EHHA Headphone Amplifier Reincarnation

[Audiodoc]

Rebuild of a year old EHHA made with gurubhai. Original design by Cavalli Audio.

Cavalli EHHA Embedded Hybrid Headphone Amp

 

[anm]

looking very beautiful. pls share the juicy details. I have the amp in my office and this reincarnation would look really cool there.

 

[grubyhalo]

Nice! Very Pass'esque...

 

[Audiodoc]

I have been a DIYer a decade back (class 12 to medical school). Met gurubhai through a common friend who rekindled the desire to go the DIY way once more. With gurubhai's efforts of getting all the components and a few late nights last September 3 EHHAs were born in Delhi, you being the proud owner of one of them.

Every component of the build was great except for the casing which had been done by a local guy who didn't know much about precision and charged a hefty 2K for the same. Since then I was searching every forum to give a new body to this great sounding soul!

Local builders like magma on this forum asked for prices like 12K:sad:

After thorough search I procured the casing from overseas for around 6.5K (price+shipping+customs). Great precision built, all aluminum, CNC finished dual texture front panel, aluminum knob, gold plated connectors, IEC socket with fuse and switch. I liked it so much that I am planning to order a few more for my other constructed DIY projects. If you are interested can order one for you too.

Dipped my boards in soldering flux, re soldered the components once more followed by an isopropyl alcohol bath to sparkle them to a new shine. Did some cable management. Added the back lighting to the volume knob by drilling few holes, drilled the base plate, reassembled the parts. Broke open the heater supply and connected the volume knob LED from its PCB to give an indication when heaters are on. The results are before you neat and compact as I like it.:clapping: More images on:

http://cdn.head-fi.org/3/3f/3f9ed61b_EHHASmall62.jpeg

 

[anm]

results are wow! Who won't like it
but I am zero at diy even though I am an engineer. What a shame!
I too would like it but sounds like too much work for a noob like me.

 

[omishra]

Broke open the heater supply and connected the volume knob LED from its PCB to give an indication when heaters are on. The results are before you neat and compact as I like it.:clapping: More images on:

Hi,

This is nice and neat DIY. Very good.
BTW if you don't mind then I have one suggestion. Your amp's volume knob seems to be wired at front. Can you move it near backplate? Use extended rod to have Volume control at same place.

 

[quad]

Beautiful case, and very nice and neatly wired. Great work, Doc!

 

[Audiodoc]

Thanks Omishra for the suggestion. A rod could have be connected to keep the signal path short and attach the pot on a DIY etched PCB board at the back but there were two problems:

1. The transformer will come in the way.

2. I still would have to bring four wires to the amplifier boards at the front as signal L, R, and input grounds.

By the way the amplifier doesn't have any hum or hiss at full volume so I am happy.

Thanks again.

 

[gurubhai]

Now, what was wrong with this 'Black Beauty' ?
I like it just fine but you had to pull out its guts, didn't you.

 

[Audiodoc]

Nothing wrong with its blackness but it was FAT:lol:

Will be using its skin as a base of a future build. Using a front fascia of lacquered wood and a fresh powder coating with the quality screws which have be left behind from the current casing.

And what about my heat sinks bro! When should I be expecting them.

 

[gurubhai]

Ya, I know you got yourself a fair & slim one ! :indifferent14:

Kidding aside, what are the dimensions of the new case ?
It does look pretty good for the price.

About the heatsinks, I can spare 4 Aavid 2" ones.
The other ones, 2.5" inchers, are aplenty. Even the 2.5" ones don't project beyond the tubes so you don't have to worry about the case size.

 

[Audiodoc]

Internal dimensions of the case are 20.3 x 30.0 x 8.4 cm.

You can send me the 4 ones you can spare and 4 of the smaller type. Don't think they can touch the top of the casing will use the taller ones on the sigma 22.

Thanks!

 

[gurubhai]

Email me your address with anything else you might need from the lists I mailed you earlier & I shall ship them together.

BTW, It seems you are still using the hook up wire for signal cabling. You should upgrade that with better cable, makes a significant experience IME.

 

[Audiodoc]

Yes I am still using the signal wire to carry my input signal to the pot though I have changed the output wires to the headphone to shielded ones but that was because of I wanted to increase their length. I don't hear any hiss or hum so didn't bother on using any exotic shielded wire.

I am also interested to buy the screwed wire binding posts for my other projects. Will post the pictures tomorrow.

Will also post my address with the components I need.

Want to design a few simple protection circuits for my headphones and speakers.

Have to get some ferric chloride and hydrochloric acid too. Will have to search for the same in Chandigarh.

 

[quad]

Have to get some ferric chloride and hydrochloric acid too. Will have to search for the same in Chandigarh.

Is this for etching PCBs? You can use a mix of Muriatic Acid (toilet
cleaning acid from your local grocery/hardware store) and
Hydrogen Peroxide (from medical shops) - just remembered...you are a doc - would have
plenty of h2o2 at hand.

Stop using Ferric Chloride etchant! (A better etching solution.)

Etching a circuit with toilet bowl cleaner

 

[Audiodoc]

Yes have a plenty of H2O2 at hand but the concentration used for wound debridement usually <5% while the chemical form available for sale has around 36-38%. Will check if HCl with 5% H2O2 does the trick.