Question:
Hi. I've got continuing problems with the Marantz SR4300 I bought a few weeks ago, in two areas, and I'm hoping someone can give me pointers, because I'm running out of ideas:
1) sub-woofer flicking; both my current Infinity Alpha subwoofer and the Eltax sub I had before include automatic power saving modes, where the amp turns off if the signal's low for an extended period. Annoyingly, I'm finding that this happens repeatedly during the course of whatever I'm watching, and obviously, the source material affects the frequency of this happening. TV and the B5, Buffy/Angel and Futurama boxes are most apparent.
The sub is connected to the unamplified sub out on the amp (as the manual states I should do) to the LFE in on the sub, using a cable 'specifically designed' for sub signals, and all the speakers are set to small (the amp therefore putting all sub-~100Hz sound on the sub out). The sub manual states that, when using the LFE input, the crossover is ignored (it being the amps job in this case), but should be left maxed out at 150Hz anyway (it is). I've tried setting all the normal speakers to -10db and the sub to +10, but it doesn't make much difference.
The sub also has line-level stereo and high-level stereo inputs; should I consider setting front left/right to large and also using the line-level inputs of the sub? If I do this, do I need to hook the front left/right speakers to it, or will it be alright to leave them directly connected to the amp? Should I then unplug the LFE cable? Is this behaviour normal for low-ish volume listening (with everything at +0 again, I've been watching B5 at -35db; films might take me up to -30, TV might go down to -40)? As I said, it wasn't much improved with the -10/+10 difference.
2) humming; as time goes by, the amp starts humming (from inside the unit; there's no effect on what comes out of the speakers) - loud enough to be audible over quieter sections of whatever I'm watching at the time.
I took it back to the shop, where they sat it under load for most of a day, and there wasn't anything like the noise it makes when connected to my mains (they left it hooked up - by the heat coming off the top of it, I could tell it had been run quite hard for a long time); just what I'd consider normal electrical/transformer buzz. Since I got it back, it seems to be worse, rather than better. They said that because it's fine there, their only recourse is to send it back to Marantz, because they can't see anything wrong with it
Thinking something might be polluting the mains, I turned everything else I could think of (fridge/freezer, computers, TV, digibox, etc) off, but it didn't make any difference. As I noted in another thread, my B-Tech 945+ SCART switching box also hums. Does this indicate I've got shoddy wiring, or a dodgy mains fuse/meter/trunk?
Can anyone give me any pointers for either of these issues? They're getting on my nerves, and I don't want anything blowing up on me (even with the 2 year warranty on the speakers and 3 years on the amp).
Cheers,
both problems could be related...it sounds like the sub is not presenting its load correctly to the amp..i mean the subs amp it is active...to test set front l/r speakers to large and the bass out to both..play some music from a cd and see if the sub is actually working..
Mm, I've wondered the same (although in rather less technical terms :) ) - one thing I didn't check is what connections they'd made in the shop, while testing the amp. Could be they connected the front three, and left the others off, or some such.
I know the sub works (Aliens SE, Rush Hour 2, Resident Evil) - when a DVD specifically makes use of the LFE, as well as having generally reasonable use of lower frequencies, it'll come on and stay on at low volume. It's where there's less - but still surely some - low frequency with no LFE that it gets pernickity.
I just tried something. I told the amp it had no sub, turned both amp and sub off (at the mains), unplugged the sub lead from the amp, and turned it back on, to see if there was an immediate difference - didn't notice anything. So I told the amp it had a sub again, turned the mains off, connected the sub lead, turned them both back on.
I put the Best of Bowie CD in my DVD player (digital coax to the amp), set the master volume to -45db (which is surprisingly loud, actually), and the sub didn't come on. I set the sub +10 again, and it came on. Now the sub, whose volume I raised to 25%/9 o'clock, is obviously there (too much so, I reckon), has stayed on for the first three or four track, and the amp isn't making any noticeable noise at all (holding my ear over the top vents).
What the? Had I somehow overloaded the amp previously (presumably during initial setup), and disconnecting the sub/mains briefly sorted it out? Raising the sub volume?
I am scared and confused. I think yoiu may well have been right (thanks for prompting my actions), but if someone could explain (or point at an explanation of) the theory, etc, behind this sort of thing, I'd be very grateful.
Oh, wait, it's still humming, just more quietly than before, so as to be masked by the music (including now-louder sub effect). Perhaps I spoke too soon.
(Edit to add further information, rather than yet another post)
I disabled the subwoofer in the amp setup (and noticed that my SR4300 has the 'rear surrounds can only be large if you have a sub' problem) and disconnected the lead (with both the amp and sub turned off, naturally), and the hum is almost gone, again. Probably still more than I'd like, but very quiet in comparison - barely audible with no other sound but my laptop in the room.
Given that I've had the same problem with two subs (admittedly, the Eltax one didn't get on with the dd5.1 decoder in my TV - it did the flicking-on-and-off thing), would this indicate the amp being knackered?
