|
|
Rank: Administration
Groups: Administration
, Customer
Joined: 10/24/2006
Posts: 966
Location: West Newbury, MA, USA
|
Any one else have any feedback or comments yet?
|
|
Rank: Member
Groups: Beta Testers
, Customer
Joined: 11/28/2006
Posts: 8
Location: Netherlands
|
My opus set is up and running now!
This is proof that the kit is foolsproof. This is the second thing I put together and it worked the first time I pluggin. It plays wel. Comparison with the analog uotput from the cdplayer is hampered because the output level of the opus dac is rather low (used single ended). I am defenitely in for a buffer (twisted sibling?).
For now cheers!!
Gr GJ
|
|
Rank: Member
Groups: Beta Testers
, Customer
Joined: 10/25/2006
Posts: 7
Location: Klamath Falls Oregon
|
I've had several days of listning and comparing. I'm comparing the Opus to the DAC that is in my Sony DVP-CX985V. This is a 400 disk changer that plays DVD, CD, and SACD material. It shares the same audio board and DAC with the DVP-CX777ES. The internal DAC is an AKM AK4358 192khz 24bit 8 channel DAC with 112db S/N and Dynamic Range. The player was configured for CD Direct mode with the Sharp roll off filter selected.
I listened to a wide range of music, from Yo-Yo-Ma cello pieces to AC/DC Live at Donnington DVD. It seemed to have a slightly larger sound stage than the Sony DAC. The higher frequency range was less harsh. Maybe because it has a little more dynamic range. I listened at the whole range of levels, from soft background to in-your-face loud (110db SPL). On the softer side I had a hard time telling one DAC from the other. They are both very good at what they do. However, when the volume was cranked up, there was a large difference. The Opus was the clear winner. The sound was crisp and clean.
I used two different combinations of amplifiers during my testing. First I used an ADCOM GFA-2535 (4 channel 60wpc) to bi-amp a pair of modified JBL E-90 floorstanding speakers. This was fed by a LR active crossover 24db/octive crossed at 320hz. The mid and tweeter were powered by one pair, and the dual 8" woofers were powered by the other pair.
Testing with the Sony DAC showed that when the volume was at high levels the Instantaneous Distortion Alert LEDs on the amplifier would flicker from time to time. I was not able to use full volume because of distortion.
Testing with the Opus DAC was a different story. The IDA LEDs never even flickered. I cranked it to the same measured SPL as the other test.
The second combination used the My-Ref amp for the mid/tweeter pair and 1/2 of the GFA-2535 for the bass pair. The My-Ref sounded just a touch more detailed than the Adcom, but the results were the same. High volume levels resulted in no distortion for the Opus.
I know that this isn't high end audio equipment that I was testing with, but it may represent what a Mid-Fi user may have.
I had a slight problem when building the DAC because some of the silk screen numbering was missing. C22 was unreadable as well as a couple of the resistor designations. I was able to figure everything out by refering to the component layout drawing.
I'm not sure why there is no output filtering. A 20khz or 25khz low pass filter may improve the S/N and dynamic range. 20khz is recommended by Wolfson.
I left my DAC configured for an unbalanced 75 ohm input and was happy with the result. This might be an option for those using only commercial equipment to feed the Opus.
|
|
Rank: Member
Groups: Beta Testers
, Customer
Joined: 12/27/2006
Posts: 2
Location: North Vancouver, B.C., Canada
|
OK guys, I finally finished mine (with the exception of the back panel of the case) due to having some time avaible due to Christmas. Everything was a breeze putting it together, didn't run into any problems. At first I was disappointed in the sound, as it was really muddy, but with several hours of playing time it has really opened up and now clearly betters the Toshiba DVD player I was using previously  . I had one good laugh during the build, which occurred when I went to set the voltage levels on the outputs of the power supply. Without touching a thing, the analog and digital supplies were exactly 7.00V and 5.50V respectively. I didn't have to put screwdriver to potentiometer at all! How Brian knew which pot I was going to use for which side I'll never figure out. Talk about coincidences. I have found one small glitch though  . If there is no signal to the DAC, it emits random clicks and pops. It doesn't do this while playing, nor when the transport is playing a disc but paused. The clicks happen whether or not the SPDIF cable is connected to my DVD, so it isn't an artefact from the DVD player. I don't have the LED or the IC for the error mute installed. Overall, for a Beta level product, the Opus is far exceeding my expectations. Thanks to Twisted Guys, I am now balanced from source to speaker. If I can figure out how to put up some pics here I'll show how mine went together. Terry
metalman attached the following image(s):
|
|
Rank: Administration
Groups: Administration
, Customer
