The $75 opamp IC

Now only $74.58 from Mouser, in a DIP-8 package:

The MUSES01

I have trouble seeing how this can be anything other than audiophoolery. But please, prove me wrong.

It's gain-bandwidth product is just over 3 MHz. Just like a sweet old TL072.

It's Common Mode Voltage Range is ±9.5V, when running on a bipolar 15V supply. Quite a bit worse than the TL072.

Of course, there's more to an opamp than these two specs...

Phoolery indeed, imo:

http://www.njr.com/MUSES/MUSES01.html

Features of the MUSES 01/02

1. Employing the high-purity oxygen free copper of lead-frame which has a greater effect on the sound quality,for the first time in the world*
2. Pursuing super low cross-talk between L and R channels
3. Pursuing the excellent sound moving person's heart that can not be shown in specification numbers

Click to expand...

Brewery material?

:

I've no doubt that, for many people, the perceived sound quality is indeed proportional to the cost of the equipment.

Samuel

Wow... It's like the TL072, but worse... Almost 5 times higher current consumption with absolutely nothing to show for it in the other specs.
So it is objectively worse and less practical than a 30 year old design.

Must sound great!

> 5 times higher current consumption with absolutely nothing to show for it...

Commodity chips minimize current consumption, same as ordinary cars minimize fuel consumption.

In AB output stages, this potentially hurts crossover distortion. Which is not a big concern to most chip makers.

I'd take more current if it addressed crossover.

I respect NJR (New JRC). They haven't been leading edge designers. They stuck with plain old '741 topology and moved to better processes to improve performance. Their chips often DO sound better.

However they have not given me $75 worth of wool-over-my-eyes in those web pages. And if they did, they really should be linked from the Mouser page.

JRC really should hire a native English-speaker to proof their stuff.

Then a better BS artist to tell us how good it is.

Even so, $75 is a lot for what amounts to a tuned selected commodity chip on magnetron copper frame.

I'll have to wait for folks with much better ears than I have now to comment on "finest sound".

Wonder if they do free samples?

PRR said:

> 5 times higher current consumption with absolutely nothing to show for it...

Commodity chips minimize current consumption, same as ordinary cars minimize fuel consumption.

In AB output stages, this potentially hurts crossover distortion. Which is not a big concern to most chip makers.

I'd take more current if it addressed crossover.

Click to expand...

Another amp stage that sometimes benefits from more current is the input LTP. 

I respect NJR (New JRC). They haven't been leading edge designers. They stuck with plain old '741 topology and moved to better processes to improve performance. Their chips often DO sound better.

Click to expand...

Respect but verify... I recall dancing with one of their sales reps years ago who wanted me to spec in their TL084 in place of the TL074 I was already using in large quantity. He argued that his TL084 was just as quiet as the TI TL074 we were using. I said OK give me a guaranteed noise spec that sys that and I'll give you an order.  He declined my offer.  :

However they have not given me $75 worth of wool-over-my-eyes in those web pages. And if they did, they really should be linked from the Mouser page.

JRC really should hire a native English-speaker to proof their stuff.

Then a better BS artist to tell us how good it is.

Even so, $75 is a lot for what amounts to a tuned selected commodity chip on magnetron copper frame.

I'll have to wait for folks with much better ears than I have now to comment on "finest sound".

Click to expand...

Sometimes prices like that are an artifact of small volume orders. I find it hard to believe that somebody is seriously trying to sell an IC opamp for that much money, and in my experience that manufacturer was more of a high volume commodity IC player, not low volume, esoteric specialty stuff.

JR

JohnRoberts said:

Sometimes prices like that are an artifact of small volume orders. I find it hard to believe that somebody is seriously trying to sell an IC opamp for that much money, and in my experience that manufacturer was more of a high volume commodity IC player, not low volume, esoteric specialty stuff.

Click to expand...

That was exactly my thought when I saw the Mouser page.  Looks like one of those random parts they carry at some unusual scale or through some unusual chain that makes the price out of line with most other things.

