Headphone Amp Photo Gallery

Thank you,
of course my changes- slightly reduced Re and BIAS transistor changed to TO126 - for easier installation .
 

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To help kickstart the thread, here is my little headamp that is still waiting for the 3D printed case I wanted to make months ago.

Definitely lot's of things to improve when I look at it now, but overall it works flawlessly (and has been for a year almost). Considering it was one of my first projects, I am pretty satisfied. It's a dual OpAmp in non-inverting configuration, followed by OPA1622 configured as a buffer and everything is powered by LM27762. The switch controls OPA1622's enable pin and everything is mounted on a 4-Layer board. Yes, the coupling caps are too big for the footprint (which was meant to also accomodate SMD film caps). Yes, voltage swing is limited because of USB specifications, voltage drop in the LDOs and the input protection Schottky. And yes, due to the buffer configuration of OPA1622 the capacitive load drive with acceptable phase margin is also limited to around 500pF. I still like it :)

500pF is a big capacitive load so your amp output is well designed ;) if one day you will have problem about long cables (and so capacitive load), just add a small resitor at the ouput of OPA1622 (5-10 ohms, do a try).

For future designs using USB power supply, you can add a dual DC/DC or a step-up switch regulator to have more "headroom".
 
My first ever working Headphone Amplifier
Based on schematic Elliott Sound Products Project 113 also using the schematic of the mini psu from the same site.
PCB was made using toner transfer method using iron.
All the parts purchased from local shop, probably counterfeit / low quality parts. The power transformer was salvaged from an old Analog Satellite receiver. It perfectly fits inside the the shiny box except the power transformer. Need to make the front plate and then will box it.

Also waiting on 10k pot for input.
 

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I had a drawer of old stuff, I was bored, and thought why not. It's not fancy, but it works exactly for what I need it to.

Had an OLD Millet RH PCB gathering much dust. Old red Cerafines, Muse FG, Kiwame, and Dale all around. Diamond buffer instead of opamps. Running 12FK6's. 30V wart to a LM317 regulator for the amp and a buck regulator to a ATXRaspi power controller for the raspberry pi Zero-W. Pi on/off button on the front and a main power switch on the back. Can stream via wi-fi and bluetooth, and I added a USB jack to pull flac files from a 256GB USB stick too. Using Moode Audio for the player. The Pi Zero gives some wi-fi and bluetooth noise when you're not playing a song, but when the song starts it goes away. I just hit random play and let it do it's thing all day through a pair of Koss KSC35's. Just using it in my office to drown out background noise and not annoy the boss.
 

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Just finished a WHAMMY in a compact Hammond case. Still need to add power indicators at some point. The XLR output is for convenience. It's not truly balanced, of course. I haven’t chosen any particular opamp just yet. Auditions to commence shortly.
 

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The Parts Bin Special

I'm gonna pollute the feed with my parts box special.

Single-ended 12HL7-triode 'spud' into Edcor XSE10-50-8K output transformers.

Choke-input power supply (12H 140 ohms), using solid-state rectifiers, passive filtering (no regulators). The heaters run on 12V AC and there's no hum at all.

Each 12HL7-triode draws 40mA plate current, running at about 6W plate dissipation.

It drives my Sennheiser HD650s to plenty-loud-for-me levels. I can switch in a Zobel network especially for those cans, but I swear I can't hear any difference between it in or out of circuit.

The amp also manages to drive a pair of Fostex T50RP to good enough levels, and cleanly. It has no problems at all driving a pair of Audio Technica ATH-30 cans to deafness-inducing levels.

The Heath W5M chassis was given to me after it was stripped of its valuable parts.

It's ugly, but I like it. It compares well to my Objective2 amp.

It lives in the bedroom, for late night listening while reading in bed.

Sorry for the ugly photo. It's a gray rainy day today and I don't have bright lighting where it lives.
 

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A headphone amp is a relatively low-powered amplifier that raises the low-voltage audio signal from a source device (be it a turntable, PC, or smartphone) to a sufficient level such that it can be converted (or transduced) into sound waves by the speakers inside your headphones. It works like the amps used to power full-sized speakers but operates at a lower scale.