The Opamp thread
Aug 29, 2018 at 5:09 AM Post #6,138 of 7,151

carlmart

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Not sure I fully understand the question, sorry. Line level means >1V RMS for at the source input of the amplifier, so most headamps are line input. Also, headamps THD and SNR is expresses at around 2V RMS input signal. Could you please be more specific?

I am referring to output voltage level. Of course you can use many opamps as headphone amps, but not all opamps can drive a headphone well.

Distortion demands are more critical on opamp that will feed a power amp, than on one that will drive a headphone. S/R and noise are not too important on a headphone amp, and they are on a line amp.

Some, including me, do not find absolutely necessary to use a line preamp between source and power amp, and modern sources are juicy enough to drive most power amps perfectly.

But I think that an output DAC chip does sound better if it's fast and low noise, besides having as low distortion as possible.


The price is just not right, feel free to remove the "." and you'll realize that too. :)

Why it's not right? Mouser is selling the 1622 for $6.

BTW, the NE5532 has the max. input voltage of Vcc+, where Vcc+ would be the positive voltage rail. I believe all audio opamps can get 1-2V RMS at their V+ or V- inputs without any issues, if that's what you're asking about.

Output level is what I mean, not input level.
 
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Aug 29, 2018 at 5:34 AM Post #6,139 of 7,151

raoultrifan

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If looking for unity gain output buffers able to drive cans, then NJM4556 will do (see O2). However, perhaps something like http://www.ti.com/lit/ds/symlink/opa551.pdf would be better...or the OPA552, depends on your needs.

If looking for preamps, then any audio opamp unity gain stable could be used.

If you’re looking for some other design, then please provide a schematic, for a better understanding.

I was not reffering to the price, instead to the number itself. Yes, I’m an orthodox. :)
 
Aug 29, 2018 at 6:21 AM Post #6,140 of 7,151

dhruvmeena96

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I am referring to output voltage level. Of course you can use many opamps as headphone amps, but not all opamps can drive a headphone well.

Distortion demands are more critical on opamp that will feed a power amp, than on one that will drive a headphone. S/R and noise are not too important on a headphone amp, and they are on a line amp.

Some, including me, do not find absolutely necessary to use a line preamp between source and power amp, and modern sources are juicy enough to drive most power amps perfectly.

But I think that an output DAC chip does sound better if it's fast and low noise, besides having as low distortion as possible.




Why it's not right? Mouser is selling the 1622 for $6.



Output level is what I mean, not input level.
Nowadays preamp is not a separate thing but a part of modern amp schematics(not all, but most of them), so there is no need to buy one until or unless it is damm necessary(and if somebody is rich, get a burson cable, the one with opamp one....)

And I agree with DAC statement.... DAC are just too sensitive with the parts they are connected with... Even the change of quality resistor change the perceived sound profile, so they will get a lot of advantages with opamps...that I am sure of
 
Aug 29, 2018 at 7:19 AM Post #6,142 of 7,151
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Responding to some questions asked above...

I've only tried the 2x Mouser Muses02 in the input stage of an iBasso PB2 amp. I have no doubts about how they sound to my ears with my gear. They suck! :)

They are anything but accurate in terms of frequency response and poorly resolving of fine detail. And I've tried using them with numerous opamps in the buffer stage, including dummy buffers, which always provide the clearest impression of what's happening in the input stage.

I personally prefer my DACs and Amps to be neutral and clean. If I want to add color, I do it by switching headphones. The Muses02 just has too much personality for my tastes.

Surely, there are people who would love what I'm hearing with the Muses02, so there's no right or wrong here.
 
Aug 29, 2018 at 8:44 AM Post #6,143 of 7,151

raoultrifan

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In this specific case I'm referring to opamps to be used as DAC output, driving a preamp or power amp. Never headphones.

Got it now, you need a good opamp as output buffer, so most audio opamps should work fine here.

If there is DC-servo or capacitors to block the DC from outputs, then I would recommend anything from: LME49720/LME4562, MUSES8820, MUSES02 to BURSON SS V6 etc.

If output DC needs to be very low, then FET-input opamps might help here: MUSES8920, MUSES01, OPA1652 etc.

Usually I got perfect results with LME49720, MUSES8820 or with MUSES8920, so unless you want to spend lot of money here you should be fone with the above opamps. Also, 8920 is able to drive less than 1KOhm impedance and has lot of mA to spare.
 
Aug 29, 2018 at 8:53 AM Post #6,144 of 7,151

raoultrifan

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[...]
I've only tried the 2x Mouser Muses02 in the input stage of an iBasso PB2 amp. I have no doubts about how they sound to my ears with my gear. They suck! :)
That’s odd, first time I hear that. These opamps need carefully designed PCB and very good decoupling, perhaps this would be the case...not sure.

