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Old 2nd May 2020, 06:03 PM   #71
gpdavis2 is offline gpdavis2  United States
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They definitely should be at the price. Like going with Lundahl xformers.
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Canton Ref 9K Cary SLP-98P & Rocket 88 Denon DP-80 w/Lyra Kleos, Ortofon Cdza Blk & K-b, AT33R Elekit TU-8500 Oppo 203 Sony ST-J75 Stax UA-7/CF
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Old 2nd May 2020, 09:19 PM   #72
Hmavv is offline Hmavv  United States
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I first found out about MUSES 8 or 9 years ago, and at first glance I thought the MUSES were just another audio gimmick, a cheaper rebranded opamp sold for 30 times the price. They are not! Having them in my Tu-8500 have left me with abig impression. I think it's time for a deeper look into what sets these apart from the rest.

So what makes the MUSES01 different from everyday opamp? Well quite a few things, I was able to find more information through online press releases and information put out by NJR at trade shows going back to 2007. Pretty hard to find since it was 13 or more years ago, there were a lot of dead links, and wayback machine was of little help.

From a press release from 2007, Announcing the start of production of the NJM5720 (which is the oldest reference I could find) states that development of the first Muses OPAMP "NJM5720" (Later renamed MUSES01) started in 2005 , and the first prototype of many, appeared in 2006. The only way to get a hold of a NJM5720 sample was to be a Manufacturer, and from what I can tell, only in Japan. Pricing for a sample at this time cost 3000 yen (about $30 in today's money) per chip. A request had to be submitted with NJR to get one. It was like that for several years. Early details of thur sound quality slowly started to make their way into audio forums, I'm guess from people who worked for manufacturers, who got to listen to the samples, this fueled a lot of hype and skepticism due to the price, and difficulty of getting one, but that made the NJM5720 even the more mysterious since nobody except manufacturers could get their hands on it in the early days.

The NJM5720 was the result of "I'f cost isn't a constraint, what kind of audio opamp can we make?" thinking. The 2007 release states that NJR's goal was to get the sound of a discreet opamp in the form and benefits of an IC.

Let's break down its features to compare to the common opamp.

The same 2007 press release of the NJM5720 says that it uses 2 seperate die, one for each channel. This was and still is a very game changing design even by today's standards, No other company used this technique in opamp before, then, and even today 13 years later, all current opamp are on a single die, NJR is the only one using this method, NJR says that is how they achieved the 150dB plus of channel separation, NJR also attributes this construction to sound you get from the NJM5720.

This here is a single die dual channel opamp LM358, all dual channel opamp look something like this on a single substrate. Remember the red circles for later
Click the image to open in full size.

I couldn't find a die picture of the NJM5720, but I did sort of find one in a MUSES03 announcement, which uses the same dual die construction of the other MUSES, the only difference is that the MUSES03 is single channel, the Gain stage is on a separate die from the output stage, rather than separate channels per die like the NJM5720, its same concept but different execution.
Click the image to open in full size.

The next feature is die size, The 2007 press release says the the die size of the NJM5720 is 3 times bigger than any other dual channel opamp die. I think this here is the real magic behind the Muses series opamp. production wise, a bigger die means less yield per wafer, traditionally the goal is to keep the die as small as possible to yield more chips from a wafer. With the NJM5720 they are yielding 3 times less per silicon wafer due to it being 3 times the size. But what this does means is that you have more real estate to make features that would otherwise be impossible on a smaller die, now NJR has been tight lipped about the actual construction of the die, they only stated that they are using "new and advanced techniques", I feel this is their bread and butter! For example capacitors are probably one of the biggest features on any chip design because they take up so much space. (see red circles on the LM358 die) since capacitance has a relation to the surface area, I imagine they are capable of making bigger and better capacitors with the extra space, and this also allows them to use different materials for other devices and features on the die, that would also take up more space. Again, they have been tight lipped, so you can only speculate what they are doing with 3 times the extra substrate space.

Another feature mentioned is the use of oxygen free copper for the lead frame and bonding, so what is this? let's start with the lead frame. The lead frame is where finished die are attached to a stamped metal pads and leads that provides its ground (die are grounded through the substrate) and their leads that provide connections to the outside world from inside the package, aka pins. I found this neat picture to share
Click the image to open in full size.

How is a OFC lead frame different? well for starters the majority of leads frames used are made of a Iron and Nickel alloy (the cheapest option) due to its strength, then sometimes a copper alloy (expensive), NJR uses pure OFC with tinned leads for the NJM5720, they state that they wanted to use the same materials used in speaker wire, this does make the pins easier to bend, extra care needs to be taken when handling.

