DAC-Burr Brown PCM1792

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  • bikerboy
    bikerboy Posts: 1,207
    edited December 2013
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    Jake,
    I have a step drill bit and drill press.. LMK if you need help.
    Main system: Lyngdorf TDAI 2170 w/ Pioneer 42" plazma-> Polk LSiM 703 w/Tivo, Marantz tuner, BRPTT: Nothingham Spacedeck-> Pioneer PL L1000 linear arm-> Soundsmith DL 103R-> SUT->Bottlehead ErosDigital: I3 PC w/ Jriver playing flac -> Sonore Ultrarendu -> Twisted Pair Audio ESS 9028 w/ Mercury IVY Vinyl rips: ESI Juli@24/192-> i3 PC server
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  • zingo
    zingo Posts: 11,258
    edited April 2014
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    It took me a while to get around to finishing, but I finished all the wiring and testing last night! The main power supply and transformer is from an Oppo BDP, with a 7805 regulator used to step one of the voltages down to 5V; a 1A fuse should keep everything safe. It has a single BNC SPDIF input, a stereo RCA output, captured power cord, and no power switch so it's always on and dedicated to my Squeezebox Touch.

    My initial A/B test against the DAC in the SBT provided better weight of voices (especially female), blacker background, greater image depth, and sharper imaging. I turned the system on again this morning and everything sounded good, so the DAC passed the first 12 hours without an issue. My next step is cable management, and ziptie all the components to the chassis.

    IMG_1468.JPG
    Jake
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  • FTGV
    FTGV Posts: 3,649
    edited April 2014
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    Its always nice when a project passes the initial smoke test.The coax is the way for the BNC to pc board connection. If you get in the tweaking mode you might want to try some these.http://www.ti.com.cn/cn/lit/ds/symlink/lme49710.pdf
    And maybe adding a pulse transformer to provide galvanic isolation. http://www.digikey.ca/product-detail/en/S22083/470-1003-ND/555461
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  • zingo
    zingo Posts: 11,258
    edited April 2014
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    Thanks Fred. I thought about galvanic isolation, but currently I have no hum/buzz/noise with the DAC, so didn't feel like it was necessary. The piece of Canare 75Ω coax was a good find in my parts bin, and the perfect connection to the board; especially since I opted for the BNC connector. The leads to the RCA jacks are silver DH Labs wire, and the ICs going from the Squeezebox to the DAC and out to the preamp are all matching custom Luminous Audio copper 75Ω coax with silver RCA plugs; expect the copper BNC plug.

    The LME49710 swap looks interesting, although one review I found stated: replacing the N5534 revealed fantastically detailed and the dynamics are awesome, also the bass is more articulate. However there are some negatives also; The treble seems a bit hard and shut in, bass level is a bit low and the overall smoothness isn't as I'd like it to be. Do you have any direct experience with that OPAMP? It looks like I could get six of them to my door for about $20 which isn't bad...
    Jake
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  • bikerboy
    bikerboy Posts: 1,207
    edited April 2014
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    Thats funny how long this dac has been "in the works". First Fred and now you. Glad you got it running and found it improved the sound of the SB. Looks like it is built with quality parts. Check out the isolation tx like Fred said. Even though you dont hear any noise now you might be surprised. I have been on a round of power supply/regulator upgrades for a while and have never heard any noise in the backround that needed to be reduced or removed. But the latest low noise regulators with minimal caps sounds much better than any of the previous ps. The opamps are always easy thing to swap and can make a real difference. Have fun.
    Main system: Lyngdorf TDAI 2170 w/ Pioneer 42" plazma-> Polk LSiM 703 w/Tivo, Marantz tuner, BRPTT: Nothingham Spacedeck-> Pioneer PL L1000 linear arm-> Soundsmith DL 103R-> SUT->Bottlehead ErosDigital: I3 PC w/ Jriver playing flac -> Sonore Ultrarendu -> Twisted Pair Audio ESS 9028 w/ Mercury IVY Vinyl rips: ESI Juli@24/192-> i3 PC server
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  • Polk&Beans
    Polk&Beans Posts: 94
    edited April 2014
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    "Thankfully all the the op amps are socketed so it will be a simple matter to try different ones.After I get acclimatized to the sound with the 5534's I will try some others.Tops on the list will be BB's own OPA627.(Their kinda pricy at $18ea and I'll need"

    You meant 8 sockets right? I still might have an assortment of op amps laying around from when I was messing with soundcards. That was a waste of time and money... I use a USB to Optical/Coax box now from the PC. You can have them if I can locate them.

