Commercial available discrete OP-AMPs - Overview wanted - diyAudio
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Old 16th October 2014, 04:00 PM   #1
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Default Commercial available discrete OP-AMPs - Overview wanted

There are many threads concerning discrete operational amplifier - here some examples:
Pass Discrete Opamp in DIP-8 Package (BF862)
AD797 discrete clone - comparison of seven variations
Anyone have made those diy discretes op-amps ?
Discrete OPAMP
discrete opamp help
My discrete opamp
discrete op amp
Yet another discrete op-amp
Discrete cfp (op-)amp
discrete op amp
Improved discrete op-amp
Discrete LM3875 ?
Are Discretes Better Than Chip Amps?
IC's vs Discretes
Discrete opamp vs regular op amps
Anyone have made those diy discretes op-amps ?
TL071 hand-made simulation using discretes
My take on a **buildable** Discrete Op-Amp...
Simple 60dB discrete low noise amplifier (lna)
Need help with discrete op amps.

But I want to know commercial manufacturers of discrete op-amps with highest sonic quality - maybe like Burson
Logitech Transporter - what a stunner! - pink fish media
http://www.seventhcircleaudio.com/OpAmps/sc99_about.htm
http://sparkoslabs.com/discrete-op-amps/
http://newclassd.com/index.php?page=55
http://www.johnhardyco.com/990OpAmpDetails.html
http://www.sg-acoustics.ch/analogue_...screte_opamps/
http://www.purpleaudio.com/discrete-opamps/
http://fivefishstudios.com/diy-kits/...discrete-opamp
http://www.hairballaudio.com/shop/pr...6TbK1ZGULz5T52
http://mnats.net/JE-990.html
http://www.hellotrade.com/sound-skul...te-op-amp.html
http://www.tonelux.com/opampinfo.html

Thank you for your advices.

Last edited by tiefbassuebertr; 27th October 2014 at 11:02 AM.
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Old 27th October 2014, 11:02 AM   #2
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no advices?
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Old 12th January 2015, 03:59 PM   #3
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Are there discrete devices available for the no longer produced AD846? Check out this thread:
AD 846 replacement
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Old 24th January 2015, 02:43 PM   #4
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diyaudio member "Wavebourn" describes an interesting topology particularly for unity gain line preamplifier, where are long connection lines go to mono power amps. Only a push-pull darlington arrangement is in use together with some diodes. Go therefore to post #332+336 from follow URL:
Addressing John Curl's concerns on low noise designs
and the NUCLON thread about
NUCLON -- My first hybrid guitar amp
The mentioned RF diodes KD213 (KD213A, КД213А) are only available as NOS parts. What currently available diode can replace this old ones?

Last edited by tiefbassuebertr; 24th January 2015 at 02:49 PM.
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Old 24th January 2015, 05:23 PM   #5
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also of interest:
Discrete Opamp Open Design
discrete opamp class A
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Old 25th January 2015, 12:01 AM   #6
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No disrespect intended, but why a discrete op amp? There are some pretty amazing monolithic op amps available now that greatly exceed the performance of any discrete op amp I've seen, if cleanliness is your goal.
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Old 25th January 2015, 01:10 AM   #7
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Quote:
Originally Posted by Monte McGuire View Post
... why a discrete op amp? There are some pretty amazing monolithic op amps available now ...
I can't speak for others but for me, I like the ability to choose the compensation network myself. This is not possible with monolithic op amps. In particular, I like to set the phase margin at unity gain crossover, according to MY criteria. Monolithic 350 MHz GBW opamps seem to be engaged in a marketing war where GBW is maximized and phase margin is minimized, simply in order to claim a higher GBW on the datasheet, than The Other Guy.

It was a joy to listen to Scott Wurcer's presentation on discrete opamps at Burning Amp 2013 in San Francisco. He showed us that the industry has been building and shipping GBW= 1 GHz discrete opamps for 30 years (!). If grandpa could do it then, I can do it now. My own personal preference is to overcompensate and "squander" a factor of 8 in GBW, taking me down to "only" 125 MHz of GBW. But the phase margin! Oh the phase margin! How delightful.

You, of course, may feel differently.
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Old 25th January 2015, 01:58 AM   #8
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Quote:
Originally Posted by Mark Johnson View Post
I can't speak for others but for me, I like the ability to choose the compensation network myself. . . .
I've heard others mention a similarly-motivated desire to adjust output-stage bias (and/or protection network) for driving particular loads, and optimizing the input stage operating points for particular signal sources.

Dale

p.s. - There does seem to be some datasheet specsmanship in various corners of the industry. Be sure to look carefully at the measurement conditions for whatever parameters you are comparing from one manufacturer to another - and sometimes you need to "read between the lines" of datasheets to infer these conditions. You may find that the published values reflect operation under the most favorable conditions, or even conditions that are unreasonable in practice.
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Old 26th January 2015, 05:18 PM   #9
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Quote:
Originally Posted by Monte McGuire View Post
No disrespect intended, but why a discrete op amp? There are some pretty amazing monolithic op amps available now that greatly exceed the performance of any discrete op amp I've seen, if cleanliness is your goal.
Because nobody is able to determine the idle currents (quiescent current) at each internal transistor, if there is an integrated op-amp in use. Additional there is no possibility to optimize the compensation dependent of the wanted gain factor and the open loop gain factor.
Another great issue (at least for me) is to find out the appropriate type (e. g. at Analog devices or TI resp. NS), because the special features are often not mentioned or mentioned incomplete. This means, anybody must study all details in the datasheet for finding out only a single difference.

Last edited by tiefbassuebertr; 26th January 2015 at 05:25 PM.
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Old 26th January 2015, 05:40 PM   #10
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Another advantage of using a discrete op amp is that that you can chose the the devices such that you are not limited to +-18 or +-22V.
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