Kameleon-2 (portable / desktop) headphone amplifier

Here you can download the build manuals for the portable and desktop Kameleon-2 versions

The Kameleon-2 is the successor of the original Kameleon.
This new version has a volume control added and can be driven from line-input sources.
It is kind of a desktop amp you can take along while being battery powered.



The 'true' desktop version is already built and in full working order but need to write an even more extensive article about it.
This takes far more time than I thought.



Bare PCB's are available and can be ordered directly from me.
So IF you want a portable amp PCB or the amp PCB + (linear) power supply/protection PCB to make a desktop version which is more powerful then simply PM me.

There are also new filter module PCB's which have an extra filter sections.
Where the old Kameleon amp board and filter board have mostly 'through hole' parts the new PCB's use (mostly) SMD components.
Don't let this put you off.
The largest sized SMD components have been used (1206) which are quite easy to solder.

prices of bare (not populated) PCB's & boards in stock (Sept 2018):

Kameleon in-line board (black) = € 9.10 may be available again soon
Kameleon 2.1 amplifier board (black) = € 9.10 now € 7.10 in stock: 3
Power supply board for Desktop Kameleon = € 12.30 in stock: 3
Filter Module PCB (SMD, black) = € 2.85 now € 1.70 in stock : 2
Crossfeed Module PCB (SMD, green) = € 4.60 in stock : 3

D.I.Y. only, no kits available only bare boards.

Supported modules till today (v 2.1 updated: April, 07, 2018)

Linear amplifier with (3) different amount of gains in case you want to boost the signal of your source.
Bass boost with a few different (fixed amount, not adjustable) types of bass boost of your choice.

AKG K501 (lowers treble peaks and lifts bass, gives more body to the sound) *
AKG K550/K551 (reduces the warmth and lowers the treble peak)*
AKG K612 (K601) (lowers treble peaks and adds subbass) *
AKG K701 (removes the 2kHz treble peak, lowers the upper treble and adds missing bass)
AKG K702 (removes the 2kHz treble peak, lowers the upper treble and adds missing sub bass)
AKG K712 (adds subbass, lowers warmth a tiny bit, removes slight treble peak)
AKG K7xx (adds subbass, lowers warmth a tiny bit, removes slight treble peak)
AKG K812 (adds subbass, lowers warmth somewhat, removes slight treble peak)
AKG Q701 (lowers warmth, removes the 2kHz treble peak and adds missing sub bass)

Audeze LCD2 Fazor (adds slight subbass and improves clarity) *
Audeze LCD3 Fazor (adds slight subbass and improves clarity) *
Audeze LCD4 Fazor (adds slight subbass and improves clarity) *
Audeze LCDX Fazor (adds slight subbass and improves clarity) *
Audeze Sine Closed (removes the ‘hollowness’ from the lower mids and the treble peak) *

Audio Technica ATH-M40X (lowers bass hump and treble peak and extends subbass) *

Beyerdynamic DT770-Pro 32 (lowers the bass somewhat and removes the treble peak)
Beyerdynamic DT770-Pro 80 (adds subbas lowers the bass slightly and removes the treble peak)
Beyerdynamic DT770-Pro 250 (lowers the bass somewhat and removes the treble peak) *
Beyerdynamic DT990-600 (old version) (lowers the bass and treble 'hump' and extends subbass) *
Beyerdynamic DT990-Pro 250 (lowers the bass and treble 'hump' and extends subbass) *
Beyerdynamic DT990-Edition (lowers the bass and treble 'hump' and extends subbass)
Beyerdynamic DT1350 with EDT1350-NL pads (adds the (sub)bass that is removed by the larger pads) *
Beyerdynamic DT1770 (lowers the bass and treble peak and extends subbass) *
Beyerdynamic DT1990 (lowers the treble peak and extends subbass) *
Beyerdynamic T1 (mk2) (lowers warmth, extends the bass and removes the treble peak) *
Beyerdynamic T5P (mk2) (removes the treble 'peak' and corrects treble response as well as lowers bass warmth) *

Denon AH-D2000 (removes the treble issues, improves clarity/presence)

Focal Elear (adds some sub-bass and adds clarity) *
Focal Clear (adds some sub-bass and removes the slight ‘stridency’ in the treble) *
Focal Utopia (adds some sub-bass and removes the ‘stridency’ in the treble) *

Modified Fostex T50RP is ONLY intended for T50RP's with SRH940 pads fitted) *
Fostex T50RP stock (adds bass and midbass bloom, extends treble and removes treble peak)
Fostex T50RP with HM5 velourspads (adds bass, extends treble and removes treble peak)
Fostex T50RP mk3 stock (adds subbass, adds body to bass, improves clarity and extends treble)*
Fostex TH-X00 Mahogany (adds subbass, adds some clarity and improves the treble quality) *
Fostex TH-X00 PurpleHeart (adds subbass, lowers bass levels, adds clarity, improves treble quality)

