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Explain A-B selector on a receiver

Discussion in 'AV Receivers' started by mylan, May 4, 2006.

  1. mylan

    mylan Well-Known Member

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    I've got an old Yamaha RXV-2092 receiver that I want to use to power four sets of speakers with impedence matching volume controls. I'll be using a hub, but was thinking I would run patio speakers to A and everything else to B. What effect would this have?
     
  2. Philip Hamm

    Philip Hamm Well-Known Member

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    Why do you need a hub if you have impedence mathing volume controls?

    Advice: You need volume controls that can handle mongo power. The amp section of that Yamaha may not be up to the task of running the speakers loud. It should be fine at low volumes. Keep the volume up on the volume controls and lower on the receiver.

    Not sure what the A/B thing would do.
     
  3. mylan

    mylan Well-Known Member

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    The hub is just a mounting block instead of a speaker selector that splits the power among speakers, the VC's are Niles rated at 100 W. I don't see many A-B switches on receivers today but they are used to run an extra pair of speakers, usually in another room.
    I have been trying for the past four months to come up with a low cost solution to get my whole house audio system up and running, instead of going with a true zoned system. My thinking is that the outdoor speakers are going to require more power, so hook them into A, which should be half of the amps power and all the rest on B, which would 50 W/3. One thing that keeps coming up is whether or not that Yammy will power everything. I may have to break down for the distributed amp after all.
     
  4. Philip Hamm

    Philip Hamm Well-Known Member

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    Run the appropriate cables for modifying things / upgrading down the road. I don't know if the A/B switch is going to work the way you want it to. If your receiver has a "Tape Out", a really easy option would be to pick up a cheap old used stereo receiver on Ebay, run the "tape out" to the stereo receiver, then power the outdoor speakers with that receiver.
     
  5. Phil A

    Phil A Premium
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    You could run into problems if you want to run too many sets at once. My bedroom system feeds 4 other places (outdoor, garage, office, dining), 3 of which room volume controls (everything except outdoor) via a speaker switcher hooked up to the 'B' outputs of the rec'r. You're right that outdoor speakers may require more power due to the extra noise. I got efficient speakers outside for that reason. Phil has made some excellent suggestions. If you can still run wiring, partsexpress.com had some affordable multi-room systems if they are compatible with what else you have incl:

    http://www.partsexpress.com/webpage....ctGroup_ID=664

    http://www.partsexpress.com/webpage....ctGroup_ID=560

    http://www.partsexpress.com/webpage....ctGroup_ID=561
     
  6. mylan

    mylan Well-Known Member

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    Thanks, Phil (s) for both of your suggestions. The parts express stuff looks like what I have been pitched by Hi Fi Buys. My house is already wired with both cat5 and two runs of 16/2 to three keypad/VC locations. All one would have to do is remove a wall blank and hook up said VC/keypads and hook up whatever it is I decide to go with. The problem is I can get a Nuvo 4 source, 30 wpc Simplesse system or hook up my old Yammy w/VC's for about the same price if you include their install price. With the more simple receiver option, it means I get to get a new Denon for the theater, so that would be a bonus. You can see i'm trying to get that new receiver.
    My outdoor speakers are 89db. Polk Atriums, so I think moderate power there would be fin, inside, I have three pairs of Polk RCi, also 89db.
     
  7. Philip Hamm

    Philip Hamm Well-Known Member

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    If you decide to go with speaker level impedance matching volume controls, do not go with the cheap Dayton ones that claim to handle "50 watts" from parts express. I fried the living s**t out of these in short order with my old circa 1982 JVC 30wpc RMS stereo receiver. They SUCK. I have new ones on order and the receiver tests out fine on other speakers - I -hope- they didn't mess up my nice Proficient in-ceiling speakers. You need robust in-wall volume controls for this application, and a beefy amp, which tha Yamaha may or may not have.
     
  8. mylan

    mylan Well-Known Member

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    No, i'm going with either Niles or Russound volume controls rated at 100 W. I don't think $60 a piece is too much to pay for peace of mind. I keep going back and forth between the receiver/hub/VC solution or for a few bucks more, the distributed 30-40 WPC Nuvo Simplesse or Russound CA-S44. These units are inexpensive enough but their tuners are what may break my bank. I just keep getting these comments about how the receiver may not be enough power.
    Thanks for bouncing ideas my way, I need to make a decision on this soon, and I need all the help I can get. I'm not usually this indecisive about HT, but whole house is a road i've never taken, the last thing I want to do is half ass it, or spend a fortune and not use it to its full potential.
     
  9. kurtZoom

    kurtZoom Well-Known Member

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    for several years I ran a set up..not exactly the same but may give some insight. I had a 1995 Denon AVR-2500 (?) that I used the A speakers as the main speakers and the B speakers were my deck speakers. I used the "Zone 2" out to a mid 80s yamaha 2x80w receiver. That receiver then went to one of the Niles hubs that fed two sets of speakers. The Denon never had a problem. I was told that the A B speakers were internally impeadence matched and the amp never had a problem. The Yamaha however, even with properly set up Niles IM volume controls, got hotter than bacon grease at hight levels. I had originally wired the hub for four sets of speakers...but only had two hooked up. I then disconnected the two un-used speaker runs from the hub and the Yamaha cooled down quite a bit. No one has been able to explain why having the unused speaker wires hooked up affected it so much...unless there is a short in the system.

    I'd suggest, as others have, using the Yamaha to run your outdoor speakers then get a second amp to run the rest of your whole house speakers. Possibly use a Zone 2 out or tape out to send the signal to the amp.
     
