best place to by headphone amps ?

[MaxEnergy]

Looking for these amps for headphone amp Burr-Brown OPA637 and Ad8620
in the U.S.A ?
Also came across 2 op opa637 amps the OPA637AP is list as
having Common Mode Rejection Ratio (Min): 100 dB and Voltage Gain dB: 116 dB the other
OPA637BP Common Mode Rejection Ratio (Min): 106 dB and Voltage Gain dB: 120 dB
What is the does the higher ratings give the OPA637BP ?
What effect would it have on music


Electronic Components & Supplies | Mouser

 

[xrk971]

Check out the TI TPA6120A2. I think it has much of the specs you are looking for 100 dB CMRR, 120 dB SNR, drives 80 mW into 600 ohms, 0.00014% THD, 1300 Volt/usec slew rate, not sure about the gain though.

http://www.ti.com/lit/ds/symlink/tpa6120a2.pdf

TI provides samples directly.

 

[gmarsh]

TPA6120A2 is a nice chip - I used it in the DAC/headphone amp project I did a number of years back, and it pretty much outperforms the fundamental limits of 16/44.1 recording.

Only thing is, it's a current feedback amp with a stupidly high bandwidth - you need a very good board layout and very good attention paid to decoupling.

 

[MaxEnergy]

Thank for the info just put in a order for a TI TPA6120A2

 

[xrk971]

TPA6120A2 is a nice chip - I used it in the DAC/headphone amp project I did a number of years back, and it pretty much outperforms the fundamental limits of 16/44.1 recording.

Only thing is, it's a current feedback amp with a stupidly high bandwidth - you need a very good board layout and very good attention paid to decoupling.

Can you share your schematic for the amp part? The TI datasheet shows pretty much only 3 resistors (in, out, feedback). This could be why the datasheet shows a pre-amp with a cap-feedback filter to reduce the bandwidth? I would imagine a nice set of 3 de-coupling caps per rail like 100 uF 35V + 1000 pF 50V COG + 0.1 uF 50V X7R mounted within 5 mm of the power leads should do the trick.

 

[Tekko]

Why is this in the class d section ? This is not a class d amplifier and is nowhere even near related to class d.

 

[gmarsh]

Can you share your schematic for the amp part? The TI datasheet shows pretty much only 3 resistors (in, out, feedback). This could be why the datasheet shows a pre-amp with a cap-feedback filter to reduce the bandwidth? I would imagine a nice set of 3 de-coupling caps per rail like 100 uF 35V + 1000 pF 50V COG + 0.1 uF 50V X7R mounted within 5 mm of the power leads should do the trick.

The "preamp" in the PCM179x application in the datasheet serves as an I/V stage for the current-output DAC, and lowpasses the high frequency sigma-delta hash that comes out of the DAC.

Minimizing the amount of stray capacitance on the - lead of the device is also necessary - IIRC the datasheet recommends keeping any poured ground plane clear of the pin.

The device schematic is pretty much the same as mine, though I use lower value resistors on the I/V and a bit more gain on the TPA.

 

[gmarsh]

Why is this in the class d section ? This is not a class d amplifier and is nowhere even near related to class d.

I figured a mod would move the thread whether it gets answered or not