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Old 7th February 2009, 04:53 PM   #21
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Superb, Calvin !! ... what he said.
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Old 15th February 2009, 03:34 PM   #22
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Quote:
Originally posted by FastEddy
Superb, Calvin !! ... what he said.
Seriously, some of you guys don't get it. Can you not read what I posted? Seriously? I already said I have 20 years DIY experience! You think I need you to tell me capacitors sound different? Maybe you guys need help more than I do!!

I already made it clear - the part I am unfamiliar with is the actual op amps. I also said, I wanted simple, subjective input: "I like the sound of this or that." I am perfectly capable of reading spec sheets... I don't need anyone to quote slew rates for me.

I really don't understand what is so difficult about this... I can only imagine how little help a newbie would get? Probably none. Why are there links to schematics when I said I don't need any input on topology?

There have been a few helpful posts, but I have to admit, they are marred by the rest. I am a little shocked at how utterly unhelpful some of the responses have been to such a simple question... maybe some of you are spending so much time on the technical side of things you forgot you're supposed to enjoy the music -- and have opinions on what sounds best?
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Old 15th February 2009, 03:42 PM   #23
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" ... Single channels for great separation, dual channels for easy circuit design ... "

" LME49720 -- $4.53 = "Dual High Performance, High Fidelity Audio" ( http://www.national.com/pf/LM/LME49720.html ) ... low THD+N and a good slew rate.

LM4562 -- $4.53 = Ferd's likes 'em enough to be a part of a "mod" upgrade to NAD CD player ( http://www.ferdsaudio.com/CDmods/C542.htm )

AD826 -- $5.60 = Op-amp input as part of A to D converter ... not for the playful or faint of heart. ( http://focus.ti.com/docs/prod/folders/print/ads826.html )

AD823 -- $5.90 = "" ""

AD797 -- $8.76 = Single channel for Instrumentation use ... very good specs but at least 2 req. for audio ( http://www.analog.com/en/other/mili...ts/product.html )

AD711 -- $2.66 = single channel instrumentation amp, again, best to look at the AD712 ( http://www.analog.com/en/prod/0,2877,AD712,00.html ). IMOP Analog makes some of the best, but steal your circuit suggestions from TI or National = they cheat and the overall results may be equal or better.

OPA228 -- $5.02 = TI / Burr-Brown = http://focus.ti.com/docs/prod/folders/print/opa228.html ... always a good choice, can't go wrong ( http://www.ti.com/lit/gpn/opa228 )

OPA227 -- $3.53 = """ """

OPA37 -- $2.57 = "Ultra-Low Noise, Precision ..." = http://www.ti.com/lit/gpn/opa37.pdf or search

TLE2071 -- $1.75 = "Excalibur Low-Noise High-Speed JFET-Input ..." JFET is GOOD, but a [bear] to get perfect "
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Old 16th February 2009, 07:35 AM   #24
Calvin is online now Calvin  Germany
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Hi,

actually I really donīt know what You want any more. I answered Your question in the most precise way possible and even added a schematic, so that You knew what it was all about. But You start offenses.
I assume You donīt want to get knowledge but just absolution for Your ideas. But this is not the catholic church and no one here is the high priest. If You think that there is a sonic quality to OP amps that can be noticed without keeping schematics, layout and other surrounding stuff in mind, than go ahead, but donīt start insulting those who donīt share Your idea. Even they invested time and effort to help You avoiding failures. So thereīs no reason to get offensive.

There have been so many threads abot OP-sound in different applications, that there is hardly a need for another one. I suggest You start reading those threads If You need anybody to tell You what to like. But donīt be surprised that one OP will sound very different to different listeners. The technical quality of most of the recommended OPs is so well, that ist is very much a matter of taste and not a matter of īBetter or worseī. Do You have the guts to stand up to Your own taste?
Quote:
I'll take someone's opinion with a good ear over a technical argument any day.
Now who could that be? The guy from Down under? The smart east asian guy? Who has the golden ears You trust, without having met him once?

jauu
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Old 16th February 2009, 05:10 PM   #25
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calvin: " "I'll take someone's opinion with a good ear over a technical argument any day." ... Now who could that be? The guy from Down under? The smart east asian guy? Who has the golden ears You trust ... ?"