Of course it just might be a printing error 8)

StephenGiles said:

Of course it just might be a printing error 8)

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That was my thought. It wouldn't be the first time that I ran across a Mouser pricing error.

regards, Jack

AMZ-FX said:

That was my thought. It wouldn't be the first time that I ran across a Mouser pricing error.

regards, Jack

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It's cheaper at Digikey - 37.50 US$ per unit if you buy 100.  ;D

Mouser drops by half to 36 and change at 250pcs as well.  They don't even have 1k pricing without quote, which tells us right there that it's a very different type of part supply chain wise than a jellybean five cent chips sold by the millions.

JohnRoberts said:

Respect but verify... I recall dancing with one of their sales reps years ago who wanted me to spec in their TL084 in place of the TL074 I was already using in large quantity. He argued that his TL084 was just as quiet as the TI TL074 we were using. I said OK give me a guaranteed noise spec that sys that and I'll give you an order.  He declined my offer.  :

Click to expand...

I respect them for using the pnp i/p topology first seen in 70's Raytheon 4136 and creating a whole range of OPAs matched to many important audio applications .. from high current headphone drivers like 4556 .. to 2068 which is quieter than LM4562 in many applications.

So what if they don't have 1ppzillion THD?  In many, even highest quality, applications, this is moot.  eg http://nwavguy.blogspot.com.au/2011/07/o2-design-process.html

Knowing something about Far Eastern mass production engineering companies, it is likely that MUSE01 was a request by one of their decadent Western distributors .. probably JR's dancing partner.  The NJM engineers will have the same bad taste in their mouths when dreaming up "Hand Built by Virgins from Solid Unobtainium" sh*t ... as JR when he had to cater for this market. 

ricardo said:

So what if they don't have 1ppzillion THD?  In many, even highest quality, applications, this is moot.  eg http://nwavguy.blogspot.com.au/2011/07/o2-design-process.html

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I didn't have the attention span to read the whole thing but generally sounds like pretty solid work. I read far enough to see that he repeated the popular misunderstanding that DC servos eliminate caps from the audio path. Bzzzt wrong, DC servos just shift the cap to an opamp buffered high impedance feedback chain, so better quality caps can be used.*** 

Knowing something about Far Eastern mass production engineering companies, it is likely that MUSE01 was a request by one of their decadent Western distributors .. probably JR's dancing partner.  The NJM engineers will have the same bad taste in their mouths when dreaming up "Hand Built by Virgins from Solid Unobtainium" sh*t ... as JR when he had to cater for this market. 

Click to expand...

Perhaps making an oddball low volume opamp would require a price point that high but I still can't imagine who would ever buy them for tens of dollars ea.

JR

*** One could actually make a DC servo that did eliminate caps from the audio path by using a microprocessor, A/D convertor, and DAC or DPOT to apply correction. The effective HPF would be set by software so no caps there.  No I do not think this is worth doing, but it could. 

PRR said:

> 5 times higher current consumption with absolutely nothing to show for it...

Commodity chips minimize current consumption, same as ordinary cars minimize fuel consumption.

In AB output stages, this potentially hurts crossover distortion. Which is not a big concern to most chip makers.

I'd take more current if it addressed crossover.

I respect NJR (New JRC). They haven't been leading edge designers. They stuck with plain old '741 topology and moved to better processes to improve performance. Their chips often DO sound better.

Click to expand...

Hardly anything is black and white with you people! This is why I love this place...

So you're saying there is merit in keeping it simple and using brute force to minimize subjective nasties like cross-over. Sounds reasonable. Point taken.

VictorQ said:

PRR said:

> 5 times higher current consumption with absolutely nothing to show for it...

Commodity chips minimize current consumption, same as ordinary cars minimize fuel consumption.

In AB output stages, this potentially hurts crossover distortion. Which is not a big concern to most chip makers.

I'd take more current if it addressed crossover.

I respect NJR (New JRC). They haven't been leading edge designers. They stuck with plain old '741 topology and moved to better processes to improve performance. Their chips often DO sound better.

