simple, high performance amp using DRV134?

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DRV134PAG4 Texas Instruments | Mouser

$5.60, DIP8, could probably push 50 mA easy (80 mA short circuit current), gain of 2 when configured as single ended with no external feedback resistors required). With input impedance 10K it would probably work better with a buffer for line level. I would run it off +/- 10 volts for low impedance cans.

Look at figure 6 "typical single ended application" - all you need is a buffer, power supply bypass, and you're good to go.

It's cheaper than the BUF series, would require minimal supporting components, and would probably provide decent performance. What do you guys and gals think?
 
the Audio - Headphone Amplifier - TPA6120A2 - TI.com has pretty good audio specs too - single digit ppm while putting up to 2 W into 32 Ohms - that's 350 mA peaks

and you get 2 amps/chip for less than a $1 more

need output series Z to isolate from cable C load (above a few MHz) - could be the 10 Ohm R shown in the datasheet - or L if you want lower audio frequency Z - I use 1812 lossy "bead" chip inductor - could even be the classic turns of wire on a carbon composition resistor body

Sjöström Audio - Hifi Projects has ben making kits for a while - seems to say hobby soldering the PowerPAD is fine


balanced drive isn't needed driving headphones - most are wired with common gnd return TRS connector

a popular audiophile tweak is rewiring for 4-pin connectors which removes the otherwise unavoidable common impedance path of the TRS ~"point contact" shared gnd return

just changing this, getting gnd and feedback takeoff points right inside the amp do virtually everything worthwhile - seems like unwarranted expense/complication to actually double the electronics for bridged/"balanced" driving to possibly cancel some even harmonics of the single digit ppm distortion
bridged drive does give higher V swing - but you probably know if you have one of the few dynamic headphones made today that actually need more V than single ended op amps, +/-15 ps
 
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That does look like a pretty nice headphone amp. But it's smd and I don't do smd. I can barely see a 1/4 watt resistor, to be honest. I have to work with big glasses and a magnifying glass just to assemble ordinary circuits.

If you look at the datasheet I referenced, it provides a single ended output with Av = 2. I think it would do a good job of driving headphones; even a 5532 does an OK job.

My angle is to build a small board with just two chips and a few capacitors and stick it in my preamp. I guess you could put it in other sources too (CD player etc) that offered a split supply.
 
optics and really bright light can get most people pretty far

soic 50 mil lead spacing isn't too bad by today's standards

a resort used for even smaller chips is the "flood and mop" method with solderwick

the tpa6120 even comes with "practice" pins - only 1/2 are used, 1/2 are NC internally
 
I've been soldering for over 40 years and never built anything with smd. I've worked on a couple of smd boards and hated it.

That chip doesn't look that bad. At least I could see it without a magnifying glass.

I have made it a point to always use through hole components. I realize that it is becoming obsolete; new and exciting devices are often not available in through hole versions. Even old devices have more smd options sometimes.

One of these days I will try a circuit with a larger chip like the 6120. No way am I going to handle those tiny resistors and capacitors; although I am amazed at just how small capacitors can be made with modern technology.
 
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