PCB for PCM2902 (digital out)

[~n00beR]

Count me in for at least 1 maybe 2 boards.

Will there be a kit available or just the bare boards?, or mabye a group buy for all the parts.

Sorry im just too lazy to do it for myself

EDIT: crappy spelling

 

[walangalam]

Are there mounting holes in this version? The 2702 pcb only had holes on one side, it was not really secure.

3 holes would be preferable.

I'm interested in 1. If theres a kit, thats better for me.

 

[Kenny12]

if theres a kit i'll be intrested in one or 2

btw usb dac rocks ^.^

 

[guzzler]

I could put holes on the board, but it will make it quite a bit bigger (probably about 1cm each way). If there is more space after adding the holes, I could include some space for bigger filter caps and possibly even the transformer if it's not too expensive. Kits; we'll see. It's a lot of work to sort out kits (not to mention money!), although it makes life a lot easier for people to buy kits. For the last batch of the PCM2702 boards, I think there were about 1500 components to get sorted, some of them on reels

I'll add the holes tomorrow, and see how big the board becomes

Deadlines:

Revision requests: 12pm Tuesday 1st March (will decide on kits by then too)
Order requests: 12pm Thursday 10th Match

g

 

[~n00beR]

Quote:

Originally Posted by guzzler I could put holes on the board, but it will make it quite a bit bigger (probably about 1cm each way). If there is more space after adding the holes, I could include some space for bigger filter caps and possibly even the transformer if it's not too expensive. g

You could add the extra holes to the board but leave the existing layout as it is, if you dont need the holes you could just cut the board down, or you could add the option of a peforated brake point on the edge to remove the holes, but I have no idea how this would effect the cost of the board manufacture.

I would rather the board would fit in the hammond 1455C also, but I'm happy to go with the majority.

Would it be worth while having a poll to finalise a desicion on having holes or not, t'would be quicker

Hope no one minds me adding my 2p' worth

Cheers

Craig

 

[guzzler]

I don't like to leave blank areas on PCBs that are meant to be small, as all it does is up the cost (you pay for area, not for content), and I don't want to do that. Anyway, holes added; less drastic than I thought it would be, only about 2mm added to the length of the board. I didn't use the full size holes in Eagle, with about 1cm of keep out zones, which makes life easier. So; here it is:

I'm going to move the via for the TTL -> coaxial converter so it's not directly connected to a decoupling capacitor, should reduce noise on the output a little, and maybe segregate input/output ground planes...

g

 

[paologatto]

Hello everybody!
I made a lot of experiments with PCM2902 and PCM2906 (quite the same chip). Maybe of your interest my final PCB layouts and prototypes.. I made 2 versions: one with the only analog IN and OUT, very little and suits perfectly in hammond enclosures. The other, bigger, includes digital (coax and optical) IN and OUT and also a mic preamplifier and a stereo VU-METER.

Here are some pictures:


Small version PCB



Small version PCB populated with components



Inside an Hammond enclosure



Digital IN/OUT with PCM 2906 (part of the big project)



Complete Big project (3 different PCBs)



Big version inside a bigger Hammond enclosure

 

[Nisbeth]

Quote:

Originally Posted by guzzler Anyway, holes added; less drastic than I thought it would be, only about 2mm added to the length of the board.

Very nice! Makes the board quite a bit easier to mount

/U.

 

[Nisbeth]

Hi Paolo and welcome to head-fi

I've seen your products before and I thought they looked very nice - now I can see that they look just as good on the inside

/U.

 

[walangalam]

Great that it worked out. Thanks

 

[paologatto]

Quote:

Originally Posted by Nisbeth Hi Paolo and welcome to head-fi I've seen your products before and I thought they looked very nice - now I can see that they look just as good on the inside /U.

Hi Nisbeth
Thanks!

I found a really interesting forum!!

Ciao

 

[dsavitsk]

Quote:

Originally Posted by guzzler Deadlines: Revision requests: 12pm Tuesday 1st March (will decide on kits by then too) Order requests: 12pm Thursday 10th Match

Just a bump so that anyone who needs to be aware of these deadlines is.

As a side note, my vote would be for 3/4 kits -- that is, the PCB with some of the hard to find parts (the wimas, the usb jack, etc.)

 

[Kenny12]

hrm.. maybie someone should make a website of what the boards / plans are, hard to find in all these posts

 

[dsavitsk]

To convince myself it could be done, here is a preliminary list of digikey parts for the project (based on Guzzler's earlier list of parts). Please PM me with changes, errors, omissions, etc.

# Descr .................................................. .......... Digikey Part #..........Price / min quantity

1 x PCM2902 (SSOP28) ................................................. 296-12986-5-ND ........ $9.00 / 1
1 x 74HC04 (SO14) .................................................. . 296-12883-1-ND ........ $0.44 / 1
1 x TPS793 4.75V (SOT23-5) <-- pain to solder! ....................... 296-12160-1-ND ........ $1.14 / 1

1 x 560µF 6.3V Panasonic FC .......................................... P12705-ND ............. $0.48 / 1 (backordered)
2 x 22µF 10V OS-CON SC (or equivalent similar, FCs are fine) ......... P11213-ND ............. $0.32 / 1 (inexact match - 25V (6.3V available))
4 x 1µF Wima MKS-02 (or similar, tantalum should be ok, 2.54mm pitch). 399-1337-ND ........... $0.41 / 1 (tantalum - 25V)
6 x 100nF 0805 ceramic capacitors .................................... PCC1843CT-ND .......... $0.06 / 10 (panasonic ecg)
1 x 10nF 0805 ceramic capacitor ...................................... PCC1991CT-ND .......... $0.09 / 10 (panasonic ecg)
2 x 33pF 0805 ceramic capacitors ..................................... PCC330CGCT-ND ......... $0.05 / 10 (panasonic ecg)

1 x 1M 0805 resistor ................................................. RR12P1.0MDCT-ND ....... $0.15 / 10 (sasumu 0.5%, .1W)*
1 x 1K5 0805 resistor ................................................ RR12P1.5KDCT-ND ....... $0.15 / 10 (sasumu 0.5%, .1W)
1 x 360R 0805 resistor (higher quality, if possible) ................. RR12P360DCT-ND ........ $0.15 / 10 (sasumu 0.5%, .1W)
1 x 91R 0805 resistor (higher quality, if possible) .................. RR12Q91DCT-ND ......... $0.15 / 10 (sasumu 0.5%, .1W)
2 x 22R 0805 resistor ................................................ RR12Q22DCT-ND ......... $0.15 / 10 (sasumu 0.5%, .1W)

1 x 12MHz HC49 crystal oscillator .................................... CTX058-ND ............. $0.94 / 1
1 x 10µH 1210 inductor ............................................... DN10103JCT-ND ......... $1.02 / 1
1 x USB B-type connector ............................................. WM17109-ND ............ $1.94 / 1
1 x RCA socket
1 x case
1 x USB cable


Edit: added usb connector.

 

[Nisbeth]

Guzzler, I can't really see this from the renderings, but can the mounting lugs of the USB-connector be soldered to the board? If not, you should try to make pads for this on the bottom as it greatly helps mechanical stability.

/U.