CMOY Parts List / Recommendations

[GendoIkari]

Here is a screen shot of my DigiKey parts order to build my first basic CMOY :

I just wanted to make sure I got everything (I should only be missing a case, 9v Battery and PCB)

Also, any recommendations on optional parts I should add or change?

I am planning on just buying a piece of bread board from radioshack, is this wise or should I go to a premade PCB? If so, who's?

Thanks guys.

 

[Pars]

You have 10K resistors on twice. I would probably recommend getting some 2.2K resistors and maybe some more 4.75K so you can play around with the gain... the stock gain of 11 is really loud and unnecessary in most cases. I would also use P12388-ND 470uf 25V Panasonic FMs instead of the 220uf you have listed. For the input caps, get the 0.47uf 63V Epcos 495-1112-ND as these will easily fit and will give you a lower corner frequency than the 0.1uf will. The battery straps you can get from Radioshack (the heavy duty ones) as well. What were you going to use for an on-off switch? I personally would use the Alps RK097 pot with switch from Tangent instead of the Panasonic, but I can understand if you are trying to get everything from one place. Of course I'd also use the BC or PPC resistors instead of the Yageo, but that is just personal preference.

I'd probably also get 1 or 2 TLE2426CLPs (rail splitters) and use one of these instead of the voltage divider (simple drop in, much better performance).

As far as PCBs go, the only ones I know of currently are these, which look pretty decent.

EDIT: Oops, Josh reminded me, you need an opamp socket... A400-ND is my favorite, the one he lists will work as well. Get a couple.

 

[Joshatdot]

Here is what I got for my CMoy parts list:
Code:

[left]1 2 P12388-ND CAP 470UF 25V ELECT FM RADIAL CMoy - C1 470 uF 0 0.50000 $1.00 2 2 P3933-ND CAP POLYPROPYLENE .47UF 50V 2% CMoy - C2 .47 uF 0 1.59000 $3.18 3 5 4.75KXBK-ND RES 4.75K OHM 1/4W 1% METAL FILM CMoy - R1 4.7k 0 0.09800 $0.49 4 5 100KXBK-ND RES 100K OHM 1/4W 1% METAL FILM CMoy - R2 100k 0 0.09800 $0.49 5 5 2.00KXBK-ND RES 2.00K OHM 1/4W 1% METAL FILM CMoy - R3 2k 0 0.09800 $0.49 6 5 10.0KXBK-ND RES 10.0K OHM 1/4W 1% METAL FILM CMoy - R4 10k 0 0.09800 $0.49 7 1 OPA2227PA-ND IC DUAL PRECISION OPAMP 8-DIP CMoy - OPA 0 3.96000 $3.96 8 1 ED90032-ND IC SOCKET 8 PIN .300 GOLD CMoy - 8 DIP Socket 0 0.60000 $0.60 9 2 BS3I-HD-ND SNAPS 9V 3" LEADS I-STYLE HD CMoy - 9v Straps 0 0.34000 $0.68 10 1 350-1560-ND LED 3MM BLUE DIFF CMoy - LED 0 2.17000 $2.17 11 5 67-1330-ND HOLDER LED PANEL 3MM BLACK NYLON CMoy - LED Holder 0 0.12000 $0.60 12 2 CP1-3513-ND CONN JACK STEREO R/A 3PIN 3.5MM CMoy - 3.5mm IN/OUT 0 0.59000 $1.18 13 1 226-2008-ND KNOB CLR GLOSS.50"DIA 6MM SHAFT CMoy - Knob 0 4.73000 $4.73[/left]

 

[GendoIkari]

I would like to get as much as possible from DigiKey, is this better?

Any more additions / changes you'd recommend?

Is Joshatdot's OPA2227PA-ND OPAMP a better choice?

 

[Sherwood]

Tangent loves the 2227, and it sounds great in my cmoy. Considering the fact that you've added a socket, you might want to get both and roll them to see which you prefer. I'm sure you could unload an extra opamp on head-fi no problem.

On a sidenote, since it's your first cmoy do you have all of your solder, hookup wire, etc.? It can be bought locally, but you seem to want to keep everything with digikey.

 

[GendoIkari]

Good point on rolling OPAMPs, I added a socket (per Pars' post) and didn't even think about it. I have some WBT silver solder but i do need to get hookup wire... any recommendations, or more importantly, what to steer clear of!

As far as keeping everything with DigiKey, I can't handle waiting for multiple packages... and I want it all coming at the same time. Some sort of weird OCD thing I guess, I don't just dislike it, it drives me crazy.

 

[balou]

you might want to get a low current led instead of a normal one.
normal led: 20mA current draw at full brightness
low current: 2mA at full brightness

opa2132 in idle: 9mA current draw. under load: 10-12mA.

so it does make a difference

 

[GendoIkari]

Parts ordered! Thanks for all the help guys, I'm sure I'll have questions once I get it all thrown together!

one last question I had asked earlier : hookup wire... any recommendations, or more importantly, what to steer clear of!

 

[Sherwood]

As always, I refer to Tangent.

He recommends 24 gauge irradiated. The irradiated is important, especially with silver solder, because it won't shrink away with heat. I use 22 gauge, and it fits fine through the pads on that radioshack breadboard. Just make sure you get some red and some black. I also have some blue for ground (i like it better than green). A couple feet of each would be fine.

In general, stay away from anything larger gauge than 22 -- it will be impossible to work through your board. The irradiated is also nice when you're as clumsy with an iron as I am.

 

[splaz]

Coincidently tangent now sells irradiated pvc hookup wire.

 

[Sherwood]

Quite the cottage industry over there at chez tangent.

 

[GendoIkari]

I ordered the 2 of the irradiated pvc hookup wire kits he sells, how convenient!

I can't wait to give this a shot!

 

[Joshatdot]

good luck on the CMoy, post WIP & final amp pics

 

[Joshatdot]

Quote:

Originally Posted by balou /img/forum/go_quote.gif you might want to get a low current led instead of a normal one. normal led: 20mA current draw at full brightness low current: 2mA at full brightness opa2132 in idle: 9mA current draw. under load: 10-12mA. so it does make a difference

What do you recommend for a blue low current LED?

 

[balou]

umm... blue low current seems to be a bit of a trouble. green, yellow, red and orange are readily available, but not blue. farnell stocks a 10mA blue 3mm led, FNL-U300B05CDSL — FORGE EUROPA, order number 1200579. but it's not marketed as low current - it's easy to make a led thats at full brightness at 10mA if its dim. part number 1200578 (also a blue led from forge) may actually be better suited - quite bright (180mcd vs 34mcd), but rated for 20mA. might be brighter if you limit the current draw with resistors to the same mA rating. I think I'll order the two and test them out, I need parts for my pimeta from farnell anyway. and I still need an led for that too.