I am new to all this, so have been trying to piece together information from forum posts/user feedback etc... Being able to speak to someone who knows their stuff directly would be very helpful!
As stock the DAC uses the following opamp setup (all swappable via DIP8 sockets)
I/V Stage = 4 x NE5532P
Low pass filter stage = 2 x NE5532P
RCA Output buffer = 1 x 4562NA
XLR Output buffer = 2 x 4562NA (I don't use the XLR outputs, so no need to change)
I have also read comments claiming the 49720HA is superior to the 4562NA/49720NA (same chip?) due to the metal cap shielding so that is the most obvious choice for upgrading the RCA output stage... I have also heard good things about the single version (49710HA) which I could incorporate using a dual TO99>DIP-8 adapter. This gets a bit more pricier though, so and I'm not sure it's worth the expense?
The NE5532P is widely reputed as cheaper/mass market chip and there is apparently more room for improvement here than anywhere else... so my main priority is to upgrade the I/V and LPF stages (which both use this chip - 6 in total).
A few users have reported excellent results using dual soic LME49990 DIP8s on adapters. I can get these from eBay:
DUAL SOIC LME49990 DIP8 ADAPTER | eBay
To upgrade all 6 will work out at £60. However I've read a few reports that these run very hot on the I/V section, and can oscillate if used on the LPF. Given that people use them regardless, is this a serious issue? Would it be a better idea stability to replace the NE5532s with 49720HA aswell?
Please bare in mind that the Xonar E1 DAC has swapabble opamp sockets through out, so I hope that the surrounding circuitry is designed to cope with different configurations as "upgrading" is encouraged.
Any advice would be greatly appreciated, I've been trying to get my head around this for a couple of days now - it's a real mindfield of information!!
Dawson
As stock the DAC uses the following opamp setup (all swappable via DIP8 sockets)
I/V Stage = 4 x NE5532P
Low pass filter stage = 2 x NE5532P
RCA Output buffer = 1 x 4562NA
XLR Output buffer = 2 x 4562NA (I don't use the XLR outputs, so no need to change)
I have also read comments claiming the 49720HA is superior to the 4562NA/49720NA (same chip?) due to the metal cap shielding so that is the most obvious choice for upgrading the RCA output stage... I have also heard good things about the single version (49710HA) which I could incorporate using a dual TO99>DIP-8 adapter. This gets a bit more pricier though, so and I'm not sure it's worth the expense?
The NE5532P is widely reputed as cheaper/mass market chip and there is apparently more room for improvement here than anywhere else... so my main priority is to upgrade the I/V and LPF stages (which both use this chip - 6 in total).
A few users have reported excellent results using dual soic LME49990 DIP8s on adapters. I can get these from eBay:
DUAL SOIC LME49990 DIP8 ADAPTER | eBay
To upgrade all 6 will work out at £60. However I've read a few reports that these run very hot on the I/V section, and can oscillate if used on the LPF. Given that people use them regardless, is this a serious issue? Would it be a better idea stability to replace the NE5532s with 49720HA aswell?
Please bare in mind that the Xonar E1 DAC has swapabble opamp sockets through out, so I hope that the surrounding circuitry is designed to cope with different configurations as "upgrading" is encouraged.
Any advice would be greatly appreciated, I've been trying to get my head around this for a couple of days now - it's a real mindfield of information!!
Dawson
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The soundcard is provided with the facility for changing the opamps because people like to change the opamps, it costs very little to socket them, and it probably swings a sale or two. The fact that people change them is indicative of the fact that people can't resist changing them, not that it results in any improvement or that there is any rational motivation whatsoever. People say that they can hear an improvement, but they hear these improvements under conditions which are known to result in unreliable observations. This doesn't stop them making the claims, or changing the opamps. That's people for you, or as I b'lieve they say in Yorkshire, 'There's nowt so queer as folk'.
If you could really get a significant improvement in measured performance by designing in different opamps, however, I think Asus would design them in. The NE5532s are cheap because they are produced in huge numbers, because they are very good.
If I had one of these Asus soundcards, I'd leave it as is. The only likely results of changing opamps are that the soundcard will run hotter, be less reliable as a result, may possibly oscillate and you will be £60 worse off. I think that's what AndrewT means, when he says 'don't'.
If you could really get a significant improvement in measured performance by designing in different opamps, however, I think Asus would design them in. The NE5532s are cheap because they are produced in huge numbers, because they are very good.
If I had one of these Asus soundcards, I'd leave it as is. The only likely results of changing opamps are that the soundcard will run hotter, be less reliable as a result, may possibly oscillate and you will be £60 worse off. I think that's what AndrewT means, when he says 'don't'.
