HC1 Headphone Amp Assembly Guide
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You'll need the tools below to complete this build.
We recommend an adjustable-temperature station, such as the $40 Weller WLC100.
You can use 60/40 "leaded" solder or lead-free. We recommend 60/40 because it flows better and is easier for beginners to use.
You'll need a pair of good "snips" for cutting of the excess leads after soldering.
These tools aren't strictly necessary but can make your build a bit easier.
If you find the color bands on resistors a bit hard to read, you can use a meter to sort them with absolute confidence.
If you accidentally solder something in the wrong place, a desoldering pump can save the day.
Print the Sorting Sheet
If you would like to sort components before placing them, download and print the HC1 Component Sorting Sheet (PDF).
Sort and place the resistors in their respective positions. Bend their leads against the bottom of the PCB to hold them in place for soldering.
Solder and Trim Resistors
Solder the resistors and trim their leads as close as possible to the solder joints.
Place Ceramic Capacitors
Place and solder the ceramic capacitors CB1-CB4. These caps are not polarized.
Place IC Sockets
Place the IC sockets for IC1 and IC2 so that the notches align with the notches on the PCB silkscreen. Then solder them in place.
Place LED and Electrolytic Capacitors
Place the red LED and larger capacitors, paying close attention to their orientation. All of these parts are polarized; the longer lead is positive, while the negative lead on the capacitors is indicated by "-" markings on the body.
Place the potentiometer VR1 and bend a few leads against the bottom of the PCB to hold it in place, then solder.
Place and solder J1 and J2 first (since they are shorter) then the input jack J3.
Place ICs in Sockets
Place IC1 and IC2 in the sockets so that the notches on their bodies align with the notches in the sockets and on the PCB.
Power and Audio Inputs
You can power the HC1 with a 9v batter or DC power supply. Most "wall-wart" supplies will work fine. The HC1 with the stock opamps can accept between 9-44DC. If you substitute a different opamp, make sure to check the datasheet for its maximium power voltage.
Attach Audio Inputs
The HC1 takes unbalanced, line or consumer-level inputs. You can attach a single, unbalanced, stereo jack as shown, or two unbalanced mono jacks. If you use two mono jacks, run the ground (sleeve) wire from both into the "G" screw terminal so they are both connected to ground.
Customize your headphone amp(s) for your set up. You can use hookup wire to daisy chain units to make a multi-channel headphone amp.
To power multiple channels, make sure your supply can provide enough current. Each HC1 draws up to 20mA. Multiply the number of channels by 20, then multiple the result by 1.5 to be safe. This is the total current your supply needs to be able to provide. For example, if you are building four-channel unit, your power supply should provide at least 120mA.
You can send a single audio output to up to four HC1s. Beyond this, the combined input impedance seen by the output will be too low.
Have fun customizing your headphone amp, and if you come up with something cool, please share it to our Facebook page.
Before you wrap up, check the following things:
All good? Congrats on finishing your build! Have a question or problem? Drop us a line.
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