HIFIMAN HE5 (adds some clarity and equalizes the treble peak)
HIFIMAN HE350 (adds subbass and removes treble peak) *
HIFIMAN HE350 with passive treble filter (adds subbass and improves clarity) and a version with SRH1840 pads *
HIFIMAN HE400i (adds bass and warmth, removes the treble peak) *
HIFIMAN HE400S (adds bass and warmth, removes the treble peak) *
HIFIMAN HE500 (adds some clarity and removes the treble peak)
HIFIMAN HE560 (adds some subbass, clarity and removes the treble peak) *
HIFIMAN Susvara (adds some subbass and clarity) *

Master & Dynamic MH40 (lowers the excessive bass and lower mids and adds ‘sparkle’) *

Meze 99 Classic & 99 Neo (lowers the excessive bass and lower mids and the treble peak) *

Monoprice M1060 (adds some bottom end and clarity as well as upper treble, lowers the 4.5kHz ringing)

Mr Speakers Aeon Flow Closed (adds some subbass and clarity) *
Mr Speakers Aeon Flow Open (adds some subbass and lowers the ‘warmth’) *
Mr Speakers Alpha Dog (adds some clarity and adds 'sparkle' up top)
Mr Speakers Ether Flow (lowers ‘warmth’ and the upper treble peak) *

Philips SHP9500 (adds some bass and body and clarity, removes some treble) *
Philips Fidelio X1 (adds some sub bass and clarity) *
Philips Fidelio X2 (increases clarity and removes treble peak)
Philips A5Pro stock pads (corrects the overall tonal balance towards a more Hi-Fi signature) *
Philips A5Pro velours pads (adds some sub bass, clarity and treble extension) *

Sennheiser Momentum OVER-ear (shaves off some bass, adds sparkle up top and extends sublows)
Sennheiser HD555 / HD595 (adds some subbass)
Sennheiser HD58X (Massdrop) (adds some subbass and lowers treble peak) *
Sennheiser HD598 (adds some subbass and lowers treble peak)
Sennheiser HD580 / HD600 (extends subbass, removes slight upper mids peak) *
Sennheiser HD650 old (black driver, old pads) version (extends subbass, removes excess 'warmth') *
Sennheiser HD650 new (silver driver, new pads) version (extends subbass and removes slight midbass hump) *
Sennheiser HD6XX (Massdrop), (extends subbass and removes slight midbass hump) = current HD650
Sennheiser HD660S (extends subbass, removes excess 'warmth') *
Sennheiser HD700 (adds subbass, lowers warmth, removes treble peak) *
Sennheiser HD800 (adds (sub)bass and lowers the 6kHz and 10kHz peak) *
Sennheiser HD800S + HD800 with SDR mod (adds (sub)bass and lowers the 10kHz peak)

Sony MDR-1A (removes overly warm signature and slight edge, overall improvement in clarity) *
Sony MDR-Z7 (removes overly warm signature and adds upper treble extension)

Crossfeed module (Narrows the stereo image) *

* = verified by own measurements, other filters are based on measurements made by others.
Superlux HD681-EVO (removes excessive warmth and small peak in the treble) *

* based on own measurements

When you would like to know if another than the listed headphones can be corrected in tonal balance please ask here and will look into it.
Not all headphones can be corrected.

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For those that have built the portable Kameleon 2 amplifier there is a small (easy to do) modification for the battery management section.
This has no influence on the audio quality.

When batteries are brand new or getting older after many many hours of usage the internal resistance of the battery is a bit higher than under optimal conditions.
This causes weird behaviour on start-up. Mostly when batteries are in need of recharging.
During the development a variable power supply was used and this one, of course, did not show this poor behaviour.
It only happens with real batteries.

The modification consists of adding a small electrolytic capacitor (10uF) with a voltage rating of 16V or higher.

HOW to do this is decribed in the latest manual on the last page, but the modification guide can also be downloaded HERE.

Do note that this applies to the portable version only so NOT the desktop version nor the inline-Kameleon as these do not run on batteries and thus do not have that circuit.
The same applies to the early (original) portable Kameleon amplifiers (the ones without the volume control).
But as this one has the parts mounted differently another instruction is needed.
The modification guide for the original Kameleon can be found HERE

There is a new version of the portable amp board (v 2.1).
It is now in glossy piano black and has the modification described above already on the PCB.