Simple Single-Ended Headphone Amp

[wrenchone]

I have lots of other ways to have fun, and about six other projects waiting for my attention. I'll be closing this one out soon, going as far as to put the current effort into a reasonably nice case. One of the projects I'm working on will really need the HP4194A to scope out its loop characteristics.

 

[kstlfido]

Hi wrenchone-

I'm making a little phono preamp for a friend, repurposing an old surplus military box.

I'm planning on using the Electronics Salon RIAA preamp, as I have it already-
Stereo Phono RIAA Preamplifier Module Board, Preamp, MD-A310. | eBay

Thought it would be handy to add a headphone amp inside.

Spotted this thread and thought your design could work well. But it needs to fit in this little box. 85x60 mm or thereabouts.

What do you think?

Cheers- Kent

 

[wrenchone]

The board I used for this romp is 2.5" by 4", containing both channels. If you split it in half, the package would be more compact. The size will also depend on how much you want to accommodate lower impedance headphones. 1000 uF output capacitors will do for 50 ohms+, 1500 for 30 ohms and above, and if you want to handle 16 ohms, you'll need 2200uF. You'd have to string the amp between the +/- supply rails of the phono preamp.

 

[wrenchone]

On reflection, I think that a boosted opamp design would be more compatible with your choice of phono preamp.

 

[wrenchone]

One I bodge the latest version of this amp into a case (the original is in India, and acquitting itself quite well), expect to see it a BA 2019. Bring your favorite headphones!

 

[wrenchone]

The latest version of this amp (using surface mount SOT-223 devices to replace obsolete TO-92L parts) went to Burning Amp 2019, and was on display along with a SE vacuum tube headphone amp using a commonly available dual dissimilar triode. A fair number of people auditioned both amps, using a Panasonic Discman as a source. The split in preference between the two amps was about 50-50, with a couple of people liking both. Those who liked this amp best generally described it as "punchy".