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New Audio-gd R7 (R2R 7) & R8 Flagship Resistor Ladder DACs

Discussion in 'High-end Audio Forum' started by Currawong, Jun 30, 2017.
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  1. FredA
    Can't wait to get mine, the early comments on audio-gd's forum are towards it being reference level...
  2. Chopin75
    Thanks ! I think my tripp-lite isolator is EI core so it the first thing AC mains go to, hopefully filtering out most of the noise. Then followed by few Schaffner AC filter cables. I am thinking of a DC blocker as I do have a toroidal transformer downstream. But I got a regenerator instead (not arriving yet). When the time comes to experiment with Bybee, I will PM you to ask you exactly how to put them (I am not electric savy), if u don't mind!
    Is there a way to block out noise coming from the fridge by putting some sort of filter/blocker (though I am not sure if mine is AC or DC fridge) at the fridge ?
  3. 517269
    I'd be happy to offer assistance on the Bybees. The board layout [in the R8HE at least] makes it very simple to implement them.

    I'm hearing two issues from your inquiry - DC and AC noise, for which I can offer a few data points as you decide what to experiment with.

    We do know that harmonics are imposed on the AC line from any AC motor [refrigerator, Air Conditioner, hot air blower motor, washer, etc.] suddenly being turned on or off or even running steady state.
    In addition, LED lighting, switching power supplies, etc.
    It sounds like you are experimenting with the right things pertaining to noise on the line - regenerator, AC filtering. Although I am less of an advocate for AC regeneration these days.
    I tried 30 R/C filters to no effect that were encased in AC plugs I distributed throughout the entire house, including at the refrigerator outlet, as the AC wiring also acts as one giant antenna.
    I found Barrows Worm from Sonore Audio a great resource regarding AC noise as when he worked for PS Audio in the early days, he was in the field measuring and testing for line noise as PS Audio were designing their first AC regererators.
    You can find him on Audiophilestyle website.
    Barrows echoed J&K Audio's assertion that DC on the line is difficult to measure.
    A basic DC blocker will block up to 1.4V of DC on the line.
    When I was looking to substantiate the high range of DC on the line, Barrows offered that he found DC blockers to add grain in his system.
    I did not find this to be so in my case, perhaps because of the high quality caps I sourced and that I used multiple times the cap sizing required to minimally stress the blocker for safety.
    Regardless, not wanting to embark on doubling the size of the blocker to allow blockage past 1.4Vdc, I took them out of my system.
    Since there is a bridge rectifier in a DC Blocker, and two required to block past 1.4V, I also wondered if additional harmionics were being added to the line as the diodes shut on and off.
    I couldn't find anyone who could answer that question.
    This is where the Bybee Gold Purifiers make a difference as it absorbs noise past the output side of the AC regenerator - the output of the bridge rectifier right after the component's transformer secondary for a linear power supply.

    For whatever reason, after removing the DC blockers in my system and moving the refrigerator to the other electrical phase, while the mechanical transformer hum was still there it was below half the level it originally was.
    My process is trial and error and not particularly scientific as there are no measurements to prove before and after.
    Also, in my neighborhood, there are 8 condos that are fed per one transformer on the street. Since the loads of each breaker panel are likely installed randomly by different crews and that different loads turn on at different times, it makes the solution more complex than theoretically assigning 4 refrigerator circuits, 4 washer circuits, 4 heaters across one electrical phase to balance the current draw as they will all turn on and off and run at different times.
    I now run all my audio equipment off 240VAC for several reasons - Because it is recommended that the entire audio system is fed off the same electrical phase to minimize RF into the system - using 240V provides balanced power and balanced current draw across both phases.
    The Krell monos have 4500W toroids in each amp and they are fully regulated drawing 300W each at idle. I mentioned in an earlier post [per Vince Galbo's AC wiring whitepaper] that upgrading the 60' dedicated runs of AC Romex from 10AWG to 6AWG made a significant audible difference in terms of naturalness and glare reduction.
    Sorry no quick fix answers but I hope some of the data points are useful as you decide what to experiment with next. :)
    Last edited: Nov 23, 2019
    GU1DO, motberg, VilMo and 1 other person like this.
  4. GU1DO
    Guys , did anybody compare the Denafrips Pontus to the R8 ?
    I am torn between them and am looking for a DAC like my Hugo 2 with good depth/3d and details but with balanced output to my M9 amp
    Any recommendation or feedback is appreciated
  5. Jackula
    If you've got the M9, the ACSS connection on the R8 is a huge advantage over other DACs.

