Using a GMOY PCB and tangents part list?

Dec 23, 2005 at 10:22 PM Thread Starter Post #1 of 15
joostoo

joostoo

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Well, I ordered my parts from Digi-key over the phone, my parents let me use their credit card number, and the parts arrived the VERY NEXT DAY! Very impressed.

The PCB of choice is going to be guzzlers PCB. However to choose the parts I was going to get, I used tangents list found http://tangentsoft.net/audio/cmoy-tu...parts.html#req there. I used all the first selection, in other words I didn't use any of the alternatives.

But I got them, and when I'm placing them on the board before soldering, they are either too big or too small. For example, the electrolytic cap doesn't really match up to the footprint, and the box-like cap is too large. The parts do fit, but I got to bend the leads abit.

So was it ok to use his part list on the GMOY board?
 
Dec 23, 2005 at 10:40 PM Post #2 of 15
g1.jpg


Should be populated like this with R2 resistor being 10 X the value of the potentiometer (ie: if the pot is 50K then use a 500K resistor in R2. If it is 20K use a 200K resistor in R2 etc.) please note the markings on the board for the 30pF cap are wrong, you'll see that if you follow the track. (connect it between the two pads with the "+" in the centre, not as shown on the board)

g2.gif
 
Dec 23, 2005 at 10:56 PM Post #3 of 15
Quote:

Originally Posted by joostoo
Well, I ordered my parts from Digi-key over the phone, my parents let me use their credit card number, and the parts arrived the VERY NEXT DAY! Very impressed.

The PCB of choice is going to be guzzlers PCB. However to choose the parts I was going to get, I used tangents list found http://tangentsoft.net/audio/cmoy-tu...parts.html#req there. I used all the first selection, in other words I didn't use any of the alternatives.

But I got them, and when I'm placing them on the board before soldering, they are either too big or too small. For example, the electrolytic cap doesn't really match up to the footprint, and the box-like cap is too large. The parts do fit, but I got to bend the leads abit.

So was it ok to use his part list on the GMOY board?


Most of them should be fine. However, since the GMoy is a modified CMoy, you will be missing some stuff if you go just by Tangent's list. The following are important (and one reason why the GMoy should outperform a CMoy), and are nearly certain that you missed them:

TLE2426 TI railsplitter
470uf caps instead of the 22uf
resistor values (different than a stock CMoy)
30pf bypass caps
1uf input caps

You hopefully got some things off the optional parts list? Like the Panasonic pot? The dip-8 socket?
 
Dec 23, 2005 at 11:35 PM Post #6 of 15
Quote:

Originally Posted by PinkFloyd
What do you need?


Well, I did take the EVJ pot, TLE railsplitter, and the DIP socket, but I used all the resistors and caps that tangent used in his list.

Also, I think we may be mixed up on the board. I'll attach a picture, and I guess you could call it his V1 board. Its single sided. For THIS board can I use tangents list?

Can't get the pic up, so I'll just get the post from where I got it. Its the very first picture on the first page in the first post
http://www6.head-fi.org/forums/showthread.php?t=87056
 
Dec 24, 2005 at 3:11 AM Post #7 of 15
Yeah, they'll work. In fact the resistor values that Pinky referenced would also work in nearly any CMoy I would think for a gain of around 4.5 or so off the top of my head.

Have fun!

EDIT: BTW, where did you get the board at?
 
Dec 24, 2005 at 3:32 AM Post #8 of 15
Quote:

Originally Posted by Pars
Yeah, they'll work. In fact the resistor values that Pinky referenced would also work in nearly any CMoy I would think for a gain of around 4.5 or so off the top of my head.

Have fun!

EDIT: BTW, where did you get the board at?


Thats great, but I don't have the resistors PinkFloyd said. Instead I have the ones tangent recommended, along with the caps.

The board was made by guzzler, AFAIK. I just went to the search button and searched "CMOY PCB". He has a link for the .brd file so you can etch your own.
 
Dec 24, 2005 at 3:40 AM Post #9 of 15
Quote:

Originally Posted by joostoo
Thats great, but I don't have the resistors PinkFloyd said. Instead I have the ones tangent recommended, along with the caps.

The board was made by guzzler, AFAIK. I just went to the search button and searched "CMOY PCB". He has a link for the .brd file so you can etch your own.


Oh, you etched it? I have guzzler's board file and had used it as a starting point for an a47 board.

The resistors you got from Tangent's list will work fine. Make sure you reference the resistor numbers correctly however as I think Guzzler's board layout picture may be one off. If in doubt, check the board against the schematic to make sure what guzzler calls "R2" is the same as the std. CMoy.
 
Dec 24, 2005 at 3:49 AM Post #10 of 15
OK, that's great.

Yes, I etched the board. For my first time it didn't come out too bad. I'll try and get pics up when I'm done the whole thing.

About comparing the board to the original cmoy, how would I know what guzzler calls R2 for example. According to the original schematic, R2 is a 100K resistor, but how do I know guzzler calls it that?
 
Dec 24, 2005 at 4:25 AM Post #11 of 15
Look at the schematic. If a certain 100K resistor is supposed to be going from pin3 of the opamp to ground, see what its called in the schematic. Then look at the board and find which resistor is going from pin 3 to ground. I think the numbering is fine... I just recall one of his versions that it was off by one.
 
Dec 24, 2005 at 12:15 PM Post #14 of 15
Quote:

Originally Posted by Pars
check the board against the schematic to make sure what guzzler calls "R2" is the same as the std. CMoy.


R2 is 10 x the value of the pot so if pot is 50K then R2 is 500K
 
Dec 24, 2005 at 5:28 PM Post #15 of 15
Quote:

Originally Posted by tess
Hi.
Check this link for resistor values.

http://www6.head-fi.org/forums/showp...22&postcount=9

Alan.


Oh, wow that's a great link. And after I saw that I noticed it was right in the link I put up. Thanks for showing it to me.

Ill probably use a 4.7K resistor for R4, and a 47 ohm resistor for R5 because those are the only resistor left that I havent used.

Thanks again for that link, I can't believe I didn't see it before.
 
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