Infinity RS1b amplification ideas

Discussion in 'Infinity Loudspeakers' started by Duckzilla, Feb 25, 2017.

  1. Duckzilla

    Duckzilla "Laugh it up fuzzball"

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    I'm in the process of househunting to include a very large listening room, which will be equipped with a pair of Infinity RS1b's. There's a lot of info and recommendations with regard to suitable amplification. What I have available to me is a pair of NAD 218's for the bass towers, and a pair of Threshold T100 class A power amps for the mid/high arrays. The NAD should have good control of the bass, and I'm thinking the Thresholds may be quite a good match for the mid/highs. I'm planning on running all four bridged, but I can't find any info on bridging the Thresholds nor their output in mono, just that they are 60w/ch in stereo mode. Anyone know anything about this particular amp/speaker combo?
     
  2. swechsler

    swechsler Frog Whisperer

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    We had a similar discussion in a different thread a few days ago. One thing that was pointed out is that the RS1a/b servo control doesn't work with bridged amps (it will cause oscillation according to the manual).

    If you're not using the servo then you can use whatever amps you like.
     
  3. Duckzilla

    Duckzilla "Laugh it up fuzzball"

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  4. Duckzilla

    Duckzilla "Laugh it up fuzzball"

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    I thought it stated in the RS manual that as long as the outputs don't go inverted that mono (bridged) was OK?

    Sorry for the short reply, having computer issues
     
  5. swechsler

    swechsler Frog Whisperer

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    Might want to check out this thread. Inverted output isn't a problem; see the manual here.
     
  6. Duckzilla

    Duckzilla "Laugh it up fuzzball"

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    Thank you. I need to understand this fully first rather than being a bit "gung ho"!
     
  7. savatage1973

    savatage1973 Super Member

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    Just keep in mind that although bridging an amp does increase its rated power, it reduces its ability to handle low impedance loads--not as much of an issue with the RS 1b as it is with the Kappa 9, but still a factor to keep in mind.
     
  8. swechsler

    swechsler Frog Whisperer

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    I'd start out by running the amps in dual channel mode and see if it's enough. This review shows that you can get slightly more power out of them if you run just one channel, but dB-wise, the difference is negligible. It does appear that these NAD amps have no problems with low impedance loads, so you could try bridging them, but since the Infinity manual specifically says not to, I think that if they don't give you enough power, you should consider selling them and looking elsewhere.
     
  9. Duckzilla

    Duckzilla "Laugh it up fuzzball"

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    Good advice. Since I haven't taken possession of the NAD's yet, I've got some options, although bridging them is out I think. I can try running one is stereo for bass towers, and try the other one on my WATT/Puppies. 225w/ch should be enough for the RS1b's and the WIlson's.
     
  10. swechsler

    swechsler Frog Whisperer

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    A couple of amps you may want to consider, that I own (but have never directly compared) and are both capable of at least 400 watts/channel into 4 Ω without breaking a sweat are the Heathkit AA-1800 (a real beast) and the Aragon 4004 (a true dual-mono design, and has been mentioned favorably with Infinity speakers both here and elsewhere).
     
  11. Duckzilla

    Duckzilla "Laugh it up fuzzball"

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  12. savatage1973

    savatage1973 Super Member

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    I have no basis for reference with the Heathkit (as I have never heard one), but can tell you that the Aragon 4004's do indeed pair well with Infinitys--I have two of them that originally served duty bi-amping my Kappa 9's--they have since been replaced by 4 Krell KMA-160 monoblocks and are doing duty with Magneplanar 3.6R's--but they handled the extremely "difficult" K9's with ease.
     
  13. whoaru99

    whoaru99 Epic Member

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    Personally, I'd use a decent-quality pro amp to run the bass/lows, then something that can keep up on the mid/highs.

    With a pro amp you can get plenty of real power without needing to go bridged.
     
  14. Duckzilla

    Duckzilla "Laugh it up fuzzball"

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    Just so happens that I own a QSC RMX850 pro power amp, 375w/ch. I've used it on subs before, but it's been a little underwhelming. Perhaps with the RS1B it'll be a good match. I tried one NAD with the WATT/Puppies last night and if the results of that test are anything to go by, then a solo NAD should work saw well with the Infinity's.
     

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