Discrete Dynamics DIY Headphone amp module project

[dziniss]

hello community,

i have my first DIY project done from Discrete Dynamics headphone amp module.
well - when i say “my DIY project” it feels like a bit of an overstatement as i was heavily helped by my brother and i had good tools available.

anyway, here it is








i was planning to have the knobs on the long side and the connects on the opposite long side, but it turned out that the box was meant for different orientation so i had to squeeze in and overpack the box as space is an issue for me and i could not go with bigger enclosure.




the aluminum box has plastic protecting layer which is supposed to be taken off (you can see i have damaged it under the on/off knob), but as there was electric concern i left it on for the time being as extra insulation for the box (but as it has proven from previous experience - whatever is meant for a "short while" turns out to be "forever").

thanks Sachin with all the assistance and my 600ohm Beyer DT-770 sounds much better with the headphone amp. i can not compare it to other such devices as this is first headphone amp i have ever used / heard - but the sound is way more detailed and full bodied than straight from the computer.

cheers
oskars

[analogadikt]

Thanks for sharing. Sachin and Aniket seem to on a roll

Regards,

[sachu888]

Hi Oskars
just saw your post, very nice build. It's a nice preamp/headphone amp. You can also use it as line level preamp. I have now got second batch with sealed Alps pot


Preamp's latest review here https://www.hifivision.com/threads/diy-preamp.72830/

Regards
Sachin

[dziniss]

Sachin
yes - it does sound good.

i will surely try it as phono preamp, although i believe DD headphone amp will be dedicated to headphones as John's (spaceistheplace) EAR 834 clone module/kit with Jessicas PSU is on my mind.
i have got the PSU already, and EAR 834 should come my way soon. but can not reach John (spaceistheplace) for some 3 weeks already.
hopefully he will be back online soon and then next DIY journey will begin.

thanks again Sachin for you help with the build
cheers
oskars

[stratokaster83]

I am playing with my Discrete Dynamics PAM1.2 at the moment. A bit disappointed that its output is capacitor coupled. The matt black PCB makes it very difficult to see traces, but it is obvious that the output of the power transistors Q3/Q4 and Q5/Q6 goes to the headphone jack through C13 and C14.

In my opinion, it is completely unnecessary since the module uses bipolar power supply. I measured DC offset before the output capacitors and it's about 0.03 V in one channel and 0.1 V in the other channel. A bit too high, but it would be better to provide trimpots to adjust DC offset than to use two low-grade electrolytic capacitors for coupling the output.

Not really criticising the circuit, the module sounds good (and I like that it is completely self-contained and needs only a suitable power transformer), but I'm pretty sure it would be even better if it were DC coupled. I might try to solder two small polypropylene caps in parallel to C13 and C14 to see (hear) if there are improvements.

[dziniss]

Hey Pavel,

Im pretty happy with my build. Not sure which version do I have, but I use mine everyday as a headphone amp on my computer.
Nevertheless it would be cool to follow your experiment, so let us know how you succeed. And as we know – if a little bit of soldering does not kill the equipment, it only makes it stronger!

Best
Oskars

[stratokaster83]

Hi Oskars,

As I said, it sounds good and it's very suitable for high impedance headphones like your 600Ohm DT770s because it uses +/-18V power rails which gives it quite a bit of headroom.

I have a couple of DIY headphones amps that are DC coupled - they sound just a tad cleaner but they don't have the same headroom because they run on +/-12V.

Cheers,
Pavel