Headphone Amplifier - Page 1
Forum section: electronics / projects

author: olsenn
author_rank: Frequent Contributor
timestamp: June 12, 2012, 10:41:32 pm
content: 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!NickPS. Both of the IC's may be obtained free of charge via Texas Instruments free samples page

author: olsenn
author_rank: Frequent Contributor
timestamp: June 12, 2012, 10:43:26 pm
content: Also, here are the datasheets for reference:

author: icon
author_rank: Regular Contributor
timestamp: June 13, 2012, 10:47:10 am
content: HiI'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.CheersJohn

author: shebu18
author_rank: Frequent Contributor
timestamp: June 13, 2012, 12:03:23 pm
content: Install the latest eagle to open the sch files.

author: olsenn
author_rank: Frequent Contributor
timestamp: June 13, 2012, 10:53:39 pm
content: QuoteHere is an image of the schematic. You may also download Eagle free of charge if you'd like.

author: Chipset
author_rank: Contributor
timestamp: June 14, 2012, 11:00:34 pm
content: Can we get some objective benchmarks or blind testing comparisons for your design?Also on the subject of headphone amps, check out the O2 amphttp://nwavguy.blogspot.se/2011/08/o2-summary.htmlIt has amazing (objectively measured) performance and if you buy the components from mouser or something it totals $30 ish, plus $9 for a pcb fromhttp://www.jdslabs.com/item.php?fetchitem=O2PCB

author: olsenn
author_rank: Frequent Contributor
timestamp: June 15, 2012, 12:59:05 am
content: QuoteNice 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.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: June 15, 2012, 03:02:40 am
content: 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.

author: Zad
author_rank: Super Contributor
timestamp: June 15, 2012, 11:21:07 pm
content: 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.

author: DmitryL
author_rank: Regular Contributor
timestamp: June 15, 2012, 11:34:28 pm
content: http://sound.westhost.com/highspeed.htmAnd whole site worth reading as well

author: olsenn
author_rank: Frequent Contributor
timestamp: June 21, 2012, 06:08:47 pm
content: 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.

author: Kibi
author_rank: Unknown
timestamp: June 22, 2012, 07:13:44 pm
content: Quote from: Chipset on June 14, 2012, 11:00:34 pmI have built the O2 amp, it's fantastic. Nice and cheap too.