1) sub-woofer flicking; both my current Infinity Alpha subwoofer and the Eltax sub I had before include automatic power saving modes, where the amp turns off if the signal's low for an extended period. Annoyingly, I'm finding that this happens repeatedly during the course of whatever I'm watching, and obviously, the source material affects the frequency of this happening. TV and the B5, Buffy/Angel and Futurama boxes are most apparent.
The sub is connected to the unamplified sub out on the amp (as the manual states I should do) to the LFE in on the sub, using a cable 'specifically designed' for sub signals, and all the speakers are set to small (the amp therefore putting all sub-~100Hz sound on the sub out). The sub manual states that, when using the LFE input, the crossover is ignored (it being the amps job in this case), but should be left maxed out at 150Hz anyway (it is). I've tried setting all the normal speakers to -10db and the sub to +10, but it doesn't make much difference.
The sub also has line-level stereo and high-level stereo inputs; should I consider setting front left/right to large and also using the line-level inputs of the sub? If I do this, do I need to hook the front left/right speakers to it, or will it be alright to leave them directly connected to the amp? Should I then unplug the LFE cable? Is this behaviour normal for low-ish volume listening (with everything at +0 again, I've been watching B5 at -35db; films might take me up to -30, TV might go down to -40)? As I said, it wasn't much improved with the -10/+10 difference.
2) humming; as time goes by, the amp starts humming (from inside the unit; there's no effect on what comes out of the speakers) - loud enough to be audible over quieter sections of whatever I'm watching at the time.
I took it back to the shop, where they sat it under load for most of a day, and there wasn't anything like the noise it makes when connected to my mains (they left it hooked up - by the heat coming off the top of it, I could tell it had been run quite hard for a long time); just what I'd consider normal electrical/transformer buzz. Since I got it back, it seems to be worse, rather than better. They said that because it's fine there, their only recourse is to send it back to Marantz, because they can't see anything wrong with it
Thinking something might be polluting the mains, I turned everything else I could think of (fridge/freezer, computers, TV, digibox, etc) off, but it didn't make any difference. As I noted in another thread, my B-Tech 945+ SCART switching box also hums. Does this indicate I've got shoddy wiring, or a dodgy mains fuse/meter/trunk?
Can anyone give me any pointers for either of these issues? They're getting on my nerves, and I don't want anything blowing up on me (even with the 2 year warranty on the speakers and 3 years on the amp).
Cheers,
Answers:
both problems could be related...it sounds like the sub is not presenting its load correctly to the amp..i mean the subs amp it is active...to test set front l/r speakers to large and the bass out to both..play some music from a cd and see if the sub is actually working..
Answers:
Mm, I've wondered the same (although in rather less technical terms :) ) - one thing I didn't check is what connections they'd made in the shop, while testing the amp. Could be they connected the front three, and left the others off, or some such.
I know the sub works (Aliens SE, Rush Hour 2, Resident Evil) - when a DVD specifically makes use of the LFE, as well as having generally reasonable use of lower frequencies, it'll come on and stay on at low volume. It's where there's less - but still surely some - low frequency with no LFE that it gets pernickity.
I just tried something. I told the amp it had no sub, turned both amp and sub off (at the mains), unplugged the sub lead from the amp, and turned it back on, to see if there was an immediate difference - didn't notice anything. So I told the amp it had a sub again, turned the mains off, connected the sub lead, turned them both back on.
I put the Best of Bowie CD in my DVD player (digital coax to the amp), set the master volume to -45db (which is surprisingly loud, actually), and the sub didn't come on. I set the sub +10 again, and it came on. Now the sub, whose volume I raised to 25%/9 o'clock, is obviously there (too much so, I reckon), has stayed on for the first three or four track, and the amp isn't making any noticeable noise at all (holding my ear over the top vents).
What the? Had I somehow overloaded the amp previously (presumably during initial setup), and disconnecting the sub/mains briefly sorted it out? Raising the sub volume?
I am scared and confused. I think yoiu may well have been right (thanks for prompting my actions), but if someone could explain (or point at an explanation of) the theory, etc, behind this sort of thing, I'd be very grateful.
Answers:
Oh, wait, it's still humming, just more quietly than before, so as to be masked by the music (including now-louder sub effect). Perhaps I spoke too soon.
(Edit to add further information, rather than yet another post)
I disabled the subwoofer in the amp setup (and noticed that my SR4300 has the 'rear surrounds can only be large if you have a sub' problem) and disconnected the lead (with both the amp and sub turned off, naturally), and the hum is almost gone, again. Probably still more than I'd like, but very quiet in comparison - barely audible with no other sound but my laptop in the room.
Given that I've had the same problem with two subs (admittedly, the Eltax one didn't get on with the dd5.1 decoder in my TV - it did the flicking-on-and-off thing), would this indicate the amp being knackered?
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