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Post by Deleted on Jan 6, 2012 10:20:13 GMT
Hi Mick, Is the above meant as, better than the on board amp of the Asus, or just different i.e. more to your taste? Ta. (I still think it looks dead tasty) Hi Chris, Lets put it this way!! If i had purchased this Assus purely as a HP Amplifier, i would be more than satisfied with its performance, as a dac- Amp combination it has to be one of the best buys i have ever made, remarkable value. I`m very careful not to go into too much detail regarding how Amps sound, all my Amps produce good results, but work at there best with different HP and source combinations to MY ears, but perhaps not to everybody elses taste. A typical example here is the fact that your not keen on the Portapro`s where as i love them, combined with my Neco portable-iPod they are my most used HP set up at present. However, i do think most of us regardless of hearing "taste" would agree when something, either HP`s or Amp, just sounds rubbish. Trust me, this Assus is an excellent, beautifully made piece of kit, and an absolute bargain for the price, infact i would be more than happy if i had paid twice the asking price. I would thoroughly recommend this Assus to anybody with only a few hours listening under my belt, time will tell of course how it will fair in the reliability stakes, but i have no reason to doubt it will stand the test of time, as all there other products certainly have ( i had used an Assus Essence ST internal sound card on my old pc, which has now been passed on to Javier still giving excellent results). So in answer to your question, so far i find the combination of Sunrise+Assus almost "perfect" to my ears driving the PS1000`s, although the Assus gives fantastic results driving my HD800`s from the onboard Amp. Still have a few different Amp- HP combinations to try over the coming week or so, which should be interesting, and yes you are right, it looks much nicer in the "flesh" and oooooozes quality. Hope this helps, as being "technically challenged" i have to go by what my ears are telling me. Mick.
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Post by Deleted on Jan 6, 2012 10:36:01 GMT
The 49710 would be ruled out because is single (unless used in a 2 x single -> dual adapter, IMHO rather pointless). The role this opamps play is I to V conversion and Low Pass Filtering, I've no idea what parameters need to be optimized for each one. Maybe different ICs are required for each job. TI uses the cheap NE5532 or NE5534 in their spec sheets for most of their DACs (sometimes they mention 2604 or 2132) but I've read somewhere that they do it, use cheap parts, to encourage far east manufacturers to use their products. ESStech mention AD797 in their Sabre DAC evaluation board schematic for both I/V and LPF and maybe they wil be a good starting point (BrownDog adapters needed) or even the LME49990 (also on BrownDogs).
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Post by Deleted on Jan 6, 2012 10:52:10 GMT
Javier I did of course mean the LME49720 which is the new name for the LM4562. With more upmarket chips you may need to play around with bypass caps .OPA2132 or OPA2134 could be worthwhile trying too Alex
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Post by Deleted on Jan 7, 2012 21:30:21 GMT
Update. After listening exclusively to the on-board Amp, both through usb and co-axial input for 5hrs today, IMHO this amp is better than all my other Amps except one. I love this dac.
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Post by Deleted on Jan 7, 2012 22:22:28 GMT
Update. IMHO this amp is better than all my other Amps except one. That's not fair - don't keep it to yourself, which one beats it?
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Post by Deleted on Jan 8, 2012 14:07:07 GMT
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Post by JohnnyBlue on Jan 9, 2012 12:36:56 GMT
And it's getting cheaper all the time... (Sadly, I'm just going to have to drool over this, and no more. SWMBO has noticed "the number of little boxes around the PC has been multiplying".)
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Post by Deleted on Jan 9, 2012 20:38:23 GMT
I have ordered 6 sets of the LME49990`s mounted on adapters to try, read a few possitive reports on their performance since you mentioned them Javier, so will swap them out with the NE 5532 when they arrive from the States. That`s a good price for that ONE John, but i have to ask why would you go to the bother of downloading the latest firmware into a "brand new" unit just to sell it on, when it takes just 10 mins to download and install yourself. Mick.
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Post by Deleted on Jan 9, 2012 21:06:50 GMT
Hi Mick,
The LME49990's are single opamps and the NE5532 is a dual opamp. I take it 2 of the LME49990's are mounted on one dual opamp adapter (and that's what you mean with sets). If a single opamp is mounted on a single SOIC to DIP adapter they are not going to work.
