Splitting [NORMAL] Pre-Out's on C80 / C85

Discussion in 'Yamaha' started by 3-way, Mar 14, 2017.

  1. 3-way

    3-way New Member

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    Can just the [NORMAL] pre out's be split to control a pair of stereo amps?

    Currently I have an ADCOM GFP-750 coupled with my M80's and it sounds great, just extremely flat. I want to try the M80's with my C80 to get a little warmth but without changing the 8 ohm load on the amps....(I can hear some snickering already) So....each amp would receive a split LEFT & RIGHT STEREO signal from the C80 [NORMAL OUT] to [MAIN IN]. The C80 should have enough output.

    Would each M80 remain the stated 250W / CH @ 8 ohm driving 1 pair of 8 ohm speakers at [A] and another at ?
    Much easier on the pre-historic amps than utilizing the [INVERTED OUT] method & it would also increase the damping, Correct?

    Thought I'd run it by you guys first, before starting any fires! You all are always very helpful.

    It certainly seems feasible, at least to me....but then again, what do I know Lol !

    P.S.- I got the Klipsch aimed pretty good, thanks for all the input, I'm sure it saved me a lot of time. Come to think of it, maybe it's not the ADCOM causing it to sound so flat....could just be those 8 mid-horns !!!
     
  2. avionic

    avionic " Black Knights" Subscriber

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    Look at the hook up instructions in the C-85 owners manual.


    The C-80 was made to run this way. Bridging two M-80's. Thats how I run my B-6's
    Each amplifier gets a "normal input" and a "inverted input"

    Look at the owners manual ...! http://akdatabase.com/AKview/displayimage.php?album=3&pos=49
     
  3. avionic

    avionic " Black Knights" Subscriber

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    Properly bridged the M-80's would make in excess of 400 wpc. But would feel a 4 Ω load on each amplifier.
     
  4. 3-way

    3-way New Member

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    I understand both of the methods outlined in the C80 & 85 manual. I don't need the theoretical 660w from the M-80's nor do I want to burden them with a 4 ohm load......Lets forget the Yamaha even has [INVERTED] outputs & instead it just has one [NORMAL] LEFT output and one [NORMAL] RIGHT output.

    Assuming the C80 has enough power......

    If we connect a Monster Cable I401 XLN Audio Y Adapter - 2 Female to 1 Male directly to the C80's [NORMAL] LEFT output and do the exact same to the [NORMAL] RIGHT output.

    Now we have two [NORMAL] LEFT Female outputs and two [NORMAL] RIGHT Female outputs, Correct?

    Now if we connect all four outputs to the [MAIN INPUTS] on the two M80's (a left & right to each)......and if we connect one pair of 8 ohm speakers at [A] and one pair of 8 ohm speakers at on each of the M80's for a total of 8 speakers. (6 La Scala & 2 Klipschorn)

    With this method of connection the load would remain at 8 ohms, with about 125w to each speaker when A+B are pushed. Correct?
     
  5. Chris Brown

    Chris Brown AK Subscriber Subscriber

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    Incorrect. Two pairs of 8ohm speakers hooked to the same amp at the same time will be a 4ohm load. A+B doesn't mean anything, only convenience. Using A+B would be the same as if you simply wired both pairs up to only the A or B output.

    You will not have issues running multiple amps from the C-80. You just want to make sure that the resulting input impedance of the amps (which is lowered every time you add another amp) remains at least 10 times higher than the output impedance of your C-80. The C-80 has a very low output impedance though, so you would have to add quite a few amps to violate that 10-to-1 rule. I am currently running 6 amps from my C-80 and everything works great!
     
    Last edited: Mar 16, 2017
  6. whoaru99

    whoaru99 Epic Member

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    Why would you bother with Y cables when you can use the normal and inverted outputs to your benefit?

    You don't have to bridge, nor do you have to burden them with 4 ohms.

    Use one normal and one inverted output to each amp.

    Personally, when I was running my Yamaha setup, I used this method and felt it did provide a small but noticeable improvement when cranking out the jams. To use two amps you'd wire one like the picture then the 2nd amp you'd wire the right channel normal and the left channel inverted with reversed polarity to the left speaker.

    c80.png
     
  7. avionic

    avionic " Black Knights" Subscriber

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    Thats a non-issue.
     
  8. whoaru99

    whoaru99 Epic Member

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    Yeah, they're rated 47 ohms output impedance. For a preamp that's damn near welder territory. LOL.
     

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