    I've never heard the Pontus, I have heard the R8 and the soundstage was very impressive, not as large as say - a MSB Discrete DAC but it was more real with more accurate placement.

    I haven't listened to the Hugo 2 either, but my past experience with Chord DACs indicate they are very forward and on the cooler side of neutral, cooler than MSB. While R8 is neutral. No idea with the Pontus.
    GU1DO likes this.
  6. borrego
    My vote is also on the R8. The ACSS connection bypass the output buffer circuit on the DAC and input buffer circuit on the amp, minimizing distortion. They result is very precise imaging and accurate sound decays. IMHO, imaging is mainly what higher priced DAC distinguish from the lower priced ones.
    Last edited: Nov 26, 2019
    GU1DO likes this.
  7. FredA
    I can add i have the r7he/he9 combination and it's just splendid. Just love it with a silver litz acss ic in between.
    Last edited: Nov 25, 2019
    GU1DO likes this.
  8. GU1DO
    from where i can get other brand of the ACSS cable ?

    Thank you all ,, now i am leaning toward the R8 :)
  9. FredA
    I make my own. But there is ACSS cables available at DoubleHelixCable, MagnaHifi, Audiophonics and a silver one at tubulus.net. I tried one from DoubleHelix but prefer my own.
    GU1DO likes this.
  10. DACLadder
    Has it only been 8 months since the Accusilicons XOs and V2 DAC hardware changed my life? Seems like eternity and If you sleep around here you may miss something important!

    Here's another solid tweak for older DACs without internal Blaster. Who hates reprogramming firmware where you have to remove the chassis from the rack and unscrew the top? Me for one! Our good friend @JaMo suggested just run a 10-pin JTAG extension cable out the backpanel gap where HDMI I2S connector sits. Brilliant! No more removing the DAC from service to reprogram firmware!!! Just connect the Blaster when needed (pwr OFF), reprogram the Altera, and remove afterward (pwr OFF) . The connector end dangles out the rear and no one sees it. The cable extension is 10-pin 2.54mm (0.1") pitch male to female 20cm in length. $5.00 on eBay. Just loosen the HDMI I2S rear panel adapter, slide the cable connector through the hole, secure on the DSP JTAG header, and reattach the HDMI I2S adapter. Easy!

    JaMo says that Kingwa is considering something more permanent going forward versus the included Blaster on the newer R7 and R8 DACs. Thank you again!

    R7 _JTAG_ExtCable.jpg
    R7 _JTAG_ExtCable2.jpg
    Last edited: Nov 26, 2019
    motberg, GU1DO, FredA and 3 others like this.
  11. Tango Sierra
  12. DACLadder
    @Tango Sierra That is the one I ordered! $4.99 ea. Delivery took about 2 weeks to USA. I just ordered two more for my S7 and M7S.
    Tango Sierra likes this.
  13. 517269
    I concurr on the ACSS. I converted a pair of my Krell homemade silver CAST ICs to the small XLR to connect the R8HE to Krell preamp and the image went from in-your-face spot-lit with the Analysis Plus Silver Oval balanced ICs [voodoo design btw] to much further back with added depth and naturalness. I also went back to the CAST between Krell preamp and Krell power amp.
    GU1DO likes this.
  14. Chopin75
    We can also slip the wire through the vent gap perhaps? But it may too large to fit in. But the extension wire is easier for me to get the blaster plug in, can we leave the extender wire inside when not in use?
  15. DACLadder
    @Chopin75 The connector is too large to fit through the vents. You could run the cable and then crimp the connector on the cable.

    Oh yes, leave the cable connected once in place!
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