Help with EAGLE CMoy design, please =)

[Joshatdot]

ATM I am still broke as a joke. I hope to have enuff $ by this weekend to order my boards and parts from Digi-Key for 2 or 3 whole amps.

 

[infinitesymphony]

Ah, very cool... So we'll see some prototypes fairly soon.

I saw that you had a Digi-Key parts list posted in another CMoy thread. Are these your recommended / ideal parts?

I've built one CMoy and plan to build a few more, so I'm also looking to order in semi-bulk to save on shipping costs.

 

[Joshatdot]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif Ah, very cool... So we'll see some prototypes fairly soon. I saw that you had a Digi-Key parts list posted in another CMoy thread. Are these your recommended / ideal parts? I've built one CMoy and plan to build a few more, so I'm also looking to order in semi-bulk to save on shipping costs.

Here is the parts list I am ordering for my CMoy boards:

Code:

[left]Number Description Customer Reference ED90032-ND IC SOCKET 8 PIN .300 GOLD CMoy Kit - Socket OPA2227PA-ND IC DUAL PRECISION OPAMP 8-DIP CMoy Kit - OPA 100KXBK-ND RES 100K OHM 1/4W 1% METAL FILM CMoy Kit - R2 100k Resistors 1.00KXBK-ND RES 1.00K OHM 1/4W 1% METAL FILM CMoy Kit - R3 1k (11 Gain) 2.00KXBK-ND RES 2.00K OHM 1/4W 1% METAL FILM CMoy Kit - R3 2k (6 Gain) 10.0KXBK-ND RES 10.0K OHM 1/4W 1% METAL FILM CMoy Kit - R4 10k Resistors 49.9XBK-ND RES 49.9 OHM 1/4W 1% METAL FILM CMoy Kit - R5 50ohm (Optional) 296-1994-ND IC 1/2 RAIL VIRTUAL GND TO-92 CMoy Kit - Rail Splitter TO-92 493-1823-ND CAP 220UF 25V ELECT PW RADIAL CMoy Kit - C1 220 uF 495-1087-ND CAP 1.0UF 50V METAL POLY CMoy Kit - C2 1.0 uF CP1-3533-ND CONN JACK STEREO R/A 3PIN 3.5MM CMoy Kit - IN/OUT 350-1560-ND LED 3MM BLUE DIFF CMoy Kit - LED Blue 67-1330-ND HOLDER LED PANEL 3MM BLACK NYLON CMoy Kit - LED Holder 226-3104-ND KNOB CLR/MATTE .50"DIA 6MM SHAFT CMoy Kit - Knob[/left]

 

[Ace o' Spades]

I suggest changing the power supply capacitor value to 470.

 

[Joshatdot]

220uF is just fine with a TLE2426 railsplitter. but for the standard resistor divider two 470uF is recommended. check out AndrewFishers reply earlier in this thread: http://www.head-fi.org/forums/showpo...5&postcount=49

 

[Joshatdot]

I just found out about Eagle3D, where it can makes a POV-Ray script & make a 3D rendered image of my board!

 

[infinitesymphony]

Lookin' good. I'm still eagerly anticipating this board. Off-topic, but what's your opinion on something like the 2132P (audio version) op-amp versus the 2227PA you have listed?

 

[Joshatdot]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif Lookin' good. I'm still eagerly anticipating this board. Off-topic, but what's your opinion on something like the 2132P (audio version) op-amp versus the 2227PA you have listed?

There is a post comparing the OPA2132 & AD823: http://www.head-fi.org/forums/showthread.php?t=244544

I have not seen a review comparing the OPA2227, but I like it in my CMoy. It has a nice flat frequency response. It drives my 70ohm & 60ohm cans well @ gain 6. Nice and detailed sound.

 

[balou]

here's a comparison between various opamps: http://www.sgheadphones.net/index.php?showtopic=2628

the conclusion about the 2132 is similar to mine (avoid!). it has no review about the 2227, but about it's faster brother, the 2228. this one seems to be a nice middle ground between the dark burr brown sound and the brighter analog devices sound. the 2227 seems to be more burr-brown like, meaning less treble detail etc. Here's a very concise review, with the 2227, 2228 and 2132 in it: http://www.tangentsoft.net/audio/opamps.html Tangent seems to like the burr brown sound. I don't, the opa2132 sounds just as crappy as the headphone out of my ipod. The 2132 is no fun in a cmoy.

 

[infinitesymphony]

Thanks for those. An AD op-amp might be in my future.

I put a 2132P in my first CMoy and thought it sounded pretty good! Though, I've never heard any other headphone amplifiers, so I have no comparison.

It seems a lot of people are using the Yageo resistors from DigiKey (including Joshatdot in his 3D image)... They must be pretty decent, right?

 

[Joshatdot]

hmm..now I am interested in getting some AD op-amps and some others. How does the LM4562 perform in CMoy's, anyone know?

I choose 1/4 watt 1% resistor Yageo's from Digi-Key cause I wanted to buy allmost everything from one supplyer. And 1/4 watt 1% resistor Vishay Dale's are popular from Mouser.

 

[Pars]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif It seems a lot of people are using the Yageo resistors from DigiKey (including Joshatdot in his 3D image)... They must be pretty decent, right?

I like the BC (PPC are the same) from Digikey personally, but I'm sure the Yageo's are fine as well.