Hoping the gurus here can help me sort out the problems I'm having with my amp. I recently build a rather large sub cabinet for my home and after hooking it up to the amp, the amp keeps clipping as indicated by the leds on the front panel.
The sub is a Dayton Quatro 15 in a ported configuration tuned to 20hz, the amplifier is Altec Lansing model 9444A rated at 300w x 2 (4 ohm per channel) or 600w x 1 (8 ohm load). At first I thought it may have been a bad box design however here is what I have done so far to test. BTW the amplifier is hooked up to my Yamaha HTR-5150 Receiver through it's sub outputs. As the Altec is a pro unit with only balanced line input, the sub output from the receiver is fed into an ART cleanbox to convert from the unbalanced output to balanced input.
The amp would clip when the volume is turned up on music, movies and pretty much anything. I have played with many different gain setting combinations on the amp and cleanbox to rule out that. I also tried hooking the sub up to each channel on the amp individually and also tried it bridged and it clips in all modes I have also seen one of the clip leds glowing even after the power has been shut off.
I tested the sub using WinISDs tone generator on a slow sweep from 15 hz to 200hz. Seems around 55hz I have some serious room gain and that is where the amp clips the worst. I even hooked the sub directly up to the receiver and ran the test sweeps. The sub needs some tweaking but even running off of the receiver (80w / ch) it was really a monster, but on the altec, it just turns to crap.
Sorry for the long post, just trying to give all the facts I have in the hopes that someone can help me out...
Thanks in advance,
Ethan
BTW, here's a pic of my monster I'm trying to power
The sub is a Dayton Quatro 15 in a ported configuration tuned to 20hz, the amplifier is Altec Lansing model 9444A rated at 300w x 2 (4 ohm per channel) or 600w x 1 (8 ohm load). At first I thought it may have been a bad box design however here is what I have done so far to test. BTW the amplifier is hooked up to my Yamaha HTR-5150 Receiver through it's sub outputs. As the Altec is a pro unit with only balanced line input, the sub output from the receiver is fed into an ART cleanbox to convert from the unbalanced output to balanced input.
The amp would clip when the volume is turned up on music, movies and pretty much anything. I have played with many different gain setting combinations on the amp and cleanbox to rule out that. I also tried hooking the sub up to each channel on the amp individually and also tried it bridged and it clips in all modes I have also seen one of the clip leds glowing even after the power has been shut off.
I tested the sub using WinISDs tone generator on a slow sweep from 15 hz to 200hz. Seems around 55hz I have some serious room gain and that is where the amp clips the worst. I even hooked the sub directly up to the receiver and ran the test sweeps. The sub needs some tweaking but even running off of the receiver (80w / ch) it was really a monster, but on the altec, it just turns to crap.
Sorry for the long post, just trying to give all the facts I have in the hopes that someone can help me out...
Thanks in advance,
Ethan
BTW, here's a pic of my monster I'm trying to power
An externally hosted image should be here but it was not working when we last tested it.
The 9444 is capable of running 600 watts into an 8 ohm load mono bridged. It WILL NOT run a 4 ohm load mono bridged. The 9444 is an older altec amp that came out in the early 90's I believe as I remember using a ton of them to drive bass bins, horns and so forth.
The 9444 WILL accept non-balanced inputs simply by paralleling the negative to the shield terminal on the terminal strip without ANY adapter. Simple terms is run the hot to the plus and the negative/shield on your unbalanced to the negative. You will then have a 60 cycle hum. Now jumper the negative to ground and hum is gone.
I have three or four 9444's and EV 2600's sitting in my garage and I use one 9444 to power two subs in my basement. With no problems.
The conclusion I might draw is this.... cheap drivers have a tendency to run a bit on the low side in impedance when you sweep them with an impedance meter. In other words your 4 ohm nominal subwoofer may very well dip to 2 ohms at 20 hz and the specs will not say this. My subs lower impedance range dips to 4 ohms when swept and they are rated as 4 ohms. In higher frequency mine hit around 7-8 ohms at 80-100 hz.
Now thinking the Altec 9444 is junk is a miss statement. I have experience and can tell you they will and do run 4 ohm loads without problems and I have no trouble getting high level output out of my 9444 without the clip lights coming on.
My conclusion is either your 9444 has internal problems or your load is lower than the spec say.
The 9444 WILL accept non-balanced inputs simply by paralleling the negative to the shield terminal on the terminal strip without ANY adapter. Simple terms is run the hot to the plus and the negative/shield on your unbalanced to the negative. You will then have a 60 cycle hum. Now jumper the negative to ground and hum is gone.
I have three or four 9444's and EV 2600's sitting in my garage and I use one 9444 to power two subs in my basement. With no problems.
The conclusion I might draw is this.... cheap drivers have a tendency to run a bit on the low side in impedance when you sweep them with an impedance meter. In other words your 4 ohm nominal subwoofer may very well dip to 2 ohms at 20 hz and the specs will not say this. My subs lower impedance range dips to 4 ohms when swept and they are rated as 4 ohms. In higher frequency mine hit around 7-8 ohms at 80-100 hz.
Now thinking the Altec 9444 is junk is a miss statement. I have experience and can tell you they will and do run 4 ohm loads without problems and I have no trouble getting high level output out of my 9444 without the clip lights coming on.
My conclusion is either your 9444 has internal problems or your load is lower than the spec say.
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