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Thread: Another Nice Acurus RL 11 Pre on the bay

  1. #61
    Forum Veteran R1200S's Avatar
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    Smoke and mirrors baby!
    I've been debating about telling you guys about this for a while now. It's either passing on information or rubbing salt into an open wound.

    I have 2 RL-11's and use them both. One of them is box stock and sounds incredible as everyone reports. The other one I had to chase for a while and I finally snagged it around the first of the year.
    Let's just say that the newest addition has had a little work done and sounds even better if that's possible. Please don't ask me about any of the specifics as it's all over my head. I'm not even sure I should tell anyone who did the upgrades because I don't think he's taking in any more work.

    The upgrade work includes the following:

    • Initial testing to verify proper operation, this includes several internal voltage checks to ensure the preamplifier is operating properly.
    • Custom built external power supply to include a low noise encapsulated toroidal transformer providing 3X the current capacity of the original internal EI core transformer.
    • Capacitive snubbing of the transformer secondary’s to eliminate circuit noise due to ringing.
    • Replacement of the stock IEC AC socket with an XLR connection for DC power feed from the custom external power supply.
    • Additional CRC filtering integrated into the original Acurus main board.
    • Wima polypropylene MKP series high frequency bypass capacitors added to the DC rails.
    • Upgrade the original 1 amp standard speed rectifiers to 2 amp ultrafast soft recovery rectifiers to minimize noise.
    • Upgraded filtering capacitance from the original 6,600 uF to 22,000 uF total.
    • Replacement of all electrolytic storage capacitors on the regulated DC rails with Nichicon audio grade caps of the same capacitance, but with increased voltage capacity to lower the ESR.
    • Replacement of all audio path resistors with Dale RN-60D exceptionally low noise mil-spec resistors.
    • Cleaning/lubing of the pots and switches with Deoxit D5.
    • Cosmetic cleaning of the entire unit during reassembly.


    The path thru the upgraded preamp right now is mainly digital files out of my Mac computer. Mostly non-compressed if possible. From there into a Schiit Bifrost multi bit DAC (freakin awesome!!). Then into the RL-11. On to 2 Aragon 8008BB amps that are biamped into my NHT 3.3 speakers.
    Sounds pretty good. A few more tweaks and getting 2 NHT SW3 subs and another 8008 into the act and I hope to be done for a little while. (Those SW3's have the same 12" woofer (Tongen?) as the 3.3's inside.) I honestly believe that RL-11 is what holds it all together.


  2. #62
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    laatsch55's Avatar
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    Halfbiass...Electron Herder and Backass Woof
    Sounds like an awesome system Bud, thanks for the info...
    taking something that's already good, and making it better...........and for the knowing smiles that cross their faces.......Nando-2011...

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  3. #63
    Forum Veteran WOPL Sniffer's Avatar
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    Screw it
    Quote Originally Posted by R1200S View Post

    The upgrade work includes the following:

    • Replacement of all electrolytic storage capacitors on the regulated DC rails with Nichicon audio grade caps of the same capacitance, but with increased voltage capacity to lower the ESR.
    Joe can correct me but if I remember correctly from school, the ESR of a capacitor has more to do with the Xc Reactance of the Capacitor in an AC circuit (Rated at like 10KHZ or maybe 100Khz) and being you are looking at just the Rail Ripple (60Hz x 2???) Buying into the Low ESR capacitors sold by some companies, may or may not do you any good where you are talking about putting them. I don't think sticking a 1000volt rated cap into the rail circuit at +100vdc and -100vdc will accomplish much of anything but increasing capacitance will gain you more. As a matter of fact, I'm not sure audio grade caps are all that great for the rails. Then again, maybe I'm high. But, in the end, my question would be: if a "Low ESR" electrolytic cap, is rated for say 5 @ 10khz, what should i expect at 60 hz? Do the data sheets even show a graph that low? And if they do, i doubt the results are a flat line from 20hz to 200khz. Joe would be able to tell you what the best option for that application would be. The ESR may be the same at your voltage for many styles of caps.Low ESR may not gain what you are interested in. I for sure wouldn't get the "Made in Cina" specials...... HUH?????
    I had the nations problems figured out one night while on blah blah blah........ huh?

    Big amps
    Kenner Close N Play

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