The Opamp thread
Jul 5, 2009 at 6:50 PM Post #16 of 7,383
Quote:

Originally Posted by Pluto2 /img/forum/go_quote.gif
Oh, I noticed that Jim Williams recommended LT1352 for filtering applications (which I need) since its input bias current is low (for BJT opamps) while LT1358 with high bias current is not suitabe there.....

Or any better suggestion other than LT1352 for filters?



What kind of filtering?


Quote:

BTW, any opamp has interesting quality for mid and bass?


Definitely the LT1469 for me, but also the LT1355, not to mention the LT1358
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I love the LT1355... without direct comparisons, it seems to be the most precise of the 13xx series. If you look at the harmonic distortion, it does have the least amount especially at high frequency.
 
Jul 6, 2009 at 6:09 PM Post #22 of 7,383
Quote:

Originally Posted by Pluto2 /img/forum/go_quote.gif
Thanks hopeless,
But what happened to your beloved LT1355?
And you don't like lt1352, why? Is opa2211 good for filtering, I thought the input current was not low, yes? ..



I'm listening to my DAC with the LT1355 still inside... Sounds great.


I didn't suggest it just because the higher quiescent current of the LT1358 and LT1364 may make them more suitable for driving heavy loads well (just in case).

While for filtering the LT1355 may not have a input current low enough. Yes the OPA2211 has low input bias current, equal to that of the LT1352. The LT1469 has it even lower, as low as the LME's.


I don't recommend the LT1352 because comparing the various steps of 'speed reduction' by lowering the internal bias levels, i.e. comparing the graphs in the datasheets
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, it is obvious that the LT1352 doesn't have a quiescent current that allows for the best distortion performance of this series's topology. It looks like the LT1357/8 and LT1354/5 are the sweet spot (for line level applications at least). I prefer the neutrality of the LT1355 to the slight exhuberance of the LT1358.
 
Jul 7, 2009 at 8:52 AM Post #23 of 7,383
Although it has been some time since I listened to it, I seem to recall finding the LT1358 fairly clear yet somewhat thin sounding and preferring the perhaps more neutral LM/LME parts from National (and later preferring the OPA211). Haven't tried the LT1355. The OPA2211A should be arriving shortly, so hopefully I'll have some impressions soon.
 
Jul 7, 2009 at 9:21 AM Post #24 of 7,383
Quote:

Originally Posted by 12Bass /img/forum/go_quote.gif
Although it has been some time since I listened to it, I seem to recall finding the LT1358 fairly clear yet somewhat thin sounding and preferring the perhaps more neutral LM/LME parts from National (and later preferring the OPA211). Haven't tried the LT1355. The OPA2211A should be arriving shortly, so hopefully I'll have some impressions soon.


Depends on your system and your preferences for tonality. Changing the LM4562 with the LT1355 I heard Leonard Cohen's voice fuller (and smoother) rather than thinner. It (and the LT1358) does have a more open sound than the LM/LME that may make it sound thinner with records that are pushing the mid-treble forward by themselves.

The LT1355 from memory should be cleaner than the LT1358, because the latter has a slightly accentuated midbass (at least @ 12V).


Regarding the OPA211, it's fine sounding except that it has a peculiar coloration that makes vocals (especially female) sound a bit too creamy. I'll try the OPA2211 as well, and compare with the LT1355, as soon as those adapters arrive...



EDIT- also the LM/LME's have, IMO, an overly smooth upper midrange that may sound audiophile perhaps but IMO is not quite right. On the contrary the treble is a bit spiky. Audiophile indeed.
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Jul 7, 2009 at 10:22 AM Post #26 of 7,383
^ AD843 is definately a contender in my book. AD744's (on OBCA adapters) are another contender. I also like the AD797's and starting to get into most of the better LT chips lately.

Having a P3 and P3+ gives me plenty of options for rolling but like most of you guys I have my favourites.
 
Jul 7, 2009 at 10:50 AM Post #27 of 7,383
My friend has tried quite a number of opamps and his favorite is AD843sq for his Promitheus DAC....

I don't have a feel if an input bias of 60nA (175nA max) for opa2211 is going to hurt the filter...while LT1352 is 20nA(50nA) and LME49860 is 10nA(70 nA)...., otherwise using opa2211 in that area would be quite tempting
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Maybe it's all system dependent? I did replace a LM4562 with LT1358. I think LT1358 has better clarity and spatial resolution and sweeter voice....
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Jul 7, 2009 at 11:20 AM Post #28 of 7,383
Quote:

Originally Posted by Pluto2 /img/forum/go_quote.gif
Maybe it's all system dependent? I did replace a LM4562 with LT1358. I think LT1358 has better clarity and spatial resolution and sweeter voice....
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I definitely don't disagree.
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BTW the LT1355 is wonderful also with Jolie Holland's latest "The living and the dead", another familiar record. That it sounds completely different (including tonality) from the former record I'd been listening to, is proof of the LT1355 transparency & coherence.
 

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