[bluemonkeyflyer]

'solderdude' has designed numerous DIY amps, power supplies, and much more...all free to the DIY community. He's also the designer of garage1217 tube amps and power supplies. He runs a very informative site HERE with tons of DIY information, guides, tutorials, and a blog about amps and headphones. All DIY'ers should check it out! His build guides, with photos and instructions are peerless and he's very responsive to newbie questions.
 
I'm currently building solderdude's Kameleon v2 amp that comes in a desktop and portable versions. The desktop amp has its own power supply. Both amps are configurable using correction filters to smooth out spikes and elevate bass and/or treble when needed for a wide variety of headphones. You simply build a correction filter for each of your headphones and easily switch them out via a DIP-8 socket mounted on the amp board. There are only a few SMDs and they're large 1206 size. I think this is a very easy amp to build as long as you follow solderdude's excellent build guide.
 
I'm looking forward to comparing Kameleon v2 with my finished DIY amps including: CK2III, Bijou, EHHA Rev A, and QRV-08;
and ready to build amps: F5 HA v2 GB and Neurochrome HP-1. I'll post listening impressions and comparisons when I finish my Kameleon v2.
 
Desktop Amp: The rear section is used for the portable version.
 
 
 

Kameleon v2 Desktop Amp and Power Supply
 

Important: Do Not use the DIP-8 shown in the picture, above,
because the correction filters will not fit! You must use a spring
loaded DIP-8 as specified in the BOM.
 

Note the yellow text, above, and the correct DIP-8. The vias
for pins 6, 7, and 8 were ripped out when I desoldered the
incorrect DIP-8. The green jumper connects Pin 6 to C104 to
make the repair. The yellow jumper is not needed since Pins
2 and 7 are not used. I clipped off the yellow wire.
 

Desoldering the incorrect DIP-8 destroyed the via in Pin 8. I
had to connect Pin 8 to C102 as a work-around.
 
 
Power Supply for the Desktop version:
 

 

 

Testing the power supply
 

Two, 15-0-15 7W toroids in parallel. The amp and
and power supply are working. Initial listening
impressions: very good.
 
EDIT: I subsequently installed a single Triad Magnetics 15-0-15, 25W toroid transformer in place of the 2 mini-toroids.

 

[bluemonkeyflyer]

Reserved

 

[bluemonkeyflyer]

I have the amp, gain board, and power supply almost finished. To avoid EMI, I installed the amp and power supply in separate Hammond enclosures per Frans' excellent and detailed build guide. I used digital calipers, multiple drill bits, and a step drill bit for making precise round holes that perfectly align with the TRS, Mute switch, Vol Pot, Neon Power Switch, RCAs, and DIN connectors. I have a Dremel Moto bench-mounted saw inbound from Amazon I hope will make tooling modifications and IEC D holes easier to cut and neat.

I'm still waiting on DIN connectors from mouser to attach the power supply to the amp. Then a bit of retooling on the amp cover so it will slide open to allow switching out various filter compensation modules. I have it working, though, and the sound quality is very good.

I look forward to building and trying filter modules for my HD650, DT990. PS1000, AKG7xx, HD600, T50RP, the crossfeed, and a few headphones.

I'll post pictures when all is complete.

Thanks. Frans, for the fun project that should prove versatile and make all my headphones sound better than stock!

~ BMF

 

[bluemonkeyflyer]

I finished my Kameleon v2 Desktop Amp and Power Supply. I also built the "No Filter" Gain Module and the Sennhesier HD-650 Filter Module. The sound quality with the HD-650 filter is better than stock: deeper sub-bass, flattens the slight mid-bass hump, and delivers more details.
 
I'm going to build filter modules for each of my headphones following Frans' guides. They are surface mount "SMDs" but they're "huge" 1206 packages and easy to solder in place. Each one takes about 30 minutes to build if you have your parts labeled and ready to go.
 
I used a Dremel Moto Saw to make the modifications to the top and rear aluminum plates of the Hammond enclosure. The mods are necessary for the top plate to slide backwards and expose the Filter Module Bay. This made an otherwise difficult job much easier.

Kameleon v2: Well designed. Versatile. Excellent sound quality. Cheap. Easy to build. A no brainer!
 

Sennheiser HD-650 Filter Module installed in desktop amp
 
 

 
 

 

Top plate slides backward, without removing panel
screws, after modifications to the top and rear plates.

 

[micmacmo]

Looks like a cool project, BMF. With the filters, do you find your headphones becoming more similar, perhaps to the point where a low cost headphone becomes the near equivalent of a more expensive one?