Well, I'm a bit prejudiced ... favoring TI, Analog and National, mostly for their great tech support and plethora of suggestions for circuits.
Bob Pease ( http://www.national.com/rap/ ) is still my go to guy for this sort of thing, Don Lancaster ( http://www.tinaja.com/ ) having dropped away years ago as the Master Guru of anything analog and gotten twisted around the digital axle.) I'm 60+ so my ears may not be golden anymore ...
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Old 6th January 2010, 04:05 AM   #26
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Over the past year or so Ive built several phono preamps, a mic preamp and modded my cambridge audio cd player with a dip socket so I could swap op amps in its audio section. I feel completely vindicated about my original question, in that I have found the LM4562/LME4972 consistently to outperform the other popular duals in all of the pieces. It just sounds better. So to answer my original question, I would have said, yeah, check out the LM4562/LME4972. I have picked up some ad797s too but since they are not duals, I havent stuck them in anything yet, but I am looking forward to trying those out. I tried many duals, most were good or close to each other, yet still easy to identify. They all sounded different. I found the 5532 extremely fatiguing in my cd player.. to the point I said id never buy another one. Which made it's audio heritage a little odd to me... maybe people consider harshness detail? At any rate the LM4562/LME4972 was stellar in all applications, reducing the noise floor and providing a clean, pleasant sound. At $5 a pop it's an expensive dip, but in audio land that is nothing and it does deliver what it promises.
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Old 6th January 2010, 04:35 AM   #27
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I always thought the AD846 sounded the best. It's a single current feedback
type. Analog Devices doesn't make it any more, but you may be able to find
some. Also, a lot of more expensive main stream gear uses the OP275 from
Analog Devices. You may want to check that out (it's a dual). And then there is
the latest and greatest from Burr Brown... the OPA1612. It has most excellent
specs for everything, but I don't know how it sounds. It's a dual, so you can
easily swap it in your test rig and give it a listen.

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Old 6th January 2010, 06:17 AM   #28
Mooly is online now Mooly  United Kingdom
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I suspect that the NE5532 and 5534 used in CD players is not ideal. Found some reading on this and a theory was put that the bipolar opamp can become non linear due to the hf noise from the DAC when used as an I/V convertor. I too have found great improvement swapping from NE5534 to OPA604 and AD845 in a CD player.
However in more "linear" and "true" audio circuits I am less sure... the 5532 seems pretty good.
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Old 6th January 2010, 09:13 AM   #29
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Quote:
Originally Posted by FastEddy View Post
" ... Single channels for great separation, dual channels for easy circuit design ... "

" LME49720 -- $4.53 = "Dual High Performance, High Fidelity Audio" ( LME49720 - Dual High Performance, High Fidelity Audio Operational Amplifier ) ... low THD+N and a good slew rate.

LM4562 -- $4.53 = Ferd's likes 'em enough to be a part of a "mod" upgrade to NAD CD player ( FerdsAudio - NAD C542 )

AD826 -- $5.60 = Op-amp input as part of A to D converter ... not for the playful or faint of heart. ( Data Converters - Analog to Digital Converter - ADS826 - TI.com )

AD823 -- $5.90 = "" ""

AD797 -- $8.76 = Single channel for Instrumentation use ... very good specs but at least 2 req. for audio ( http://www.analog.com/en/other/mili...ts/product.html )

AD711 -- $2.66 = single channel instrumentation amp, again, best to look at the AD712 ( AD712 | Dual Precision, Low Cost, High Speed, BiFET Op Amp | Operational Amplifiers (Op Amps) | Amplifiers and Comparators | Analog Devices ). IMOP Analog makes some of the best, but steal your circuit suggestions from TI or National = they cheat and the overall results may be equal or better.

OPA228 -- $5.02 = TI / Burr-Brown = Precision Amplifier - Low Offset Voltage - OPA228 - TI.com ... always a good choice, can't go wrong ( http://www.ti.com/lit/gpn/opa228 )

OPA227 -- $3.53 = """ """

OPA37 -- $2.57 = "Ultra-Low Noise, Precision ..." = http://www.ti.com/lit/gpn/opa37.pdf or search

TLE2071 -- $1.75 = "Excalibur Low-Noise High-Speed JFET-Input ..." JFET is GOOD, but a [bear] to get perfect "
I have test in front of a Quad amplifier with triangle antal ES as speakers and a CD player as source the following AO :
LME49720
LME49710
OPA227
TLE2071
AD823
NE5532
each one with the recommended schematics from the producer .
The most crappy sound came from NE5532 which are most worse follow by TLE2071 .
The best was LME49710 .
On the second place was at the equal and cannot be recognise in blind test all 3 AO :
LME49720 , OPA227 , AD823.
So this is my top made with my own ears.
Also I have try some BUF from BB : very good AO !!!
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Last edited by danzup; 6th January 2010 at 09:21 AM.
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Old 6th January 2010, 03:47 PM   #30
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danzup: "I have test ... each one with the recommended schematics from the producer ...

The most crappy sound came from NE5532 (older, legacy design ...) which are most worse follow by TLE2071 (A real bear to get right = broad bandwidth, JFET input. ).

The best was LME49710 (single channel).

... second place was at the equal and cannot be recognise in blind test all 3 AO : LME49720 (dual channel), OPA227 (single channel) , AD823 (dual channel)

So this is my top made with my own ears. "

Thanks for all the effort ... Your ears are probably well "burned in" by now.

Dual channel usage = filters, I/O matching, signal splitting, signal breakout, unbalanced to XLR. ... Discrete, single channel op-amps = better stereo separation.

Last edited by FastEddy; 6th January 2010 at 04:03 PM.
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