Headphone Amplifier

[olsenn]

In case anyone is interested, I am putting my first design out on the interweb; it is a headphone amplifier, which in my opinion sounds better than my JDS Labs cmoy + bass boost. I have attached the Eagle schematic and board files, gerber files, and some photos of the populated board for reference.

Please feel free to make any modifications you'd like to the design. I didn't have any dual pots in stock when I built this, so right now the volume can only be controlled by the source. With a resistor and capacitor placed in parallel in the op-amp feedback loop (not the current-based op-amp) one can add bass boost if desired.

If you have any questions or comments, please feel free to post them here or send me a private message. Enjoy!

Nick

PS. Both of the IC's may be obtained free of charge via Texas Instruments free samples page

[olsenn]

Also, here are the datasheets for reference:

[icon]

Hi

I'm casting around at the moment for headphone amp to build. Is there any way you can export the schematic to pdf or DaveCAD? I haven't got anything that will open .sch files.

Nice use of H&H as a background for the photos.

Cheers
John

[shebu18]

Install the latest eagle to open the sch files.

[olsenn]

I'm casting around at the moment for headphone amp to build. Is there any way you can export the schematic to pdf or DaveCAD? I haven't got anything that will open .sch files.

Here is an image of the schematic. You may also download Eagle free of charge if you'd like.

[Chipset]

Can we get some objective benchmarks or blind testing comparisons for your design?
Also on the subject of headphone amps, check out the O2 amp http://nwavguy.blogspot.se/2011/08/o2-summary.html
It has amazing (objectively measured) performance and if you buy the components from mouser or something it totals $30 ish, plus $9 for a pcb from http://www.jdslabs.com/item.php?fetchitem=O2PCB

[olsenn]

Can we get some objective benchmarks or blind testing comparisons for your design?
Also on the subject of headphone amps, check out the O2 amp http://nwavguy.blogspot.se/2011/08/o2-summary.html
It has amazing (objectively measured) performance and if you buy the components from mouser or something it totals $30 ish, plus $9 for a pcb from http://www.jdslabs.com/item.php?fetchitem=O2PCB

Nice product placement, haha. To be frank, this thread is intended to serve as evidence that my design performs favourably against other common solutions. I have listened to it for many hours, and I prefer it to my JDS Labs Cmoy amplifier, to which I also have listened to for hours. Considering that the IC's are obtainable free of charge as samples (assuming you intend on building less than 5 units per month) the total production cost is less than $5 per unit.

If it helps to give you an idea of how I use this thing; I listen to a broad range of music using Sennheiser HD-280 Pro headphones.

[StubbornGreek]

Pretty cool, I may have to throw one of these together (I am a bit addicted to headphones - have lots), thanks for putting this out there for everyone. BTW, in fairness, I don't think Chip set was doing any sort of guerrilla marketing. The O2 is a beautiful piece of silent, non-intrusive audio engineering - truly.

Again, thanks - looking forward to playing with this.

[Zad]

It would be interesting to hear a comparison of those. I must admit, I haven't heard anything that will beat OPA627+TPA6120, but my ears are rubbish. The 627s are hugely expensive though now. Lots of fakes appear on Ebay, just re-printed lower grade op-amps.

[DmitryL]

http://sound.westhost.com/highspeed.htm

And whole site worth reading as well

[olsenn]

I forgot to mention, the two voltage op-amps are in a standard package type, so feel free to swap them for your preferred audio op-amps. Still make sure they meet the same pinout of course, and also make sure the minimum supply voltage is no larger than +-4.5V. Sometimes datasheets will specify values of 5V+ but many times they still work fine.

[Kibi]

Can we get some objective benchmarks or blind testing comparisons for your design?
Also on the subject of headphone amps, check out the O2 amp http://nwavguy.blogspot.se/2011/08/o2-summary.html
It has amazing (objectively measured) performance and if you buy the components from mouser or something it totals $30 ish, plus $9 for a pcb from http://www.jdslabs.com/item.php?fetchitem=O2PCB

I have built the O2 amp, it's fantastic. Nice and cheap too.