Next is bonding, extremely small wires that connect on pads on the die to the pins. Like in this picture. NJR states that they are using OFC here as well, again they wanted to use the same material used in speaker wire. Copper, at the same diameter when used in bonding can transfer higher currents and is a stronger material when compared to gold. here's an example of what bonding wires look like.
Click the image to open in full size.

Gold has been used for longest time because it's the easiest to work with. During the development of the NJM5720, copper bonding was still under research, due to the increasing cost of gold vs copper, It was mostly used in incredibly rare situations for bonding. Due to the difficulty and expense of using copper bonding, you need a special environment for it free of oxygen to prevent corrosion caused by heating during building, plumbing gas lines alone can run up to a few million in cost for a manufacturer switching over from gold to copper. you can read more about it here.
Wire bonding - Wikipedia. As of 2015 only about ⅓ of IC were using copper bonding.

In the end of the 2007 press release NJR states that they have started development of a Bipolar input version of the NJM5720, that will later be named the MUSES02.

Fast forward to May of 2009, NJR announces that after receiving heavy requests for several years from the public to make the NJM5720 available for consumer purchase, They state that its under consideration, and if it happens it will become available later in 2009 to the general public. They also announce that the NJM5720, will be renamed the MUSES01, and the Bipolar version, The MUSES02 will be released later that year.

December of 2009 I started finding the first Japanese reviews, blog posts, and forum posts of the MUSES01 and MUSES02. They were in high demand and still hard to get a hold of since going on sale publicly. I even found one guy's blog post where he took a day trip to Tokyo to buy a pair.

Sometime in 2010 NJR announced a production (cheaper) versions of the MUSES01, and MUSES02, the MUSES8820 and MUSES8832. These use more commonly used materials for the lead frame and bonding, and who knows what else to lower cost, But I did find a rumor on one forum saying that these are single die but with a big empty space of silicon between channels, I could not verify this, so it's only rumer, These are suitable for use in high volume manufacturing of audio gear. It is around this time that I start seeing posts about MUSES01 and MUSES02 on American and Canadian forums and blogs. And just like their Japanese audio enthusiast counterparts. The price was shocking. It wasn't until around 2012/2013 that the MUSES became easier to get a hold of for Western customers.

I hope this helps shed some light on how the MUSES series opamps differ from conventional opamp, and why the price is steep, The MUSES are like the Ferrari of the OPAMP world, more has gone into it, especially under the hood, Yeah you can buy a brand new car for $15,000 and laugh at the idea of people who spend over $250,000 on a Ferrari, they essentially have the same things, power windows, a radio, 4 wheels, an engine, and they can both get you from point A to point B. But the experience getting there will be completely different!
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Old 2nd May 2020, 11:52 PM   #73
Mancave62 is offline Mancave62  United States
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Wow, thanks for all the great feedback and info., so what about tubes in the 8500? I started with the Tungsol 12at7 and then the Sylvania JHS 12at7 (TubeDepot.com | Early 1950’s JHS Sylvania 12AT7 - Military Stock) which I'm listening to now. Never even tried the stock tubes. I'm thinking with the OPA2227's and these tubes, I'm getting some really great sound at budget prices?
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Old 4th May 2020, 04:54 PM   #74
gpdavis2 is offline gpdavis2  United States
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No question that you are getting some great sound. I'm using JAN Phillips with the 4562 opamps, but the 2227 was also fine.
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Canton Ref 9K Cary SLP-98P & Rocket 88 Denon DP-80 w/Lyra Kleos, Ortofon Cdza Blk & K-b, AT33R Elekit TU-8500 Oppo 203 Sony ST-J75 Stax UA-7/CF
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Old 5th May 2020, 05:53 AM   #75
Hmavv is offline Hmavv  United States
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Quote:
Originally Posted by Mancave62 View Post
Wow, thanks for all the great feedback and info., so what about tubes in the 8500? I started with the Tungsol 12at7 and then the Sylvania JHS 12at7 (TubeDepot.com | Early 1950ís JHS Sylvania 12AT7 - Military Stock) which I'm listening to now. Never even tried the stock tubes. I'm thinking with the OPA2227's and these tubes, I'm getting some really great sound at budget prices?
I don't think you can go wrong with any NOS tubes in the Tu-8500, I haven't had any tubes I didn't like. but I do have favorites.

I've been interested in some Sylvania blackplates, or even some Mazda tubes as well, I've read a lot of good things about them.

I tried the stock tubes once just to get a feel for them, don't remember much about thern since it's been a while, but they weren't bad. Im using NOS Blackburn Mullard now, My favorite so far, I used NOS Telefunken for a a week and they sounded very nice, very open at the top end.

The GE 5963 five star was very present pleasant too, even though it has a little less gain.
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