I have now built up an Headphone amp with the NE5532 and the opa2134. It sounds amazing! But the noise is litle bit hearable. I think with the NE5532 its litle bit better but i am not sure!
Wich opamp you can suggest me with DIP8 socket and lower Noise than the other two above?
And generally whats the real difference between BJT and Fet Opamp? BJT have more current noise and FET more Voltage noise. Thats the only difference? How to decide wich do choose?
Wich opamp you can suggest me with DIP8 socket and lower Noise than the other two above?
And generally whats the real difference between BJT and Fet Opamp? BJT have more current noise and FET more Voltage noise. Thats the only difference? How to decide wich do choose?
Have you included a series resistor in the headphone feed ? Sensitive headphones connected directly will make noise audible, a bit like putting your ear to a tweeter fed from a power amp.
Bjt vs FET isn't always cut and dried. There can be added distortion with the FET device due its non linear input capacitance being modulated by the driving voltage. If the impedance is high the distortion can suffer a little.
The big big difference between bjt and FET is in the input bias currents. AT DC a FET inout draws essentially zero current, a bjt can be in the high micro amp or tens or hundreds or micro amps. That makes a massive difference to the DC offsets are created withi the circuit structure.
Bjt vs FET isn't always cut and dried. There can be added distortion with the FET device due its non linear input capacitance being modulated by the driving voltage. If the impedance is high the distortion can suffer a little.
The big big difference between bjt and FET is in the input bias currents. AT DC a FET inout draws essentially zero current, a bjt can be in the high micro amp or tens or hundreds or micro amps. That makes a massive difference to the DC offsets are created withi the circuit structure.
Yes I have a series 10 ohm resistor after the buffer output.
Then the FET have better DC offset characteristic and the bjt better noise performance?
10 ohm is pretty low... it might help if we saw the full circuit and all resistor values.
You need to understand why offsets occur before saying the FET is 'better'. An opamp like the 5532 has a bias current that can be as high as 800 nano amps (worst case) flowing out of the two input pins. Sounds small but 800na across say 100k develops 80mv. If the impedance seen by both inputs is identical, say both see 100k, then the offset is equal for both and the overall result is good. If one input sees 100k and the other 1k then an offset results. If the opamp stage has DC gain then the offset gets amplified by that factor as well.
The FET opamp has zero bias current and so can not generate that particular type of offset.
You need to understand why offsets occur before saying the FET is 'better'. An opamp like the 5532 has a bias current that can be as high as 800 nano amps (worst case) flowing out of the two input pins. Sounds small but 800na across say 100k develops 80mv. If the impedance seen by both inputs is identical, say both see 100k, then the offset is equal for both and the overall result is good. If one input sees 100k and the other 1k then an offset results. If the opamp stage has DC gain then the offset gets amplified by that factor as well.
The FET opamp has zero bias current and so can not generate that particular type of offset.
I remember a preamplifier i've built some years ago with a low noise double transistor LM394 as input stage of LM318 opamp. it was based on an Audiophile design. Power supply was +-15V and LM394 was polarized wit 120 uA. Intent was to have a low noise phono pre with 50 Mhz bandpass and 50v/uSec of SR. I've tried also a cascode fet input option but i've returned to transistor loaded by a simple resistor. Result was 85db S/N with pickup (a Shure V15, if a remember well), the noisy part of pre was the 47K resistor loading the input! Ineliminable.
not nV/rootHz.
I suspect JIS A is an equivalent to the A weighting we see.
That takes account of the rootHz part since it would band limit at both ends of the passband.
4nV/rootHz times sqrt(20kHz) gives very close to 0.56uV, the figure in the datasheet that I can see.
Multiply by your gain to find the output noise due to the opamp. Add on the noise due to the resistors on the input pins.
I suspect JIS A is an equivalent to the A weighting we see.
That takes account of the rootHz part since it would band limit at both ends of the passband.
4nV/rootHz times sqrt(20kHz) gives very close to 0.56uV, the figure in the datasheet that I can see.
Multiply by your gain to find the output noise due to the opamp. Add on the noise due to the resistors on the input pins.
AD797BRZ, AD8597ARZ. are the bestttzzz , try to find a mono for ad8597, hard to find!!!!!!!!!!!!
Now listening to prodigy hd2 through differential LM456NF , output is through AD8620 which is heat-sink mounted.
Sounds better than stock watever hifi motherboard, hifi? NOT.
Dac + only one ad8599 is the most transparent, forget the highly praised expensive 100$ piece 613... total crap.
(LM456 + ad8620 through HD600 is seriously good for solid state crap )
Now listening to prodigy hd2 through differential LM456NF , output is through AD8620 which is heat-sink mounted.
Sounds better than stock watever hifi motherboard, hifi? NOT.
Dac + only one ad8599 is the most transparent, forget the highly praised expensive 100$ piece 613... total crap.
(LM456 + ad8620 through HD600 is seriously good for solid state crap )
None of the above - looks like the back story is they're shutting down a whole fab.
http://www.diyaudio.com/forums/headphone-systems/280990-ti-discontinue-many-ics-new-post.html
http://www.diyaudio.com/forums/headphone-systems/280990-ti-discontinue-many-ics-new-post.html
The best sounding audio integrated opamps
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Simple:
For me AD826, LT1208, LT1358, LT1364, LM6172. All videoamplifiers!
Bipolar unity gain with full capacitance cable drive capability are always better than any JFET available on the market. And I haved tested many for many years...
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Simple:
For me AD826, LT1208, LT1358, LT1364, LM6172. All videoamplifiers!
Bipolar unity gain with full capacitance cable drive capability are always better than any JFET available on the market. And I haved tested many for many years...
AD846 - "precision CFA" didn't seem to find a market - too early?
but plenty available: Search Results for 'AD846A' | Rochester Electronics
Have to agree on LT1208 and LM6172. I would rate LT1361 better than LT1364, and it's also better behaved on stability. I'd also suggest giving AD8022, LT1057 and LT1213 a listen.
With a lot of the TI/NatSemi LME49xxx parts going to EOL status, it may be worthwhile to hoard a few of those as well, before the only ones that remain are EBay fakes.