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Build your own high quality CD player - Page 2  

post #16 of 92
Thread Starter 
Quote:
Originally Posted by 00940
E-mailed Ken but haven't heard anything back yet. Might have to give him another ring.
post #17 of 92
Thread Starter 
Finally, some progress pictures... (edit: please excuse the lighting, it's rather poor in my office)

The transport is integrated into the top of the player, as so:



The CD player power, display, and DAC boards go on this aluminum plane that will be suspended above the transformers (with the transformers arranged so they're as far as possible from the signal path):



The CD player power board is the one directly behind the display board, with the DAC right above where the transport will go. The Dynahi boards will go to the right of the DAC, with the power board for it on the lower level.



And yes, I realize the display board is upside down -- remember, I said I wasn't going to propagate the filament supplies for it, thus the front of the CD player will look approximately like:



I'm a minimalist at heart. The hole there is directly in front of the display sensor. Eventually, to its right will be the headphone out and non-dinky knob for the Dynahi. Here's what it'll basically look like when complete (less a cover for the CD transport and the Dynahi outs):



post #18 of 92
Good to see that things are proceeding well. This is a project that I'd like to undertake in a few years myself.

Just curious, when you say that you need to minimize the distance I2S has to travel, how short of a distance are you talking about? Like under a foot or under a few inches?
post #19 of 92
Thread Starter 
Quote:
Originally Posted by blip
Just curious, when you say that you need to minimize the distance I2S has to travel, how short of a distance are you talking about? Like under a foot or under a few inches?
The I2S path should be as short as is humanly possible, and you generally don't want to run it more than a foot if possible. I'll personally be running my cable approximately three inches, from the output on the transport to the input on the DAC almost directly below.
post #20 of 92
Quote:
Originally Posted by strohmie
The I2S path should be as short as is humanly possible, and you generally don't want to run it more than a foot if possible. I'll personally be running my cable approximately three inches, from the output on the transport to the input on the DAC almost directly below.
Nice job man. The write up is good and interesting too. Thought I'd chime in on the I2S bus and jitter.

The most common jitter to hear about is from signal transmission down a line. The best way to handle that is to use the highest bandwidth cables possible. But there's also a lot of jitter added during the clock recovery from an AES or S/PIDF interface. The best way to combat this is to use a very high-quality receiver, hopefully one that recovers the clock from the preamble and not the data (preambles don't transition from 0->1->0 as frequently as data does). Of course you can also do fancier things with ASRC, reclocking, etc but these things aren't prefect either so every little bit helps.

By using the I2S connection, you are avoiding two potential problems: packing the data into a stream at the transport and then unpacking it with the receiver at the DAC. I2S is a standard three wire interface: data, word clock, and bit clock. It is still subject to transmission-line jitter, but Strohmie made sure to keep those traces short. Care should also be taken to guard band the traces as much as possible, keep them on one layer, and keep them as straight as possible.
post #21 of 92
Thread Starter 
Thanks for the thumbs up jefemeister. Still no idea how much noise I'm going to have in this thing though, but I'm keeping my fingers crossed.

Oh, and someone has to help me come up with a name for this behemoth. CD-Pro2M with a Dynahi installed...

DynaPro?
StrohnaPro?
Strohprohi?
CDKG?
Pronahi?

pRonahi?

(edit: over a thousand hits! I feel so loved)
post #22 of 92
Some names from Hindu Mythology just for that "ethnic" touch...

1] Bramha
2] Shiva
3] Yama
4] Shakti


or just go nuts with something like

1] Junkie
2] Stoned Monkey
3] Coke Head (like Air Head, Hot Head etc. )
4] iMpWnEd

Gah!
post #23 of 92
very nice job. One question though : how are you dealing with vibrations ? It's a bit difficult to see how the transport is attached to that huge thin sheet of metal which looks like a nightmare from this point of view. Do you plan to brace the internal and add bitumen ?
post #24 of 92
Thread Starter 
Quote:
Originally Posted by 00940
very nice job. One question though : how are you dealing with vibrations ? It's a bit difficult to see how the transport is attached to that huge thin sheet of metal which looks like a nightmare from this point of view. Do you plan to brace the internal and add bitumen ?
This semester (hopefully my last) I'm taking a class called Physics of Music, and in the lab section of the course I'm doing a vibration and noise analysis of the player. So I'll basically see how much of a problem it is, then decide from there.

And yes, the transport was a pain to mount and yes, more likely than not it's going to vibrate a good deal. Some form of damping material is in order, but as to what, we'll see.
post #25 of 92
progress pics are looking good

edit: where did you get the dac board from?
post #26 of 92
Quote:
Originally Posted by individual6891
progress pics are looking good

edit: where did you get the dac board from?
I'm building the same one,

http://users.verat.net/~pedjarogic/audio/

TDA1541A project revision

speaking of which

what transformers are you using for the DAC strohmie?
post #27 of 92
Thread Starter 
Quote:
Originally Posted by Figo
what transformers are you using for the DAC strohmie?
I didn't propagate the CS8412 stage, so I don't need the transformer for that section. Many people were getting custom-built toroids covering all the secondaries, but I decided to use three:

One dual bobbin for the digitl supplies (+5 and +5)
One toroid for +24V (DAC analog)
One toroid for +/-18V (output stage)
post #28 of 92
Quote:
Originally Posted by strohmie
Thanks for the thumbs up jefemeister. Still no idea how much noise I'm going to have in this thing though, but I'm keeping my fingers crossed.

Oh, and someone has to help me come up with a name for this behemoth. CD-Pro2M with a Dynahi installed...

DynaPro?
StrohnaPro?
Strohprohi?
CDKG?
Pronahi?

pRonahi?

(edit: over a thousand hits! I feel so loved)
Audio DynaMite
(well, I guess you aren't building balanced Dynahi, right?)

DynaHybrid

DynaHiCD
Dynahi-CD

-Ed
post #29 of 92
Thread Starter 
Quote:
Originally Posted by Edwood
(well, I guess you aren't building balanced Dynahi, right?)
It's hard enough fitting one Dynahi into this case. You should see the size of the transformer I just got in the mail.

I'm leaning towards DynaPro momentarily. Though Shiva might not be bad either.
post #30 of 92
* DynaSource

(nice name for a company...DynaSource Audio or www.dynasource.com )


* CDyne V1.0
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