Joined
·
20 Posts
Hello all, I used this forum quite a bit years ago when purchasing my HT setup, and have a new issue I thought the experts could help me on. I did searches for similar problems, but haven't found a solution yet. Hopefully you guys can help.
Here's the situation. I bought (for practically nothing) two monoblock PA amps. They're Bogen HTA-250A's, rated at 250watts rms each. My thought was to use one to power a subwoofer, or maybe party speakers at some date. I wasn't concerned about super clean power, but that they'd have some decent power. I had heard of a few people doing this online, and they were surprised at how clean they DID sound, so I thought I'd try it.
The issue was inputs, and it has RCA unbalanced Hi-Z (52k ohm), and low-z balanced (600ohm) inputs. I wanted to use the low-z preamp outputs from my receiver. I asked Bogen if they had some sort of module to add to connect these correctly and they said plug the RCA from your receiver to the Hi-z inputs". That's it.
Now here's the problem; plugging into the hi-z only creates a loud ground loop hum, and very little music. Just to test to see if it was the input creating the noise, I disconnected the preamp and plugged an ipod directly into the RCA, figuring there's no ground issue with a battery powered source, and the hum/buzz is completely gone, replaced by music. However, even at its max (the source output and the amps input knob. I was able to turn it up that loud, if that gives you any idea how NOT loud it was), it certainly wasn't delivering full power.
What can I do? Convert the RCA unbalanced to a balanced input? I've read online that a low-z output to high-z input is common, and it's usually on the magnitude of a 1/10 ratio of impedance. I'm not sure what a typical rca preout is rated at, but this imbalance in impedance seems to be too great and then there's the issue of the ground loop. Any advice is appreciated
Here's the situation. I bought (for practically nothing) two monoblock PA amps. They're Bogen HTA-250A's, rated at 250watts rms each. My thought was to use one to power a subwoofer, or maybe party speakers at some date. I wasn't concerned about super clean power, but that they'd have some decent power. I had heard of a few people doing this online, and they were surprised at how clean they DID sound, so I thought I'd try it.
The issue was inputs, and it has RCA unbalanced Hi-Z (52k ohm), and low-z balanced (600ohm) inputs. I wanted to use the low-z preamp outputs from my receiver. I asked Bogen if they had some sort of module to add to connect these correctly and they said plug the RCA from your receiver to the Hi-z inputs". That's it.
Now here's the problem; plugging into the hi-z only creates a loud ground loop hum, and very little music. Just to test to see if it was the input creating the noise, I disconnected the preamp and plugged an ipod directly into the RCA, figuring there's no ground issue with a battery powered source, and the hum/buzz is completely gone, replaced by music. However, even at its max (the source output and the amps input knob. I was able to turn it up that loud, if that gives you any idea how NOT loud it was), it certainly wasn't delivering full power.
What can I do? Convert the RCA unbalanced to a balanced input? I've read online that a low-z output to high-z input is common, and it's usually on the magnitude of a 1/10 ratio of impedance. I'm not sure what a typical rca preout is rated at, but this imbalance in impedance seems to be too great and then there's the issue of the ground loop. Any advice is appreciated
