Checkout my DIY Corda HA-1
Jun 8, 2002 at 2:32 AM Thread Starter Post #1 of 29

sunshine

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Bought the DIY Corda HA-1 Kit together with the Senn HD600 from Jan. This is my first real headphone set other than the Senn 497 I tried and returned at Circuit City. Needless to say I'm very happy with the outcome especially so since I put the Corda together with little prior electronics and soldering experience. It took about 2 evenings to put the Corda together and though I found the picture at Jan's website helpfull in putting the amp together the picture wasn't especially clear. So here is a better picture for anyone who might be putting this amp together.

corda.jpg
 
Jun 8, 2002 at 3:11 AM Post #3 of 29

Nezer

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SEXY!!

So now it's time to upgrade those MDR-V700DJs right? :wink:

The Corda does a GREAT job on HD600s and K-501s...

Hows it sound? Those opamps scare me. I'd always wonder if they were oscillating and not sounding as good as they should. but I'm a neurotic freak... :wink:h
 
Jun 8, 2002 at 12:53 PM Post #5 of 29

Ken

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wow stunning pic.
I too would like to put a corda together and I have visions of me creating a peice of junk

But your project looks perfect.
You make it sound easy
what was hardest part to do ?
did it work first time:
 
Jun 8, 2002 at 1:04 PM Post #6 of 29

tangent

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Ben: There is no single "oscillation sound". You can get a kind of thin, weak sound if the op-amp is oscillating supersonically (as fast chips like LM6171s are wont to do), or you can get a buzzing sound, or nothing at all, or crunchiness on musical peaks, or.... The only way to be sure you've got oscillation is to run a test tone through the amp and examine the output with an oscilloscope.

Simpler ways to get a hint:

- The amp is drawing more current than it should (I estimate 50-60 mA for a Corda HA-1 -- haven't measured mine, just a guess)

- The chips are getting hot.

- There are ways to use an AM radio to pick up the RF generated by high frequency oscillation, but I've only read about it, so I can't describe the procedure.

Not that you have to worry about oscillation in this amp. Jan's done a very good job of power supply bypassing, which helps. He also puts a small capacitor in the feedback loop, which rolls off high frequency components, since HF noise can start a chip oscillating.
 
Jun 8, 2002 at 5:45 PM Post #7 of 29

sunshine

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The DIY kit came with a schematic diagram and a laymans layout diagram showing where each part went. I mainly used the layout diagram because I don't know how to read the schematic. Also included was 1 page of hints from prior builders which was also helpful. I hazard a guess that I had probably 4 hours total soldering experience in my lifetime prior to this project. Since the last time I soldered anything was years ago I went ahead and practiced on an old modem I had lying around. This site is very helpful on soldering technique and includes nice photos as well.

All the risistors, caps, etc were mixed together in a bag when they arrived so I spent about 1-2 hours sorting them with a meter. Some parts were hard to identify even with a meter and the color photo from Jan's site actually helped here. I spent 2 evenings, about 6 hours total, putting the board together. It worked the first time and believe it or not I didn't even have to desolder anything. However there was a few joints which I wasn't happy with. I left those alone for now as I was waiting for Jan to send me a replacement for the fuse holder which arrived broken (I hard wired this part for now). When the replacement arrived I spent another 2 hours putting the part in and fixing about 5 or so bad joints.

Overall I would say the hardest part of the project was probably identifying the parts. I was a little unsure at times as I had never really used a meter before. The soldering was not too difficult but it was rather a tedious and repetitive chore. I got tired quickly but was thankful I didn't burn myself.

As this is my first heaphone amp I really have no comparisons to make. Also the HD600 is my 1st true set of cans. However needless to say I am quite happy overall with the sound. My home system is a set of mid end NHT 1.3's with subwoofer. The NHT are detailed speakers and the HD600 and Corda really bring out the details like the NHT. I listen to mainly classical and the ability of this combo to pick out individual instruments is quite amazing. I find the low end a little dissapointing but then the comparison I'm making here is with a home system with a sub. Hopefully the low end will improve as I break in the cans.

Now I need to find myself a portable amp. Tangent, any chance that the META42 will be available in a DIY kit?
 
Jun 8, 2002 at 6:12 PM Post #9 of 29

Nezer

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Quote:

Originally posted by qwerty870
Where can I get one of those DIY Corda kits?


www.meier-audio.com

You can also get it built too. I have the Corda and the Analoguer and they are quite the combo.
 
Jun 8, 2002 at 9:01 PM Post #10 of 29

BenG

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Thanks for the info, Tangent.

I just remember in one of Jan's recent, longer posts he mentioned something to the effect that there was a batch of defective/oscillating opamps (once) that intially passed through him(this was probably only applicable to the kit).
 
Jun 8, 2002 at 11:52 PM Post #13 of 29

kelly

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Kick ass, sunshine. Awesome job on the pics, too. You should offer them to Jan to use on his website.
wink.gif


I didn't have the guts to build my Corda from scratch at the time so I ordered it pre-made. Maybe some day I'll order a kit and build it and sell it or something. As some of you already know I'm a big fan of this amp. How do you feel about the sound out of it, sunshine?
 
Jun 9, 2002 at 3:35 AM Post #14 of 29

tangent

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Sorry, no, I won't be offering kits. Just the boards and the "rare" parts. Everything else you gotta source yourself.
 
Jun 9, 2002 at 3:54 AM Post #15 of 29

Nezer

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Between Digikey, Mouser and Erix you should be able to get everything you need for quality parts. Of course, you could always go esoteric...

Tangent, whn do you think those boards will be ready to ship?
 

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