  10. mylan

    mylan Well-Known Member

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    Interesting.... I was worried about heat build-up inside the cabinent, should be real hot with two amps, now i'm leaning towards the Nuvo/Russound, at least for the moment....
     
  11. Philip Hamm

    Philip Hamm Well-Known Member

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    I will tell you this. I went with a central older receiver with impedence matching volume controls for my in-ceiling speakers. I hope the volume controls were my only problem. When things were working it was a great system, really convenient. Great for parties and TV watching and stuff. I think the more sophisticated distributed amp system is better, and I kind of wish I had gone with that.
     
  12. mylan

    mylan Well-Known Member

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    Yes, I seem to remember some problems you were having back on my other thread about this subject, I need to go back and re-read. The problem I still can't wrap my mind around is, I did not run cat5 and sp. wire to a fourth wall location for keypad/vc because I was going to use the receiver's vc, now it looks like i'll have to mount a keypad inside or near the cabinent if I go with a distributed audio.
    My problem is that I overthink things to a point at which nothing gets accomplished.

    Edit:you must have P.M.ed me I didn't see your post, on "best way to do whole house audio" but I do remember something about low sound output levels from your set-up.
     
  13. mylan

    mylan Well-Known Member

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    Well, I have gone and did it. I just got home with four Polk TC60i in-ceiling speakers, a Polk xrt12 XM tuner, Niles volume controls (to be picked up tommorow, did not have almond), Niles hub, and a Denon 3806 to replace the Yamaha that was in my theater to be used for whole house duties.
    In the end it came down to the fact that I did not want to have a custom keypad mounted inside the cabinent (because I stupidly did not run for a fourth KP location) and the want of an AM/FM tuner. I hope I have no issues with not having enough power, if so there is a $300 Russound amp out there I could use for the outdoor sp.
    I think I did well on my equipment, everything was on sale, the Denon 3806 was $999.99, I just hope I like the remote, if not there goes another two bills for a Harmony 880.
     
  14. Scotty P

    Scotty P Active Member

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    That should be fine. One thing I did for my zone 2 was to get an inexpensive surround receiver (a sherwood for about $150 at Circuit City), cheapest I could fine with Multichannel inputs. I split the stereo zone 2 output of my main receiver, sent 1 stereo LR to the front multi inputs, and another stereo LR to the rear multi inputs. Basically having 2 stereo amps in one box. Then I keep the sherwood on the multi channel input. That breaks my house down to 2 pairs of amps, reducing the number of speakers on 1 amp, combined with impedance matching volume controls, works great. An inexpensive receiver with a "all stereo" type listening mode would work instead of splitting the feed to a multi channel input.

    I don't know how common it is for receivers to have the A/B speaker connections impedance matched, I would think it is rare, most I think are just a parallel split off the stereo LR amps. the only advantage to putting some speakers on A and some on B would be to provide a convenient switch to turn off unused speakers without having to go outside and turn them down at volume control, they should all (both on A and B) be counted when setting jumpers on volume controls. No more power available to one as opposed to the other.
     
  15. Philip Hamm

    Philip Hamm Well-Known Member

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    Scotty you are a genius. I love the solution you describe in the first paragraph. What a clever way to set up two isolated stereo pairs out of a surround receiver!!!!!!!! I've taken note for the future.

    The second paragraph sounds spot-on to me also. I got my new more robust volume controls from Parts Express. We'll see how they work.

    Nobody's bought my Harman/Kardon HK3270 so setting that up in the basement without any in-wall volume controls at all and an IR repeater is still an option (probably a better option) for me. I'm hoping to get back in business with my through-house sound.
     
  16. Philip Hamm

    Philip Hamm Well-Known Member

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    I'm sorry, I'm a bit confused.

    So Mylan, is the 3806 running surround sound anywhere? If you're using it only to drive stereo speakers in multiple locations, Scotty's 5.1-in - two sets of stereo amps out solution will work well for you. But if you're only running stereo you'd be better off with a beefy dedicated stereo receiver instead of a surround reciever. Rotel, Outlaw, and Harman/Kardon offer very beefy stereo receivers for reasonable prices that can handle low impedence loads of multiple speakers. Harmon/Kardon probably would be the most cost effective way to go.

    Or is the 3806 the new theater receiver and the Yamaha going to the whole-house duty? If you're using the Yamaha for whole-house and it has 5.1 inputs, Scotty's solution in paragraph 1 is the way you want to go!
     
  17. mylan

    mylan Well-Known Member

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    The 3806 is going to be my new theater receiver, the Yammy, which has served me well I might add, is going upstairs to the greatroom to power the whole house (well upstairs) audio system. My problem now is that I need to get down to pick up my VC's and begin the install but I am working all weekend 7AM-7PM. I'm not going to take the Denon out of the box until I know the Yammy is going to do what I need it to do. Yes, I need to re-read that, either that or get a separate two ch. amp, Russound has one for $300.

    Oh, BTW, Scotty, you are a genius, I had thought of something along those lines but shrugged it off as flawed thinking.
     
  18. Philip Hamm

    Philip Hamm Well-Known Member

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    Whoah. Forget the stuff that was in these posts before.
     
  19. Philip Hamm

    Philip Hamm Well-Known Member

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    a bunch of speculation and troubleshooting was here.
     
  20. mylan

    mylan Well-Known Member

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    Hmmm, keep me posted on this. This may affect me also, if I could ever get the time to start. I'm working all weekend [​IMG].
    Were the speakers over your pool table connected through a VC? I'm thinking the impedence matching vc's may be set incorrectly for the load. I don't know about infinite baffle, but I plan to cover mine with large amounts of my blown-in insulation, which is made of wool. Hopefully this will act as a baffle of sorts.
     

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