What's the DAC chip in this device? If its the same as the Xonar ST which I think is PCM1792 then I found LM6172 the best upgrade amongst those I tried. It got even better when the feedback caps were reduced. There's already a thread about opamp rolling for the Xonar STX - http://www.diyaudio.com/forums/digital-line-level/216694-choosing-op-amps-essence-stx-i-v-stage.html
You raise some good points there counter culture - I tediously trawled through many pages on headfi thread and there is very little in the way of academic advice/guidelines with regards to what to upgrade. There are however a "try it yourself" mantra and tonnes of subjective user opinions, some of which seem happy to let their gear run hot/oscillate as it sounds so good(!)
The NE5532 seems to have a bad rep, despite the fact it's used in some top gear (e.g the Benchmark 1 DAC).
@abraxalito
It uses twin PCM1795 dacs, so is a bit of step up from the Xonar ST/STX. Funny you should mention the LM6172 - I've read: it's an extremely fast opamp, and there's a risk that you might come into stability problems and high frequency oscillation.
I've yet to buy an chips for the Essence one, but I've bought 3 for my STX last night... Decided on 3 x LME49720HAs to replace the poor(?) JRC2114Ds in the I/V stage. I chose because Asus used to sell their own "upgrade" kit which included two of the plastic LME49720NAs to do just this.
The NE5532 seems to have a bad rep, despite the fact it's used in some top gear (e.g the Benchmark 1 DAC).
@abraxalito
It uses twin PCM1795 dacs, so is a bit of step up from the Xonar ST/STX. Funny you should mention the LM6172 - I've read: it's an extremely fast opamp, and there's a risk that you might come into stability problems and high frequency oscillation.
I've yet to buy an chips for the Essence one, but I've bought 3 for my STX last night... Decided on 3 x LME49720HAs to replace the poor(?) JRC2114Ds in the I/V stage. I chose because Asus used to sell their own "upgrade" kit which included two of the plastic LME49720NAs to do just this.
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I've found the LM6172 is worth the effort because the sound is a step up above the typical audio range of opamps. If you were to put a spectrum analyser on the current steps emanating from the PCM DAC, you'd find the bandwidth extends into the 100's of MHz. Lynn Olson did this with a much older (hence considerably slower) DAC, the PCM63 and found a 3dB bandwidth of >20MHz. Audio type opamps really aren't designed to take such high amplitude wideband RF signals, the LM6172 is better suited.
I doubt that stability would be an issue where the layout already has planes for power as I expect the Asus has.
I doubt that stability would be an issue where the layout already has planes for power as I expect the Asus has.
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Thanks for the explanation - plenty to think about there! Do you use those for I/V stage or output buffer (or both?).
Since the LME49820HAs are on their way now I'll try those first - I bought another one for the output stage too as it seems like a logical step up from the stock 4562NA.
So I'll be running three of them vs asus's stock "upgrade" of 2 x LME9720NAs/ 1 x 4562NA.
Since the LME49820HAs are on their way now I'll try those first - I bought another one for the output stage too as it seems like a logical step up from the stock 4562NA.
So I'll be running three of them vs asus's stock "upgrade" of 2 x LME9720NAs/ 1 x 4562NA.
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Back when I was listening to my Essence ST I only used the 6172s for the I/V stage and kept the NJM2114 (I think) for output duty. But I've had good results recently building them into active filters. I have also modded a CS4398 DAC stage with them and they work OK driving line outputs but that's because the output stage there is also the differencing/filter stage.
Hmm interesting development... Asus are releasing a special "MUSE" edition using 6 x NJRC MUSE 01 opamps for the I/V and LPF stages:
6moons audio reviews: ASUS Xonar Essence One Muses Edition
It's considerably more expensive, so I checked out these chips are they're $50 each on digikey?! Wow, I sure hope they're worth the money - strange how Asus have gone for this seemingly little known estoric chip and not something reputable from Texas Instruments, Burr Brown et al.
6moons audio reviews: ASUS Xonar Essence One Muses Edition
It's considerably more expensive, so I checked out these chips are they're $50 each on digikey?! Wow, I sure hope they're worth the money - strange how Asus have gone for this seemingly little known estoric chip and not something reputable from Texas Instruments, Burr Brown et al.
Op Amps tried so far
Hi Guys
I have been playing around with different Op Amp combo's in my XEO for the last few weeks and thought I'd share some of my findings:
I started out by getting more LM4562's So I removed all the 5532's and replaced them all with the 4562's and then also replaced the XLR and RCA ones with LME49860's...this was already a major improvement over the stock setup, much warmer sound, more punchy and controlled bass, wider soundstage...general improvements throughout!
I then got my hands on some LME49720HA, the HA are TO-99 amps, but you can fir them by bending the pins slightly to fit the PDIP config, they are a definite improvement over both the 4562's and the 49860 in any of the slots, and they are highly recommended especially considering the price in comparison with some of the other chips out there. I continued to swap around between those chips in different combinations, and even tried it with all LME49720HA, the sound is a lot better than the stock setup, and considering that you can get these from around $5 they are definitely a good buy.