NE5532 is a cheap but good performing amp. The LME49990 is a very high performance amp. Judging from the PCB pictures using them should be trouble free (if on a dual single SOIC to 8-DIP converter). Noise floor might be lowered a tad (max a few dB)
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Post by Deleted on Jan 9, 2012 21:47:23 GMT
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Post by Deleted on Jan 9, 2012 22:33:11 GMT
Hi Mick, The LME49990's are single opamps and the NE5532 is a dual opamp. I take it 2 of the LME49990's are mounted on one dual opamp adapter (and that's what you mean with sets). If a single opamp is mounted on a single SOIC to DIP adapter they are not going to work. NE5532 is a cheap but good performing amp. The LME49990 is a very high performance amp. Judging from the PCB pictures using them should be trouble free (if on a dual single SOIC to 8-DIP converter). Noise floor might be lowered a tad (max a few dB) Hi Frans, nice to hear from you. Yes thanks for that, nice to get your thoughts on them, i`m hoping they sound as good as they perform!!, and yes Javier has confirmed that i have indeed ordered the right configuration. Hope all is well with you an yours, my Champ amp kit is about to start assembly, thanks to Javier on that, in return for enclosure work for his. ATB. Mick.
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Post by Deleted on Jan 10, 2012 13:09:25 GMT
Mick, Javier and Frans, As I have the PCI card version of this which also has interchangeable op amps I would be interested in exploring the options for op-amp swapping perhaps in the future. I would be interested in knowing the correct spec of these op-amps for my PCI card, where can these be sourced and at what cost please, if you'd be so kind. TIA, Dave.
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Post by Deleted on Jan 10, 2012 14:19:21 GMT
Dave, for source and price check the link I gave 3 posts above this one. You can use those ones.
Your ST only has one DAC IC (BB PCM1792A) instead of two like Mick's Essence One (2 x BB PCM1795) so you'll find 3 opamps and not six like in his case. In you soundcard there are 2 x JRC2114D for I/V and 1 x LM4562 for buffer/LPF. The stock opamps for I/V could be replaced by the ones Mick got but for the buffer/LPF the stock opamp is a LM4562 which is better than the NE5532s in Mick's Xonar and maybe is not worth changing. The LME49990 has better specs than the LM4562 but the latter's are already very good so maybe you can it leave it "as is" and save $19.
Cheers
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Post by Deleted on Jan 20, 2012 11:42:29 GMT
I have just changed the six 5532 op-amps for the LME 49990`s, will let them burn for a while but initial impression is wow!! "this sounds great". I can highly recommend the guy who supplied these op-amps, cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=190629659561They were beautifully put together, superbly packaged(only Mike has ever sent me his products packaged and presented as well as this). Will give a more informed report of their performance when they have had a few more hours burn-in time. Happy bunny Mick.
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Post by Deleted on Jan 20, 2012 12:56:05 GMT
Those opamps do indeed look fantastic quality, if they sound only half as good it is no wonder you are a happy bunny!!! Congrats Mick
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mrarroyo
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Post by mrarroyo on Jan 21, 2012 14:55:13 GMT
I found the sound of the NE5532 to be very nice and any bad rep they get is from (IMO) over zealous users. The AD797 is another op-amp I enjoy a lot but do not know if they would work in this unit. Regardless enjoy your new toy.
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Post by Deleted on Jan 21, 2012 15:19:14 GMT
Yup, can`t argue with that Miguel, the AD797 is another one that i will try at a later date, happy with the LME 49990`s at the moment though!!.
Mick.
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Post by Deleted on Jan 21, 2012 22:00:18 GMT
If you use iTunes and listen mainly to 16/44.1 .flac you could also try a couple of LM741s on browndog adaptors.
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Post by daws0n on Sept 24, 2012 9:35:30 GMT
Hey fellas, Hope you don't mind me bumping up an old thread, but I've a couple of questions about opamp rolling the E1 DAC... Mick's upgrade looks great, but I've been digging through some of the fat on the huge thread over at headfi: www.head-fi.org/t/542563/asus-essence-one-headphone-amp-dac-cebit-2011And apparently running 4x LME 49990 on the I/V stage can get very hot.... Also when used on the low pass filter someone measured oscillation (this was also the case with the AD797). Is this a major issue? In light of this I am considering upgrading the NE552s with metal topped LME9720HAs instead (asus recommend the sibling LME920NA/LM4562NA in their opamp rolling guide too so I'd assume they're more stable?). What do you guys think? Presuming the LME 49990 is an audibly superior chip is it worth the compromise in stability?
