Hi to everybody,
i'm going to buy a MACRO TECH 1202 by Crown and i would know some reviews about this item. I will use it for my autoconstructed subs (coral HDS 815) in reflex. Now i'm using one EP 1500 (behringer) who has a damping factor of 300 at 8 ohm and the MA 1202 has 1000 at the same ohms.
I think i'm going to improve my subsound and control!!...I have only one dubt, the EP has the possibility to cut under 30 Hz and the MA not....what is your opinion?
Thanks a lot.
Luca
i'm going to buy a MACRO TECH 1202 by Crown and i would know some reviews about this item. I will use it for my autoconstructed subs (coral HDS 815) in reflex. Now i'm using one EP 1500 (behringer) who has a damping factor of 300 at 8 ohm and the MA 1202 has 1000 at the same ohms.
I think i'm going to improve my subsound and control!!...I have only one dubt, the EP has the possibility to cut under 30 Hz and the MA not....what is your opinion?
Thanks a lot.
Luca
Dunno for sure what they changed from a 1200 to a 1202.
IF the output devices are the same in quantity - then the DF ought to be more than 1,000, iirc.
In general the Crown amps of this type are known for LF control. Likely better than any current digital amplifier can do.
But also you did not say if you were running in bridged or dual mono??
For LF cut, you'd need either a passive circuit on the input, or an outboard EQ, or else I think Crown sold an input module that has that feature - not sure if the 1202 has removable input modules.
The 1200 is not terribly super powerful in terms of raw watts when run in mono, but likely is sufficient.
It is heavy...
_-_-
IF the output devices are the same in quantity - then the DF ought to be more than 1,000, iirc.
In general the Crown amps of this type are known for LF control. Likely better than any current digital amplifier can do.
But also you did not say if you were running in bridged or dual mono??
For LF cut, you'd need either a passive circuit on the input, or an outboard EQ, or else I think Crown sold an input module that has that feature - not sure if the 1202 has removable input modules.
The 1200 is not terribly super powerful in terms of raw watts when run in mono, but likely is sufficient.
It is heavy...
_-_-
Yeah, the Crown Macrotech series will keep running after every nuke has dropped. Literally, I suspect.
We do have some VZ5000s that are dead on one channel, though, and some 2400s that have clogged/missing filters, and have been generally kicked about and abused for >20 years. Still going fine, though have a bit of hiss.
Chris
We do have some VZ5000s that are dead on one channel, though, and some 2400s that have clogged/missing filters, and have been generally kicked about and abused for >20 years. Still going fine, though have a bit of hiss.
Chris
"Back EMF" tends to raise the driver impedance. An opposing voltage source reduces the current in the loop - it doesn't raise it. Damping is actually the worst when the back EMF is zero.
What happens with cheap amplifiers is that small signal and large signal output impedance are NOT the same. I wouldn't be surprised if the effective DF of the EP1500 gets down to 5 or less when it's on the verge of clipping. In the Crown Macrotech amps, it doesn't go down *at all*, even when driven 6dB into clip. The Crowns sound so powerful because you can drive them well into clipping (more average power= louder) before the sound goes to pot.
What happens with cheap amplifiers is that small signal and large signal output impedance are NOT the same. I wouldn't be surprised if the effective DF of the EP1500 gets down to 5 or less when it's on the verge of clipping. In the Crown Macrotech amps, it doesn't go down *at all*, even when driven 6dB into clip. The Crowns sound so powerful because you can drive them well into clipping (more average power= louder) before the sound goes to pot.
Back EMF and inductive freewheeling are compeltely different phenomena. Inductive freewheeling does not occur with voltage clipping. It can and does occur with *current* clipping - and without the diodes it will destruct the output stage. That cheapo transnova with only 2 stages of current gain driven off a 5532 is far more likley to suffer from current clipping than the 3EF used the the Crown.
anyhow, the Macro Techs afaik have a DF of 10,000. The Macro Reference, using an extra FB loop and max'd out number of output devices has 30,000 iirc.
