps?

Obviously, we are talking about audio equipment manufacturers, video and other higher bandwidth applications by nature require something better than TL072.
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Actually, its been pretty informative.  Most competent designers don't see the need for da uber OPAs for good reasons ... some of them listed here.

That's a good sign as it suggests the number of incompetent designers has fallen.

But if you want a list of inco... oops!  I mean OEMs who use uber OPAs, just look at the Headphone Amp forums.

http://nwavguy.blogspot.com.au/2011/07/o2-design-process.html has links to these too.
 
I know lots of designers using these newer parts in modern gear - Dave Collins at Manley in their newer designs, Leif Mases at Maselec, Bruno Putzeys for Hypex, and now Mola Mola, John Siau at Benchmark.  All very smart guys.
 
ruairioflaherty said:
I know lots of designers using these newer parts in modern gear - Dave Collins at Manley in their newer designs, Leif Mases at Maselec, Bruno Putzeys for Hypex, and now Mola Mola, John Siau at Benchmark.  All very smart guys.
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This incompetent grovels before this list of luminaries.  :eek:

Any of them use OPA627 or other supa slew stuff?

I can only think of one application where OPA627 might be preferred.
 
ruairioflaherty said:
I know lots of designers using these newer parts in modern gear - Dave Collins at Manley in their newer designs, Leif Mases at Maselec, Bruno Putzeys for Hypex, and now Mola Mola, John Siau at Benchmark.  All very smart guys.
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It's interesting that you mention Benchmark. I remember when a furore was caused on various message boards when it came out that their famed DAC-1 used the 5532. Representatives from the company had to 'defend' their decision (which was a good decision, I'm sure - the product appears to have done very well). Have they replaced the 5532 on their later designs? Was this decision driven by market demand for something more exotic, or genuine engineering requirement? 
 
I can't talk for others, but the performance of my latest commercial DACs can't be achieved with NE5532s, mostly because of their relatively high voltage noise. Whether there is actually any relevant audible benefit from some dB lower noise floor is another question (but not the one of this thread).

Samuel
 
The customer is always right  :p  and for the markets that Benchmark serves, it is never good to have to defend design decisions. For every customer that you get the opportunity to educate about why your decision was correct, 10 customers buy something else out of ignorance based doubt.

The 553x remains a respectable performer today, but it may be an uphill struggle to convince customers that any op amp older than they are belongs in a modern SOTA design. So a newer part, even if roughly equivalent will reduce the cognitive dissonance with customers.

As I recall the 553x was roughly 4.5nV/rt HZ. Modern high performance op amps are delivering 1nV/rt Hz noise levels. While I don't expect a usable 12 dB drop in noise floor, better is always better, especially for marketing to customers who barely understand specs and the like. 

JR
 
JohnRoberts said:
As I recall the 553x was roughly 4.5nV/rt HZ. Modern high performance op amps are delivering 1nV/rt Hz noise levels. While I don't expect a usable 12 dB drop in noise floor, better is always better, especially for marketing to customers who barely understand specs and the like. 

JR
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while the AD797 as an example has a roughly four times lower voltage noise (0.9nV/rt Hz) is also has a roughly four times higher current noise.... that combination of respectable voltage noise and very decent current noise of the NE5534 / NE5532 is difficult to find - even in modern opamps.

- Michael
 
audiomixer said:
JohnRoberts said:
As I recall the 553x was roughly 4.5nV/rt HZ. Modern high performance op amps are delivering 1nV/rt Hz noise levels. While I don't expect a usable 12 dB drop in noise floor, better is always better, especially for marketing to customers who barely understand specs and the like. 

JR
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while the AD797 as an example has a roughly four times lower voltage noise (0.9nV/rt Hz) is also has a roughly four times higher current noise.... that combination of respectable voltage noise and very decent current noise of the NE5534 / NE5532 is difficult to find - even in modern opamps.