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Post by Deleted on Sept 24, 2012 9:59:46 GMT
DawsOn Running quite hot can be due to oscillation, and is normally due to inadequate supply bypassing or poor layput.Not only can it sometimes result in a gritty or veiled sound, it isn't good for device longevity. The LME49720HA/LM4562 have half the gain bandwidth product (55MHZ typical) and you are unlikely to have stability problems with them given reasonable precautions. Alex
From the LME49990 Datasheet: SUPPLY BYPASSING To achieve a low noise and high-speed audio performance, power supply bypassing is extremely important. Applying multiple bypass capacitors is highly recommended. From experiment results, a 10ìF tantalum, 2.2ìF ceramic, and a 0.47ìF ceramic work well. All bypass capacitors leads should be very short. The ground leads of capacitors should also be separated to reduce the inductance to ground. To obtain the best result, a large ground plane layout technique is recommended and it was applied in the LME49990 evaluation board.
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Post by daws0n on Sept 24, 2012 10:13:48 GMT
Very informative Alex, thank you very much!
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Post by Deleted on Sept 24, 2012 16:30:10 GMT
Very informative Alex, thank you very much! Yes it does get warmer running the 49990`s over the standard 5532`s, usually have it powered up for 3-4hrs, in which time the top casing is only warm and certainly not hot to the touch. I did on one occasion leave it running for 24hrs by accident, but still the top cover remained comfortably but not alarmingly hot to the touch. My unit now has something like 400hrs of use on it with the 49990`s, without any issues, and sounds extremely good. How would oscillation reflect in the SQ of this unit, as everything sounds as it should to my ear.!!!! Mick. PS. I am also running 2X 49990`s on a single adapter in my HiFiMAN EF5, with no "ill effects", which is also sounding great.
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Post by Deleted on Sept 24, 2012 19:07:35 GMT
Mick,
You can only tell by putting your finger on the opamps themselves to see if it is relatively hot compared to other ones. The adapter itself and the way it is made (wired) and or decoupled also determines if those opamps start to oscillate or not.
As Alex already mentioned extreme decoupling is needed including a really good PCB layout (with proper ground planes) to get these to work correctly. This should be done as close as possible on the pins (on the brown-dog in this case). Relatively long wires (and I am talking about millimeters in this case) MAY be problematic in certain cases. The relatively long wires and sockets with rather large surface area wiring/pins close together can easily make them oscillate. It all has to do with the speed V/us, bandwitdth, amount of feedback, input and output conditions (stray) capacitances, impedances. If any of those conditions isn't O.K. things might not work as it could/should.
I am willing to bet a substantial sum of money on the fact that MANY of the DIY'ers are listening to gear that oscillates and never will even hear, notice or know it, or might even like what it does to the sound and see it as an 'asset' or 'property'.
depending on the severity (amplitude) and frequency it may or may not become audible. Opamps can even oscillate without getting warm at all b.t.w. the test I recently did with a C'Moy shows this and I could only see the oscilations on the scope and not hear it (around 600kHz) and had no influence on the sound at all. Also there are LOTs of soundcards and players/DAC's around with even bigger amounts of RF garbage on it's output and no-one hears that. These (way beyond) ultrasonic frequencies are not reproduced in any case by any transducer.
Alex does also have a point about longevity of an oscillating device, also when these devices oscllate that will also be on the powersupply lines of the circuit FOR SURE. No telling how and if other components on that same powersupply circuit might be affected.
For instance oscillations MIGHT interfere with clocks or digital signals or might introduce a DC offset somewhere because the 'carriere wave' is rectified (detected as in a radio receiever detector circuit) by PN crossings in semiconductors.
Only an oscilloscope OR perahps a world-radio (LW to SW) could tell by holding it close and listening out for 'strong' radio signals that have no modulation (sound) and 'disappears' when the amp is turned off.
If you don't hear it and it works O.K..... don't worry about it.
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Post by daws0n on Sept 24, 2012 20:01:11 GMT
Cheers solderdude, that was a good read My ultimatum is: Do I shell out on the LME9990s as Mick has done and just enjoy the music.... Or, spend half the ££ and settle for the more stable/less fussy LME49720HAs instead? IMO, asus should provide more comprehensive feedback/advice on which opamps work and which ones don't. They have a small list on their site along with subjective listening impressions... They state that swapping positions between the LME9720 and LM5462NA changes the sound, quite funny really considering they're both the same chip
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Post by Deleted on Sept 24, 2012 20:07:00 GMT
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