It will sound different in the bass than most power amps... regardless of the series cable impedance (within reason). One would want to use cables with low DCR for high power bass anyhow.
So there.
_-_-
It will sound different in the bass than most power amps... regardless of the series cable impedance (within reason). One would want to use cables with low DCR for high power bass anyhow.
So there.
_-_-
"IF the output devices are the same in quantity - then the DF ought to be more than 1,000"
The DF is a red herring, the DCR of the voice-coil determines the real driver dampening.
The DR of an amplifier is just a function of how much feedback the design has.
If you want tighter bass, add power supply bypass caps.
"current clipping haven't heard that one before."
I suspect he means foldback-current-limiting.
Current clipping on a test bench looks like someone took a semi-circular 'bite' out of the 2nd and 4th quadrants of a sine-wave.
The DF is a red herring, the DCR of the voice-coil determines the real driver dampening.
The DR of an amplifier is just a function of how much feedback the design has.
If you want tighter bass, add power supply bypass caps.
"current clipping haven't heard that one before."
I suspect he means foldback-current-limiting.
Current clipping on a test bench looks like someone took a semi-circular 'bite' out of the 2nd and 4th quadrants of a sine-wave.
answers
First of all thanks for your replies.
For Bear: i use the EP1500 in stereo mode so with 400 watt RMS on subs of 4 ohm, i don t need so much power. I have a EQ (ULTRAGRAPH PRO FBQ 3102) but it cuts the frequencies not in an offhand way but with a curve. Your first idea is better. I will look for what you say.
For SRETEN: Why did you say it? i know that the DF of the ampli is different from the DF seen by the subs because there is the impedence of the cable wich is much more bigger than the output impedence of the ampli. so the DF seen by the sub is: DF=8/(Rout+Rcable), but the Rcable (about 2 to 6 ohm) is one order of magnitude bigger than the Rout (about 8 milli ohm). So DF seen by sub is about 6...is it right?
First of all thanks for your replies.
For Bear: i use the EP1500 in stereo mode so with 400 watt RMS on subs of 4 ohm, i don t need so much power. I have a EQ (ULTRAGRAPH PRO FBQ 3102) but it cuts the frequencies not in an offhand way but with a curve. Your first idea is better. I will look for what you say.
For SRETEN: Why did you say it? i know that the DF of the ampli is different from the DF seen by the subs because there is the impedence of the cable wich is much more bigger than the output impedence of the ampli. so the DF seen by the sub is: DF=8/(Rout+Rcable), but the Rcable (about 2 to 6 ohm) is one order of magnitude bigger than the Rout (about 8 milli ohm). So DF seen by sub is about 6
...is it right?Attachments
When output transistors saturate, the effective damping factor is at the mercy of the power supply's output impedance. Which is low for the Crown and not so low for the Behringer. Especially at 20 Hz. If it goes into current limit (either fold back linmiting or the output transistors simply running out of gain) the output impedance skyrockets. See the thread in solid state about measuring the impedance of a current source. With transients, you will get distortion artifacts from your woofer that sound like tapping on the speaker cone with the terminals open. An amplifier that can deliver all of the current that is requested (given the voltage waveform) will be free of these spurious artifacts, even if overdriven.
WG_sky : yes i understand what you say and i read what you suggested me, but the DF seen by the sub is different because there is the cable's impedence which is bigger than the ampli' output impedence. This is also what SRETEN said before i think. So at this point if the DF is not so influent at all i don t know if chose the XTi series in class D wich has 500 of Df but more power or the Macro tech in AB class with much control but less power....each in stereo mode of course.
If you can't get your cable resistance down to two tenths of an ohm or less, you need a bigger cable, not a bigger amplifier. 2 ohms is ridiculous - because you lose real power, not just a little bit of damping. Once you get your cable resistance down to something reasonable, the amplifier's output impedance has little to do with it - unless it gets as bad as a 2 ohm cable. You overload a cheap amplifier, and it WILL get that bad (single digit damping factor), where the Crown will stay above 50 where a 0.2 ohm cable dominates.
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