Click to expand...

Hardly anything is black and white with you people! This is why I love this place...

Click to expand...

Life is in living color.

So you're saying there is merit in keeping it simple and using brute force to minimize subjective nasties like cross-over. Sounds reasonable. Point taken.

Click to expand...

I guess you can hear what you want to, I detest brute force. IC are the antithesis of brute force, where miniaturization supports complexity like using tens of active components to perform simple functions we would do with one or two active parts discrete. In fact there are a number patents involving improved topologies to reduce crossover distortion.

One area where there is no escape from brute force is input stage geometry where you generally must throw silicon at the input devices to get Rbb noise down. Silicon real estate is the cost driver for ICs. But who knows they may yet finesse that too with improved process. With modern uber op amps claiming distortion floors down -144dB*** I suspect crossover distortion is well under control.

JR

*** I am not completely comfortable with the -144dB THD floor since they can not measure that directly. Instead they run the op amp up to elevated noise gain and then scale the measured THD down by that noise gain. But still very respectable performance, any way they measure it, especially if you use those uber op amps at higher noise gains. 

JohnRoberts said:

I guess you can hear what you want to, I detest brute force. IC are the antithesis of brute force, where miniaturization supports complexity like using tens of active components to perform simple functions we would do with one or two active parts discrete. I

Click to expand...

One can have a differing opinion of "brute force".

IC's are a prime example of brute force.  The ancient 5534 uses 22 transistors whereas a Quad/Eight AM10 has 10.  The modern ultra low distortion op amps have a even more active parts in order to get their fancy numbers.

One possible reason that discrete op-amps are in voque with the studio guys that actually listen IS
the low parts count. 

gridcurrent said:

The ancient 5534 uses 22 transistors whereas a Quad/Eight AM10 has 10.  The modern ultra low distortion op amps have a even more active parts in order to get their fancy numbers.

One possible reason that discrete op-amps are in voque with the studio guys that actually listen IS the low parts count.

Click to expand...

Presumably you have an application where you have conducted Double Blind Listening Tests of AM10 vs 5534.

DBLTs are one of my real specialties going back to 1978.  I spent a lot of time trying to make circuits that didn't change the signal so I could then introduce my evil stuff.  eg http://www.aes.org/e-lib/browse.cfm?elib=3798

The first OPA which was acceptable was Raytheon 4136, the grand daddy of practically all NJM stuff and loadsa other makers like Motorola.

But even that could be detected under certain conditions.  When 5534/2 came out, I swept all my DOA work into the Don't Recycle Bin.

This Millenium, I've re-surrected some of it .. but its just a mental exercise pursuing 1ppzillion THD.  There's loadsa important factors in the choice of an OPA, the NWAVguy pages are a good summary.

Some uber OPAs have really nasty behaviour in certain circuits which they don't tell you about in da datasheets.  I'm sure all DOAs have similar Evils. 

PS  Some of you will know that 'simplicity' is one of my Holy Grails ... often taken to obsession.
____________________

PRR, BTW, 4136 isn't really 741.  Its classic pnp i/p topology is much simpler and was a substantial improvement on 741, 301 and earlier topologies.

gridcurrent said:

IC's are a prime example of brute force.  The ancient 5534 uses 22 transistors whereas a Quad/Eight AM10 has 10.  The modern ultra low distortion op amps have a even more active parts in order to get their fancy numbers.

Click to expand...

I don't understand the obsession with parts count, specifically number of transistors.

If you think about it, it's easier to synthesize an accurate current source on a die using a transistor than a resistor. So now your long-tailed pair input has a current source instead of collector resistors. It works better, especially that the current-source transistors can be accurately matched. Better tracking over PVT, and more predictable performance, and lower distortion. Those numbers aren't fancy, they're real.

I mean, if you prefer to hand-match resistors to build a discrete diff-amp, by all means do so. But really, the improvements in both op-amp design and process aren't bullshit.

-a