They are anything but accurate in terms of frequency response and poorly resolving of fine detail.
I tried MUSES02 in too many devices and everytime I measured the outputs are perfect (low DC, perfectly flat, good separation), so unless there’s a clear incompatibility there should be no issues with freq response or fine resolution. Also, because channel separation is usually better with MUSES02, soundstage is a bit bigger.

Perhaps iBasso PB2 is not the best equipment to pair MUSES02 with.
 
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Aug 29, 2018 at 9:20 AM Post #6,145 of 7,151

dhruvmeena96

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Responding to some questions asked above...

I've only tried the 2x Mouser Muses02 in the input stage of an iBasso PB2 amp. I have no doubts about how they sound to my ears with my gear. They suck! :)

They are anything but accurate in terms of frequency response and poorly resolving of fine detail. And I've tried using them with numerous opamps in the buffer stage, including dummy buffers, which always provide the clearest impression of what's happening in the input stage.

I personally prefer my DACs and Amps to be neutral and clean. If I want to add color, I do it by switching headphones. The Muses02 just has too much personality for my tastes.

Surely, there are people who would love what I'm hearing with the Muses02, so there's no right or wrong here.
Not a DAP thing...

Never performed good on DAPs
 
Aug 29, 2018 at 9:25 AM Post #6,146 of 7,151

carlmart

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Got it now, you need a good opamp as output buffer, so most audio opamps should work fine here.

If there is DC-servo or capacitors to block the DC from outputs, then I would recommend anything from: LME49720/LME4562, MUSES8820, MUSES02 to BURSON SS V6 etc.

If output DC needs to be very low, then FET-input opamps might help here: MUSES8920, MUSES01, OPA1652 etc.

Usually I got perfect results with LME49720, MUSES8820 or with MUSES8920, so unless you want to spend lot of money here you should be fone with the above opamps. Also, 8920 is able to drive less than 1KOhm impedance and has lot of mA to spare.

All these chips are not that good in slew rate, which I remember was important on DAC outputs.

This is from the time first CD players were released and modified, particularly in The Audio Amateur. My subjective findings were similar.

Current capability was another one.

That doesn't mean I won't be willing to try some of these options and which sounds best to my ears.
 
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Aug 29, 2018 at 9:43 AM Post #6,147 of 7,151

selvakumar

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Please, don’t remember me about MUSES01 price, I have 4 of them installed in my Essence One combo. :) For some reason these expensive chips are the best I’ve tried in I/V for E1 DAC.

However, 8920 is also a wire-with-gain in most circumstances and it’s way cheaper if you want to try it out.

Both of the above could be a good match for I/V and a very good choice for gain-stage and output buffer, given their high current output and very low DC-output.
hi will it be good for Burson Play Muses opamps
 
Aug 29, 2018 at 10:18 AM Post #6,148 of 7,151

raoultrifan

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All these chips are not that good in slew rate, which I remember was important on DAC outputs.[...]

Forget about the slew rate, this is snake oil: https://www.radio-electronics.com/info/circuits/opamp_basics/operational-amplifier-slew-rate.php. I don’t know what do you understand by “line level”, but for quitar that’s 0.8-0.9V RMS and for a regular DAC that would be 2-2.2V RMS. That means any audio opamp can handle line-level voltages when used in output buffer.
 
Aug 29, 2018 at 10:26 AM Post #6,150 of 7,151

dhruvmeena96

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Forget about the slew rate, this is snake oil: https://www.radio-electronics.com/info/circuits/opamp_basics/operational-amplifier-slew-rate.php. I don’t know what do you understand by “line level”, but for quitar that’s 0.8-0.9V RMS and for a regular DAC that would be 2-2.2V RMS. That means any audio opamp can handle line-level voltages when used in output buffer.
i was not clear by the snake oil. are you saying that slew rate is snake oil?????

by the way, i was working on a project where i am using a Khadas Vim2 max development board as slave to Khadas Tone(ESS 9038) and then using the balanced L and R line out to a portable headphone amp which can operate on both balanced and unbalanced mode. this is all in one portable package

i need help with
1. size of amp should be small and should be as powerful as CMOY(Good driving till 300ohms)
2. what are the best opamps which consume very tiny power yet perform very good(OPA1622 is hard to deal so i am still on OPA1688, but better opamps are welcome)
3. battery is 10,000mAH 7.4V which has to be shared with all components, so if i can get a battery management circuitary info from somebody on personal chat.
 
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