 

[bluemonkeyflyer]

Looks like a cool project, BMF. With the filters, do you find your headphones becoming more similar, perhaps to the point where a low cost headphone becomes the near equivalent of a more expensive one?

Hi micmacmo,
 
It's good to hear from you! 
 
I have not tried Kameleon v2 with low cost headphones. So far, I've only made filters for HD650, DT990 Pro 250 ohm, and the "no filter" straight gain module. HD650 and DT990 now sound very much the same...Flat...I like flat. So, I conclude you can use either one for virtually the same sound quality. I expect this will prove true for most, if not all, the headphone filters that Frans has actually measured and where he used the measurements to create the corresponding filters.
 
BMF

 

[micmacmo]

Hey, Hey, BMF. Good to see you're still noodling with the audio gear!
 
How does the Kameleon's sound compare to Solderdude's other products? I liked his tube designs, but the Polaris didn't entirely win me over. 
 
I picked up a pair of Phillips SHP9500s for a great price and I've been impressed with their performance. But they lack body and warmth in the vocals. Rather than mod them (the build is okay, but they aren't mod friendly—Seriously? Non-removable pads?), I was thinking that an EQ filter might be a better approach. 
 
If you don't mind my asking, how much was the cost of your build, all in?
 
Mo

 

[bluemonkeyflyer]

  Hey, Hey, BMF. Good to see you're still noodling with the audio gear!
 
How does the Kameleon's sound compare to Solderdude's other products? I liked his tube designs, but the Polaris didn't entirely win me over. 
 
I picked up a pair of Phillips SHP9500s for a great price and I've been impressed with their performance. But they lack body and warmth in the vocals. Rather than mod them (the build is okay, but they aren't mod friendly—Seriously? Non-removable pads?), I was thinking that an EQ filter might be a better approach. 
 
If you don't mind my asking, how much was the cost of your build, all in?
 
Mo

Mo,
 
I don't know exactly the total cost because I ordered a lot of extra parts from mouser and digi-key for other projects. The PCBs for the power supply, amp, and filter modules is ~ $45 shipped. As a rough guess, I'd say to build the amp as I did cost me ~$150.00 which is cheap compared to other amps I've built and currently building. Sjostrom QRV-08 costs about $250.00 and Neurochrome HP-1 about $850.00...I'm done with QRV-08 and almost done with HP-1.
 
If you're looking for an excellent SS amp that's easy to build and costs around $200.00, look at Cavalli-Ti Kan CK2III.
If you're looking for an excellent All tube amp that's easy to build and costs about the same money, look at Cavalli Bijou.
If you're looking for an excellent SS/Tube Hybrid amp, look at Cavalli EHHA-Rev A, but it's a bit more complicated to build.
 
K

 

[bluemonkeyflyer]

The Priceerformance of Kameleon v2 with various filter modules is excellent. It's also easy to build and sounds very good. This is another example of Frans' creativity and generosity to the DIY community.
 

 

 

 

 

 

[micmacmo]

I like the whole idea of the Kameleon. It really takes the guess work out of matching different headphones with different amps. Thanks for sharing your efforts, BMF. 
 
Oh, boy, I think I should order a set of these boards soon. (I'd really like to try the Cavalli hybrid you mentioned earlier. But the concept behind this amp has me hooked.) 

 

[bluemonkeyflyer]

I like the whole idea of the Kameleon. It really takes the guess work out of matching different headphones with different amps. Thanks for sharing your efforts, BMF. 

Oh, boy, I think I should order a set of these boards soon. (I'd really like to try the Cavalli hybrid you mentioned earlier. But the concept behind this amp has me hooked.) 

Great choice.

I just ordered 2 more sets plus 12 filter boards.

 

[derekphone]

I’m trying to to understand how this works. I’m pretty new to headphones let alone DIY. I did make some sweet bi-wire speaker cable for my Usher BE-718’s, but I’m lost here.

I’m looking at getting a used pair of HD800 and definitely want to fix the treble issue and generally make it more sweet, musical to balance out the analytic cool sound. I’ll be using a Rega Dac and an undecided tube amp.

Can I use one of these Kameleon products with another amp? I’m not sure where in the chain I can slot this product. I am willing to build it as long as soldering is not involved because I’ve never done that.

 

[bluemonkeyflyer]

Soldering is required. You can learn by watching YouTube videos and practicing using cheap components from radio shack.

You'll need a source and DAC to use with the amp described in this thread.