Joined: 10/24/2006
Posts: 1,359
Location: Nashville, TN
|
metalman wrote:OK guys, I finally finished mine (with the exception of the back panel of the case) due to having some time avaible due to Christmas. Everything was a breeze putting it together, didn't run into any problems. At first I was disappointed in the sound, as it was really muddy, but with several hours of playing time it has really opened up and now clearly betters the Toshiba DVD player I was using previously . I had one good laugh during the build, which occurred when I went to set the voltage levels on the outputs of the power supply. Without touching a thing, the analog and digital supplies were exactly 7.00V and 5.50V respectively. I didn't have to put screwdriver to potentiometer at all! How Brian knew which pot I was going to use for which side I'll never figure out. Talk about coincidences. I have found one small glitch though . If there is no signal to the DAC, it emits random clicks and pops. It doesn't do this while playing, nor when the transport is playing a disc but paused. The clicks happen whether or not the SPDIF cable is connected to my DVD, so it isn't an artefact from the DVD player. I don't have the LED or the IC for the error mute installed. Overall, for a Beta level product, the Opus is far exceeding my expectations. Thanks to Twisted Guys, I am now balanced from source to speaker. If I can figure out how to put up some pics here I'll show how mine went together. Terry Hi Terry! I knew I could count on you man. :) Balanced (or even better X'd) all the way brother. Very very interesting findings.... :) Mirrors a much of my own opinion. Now for your clicks and pops, I have an idea. Try lowering the value R19, maybe by half. The funny thing is, I cannot duplicate this... :( So I a wondering what is going on. Thank you very much for your support and kind words. I knew I could count on some good feedback from you. :)
|
|
Rank: Member
Groups: Beta Testers
, Customer
Joined: 12/27/2006
Posts: 2
Location: North Vancouver, B.C., Canada
|
Thanks Russ,
Your suggestion also gives me a couple of other ideas too. Let me try a couple of things and report back.
Just finished listening to the Reference Recordings production of Bolero, and switched over to Indie Arie. This DAC handles the deay after transients very well, and doesn't get jammed up by a densely layered soundstage. Bass is solid and clean.
|
|
Rank: Administration
Groups: Administration
, Customer
Joined: 10/24/2006
Posts: 1,359
Location: Nashville, TN
|
Ok did some testing on my own, I wonder if actually omitting R19 might solve it. I just tried the DAC without R19 and all is well. But then I never had a problem. I am just thinking this should "totally" isolate the SPDIF input from the DAC digital PS.
|
|
Rank: Member
Groups: Beta Testers
, Customer
Joined: 11/28/2006
Posts: 1
Location: Glendale, AZ
|
Finally up and running, thanks to a few emails with Russ and what must have turned out to be dumb luck. Spent a day and half trying to figure out why I had a dead OPUS. At last, I studied the OPUS schematic and realized the 5 pin header is a great set of debug test points. So moved the whole set up over where my scope probes would reach. Checked the input. Had signal, so turned on the unit to begin the debug.
Wait a minute! What is that music coming out of the speakers???? Yeah, the optimist had hooked it up to the amp and speakers. Ran it for a while. Switched to the differential inputs on the amps (a couple of Audiosource 5.1's in my lab) and OPUS is putting out some real sweet music.
I don't know what was wrong. Suspect I was stretching the digital cable, but moving things to the new setup and she works just fine. Differential sounds great with a sound stage better than others I have had in my lab.
So that was yesterday. Today I boxed it up and it is now running the output of a Cal Audio CL-10 into a Twisted BOSOZ and from there to a pair of Aleph-2 clones made from BrianGT boards. Finally feeds some homemade speakers using Focal's.
With this setup I can directly compare with the DAC in the Cal Audio and with the Benchmark DAC-1 that I have been using. First impression is that the soundstage is broader with OPUS. Very solid imaging, maybe better thand the DAC-1. Bass is a bit deeper and not sure about the high end yet. Both Joan Baez and Eric Clapton sound great (Sorry have to test with somebody's voices), but what really hit me was the detail and dynamics in ELP Tarkus (MFSL).
I hope to get a couple more pairs of ears over for some A-B blind testing relative to the DAC-1. Will say more and post pics later, but for now am finally a very happy camper.
Craig
|
|
Rank: Administration
Groups: Administration
, Customer
Joined: 10/24/2006
Posts: 1,359
Location: Nashville, TN
|
I found something very important on the Opus.
On a couple of my CDPs the OPUS exhibited the same popping sound that Terry was hearing. Luckily the fix it quite simple.
Exchange the 10K resistor R19 with a 10R (or lower even) resistor. Now all of my sources are "pop" free.
|
|
|
GuestUser |
