- ... Hi, I had built this kit with the same goal. The kit is sold by the author of the article and my results are a mix of good and bads. First the bad ones:Message 1 of 54 , Apr 1, 2007View SourceTerry wrote:
> Hello Tom,
> Have you played with the PCM2900 to see how well it works with
> SoftRocks? Are there appropriate drivers for Windows XP and/or Linux?
> VERY INTERESTING....
> I ran into a reference to an article in Nuts and Volts from June 2005
> that has a board available for $25-35 that incorporates this chip,
> and was wondering it this setup would be good for laptop softrock
> use. I presently use either the Audigy 2 ZS PCMCIA, or an Extigy.
> Web site for board is: http://users.skynet.be/bestelectrix
I had built this kit with the same goal. The kit is sold by the author
of the article and my results are a mix of good and bads. First the bad
There were a couple of errors in the kit, the first one was a pcb layout
error that I had to correct cutting a lane and adding a wire. The other
error was a component layout error, which caused a lot of imbalance
between channels due to a couple of resistor swapped. The worst thing
was that this error was also in the published and doc pictures, so after
a lot of frustration and realizing that this kit was a transcription of
TI recommended circuit, finally I found the bug.
I sent an email to the author complaining and I got a response several
months after, apologizing for the problems and telling that his kit
bussines has been launched again and assuring the problems were solved.
The card is a low end class, can't extract all the quality of a
softrock, but the price is right for what you get. It skews one channel
one sample, but this is supported by several programs we use. The card
has not mixer.
Now the good things:
It doesn't need a special driver, the USB audio driver of windows
I coupled it with a softrock 40, the version powered by USB so I got a
compact self contained unit very useful for demos to clubs and so, with
just a cable to the USB port of a laptop.
It is also a useful front end for virtual instruments, like counters,
oscillators and scopes that use soundcards.
If anybody is interested in building this kit, tell me. I´ll supply my
findings in the case the author has not modified the bugs.
73 de Ignacio, EB4APL
- ... a year ... so I can ... affects the ... components, ... should be ... the ... the ... the ... and ... done ... that ... codec. I ... in the ... affactedMessage 54 of 54 , Jul 31, 2007View Source--- In email@example.com, Ignacio Cembreros <eb4apl@...>
> Guido wrote:
> > On 7/30/07, *Ignacio Cembreros* <eb4apl@...
> > <mailto:eb4apl@...>> wrote:
> > Terry, Guido et all.
> > I bought the same kit mentioned in Nuts and Volts, more than
> > ago. Finally I found the kit documentation in digital formatso I can
> > describe the problems I had.affects the
> > The picture has an error, a swapped resistor pair, which
> > balance. If you have followed the picture for placing thecomponents,
> > like me, you swapped R11 and R13. R11 should be 6k8 and R13should be
> > 3k9 and they must be located as per the silkscreen, not perthe
> > picture.the
> > Another error is in the PCB itself which doesn't agree with
> > schematic and is related to the supply method. This affectsthe
> > performance, according to TI.and
> > My solution is to cut the trace which goes from C2 to a via
> > finallydone
> > to U3 pins 8,9 and 27; do it just after C2 and solder a wire
> > jumper from
> > C2 (or C1) to R9 (VBUS in the schematic). All this rework is
> > in thethat
> > bottom side of the card.
> > As you can see, both problems can be easily fixed, and after
> > I usecodec. I
> > this mini card for demos with an SR40 with reasonable results.
> > 73 de Ignacio, EB4APL
> > Hello Ignacio,
> > Thanks for reporting about your experience with the PCM2900
> > have no access to the Nuts and Volts schematic, but presume thein the
> > circuit is not different than the typical circuits as published
> > datasheet  ? Could you indicate which of the componentsaffacted
> > the performance?<snip>
> I was referring to a PCB layout error in the Nuts and Volts kit
> not in the schematic which is close to the TI evaluation boards,with
> minor variations.. If you are interested in the schematics and thekit
> description, let me know it and I will send it directly to you.regulator
> According to TI, the circuit can be powered from the internal
> or an external one. The use of the internal regulator affectshave
> negatively to the harmonic distortion and maybe the noise, I don't
> the application notes here but are on the TI site. So TIrecommends to
> use a cheap external regulator, except for very cost sensitive lowend
> 73 de Ignacio, EB4APL
Thank you for the above information. I checked my ADDA board, and it
has both the problems you mentioned above. I purchased the assembled
units, not the kits, but the resistors were wrong anyway.
I ahve made both the changes you outlined above, and will test the
board for improvements. It certainly cannot be worse that the board
It will likely be a week before I can test it, as I have some travel
Thank you again for highlighting the two problems above. I do not
have the original Nuts & Volts article. I have only the schematic
that came with the board, and the TI datasheet.