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The Opamp thread - Page 314

post #4696 of 4703
Quote:
Originally Posted by razzz42 View Post


Install it, turned it on and I go, "What a waste of time and money this was." Lows were missing, highs were clear to the point of being shrill, mids nowhere to be found. If it needed breaking in, I doubted it would ever recover. Having the DIP 8 socket installed, I begin digging for some old standby opamps to checkout and discover I have two 49860NA in the mix. Go check the occupied DIP socket and confirm it is a 4562NA sitting in it and grab the eBay $5 special yellow handled opamp tweezer/removers and install the 49860NA and turn the system back on.



 



The difference is between night and day. Clarity with clean highs and lows and mids mixed right in between, nothing really stands out unless there is a flute playing or bass drum hit. Vocals are clear and true. If I am missing warmth or am hearing sibilance, hard to tell, may be the recording(s) but the great detail adds to the separation (staging).


 


Not even sure if this is a sarcastic or a "true hifist" message...
You do realise that LM4562 is pretty much same as LM49860NA, but with higher maximum voltage range and manufacture year?
If you actually managed to find differences, either of those opamps is probably fake and thats why it might sound a little different.
post #4697 of 4703
Quote:
Originally Posted by P701 View Post


Not even sure if this is a sarcastic or a "true hifist" message...
You do realise that LM4562 is pretty much same as LM49860NA, but with higher maximum voltage range and manufacture year?
If you actually managed to find differences, either of those opamps is probably fake and thats why it might sound a little different.

Here is some older discussions at DIY about this opamp lineup which I guess includes can variations. Seems the 4562 is a bit temperamental and could suffer from oscillations in the wrong environment which I am trying to avoid like with the 5532D and confirms the 49860 might be somewhat weak or not warm in the mid range but to my ears is crystal clear with the highs, for the lows I have an AD 8066AR handling those duties.

 

The 49860NA is labeled LME, 'E' for enhanced, whatever that means. I admit I have many opamps from Chinese/Hong Kong and anything is possible involving knockoffs. I also have a sub with BASH surround circuitry that will amp up the preamp input signal to an audiophile level where I can hear subtle differences via some decent speakers. And my starting point is a PCI sound card AUDIOTRAK Prodigy HD2 ADVANCE DE with LME 49990 on adapters buffered by LT1028ACN8 on an adapter. Checking my old notes, I have the LM 4562NA down as 'flat but true across the range' from previous sound card testing. It could be the 4562 just didn't like the position it was put in this time around.


Edited by razzz42 - 5/1/14 at 7:20pm
post #4698 of 4703

Anyone interested in a pair of OPA627SM op-amps for $100?

 

http://www.head-fi.org/t/718227/interest-check-pair-of-opa627sm-op-amps


Edited by zachchen1996 - 5/10/14 at 6:49pm
post #4699 of 4703

I've tried to get rid of a single genuine MUSES01 (obo $60) in this thread and it's like nobody trusts buying from people in this thread,

post #4700 of 4703
Hello all,

I really know nothing about opamps but would like to learn. I purchased the Leckerton Audio UHA 6S.MKII amp and it came with 4 sets of opamps. I have attached pictures of them. It appears they are the following opamps.

OPA209
AD797ANZ
LME49990MA
OPA627AP

Would anyone be able to tell me what to expect from them, or what characteristics they are know to have? Im still knew to the audiophile thing. I havn't spent much time with them, and so havn't noticed much differance. Im using the OPA627AP in my amp right now with my iMod and Beyerdynamic DT 880 250ohm cans. Thanks for the education guys! Im doing a lot of learning via the search function as well.

Sorry for the quality, the pics were taken with my camera phone redface.gif

sa4e4y6e.jpg
y6a9a3yn.jpg
post #4701 of 4703

there's hope if you're really interested in learning - hanging with your buds in this thread, looking for positive social feedback however...

 

if subjective evaluation is your focus then http://www.linearaudio.net/images/LA%20Vol%202%20Yaniger(1).pdf should be required reading - and practice - you really need 2 complete "blueprinted" (trimmed to exact same gain/frequency response, at least better than 1%, ~ 0.1 dB) systems/circuits to do real listening tests - and a blinding protocol

 

it also wouldn't hurt to learn enough electronics to recognize different op amp applications in audio circuits, have schematics of the equipment you want to mod - know the circuit conditions like source, feedback and load impedance, how these change "optimum" op amp specs

 

learn about construction details of PCB layout, op amp bypass, gnd planes/power routing (or lack of quality of same) which can rule out many fast op amps being stable when rolled into layouts that work for order of magnitude slower chips

 

 

hopefully my pointing this out every few thousand posts, in response to new participants, isn't going to derail the thread


Edited by jcx - 6/6/14 at 3:56pm
post #4702 of 4703
Quote:
Originally Posted by jcx View Post
 

hopefully my pointing this out every few thousand posts, in response to new participants, isn't going to derail the thread

 

Its still rolling along same as it ever has... 

post #4703 of 4703
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