- Michael
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Yes but there are new JFET input op amps that can deliver lower than 4.5nV noise voltage with even lower noise current, but this is all academic without knowing the source impedance we are dealing with.

JR
 
JohnRoberts said:
The 553x remains a respectable performer today, but it may be an uphill struggle to convince customers that any op amp older than they are belongs in a modern SOTA design.
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It's time we jazz up modern design and create an entirely new industry based on NOS OPAs.  ;)

The best OPAs have always been NOS Mullard NE5532/4s hand built from solid Unobtainium by Southampton virgins.  They have a clarity, definition & sweetness unavailable in modern stuff and were of course used in the last of the great analogue mixing desks of the 80s.  Sorry Mr. Groner  8)

Why should da tubophools have all the fun.
 
ricardo said:
JohnRoberts said:
The 553x remains a respectable performer today, but it may be an uphill struggle to convince customers that any op amp older than they are belongs in a modern SOTA design.
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It's time we jazz up modern design and create an entirely new industry based on NOS OPAs.  ;)

The best OPAs have always been NOS Mullard NE5532/4s hand built from solid Unobtainium by Southampton virgins.  They have a clarity, definition & sweetness unavailable in modern stuff and were of course used in the last of the great analogue mixing desks of the 80s & 90s.  Sorry Mr. Groner  8)

Why should da tubophools have all the fun.
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Perhaps because NOS op amps built on process lines that are inferior to modern process lines are not likely to be better. More likely they will be worse.

I'm not in...  8)

JR
 
Great thread everyone, thanks

thermionic said:
Hi Micheal,

The oscillation was seen by connecting a probe to the o/p socket, with the i/p socket shorted. My audio analyser picked up broadband fuzz at around -50-ish. I then hooked the scope probe and saw 18mV of something sine-shaped at 18Mhz.

The layout is on stripboard! The next stage is to give it to the PCB designer I work with. It seems daft to prototype anything with a 'relatively' quick opamp such as the 4562 on strip-board, but you have to get proof of concept somewhere, right? With anything faster I suspect you'd have to go for a multi-layer PCB from the start. Just the inductance of an IC socket can set off some OAs.

edit - trust me, you don't need to see the layouts. The moral of the story is that just a couple of mm here and there can trigger bad behaviour if the OA is quite fast.
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This is exactly the problem I am having right now. Trying to prototype on a solderless breadboard with LME49990 and OPA1612 is a time consuming process!
 
Trying to prototype on a solderless breadboard with LME49990 and OPA1612 is a time consuming process!
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I'm wondering if there's a way to get a shielded breadboard. Maybe fit one inside a biscuit tin? Does anyone make such a thing?

With a conventional OA I find lifting the lid on an enclosure might add a couple of dB to the noise floor. With a fast OA the noise seems to increase by 10 or 20 dB. Speed = propensity to pick up undesirable signals. You can put an RC filter at the i/p, or even a Zobel on the o/p or FB loop, but they can introduce a penalty. One benefit to discrete OAs is that you can limit bandwidth locally inside the OA.
 
hi,

to get anything like a meaningful measurements on my wood (!) table I had to either put a rather large steel plate (insulated.... power leads tend to fall off at undesirable moments) and ground it. on a other occasion I used household aluminum foil between two sheets of paper. also 'grounded'. worked ok for me, but if you are tracking the last bit there's nothing like a proper enclosure.

- Michael
 
The best way to get a 'shielded breadboard' is to use the dead bug approach. Basically, you take an un-etched piece of copper clad board, flip the chips over, and solder components and jumpers directly to the pins. You have a nice, huge ground plane everywhere, but little else. Also, while this was somewhat reasonable to handle with 0.1" DIP pin spacings, it's much more annoying with SO packages, and downright unfeasible with more modern SMT packages. However, the old 0.1" 5-hole plastic breadboards are less than useful with any chip fast enough to listen to, so at least the deadbug approach works.
 

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