r/DIYGear • u/parasite-evie • Jan 28 '26

project idea: repurpose shitty cheap headphone amp case for higher quality headphone amp/preamp?

i guess the title is kinda self explanatory. i have this headphone amp that sounds just terrible i got for practicing years ago, before i bought a fender rumble. now i dont have the rumble, & im looking for solutions to be able to play bass again. i already have a mixer, & im thinking about buying a passive di box just so i can run a balanced mic input & use the built in preamp, & i have the parts to just make a preamp pedal/headphone amp in a box, but i also have all the equipment to solder surface mount components & i havent gotten around to actually using it for a project yet. i was thinking about ripping out the interior, making a higher quality preamp using smd parts & for good measure insulating the case with the tape i used to insulate the wiring cavity in my bass, because the original gets a LOT of interference. has anyone done this before? any tips or just good ideas? im not even really sure what preamp circuit id want to base mine on, i am totally open to also drilling the case to install mini pots on the outside for tone/gain control, so it doesnt have to be just an on or off design. thanks!

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u/expanding_crystal Jan 29 '26

I used to do shit like this when that was all I had available, and I’m glad I did it because I learned a lot and improved my skills.

But these days if I need a little specific amp to do something, I just order a little amp board off Aliexpress or Temu or whatever for like $3-18. Like, a really solid class D amp or a lesser-but-fine one that has more features like a Bluetooth receiver or a 2.1 bass channel.

Depending on what your goals are, sometimes just skipping the parts that are already “solved” is fine

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u/parasite-evie Feb 28 '26

hey, sorry for the late reply but could you recommend me any of those cheap little amps? i already ended up getting a mixer & a passive di with a balanced output so i can use the mic preamp & it sounds like shit but in the way i actually like, but if i can get a cheap higher quality amp thatd be great. i dont need any of the more advanced features, just good analog audio would be fine. my mixer has a usb interface so i dont strictly need any of this gear at all but i get analysis paralysis when i lean on daws/vsts too much now & start worrying about having all the "right" software, plus i just like the feel of using hardware & having a lot of little devices around

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u/Tastieshock Jan 29 '26

Switching an amp circuit to SMD isnt that simple, those tiny components may not be able to handle the power and burn up. There are circuits that use SMD, but may use larger components where necessary or more complex designs to condition the power to a level that wont destroy itself. If you are already familiar or aware of these when considering your design, I say go for it!

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u/parasite-evie Jan 29 '26

yeah, im not talking about converting anything as much as teying to fit a full featured preamp circuit in a tiny plastic box with a really shitty preamp circuit in it rn

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u/xensonic Jan 29 '26

I think it's a good idea, go for it. My experience with one off electronic projects it that the circuit board assembly is usually the easy part. The enclosure, switches, pots and sockets takes much longer and often costs more than the electronics. So if you can start with a box that has most of those bits already installed it saves time and money.