Kameleon portable headphone amplifier

I f-ed that up the first time and recommend to do the front panel FIRST.
If you f that up (LED's didn't line-up nicely) you can always turn that panel into a rear panel.

In the pictures of the proto you can still see how I 'filled' the switch hole by using a large bolt by which you can pull off the rear panel.

Also you should file off the sides of the top panel somewhat at the position of the front screws otherwise you cannot pull the lid off or push it all the way to the front.

I have 2 ways to remove the top plate.
One where the rear is 'fixed' by using the 4 plastic 'plugs' that hold the front an rear panel when new in the box.
I use 4 of these that hold the back.
It can be pulled off easily and remains fixed good enough during usage.
A disadvantage may be it is easy to loose these 'plugs'.

The other way is shown in the desktop version.
In this one I filed down the rear panel so the lid can slide in and out easily.
The problem for a portable version is that the lid isn't fixed and can slide out (partly, as far as you filed down the edges of the top plate) easily when holding it upright.

Maybe this could still work well if a small 'locking slider' is created on the rear panel that prevents the lid from sliding out.
Perhaps using 1 of those plastic plugs in the upper hole is enough to keep it from sliding out yet is easily removed.

I wanted to 'revisit' the HD650 and make a filter that removes the warmth and makes it a neutral boy of wonder.
The earlier HD650 filter design was based on leaving the character but adding subbass extension and brightening it up.
It remained a 'speaker in room' emulator.

original plot of my HD650:



Below how it measures via the Kameleon with 'HD650 module' installed.



Good part is it not only measures better, it sounds just as 'real' as well.
Talking about sound...

In THIS DOWNLOAD LINK there are 2 files for those wanting to know how the headphone sounds (in comparison with the earlier uploaded headphone recordings) and a file that must ONLY be played back on a stock HD650 via a 'normal' amp and you can hear how it sounds via the Kameleon.

The component values for this filter will be listed in a coming update and would like some feedback of HD650 owners if they liked what they heard.

www.filemail.com/d/owkrelqaicwyehf

Added Superlux HD681-EVO filter and Audio Technica ATH-M40X

www.mediafire.com/view/0i2zm9094g7cqly/Kameleon_portable_headphone_amplifier.pdf

Yes,

More than close enough.
Most of my filters have been made with paralleled capacitors.

First 3 amp boards finished, only filters and enclosures left to go.




PS. The pic is a little crappy but only had the phone and not enough light.

I recommend the BC547's (on the right) should be lying 'flat' on the board.
The reason for this is when taking out the filter board your finger may push it down and eventually break off one (or more) of the legs.

Also remind your self that the labelling of the 2 front LED's is 'swapped'

The 'guide' posts (M3 bolts) will have to be placed as well.
The filter will be a tight fit with those large diameter caps but should just fit.

Do the headers fit nicely in those sockets ?
Haven't tried it as I use another header and socket myself.

Yes Dave, the one with the socket is your board. I put it in because you are doing the enclosure yourself, the others I'll solder in when the front plate drilling is done. I won't be able to resume building until next Monday. I'll try my best to have your filters finished and everything shipped before next Friday but can't promise. Once shipped it should reach you within 5 working days, maybe less.