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glt  
#1 Posted : Tuesday, April 7, 2009 11:07:14 PM(UTC)
glt

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With all attention given to Buffalo, here is a bit of love to little orphan OPUS :-)

Just completed another stage in my Arduino controller for OPUS WM8741

I have enabled:

1- Filter selection from filter 1 to filter 5
2- Volume control from -63 dB to -0 dB in 1 dB increment
3- LCD showing selected filter and volume

Selections and volume are done with button switches.

Have done some comparisons with the filters:

Filter 1 vs filter 5: prefer filter 1, I compared the sound of the cowbell. Filter 5 the cowbell sounded a bit "deader". Prefer filter 1

Filter 2 vs filter 2: the cowbell sounds the same on both. Compared acoustic guitar: Filter 1, the sound is fuller and the resonance lingers a bit longer. Prefer filter 1, but very close to filter 2

Still to compare filter 1 with filter 3 and filter 4.

This is an ongoing project... Can add more bells and whistles. The Arduino controller can hold 14K of code. Right now the code is less than 5K in size. I've put the code in my blog

Edited by user Tuesday, April 7, 2009 11:08:46 PM(UTC)  | Reason: Not specified

naa3e5  
#2 Posted : Wednesday, April 8, 2009 3:29:22 PM(UTC)
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awesome work, I wish I knew how to program! Sounds like that little arduino is pretty powerful.
Brian Donegan  
#3 Posted : Wednesday, April 8, 2009 3:41:12 PM(UTC)
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Good job.
glt  
#4 Posted : Wednesday, April 8, 2009 5:37:25 PM(UTC)
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naa3e5 wrote:
awesome work, I wish I knew how to program! Sounds like that little arduino is pretty powerful.


Very simple setup and code. You can just copy what I did...
glt  
#5 Posted : Friday, April 10, 2009 11:09:46 AM(UTC)
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I know of only one other DAC that can select the 5 filters (besides mine :-) ): The PS audio PerfectWave DAC: http://www.psaudio.com/p...erfectwave-dac?cat=audio

Russ White  
#6 Posted : Friday, April 10, 2009 12:00:21 PM(UTC)
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I can select any filter I like, and any other register setting using an IR remote and a Volumite. All this with a nice VFD display. :)

The volumite can be connected to an RE and or a IR receiver easily.

But its even easier with the AC1. Which I am working with at the moment. :)

One really nice thing about the AC1 is the on-board fast FRAM which makes saving state a breeze.

Also I can leave the USB cord plugged into the Femto and program changes on the fly. Its pretty fun :).

The whole idea behind exposing the SPI and I2C interfaces on our modules is to allow people like you and I do be able to do just this. :) So have fun no matter which platform you like to use.

Cheers!
Russ
glt  
#7 Posted : Friday, April 10, 2009 2:08:59 PM(UTC)
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Russ, didn't mean to exclude yours. :-). But proud of my little accomplishment and definitely thanks to you/Brian for exposing the spi/i2c pins. It seems Femto and Arduino are 95% the same.

While reading the PS Audio product, they have a lot of pride on the output stage. Right now I am using OPUS w/o output stage, but have ordered and IVY I to try out. I will follow the values in the manual, but any thoughts in tweaking the IVY for OPUS?
Russ White  
#8 Posted : Friday, April 10, 2009 2:21:26 PM(UTC)
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Now worries. :)

The only think I would suggest on IVY for Opus is don't use the feedback caps at all. Just use the Rs.

Cheers!
Russ
glt  
#9 Posted : Friday, April 10, 2009 3:32:49 PM(UTC)
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Russ,

Do you mean C1-C4? Thanks.
Russ White  
#10 Posted : Friday, April 10, 2009 5:54:57 PM(UTC)
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Yes. :)
glt  
#11 Posted : Sunday, April 12, 2009 10:36:18 PM(UTC)
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Further listening...

Had to increase the volume control from -99 db to 0 db as -60 db was plenty loud. For most modern recording, my normal listening level is in the -50 db. range...

Also enabled the anti clipping feature of OPUS and that's -2db

Now using the OPUS straight to a balanced Hypex AMP. Sounds superb. Excellent module.

Russ, would it make sense to lower the gain of IVY to <1? That way I can increase the volume of OPUS.
Russ White  
#12 Posted : Monday, April 13, 2009 7:17:53 AM(UTC)
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Sure, just reduce the value of R1-4. You can easily go down to 357R. 392R would be roughly ~14db reduction.
glt  
#13 Posted : Friday, May 1, 2009 10:37:59 AM(UTC)
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Some TLC for OPUS: Here is a review on the WM8741 http://www.lampizator.eu...ac/WolfsonWM8742DAC.html

Also, I've added remote control to my project. I'm way, way slower than Russ, but catching up :-)

I also did some more listening tests with the filters (now that I can select them with the remote). But this time rather than focusing on specific sounds, I tried to just listen to the music as a whole. Well, couldn't tell any difference switching the filters on the fly. I guess this type of test would require a more extended listening session.
neb001  
#14 Posted : Tuesday, May 5, 2009 5:54:22 AM(UTC)
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I've been following your blog glt, and I think I might pick up an arduino to play around with myself! It looks quite powerful, though I'm sure it'll take some time to even get started.
glt  
#15 Posted : Tuesday, May 5, 2009 2:09:46 PM(UTC)
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neb001, please share your experiences. I'm not a software guy by profession, and my level of programming is basically what I learned in college. But the platform is easy to use and most of the code are derived/copied from examples in the forums. I've enjoyed tinkering with it a lot. That is an advantage over AC1 because Russ already did all the tinkering thus taking the fun factor away :-) :-)

I'm actually surprise that the the WM8741 is getting such good reviews and for us DIYers, the OPUS is the only source. I think on a price/benefit ratio, the OPUS beats the Buffalo. I think the 5 selectable filters is a added plus.

Edited by user Tuesday, May 5, 2009 2:10:21 PM(UTC)  | Reason: Not specified

Russ White  
#16 Posted : Tuesday, May 5, 2009 2:15:02 PM(UTC)
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LOL, well yes I have done some hard coding work on AC1, but its up to the user to use it. ;) So people can still tinker as much as they like. The choice is yours. :)
neb001  
#17 Posted : Wednesday, May 6, 2009 12:16:49 AM(UTC)
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Unfortunately I'm not a software guy by any means either. I enjoy tinkering with hardware mostly, but I think it'll be a fun challenge to get it to do what I want. I have a bunch of ideas that I'd like to do and will have a grand time finding out if it's possible to do it, then figuring out how to do so :d/

Any tips on stuff I should pick up to ease the learning/tinkering/development process? I was thinking of picking up the Duemilanove, a protoshield kit, a pot or two, a button or two, and a bunch of led's.

I think I will probably end up also picking up the AC1 when it comes out.

Edited by user Wednesday, May 6, 2009 12:20:24 AM(UTC)  | Reason: Not specified

glt  
#18 Posted : Saturday, May 9, 2009 1:51:55 PM(UTC)
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With case...

UserPostedImage

Edited by user Saturday, May 9, 2009 3:14:30 PM(UTC)  | Reason: Not specified

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