Sunday, October 28, 2012

audioPhile rx (headphone tube amp)

12h burn in test - succeeded :-)
update: 11th november 2012

i just did a burn in test over 12 hours to make sure everything works perfect (cooling etc.) and i am happy to announce that my amp passed the test!

also there is absoluetly no noise on the amp, which is great because this was one of my main concerns.
even when receiving a phone call and having the phone laying near beside the case - nothing, no noise.

i am so happy that after all the time and money i spent on my project, i finally have a full working unit that will bring me much joy and fun in the future :D

update: 9th november 2012

yes ! finally its done, and its perfect for my needs. i finished my amplifier today, it looks nice and the sound is so nice. i am really happy how it all turned out..
the dc offset of the headphone output is around 2 mV (highest) which is totally acceptable and fine.
i am running "ge five star 12au7" at the moment but will test out other tubes soon (rca clear top, mullard, telefunken).
i used ferrite on the headphone out and power inputs (may not help much, but better than nothing).

the heatsink is also connected to the case, so the whole case acts as a big heatsink which helps cooling down the ic's really nice even on high volume and long time use.

 all in all i never thought that it would come out this nice in the end, i cant stop the smile in my face everytime i look at it and everytime i turn it on to listen to some music.

the macassar ebony wood stands give the whole amp a nice finish, allthough you cant see them very good in the pictures.

i got to admit i really love the uv light that shines through the bottom, it was pretty hard to mount it inside of the ceramic socket, but it shines through the tube as desired :-)

i sealed the traces with transparent pcb paint

sand blasted case

uv tube light

my audio technicas

what a perfect match

now i will take my time to listen :-)

update: 4th november 2012

just did some more work on the case, it is sand blasted now but the power switch in the front has not arrived yet. but you get the idea.

update: 31st october 2012 (second update)

i did a little work on the case, to see how it will work out, the case will be sanded and sandblasted after i am finished with all the drilling and stuff.

i still dont know which screws to use for the front, maybe those stainless steel nutbolts ? or maybe some other stainless steel countersunk bolt ?

some marking and drilling done, lets see how it will all work out :-)

notice: the bolts are not tightened yet i just sticked them in to make a quick photo

update: 31st october 2012

the first test of the amplifier went fine, all check voltages are like they should be. i just need a non conducting heat pad to get the lm317 and the irl530 mounted on the same heatsink without problems.

bias adjustment is fine (the trimpots), i also tested the uv tube light which will light the tube from the bottom for nicer looks.

looking like a battlefield ;-)
i am still missing alot of parts, at least the nichicon kz muse capacitors and some parts of the case are here already.

i didnt have much time to go further in my project because i had to repair a pioneer cdj-800 which i bought defect from ebay.
its already up and running and fits nicely in my setup, now i just need another one (hopefully a dead one will be on ebay soon).
my new baby.... brand new

update: 30th october 2012

printed the layout on a flyer sheet with my laser printer and ironed it on the surface
NaPS bath for the board

the copper will make the water blue coloured while etching

first etched board, pretty nice for first try

drilled the holes and tested the fit of the parts, all perfect :)


i am currently building a headphone tube amp to power up my Audio Technica headphones.

this is my current layout that i will use for my first selfmade prototype pcb.
this is the newest layout..

which one should i use ?
i dont know yet...

also after reading through several forums i found out that using other mosfet's will give better high end sound.
also there are trimmer pots that you can use to fine adjust the bias for every channel.
i will use high end parts like nichicon kz muse capacitors, gold pin ceramic tube sockets, low tolerance resistors etc.
i hopefully will get the most out of this project.

the case will be made out of aluminium, with a tube guard and tube damper. also some nice uv led will light up the bulb from the inside of the case.

i am still waiting on parts but will post news as soon as i make progress.

stay tuned...

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