    Pablo
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  • FTGV
    FTGV Posts: 3,649
    edited April 2014
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    zingo wrote: »
    I thought about galvanic isolation, but currently I have no hum/buzz/noise with the DAC, so didn't feel like it was necessary.
    Not with your SB but it's an option as you may find it benificial with other sources down the road.
    The piece of Canare 75Ω coax was a good find...
    The Canare LV61 is my go to digital cable.An excellent cable and I have never felt the need to spend big bucks on a higher bling factor cable.
    The LME49710 swap looks interesting, although one review I found stated: replacing the N5534 revealed fantastically detailed and the dynamics are awesome, also the bass is more articulate. However there are some negatives also; The treble seems a bit hard and shut in, bass level is a bit low and the overall smoothness isn't as I'd like it to be. Do you have any direct experience with that OPAMP? It looks like I could get six of them to my door for about $20 which isn't bad...
    Yes I have used them and the dual version(49720) in several projects,a pair of active crossovers,several Dac's and as an input buffer in a pre I,m dabbling with.I find them to to be clean, neutral,detailed and low noise.However depending upon system synergy and personal taste some may find them a bit too squeeky clean and clinical.I like them and my impression is they are more open and resolute sounding than the 5534.
    FYI.If you look at the link I post you will see near the top in blue letters "Samples".You may be able to snag a few free samples.
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  • zingo
    zingo Posts: 11,258
    edited April 2014
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    Polk&Beans wrote: »
    Thankfully all the the op amps are socketed so it will be a simple matter to try different ones.After I get acclimatized to the sound with the 5534's I will try some others.Tops on the list will be BB's own OPA627.(Their kinda pricy at $18ea and I'll need) You meant 8 sockets right? I still might have an assortment of op amps laying around from when I was messing with soundcards. That was a waste of time and money... I use a USB to Optical/Coax box now from the PC. You can have them if I can locate them.

    The board does only require six, as I believe the other two do I/V conversion, but Fred the master could correct me as always. I'd be willing take those opamps off your hands instead of tossing them in the trash... :mrgreen:
    FTGV wrote: »
    Yes I have used them and the dual version(49720) in several projects,a pair of active crossovers,several Dac's and as an input buffer in a pre I,m dabbling with.I find them to to be clean, neutral,detailed and low noise.However depending upon system synergy and personal taste some may find them a bit too squeaky clean and clinical.I like them and my impression is they are more open and resolute sounding than the 5534.
    FYI.If you look at the link I post you will see near the top in blue letters "Samples".You may be able to snag a few free samples.

    I'm not sure then if I'll seek out the LME49710 as the combination of my system already boarders on clean and technical sounding. Thanks for the sample link, but they'll only send two units, and it would be about the same price to order two less and have them shipped.
    Jake
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  • zingo
    zingo Posts: 11,258
    edited April 2014
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    Listened to some more music last night as the DAC is starting to burn-in. No issues with any of the connectors or parts, and the music is sounding full, natural, and dynamics, so I'm pretty happy. I am however playing with the idea of adding a filter to the power cord inside the case, as I received two of the BlackDiscus samples, but found their results lacking when placed on the cable connections as suggested.

    http://www.madscientist-audio.com/simplepowerfilter/
    Jake
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  • SCompRacer
    SCompRacer Posts: 8,375
    edited April 2014
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    I like and use the Shurter DD12 series, specifically the DD12.9321.111. Digi-Key 486-1304-ND. IEC with filter, fuses and switch. ~$25. They sell the fuse drawer separately. 486-1274-ND, like $5.

    MFG_DD12%20SERIES.jpg
    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *
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  • FTGV
    FTGV Posts: 3,649
    edited April 2014
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    zingo wrote: »
    The board does only require six, as I believe the other two do I/V conversion...
    Yes six.Two for I/V conversion and one output buffer per channel.You could also use a different op amp in the output buffer position than in the I/V section.
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  • FTGV
    FTGV Posts: 3,649
    edited April 2014
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    http://www.madscientist-audio.com/simplepowerfilter/
    Lol .
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  • zingo
    zingo Posts: 11,258
    edited April 2014
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    FTGV wrote: »
    Lol .

    You don't think it would be a free and simple ferrite filter?
    Jake
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  • FTGV
    FTGV Posts: 3,649
    edited April 2014
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    zingo wrote: »
    You don't think it would be a free and simple ferrite filter?
    http://www.madscientist-audio.com/blackdiscus/ I had a good chuckle after reading the how it works section at the bottom.More mad than scientist.YMMV.
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  • zingo
    zingo Posts: 11,258
    edited April 2014
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    Ah yes... Those descriptions...
    Jake
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  • zingo
    zingo Posts: 11,258
    edited April 2014
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    It's been about two weeks and everything is sounding and looking good! My next step is to open the chassis back up and secure all the boards and components down in their final configuration since it all works. Adding galvanic isolation may be a good step in the future, but I'm not sure there is too much more I do to this DAC. Maybe add a second 5V regulator instead of driving two 5V sections from one, but there is plenty of current capability from the IC, and the linear power supply. It might help reduce noise? Hmmm....
    Jake
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