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AMP2: Stereo 2x30W or Mono 1x60w?

John Steg

May 26, 2020 05:07

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Hi guys,

my AMP2 is already in delivery and I have a question regarding speaker selection. For the experts here those might be fairly stupid questions, but I didn't find a proper thread looking around and I was wondering if I operate an AMP2 that outputs 2x30W but I only connect a single mono-speaker that is more capable, would the output be 1x60W and 1x0W (nothing connected) or is it still 1x30W and 1x0W?
If so, could I simply hook up both stereo channels to the same speaker and thus get  a) stereo to mono and b) 1x60w at the speaker? How does impedance play into this?
(My guess is however: it's 1x30W and i can't connect both outputs :-), but let's see)

Thanks and best regards

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9 comments

• 1
  
  HiFiBerry team May 26, 2020 05:20

  It's 60W if you connect only one speaker. However, the Amp won't convert to Mono internally. Therefore, you need to make sure, you have your software converting to Mono. 
  With HiFiBerryOS (https://www.hifiberry.com/os) you can set this in the "Sound"/"Channels and limits" menu.

• 0
  
  Mark Round June 05, 2020 15:19

  Team - this is cool, any chance you might be looking at letting the hifiberry os select a left or right channel this way ?

  we could group a couple of AMP2's set one as L and one as R and use 60W with some decent floorstanders ?

  or is this a dumb idea?

  (p.s. I'm trying to replace a bunch of SONOS Play1's I have around as I don't like the changes to the EULA and Privacy policy, so this is more than hypothetical - setting a AMP2 to mono gets rid of the SONOS in the kitchen, but I have another room with a large window between the speaker positions - hence a pair of SONOS speakers set as L and R)

• 0
  
  HiFiBerry team June 05, 2020 15:22

  Synchronisation of multiple players is quite complicated. You probably have the best chances to do this with Roon and Logitech Media Server, buut other source won't be able to do this. Therefore, this won't make it into HiFiBerryOS. We recommend to use a single system on a Stereo pair.

• 0
  
  Mark Round June 05, 2020 15:29

  Darn - I am a ROON user :) hence thinking the multiroom synchronisation is cute and could be used this way.

  thanks for the quick answer :)

• 0
  
  John Steg June 05, 2020 15:41

  While I was playing around with the AMP2 and integrated it into my Max2Play (+Squeezebox Server) environment I sometimes noticed slight differences with the timing while connected via ethernet (my wife didn't even hear it). For enjoying stereo that would drive me nuts, but when used for multiroom audio it is definitely not noticeable - but well, I wouldn't want my music experience to be influenced by the network load.

  However I also didn't notice much difference in speaker performance regardless of having a single speaker connected or two (or setting mono/stereo in Hifiberry OS), which is fine for me, as 30W is more than sufficient for me firing up some ambient multiroom speakers. Maybe I also have no clue about how physics in any of this works :-)

• 0
  
  HiFiBerry team June 05, 2020 15:47

  2 independent systems will always run at slightly different speed. This has noting to do with the network load. The software has to synchronize this. If the software does this really well and keeps 2 systems in sync at <1ms, that should work fine. However, if e.g. the software only synchronized if the drift is already 5ms, this will result in a bad stereo imaging. 
  
  Mark Round: You might just have a loo at /etc/asound.conf. The channel map can be modified ;-) However, future upgrades might break something as it isn't designed to be edited by the user.

• 0
  
  Jose Salvado October 15, 2020 09:59

  In case still interested. I have done exactly what Mark suggests, 2 amps [becreate] running Hifiberry, each set up as L and R respectively. Then the joining/synching  of the audio is done via a mac-mini sever running Airfoil by rogueamoeba. Music control is done via Spotify Connect playing into the Mac-Mini.

  Works very well. Except for the always on mac-mini, very much comparable to my use of Sonos/Spotify.

   

  JG

• 1
  
  HiFiBerry team October 15, 2020 10:02

  Very interesting. Do you have a stable stereo sound image with this setup? Even slight variations in the timing of the two systems should an impact on this. 

• 0
  
  Jose Salvado October 15, 2020 12:01

  No variations that I can notice. To be fair I'm just an "user" and not an expert. However, I do not experience any discernible difference when compared to my Stereo Play 5 Sonos setup, and the addition of the bass (forgot to mention) from the B&O Cona sub (Amp2 + Hifiberry Os) makes it even better.

   

  JG