I then also got two OPA2107, and I have to say that the combination between them and the LME49720HA are a really good sounding setup, currently I have mine configured using
4 X LME49720HA for the I/V
2 X OPA2107 for the Low Pass
2 X LME49720HA for the XLR buffer(what I am mostly using)
I am using a balanced set of Senn HD650, and a balanced set of Beyer DT880(600Ohm) and this setup is really the best I've had so far. Good Tight bass on both, clean clear midrange, and nice warm highs, and the soundstage is as good as I've had it with both sets of headphones.
I am currently waiting for more OPA2107's to arrive, and also have ordered a pair of OPA2111's will post an update once I've played around with them as well.
Hi Guys
I have been playing around with different Op Amp combo's in my XEO for the last few weeks and thought I'd share some of my findings:
I started out by getting more LM4562's So I removed all the 5532's and replaced them all with the 4562's and then also replaced the XLR and RCA ones with LME49860's...this was already a major improvement over the stock setup, much warmer sound, more punchy and controlled bass, wider soundstage...general improvements throughout!
I then got my hands on some LME49720HA, the HA are TO-99 amps, but you can fir them by bending the pins slightly to fit the PDIP config, they are a definite improvement over both the 4562's and the 49860 in any of the slots, and they are highly recommended especially considering the price in comparison with some of the other chips out there. I continued to swap around between those chips in different combinations, and even tried it with all LME49720HA, the sound is a lot better than the stock setup, and considering that you can get these from around $5 they are definitely a good buy.
I then also got two OPA2107, and I have to say that the combination between them and the LME49720HA are a really good sounding setup, currently I have mine configured using
4 X LME49720HA for the I/V
2 X OPA2107 for the Low Pass
2 X LME49720HA for the XLR buffer(what I am mostly using)
I am using a balanced set of Senn HD650, and a balanced set of Beyer DT880(600Ohm) and this setup is really the best I've had so far. Good Tight bass on both, clean clear midrange, and nice warm highs, and the soundstage is as good as I've had it with both sets of headphones.
I am currently waiting for more OPA2107's to arrive, and also have ordered a pair of OPA2111's will post an update once I've played around with them as well.
Hi Bob
At the moment I'm only using it as a portable headphone amp, but I have balanced my headphones, and I am using the XLR outputs, I must say that it does a great job, especially after rolling the opamps. One thing I need to mention is that I am using the BeyerDynamic DT880 600Ohm cans, and these can be a problem to drive properly, and the XEO does it with ease.
I'm planning on building two poweramps probably next year, which I will also drive from the XLR's, I have some decent speakers at home, but my amp gave up earlier this year...so till then it's all cans for me!
At the moment I'm only using it as a portable headphone amp, but I have balanced my headphones, and I am using the XLR outputs, I must say that it does a great job, especially after rolling the opamps. One thing I need to mention is that I am using the BeyerDynamic DT880 600Ohm cans, and these can be a problem to drive properly, and the XEO does it with ease.
I'm planning on building two poweramps probably next year, which I will also drive from the XLR's, I have some decent speakers at home, but my amp gave up earlier this year...so till then it's all cans for me!
What's the problem you have found?
Insufficient voltage drive, or something else?
Thanks, both the Xonar and the headphones are very impressive. It will be interesting to hear about the results when combined with a good amp. Pleas let us know when you get close to that phase. I've been close to pulling the trigger on the purchase of a Xonar unit of some type for over a year. These posts may just push me to give it a try.
Edit: Did you DIY the balancing of your phones or use a commercial unit?
Edit: Did you DIY the balancing of your phones or use a commercial unit?
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DIY'd both...got some Mogami Cable on th DT880's and the stock Sennheiser Cable is already quad, just had to replace the TRS connector with two XLR's...I can honestly say if you can get the Xonar at a good price it is one of the best buy's especially for the fact that if you don't like the why it sounds you have a whole slew of option as far as Opamp combinations go, and then add the fact that is balanced as well, and supports 192khz, etc etc, it's definitely worth it! 
What does this mean?
Are you talking about a lack of amperes or a lack of volts or a lack of watts?
I like the idea of using op-amps in parallel for DAC output. For example a pair of stereo op-amps run as a pair of mono parallel amplifiers. There's lower noise and greater linearity when driving heavier loads, such as headphones. I think the "sound of" plentiful current headroom is a lovely upgrade. The silver output jack on the M-Audio Revo that Ostripper likes, does have this form of plentiful current headroom.
A DAC equipped like this won't be needing an added buffer, and thus an extraneous stage is eliminated. It may still need a preamp due to low voltage.
A DAC equipped like this won't be needing an added buffer, and thus an extraneous stage is eliminated. It may still need a preamp due to low voltage.
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