OTL Headphone Amp project.

[fender3x]

That's great! Are you planning to use it with a guitar? If so, can you use it like you'd use a guitar amp and drive it?

[DrNomis_44]

That's great! Are you planning to use it with a guitar? If so, can you use it like you'd use a guitar amp and drive it?

You could use it as a guitar amp if you connect a preamp, such as a Marshall JMP-1, or a TriAxis, or an ADA Tube Guitar Preamp to the inputs, or a Digitech 2112, it is mainly a piece of Tube HiFi gear, but you can use it with anything that puts out a stereo line level signal, I have successfully used it with a Digitech RP 50 guitar FX processor that I have in my stash of bits and pieces, you could also use it with other guitar FX processors too, you can even use it as a line amplifier too, or as a preamp itself, it is a very versatile device for such a simple circuit.

Just out of curiosity, I just tried connecting the output of my Steinberger Spirit GT Pro Deluxe guitar directly to one of the line inputs of the amp, to see if it would work, and yes it does, it actually sounds pretty good too, I tried turning the volume up full to get the amp to go into overdrive and it actually sounded pretty smooth and dynamic, the harder you strum/pluck the strings, the more the amp overdrives in a musically pleasing way, so yes, using it as a guitar amp in it's own right is quite do-able, and actually sounds good too.

One thing I noticed while I was trying out the idea of plugging the guitar's output directly into the amp, was that there was virtually zero-hum noise, the amp was dead-quiet even at full volume settings.

From my calculations, the amp is capable of outputting at least 5.0 milliwatts into a 38 Ohm load, so, you could send the output to two DI Boxes with 600 Ohm inputs, and then send the output of the DI boxes to two line inputs of a mixer.

You could even use the circuit to build a guitar practice amp for practicing via headphones, all you would need to do is build the preamp circuit of a Fender, Marshall, or Mesa/Boogie, or a Soldano, Vox, or any other amp, and connect it to the line ins of the headphone amp, there's a few ideas for experimenters.

I might actually give that idea a go one day and make an all-Tube rackmount guitar practice amp that you can use to practice via headphones, and build it into a 19-inch rackmount case, would be quite interesting.