Phast PLB-AMP8 Issues
Brooks Whiteford
Posts: 38
in AMX Hardware
Hey all,
I have two PLB-AMP8's that I use along side a PLB-AS16 switcher. Up until now, I had only been using one AMP8 as I did not have enough zones to merit running the other. I just added two zones, so I fired up the second AMP8 and was having a very strange issue where turning up one zone connected to that amp would cause some "crosstalk" with the other zone.
Call the two zones on the second AMP8 numbers 5 and 6. The problem was that when I changed the routing on the switcher to send audio to zone 5, I would also hear that audio on zone 6 (but garbled) and vice versa. At first I thought that the switcher was dying, but testing with another amp confirmed that this wasn't the case.
After lots and lots of testing, I narrowed down the problem to the second AMP8 without question. I believe it is a grounding problem as using ground loop isolators between the amp and switcher makes all of the problems go away. The amp works perfectly well as long as the switcher and amp are isolated in this way. Of course, I could leave it that way, but my curiosity to make this AMP8 work just as well as the other one is taking over.
Does anyone have any suggestions? I've already popped the cover off and nothing seems to be in disarray. Please help if you can!
Thanks so much,
Brooks
P.S. Those of you who like to bash old Phast equipment... save it.
I have two PLB-AMP8's that I use along side a PLB-AS16 switcher. Up until now, I had only been using one AMP8 as I did not have enough zones to merit running the other. I just added two zones, so I fired up the second AMP8 and was having a very strange issue where turning up one zone connected to that amp would cause some "crosstalk" with the other zone.
Call the two zones on the second AMP8 numbers 5 and 6. The problem was that when I changed the routing on the switcher to send audio to zone 5, I would also hear that audio on zone 6 (but garbled) and vice versa. At first I thought that the switcher was dying, but testing with another amp confirmed that this wasn't the case.
After lots and lots of testing, I narrowed down the problem to the second AMP8 without question. I believe it is a grounding problem as using ground loop isolators between the amp and switcher makes all of the problems go away. The amp works perfectly well as long as the switcher and amp are isolated in this way. Of course, I could leave it that way, but my curiosity to make this AMP8 work just as well as the other one is taking over.
Does anyone have any suggestions? I've already popped the cover off and nothing seems to be in disarray. Please help if you can!
Thanks so much,
Brooks
P.S. Those of you who like to bash old Phast equipment... save it.
0
Comments
It is entirely possible that you'll have to float the ground on the second unit.
I tried operating the amp with and without the ground pin intact (using one of those ground lifting plugs) and I had the same experience either way. It almost seems to me that perhaps the issue is that the ground for the AMP8 is already not intact, and thus when I connect it to properly grounded equipment (like the switcher) it starts having it's issues. I assume this is why an isolator on the audio lines between the switcher and the amp makes the problem go away.
Am I on the right track or no?