Headphone amp with 0.000021% distortion

I did one day discover the TPA6120 from Texas Instruments. I decided to let this IC have a go. The result can be seen below.

I have listened to the amp now and the result is that this may be the best headphone amp in the world. I don't think anybody can't say that this amp isn't in world class. The TPA6120 is an amp which can handle DC-100 MHz with ultra low distortion.

If you download the datasheet you can see the extremely good data this IC has. In order to really take out all possible performance I have made a pcb with groundplanes on both sides. They serves also as heatsink for the TPA6120 and the regulators.

http://sjostromaudio.com/pages/hifi-projects/36/112-qrv09-headphone-amp

That's a very neat PCB you have designed, are you a hobbyist? What is the power output of your board?

very nice wrt to gndplanes - have u got both analog and digi gnd planes split on both sides? are they joined on the pcb or at psu?

Cheers!

[quote author="daArry"]very nice wrt to gndplanes - have u got both analog and digi gnd planes split on both sides? are they joined on the pcb or at psu?

Cheers![/quote]
Digital what? This is a headphone amp :grin:

[quote author="Steve Jones"]That's a very neat PCB you have designed, are you a hobbyist? What is the power output of your board?[/quote]

Thanks! Audio is a hobby for me but I'm a professional in industrial electronics so I use my professional knowledge in my audio stuff.
The output power is 70 sufficient to drive any headphone... loud. 80 mW according to datasheet.

looks great!
Expensive?

The TPA6120 cost 1.9 USD i 1K, cheap I would say.

i mean the total like what you've build...
thanks for staying on the button :grin:

Cheers,

Tony

more or less :razz:
:sam:

Hi Per,

Thats a great looking project. Cant get onto TI's site just now but did you take the design from the data sheet or is it your own.
It looks like a great stand alone idea or an add on to desks, preamps etc.
I would like to know more if Per would like to tell us.
Steve

Tony, if you download the partslist you can check where the price end up with. Most parts are rather cheap.

[quote author="microx"]Hi Per,

Thats a great looking project. Cant get onto TI's site just now but did you take the design from the data sheet or is it your own.
It looks like a great stand alone idea or an add on to desks, preamps etc.
I would like to know more if Per would like to tell us.
Steve[/quote]
If you download my schematics

http://www.sjostromaudio.com/hifi_files/qrv/qrv07r0schema_p1.pdf
http://www.sjostromaudio.com/hifi_files/qrv/qrv07r0schema_p2.pdf
http://www.sjostromaudio.com/hifi_files/qrv/qrv07r0schema_p3.pdf
http://www.sjostromaudio.com/hifi_files/qrv/qrv07r0schema_p4.pdf

you can see for yourself how advanced this design is. The TPA6120 runs ininverting mode (in order to get ten times lower distortion :grin: ) and the gain is 2 and the input buffers have the gain of almost 1. As you can see I have used the ultra extreme AD8610 from Analog Devices.

The TPA6120 is a bit special so it needs a very low-ohmish drive due to it's rather high input bias currents.

Cheers Per! :sam:
Great stuff.

Another have to build thing... this list is getting endless :?

Digital what? This is a headphone amp

Click to expand...

ah yes ;P I was thinkin of a digitally controlled vol PGAxx chips

Seriously, this design am I very pleased with because of it's looks, it's usage of an extreme power IC and it contains everything. 230 volts in, signal in, headphone out.

I have no problems with audiable hum from the transfomers in case anyone wonders.

It took me approx. 2 hours to solder but then I was extremely careful since there could be errors in the pcb. I expect 1-2 hours is a normal building time.

This IC has a "PowerPad" which means that metal is on the backside. This is for transporting heat. The metal peice is connected to the groundplane on the solderside via 18 pcs. of via holes. It's not very hard to solder. Just solder the IC as usual and then burn thouroughly with the iron on the solderside for 10-15 seconds.

Per,

I never soldered those tiny smd's before, do you think i need to order extra parts? (might burn a few?)

edit: i just googled this "TPA6120 from Texas Instruments" and found a nice extra info page! :grin: Thanks!

The only heat sensitive part is the plastic cap. You must have a temperature controlled soldering iron and use 300-350 deg C max except when you solder the PowerPad.

I just noticed this bit: "0.000021% distortion"

Why should that matter? According to many studies everything below 1% in inaudible...

Best regards,

Mikkel C. Simonsen (who uses amps with a lot more than 0.000021% distortion :green

> According to many studies everything below 1% in inaudible...

Many studies are wrong.