HC1 High Current Headphone Amp


  • Partial Kit
  • Documentation
  • Intermediate

The HC1 is an expandable, high-powered headphone amp designed specifically for critical studio monitoring.

The HC1's circuit employs parallel amp stages for greater power and lower distortion. This parallel-opamp concept has been known in theory for decades and was put to practical use in Douglas Self's "5532 OpAmplifier" power amplifier. As a result, the HC1 sounds clean and clear even at high gain and when driving low-impedance headphones.

Because everyone's monitoring needs are different, the HC1 is designed to be customized. The power and audio input connectors are screw terminals, so you can attach whichever jacks you need without soldering. You can also daisy chain multiple HC1s to make a multi-channel headphone amp.

The HC1 is a great project for intermediate builders who enjoy the challenge of choosing their own chassis and inputs.


  • High-current, dual-amp design
  • Screw terminals for power and audio input
  • Stereo, unbalanced audio input
  • Accepts 9v battery or DC wall-wart power input
  • Mounting holes for case mounting
  • Runs about 50 hours on a single 9V battery
  • Does not include power or audio input jacks

Partial Kit Includes

  • Printed Circuit Board (PCB)
  • 2x NE5532 opamps
  • All resistors and capacitors required
  • TRS 1/4" headphone jack
  • Volume potentiometer and knob
  • Screw terminals for power and audio input

Source Your Own

  • Power supply or batteries
  • Chassis
  • Input jacks



  • Input Impedance: 20kΩ
  • Current Draw: 10-20mA
  • Gain: 0-10dB (customizable)
  • Power Supply: 9 to 44VDC

Customer Reviews

Based on 21 reviews
Richard Lam
Love It!

I hoped for a sonic improvement from the (terrible) HP4 that I was using to record others in my home studio. What I got was an improvement from the(IMO very good) stock amp in my interface (iD22)...didn’t see that coming...couldn’t be happier! I built a 2 banger into an ammo box. Really fun and easy project! Check out my YT video. YouTube video placeholder
Sounds Amazing!

I recently unearthed my old FM Tuner (a Denon TU-260L) , but I do not have my amplifier any more, so I was looking for a good headphone amp to connect directly to the LINE OUT of the tuner.
I have bad experience with every single LM386-based amp and I could not be convinced to spend $50+ for something that has no specs but is labelled "HI-FI"...

I came across HC-1 completely by accident and since the schematic was online and it looked so simple, I thought to put it together to check how it sounds...I had all the components, no hacks other than using 2 separate pots as I did not have a dual one.

Worked without issue on the first power up and it blew my socks off!!

It's been years since I listened to such a clear and nice sound! Amazing dynamics, no-compromise frequency response, unbelievably quiet at full volume when no input is connected (no hiss, I thought it was dead!), extremely loud with no distortion or muffled sound at full volume (driven from LINE OUT, driving my Sennheiser hd 497 , 32 Ohm , 112db sensitivity...all this with just a single 9V battery)..So transparent and so good!

This Denon tuner always sounded nice, and with this amp, it is almost CD-quality! It is a pleasure to listen!
I still cannot believe how amazingly it sounds for such a simple circuit!
You have to listen to it to believe it...

Thanks for the design and for making the schematic available.

Eric Boyd
Spectacular value

Built this thing in about an hour on my back porch with Walmart's finest, cheapest soldering iron. Using a Ryobi battery for power. Highly recommended, this thing is really capable and has no noise whatsoever that I can hear at max volume on sensitive headphones. These cases were cheap, their contents were delicious, and I find the stupid sight gag to be delightful.

Paul Musco

A truly fantastic headphone amp.

John David Kassai
What a cool/useful little thing!

Fit it in 1590b enclosure. Use it to mix on my laptop and occasionally as a hard wired IEM for drummers and other studio work. Wow. Sounds amazing. Started using it for video games and anything else I could find. Easy kit to build. Super flexible. 10/10

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