Amp for my sub

qwerty · Post by **qwerty** » Tue Apr 28, 2009 2:22 am

Hi,

Does anyone know if exist an PG amp. for my sub Boston 10.5LF (2Ohm) ?

At this moment I use an Orion HCCA 250 (digital reference)

MPS-2500 ?
Ti800.1 ?
ZPA ?

Who is the best for SQ at 2Ohm bridge ? Who have the same quality of my Orion ?

Thanks

GX3 · Post by **GX3** » Tue Apr 28, 2009 5:39 am

qwerty wrote:
At this moment I use an Orion HCCA 250 (digital reference)

Old school DR nice ......hold on to that even after you replace it with the ZPA 0.5 ( that would be my pick out of that list)

qwerty · Post by **qwerty** » Tue Apr 28, 2009 5:46 am

zpa 0.5 ? but does it work at 2Ohm bridge ?

2 x 150W @ 4 or 1 ohm (12V)
2 x 300W @ 4 or 1 ohm (13.8V)
2 x 500W @ 2 or 0.5 ohm (13.8V)
1 x 1000W @ 4 or 1 ohm bridged (13.8V)

Found on PG Faq

Realistically the ZPA 0.5 will do about 1200 watts into a 4 or 1 ohm bridged load. At 2 ohms bridged there is a little catch. You have to understand that the amp's power supply switches between two modes, High Current and High Voltage. That's how it does equal power at 1 or 4 ohm bridged. There is two extra LEDs on the ZPA series which indicate which mode the amp is in: Green is High Voltage, and Yellow is High Current.

In most cases of a 2 ohm bridged load this is what happens. When you are at lower listening levels the amp will stay in High Voltage, (the green led on center circuit board will be lit). But once you start increasing volume the amp will switch in High Current Mode (yellow led will be lit) and your power will be slightly reduced (ie 900 watts ballpark figure). It will try to limit the amount of power the amp can do to remain more stable into lower loads such as 1 ohm bridged. So at 2 ohms bridged when the amp won't provide as much power as 4 ohm bridged. Once the amplifier has switched into High Current mode it will remain in that mode until the system is turned off.

Post by **Francious70** » Tue Apr 28, 2009 6:39 am

Welcome to the forum friend!

As for your question, I personally would use a Xenon 600.1

Post by **kg1961** » Tue Apr 28, 2009 6:46 am

I would use Toms MPS2500
it has all the caps replaced

qwerty · Post by **qwerty** » Tue Apr 28, 2009 7:52 am

Xenon it's an D amp not for the SQ

dBincognito · Post by **dBincognito** » Tue Apr 28, 2009 7:57 am

The MPS2500 would be the only close comparison to that Orion SQ wise...IMO

dBincognito · Post by **dBincognito** » Tue Apr 28, 2009 8:00 am

A 2125 or a 2250 I think would be the closest

qwerty · Post by **qwerty** » Tue Apr 28, 2009 8:15 am

zpa it's an AB class or D class amp ?

Post by **Francious70** » Tue Apr 28, 2009 8:16 am

qwerty wrote:Xenon it's an D amp not for the SQ

That's a highly debatable opinion, but this is your system so I'll concede the point.

Post by **Bfowler** » Tue Apr 28, 2009 8:21 am

i would vote for the ti800.1.

its definitely more then you need....but a great amp, and wouldn't even break a sweat moving that woofer

dBincognito · Post by **dBincognito** » Tue Apr 28, 2009 8:22 am

Francious70 wrote:
qwerty wrote:Xenon it's an D amp not for the SQ
That's a highly debatable opinion, but this is your system so I'll concede the point.

How would it be up for debate ?

Class D has very low SQ, that is why it is used on subs

http://en.wikipedia.org/wiki/Electronic_amplifier

dBincognito · Post by **dBincognito** » Tue Apr 28, 2009 8:23 am

and a Xenon against that Orion stands no chance in a SQ comparison....that Orion is built with all +/-1% components

dBincognito · Post by **dBincognito** » Tue Apr 28, 2009 8:40 am

“Class D” switching uses pulse-width modulation (PWM)technology. PWMswitching is relatively slow and fixed at a switching frequency anywhere from 75KHz to 200KHz. This produces an audio output quality that is inferior to “ClassA” or “A-B,” so efficiency is gained at the expense of sonic fidelity.
A basic rule of thumb of audio amplifier design dictates that the minimum circuit swithching frequency is 10x greater than the audible range. This bare minimum is necessary to keep transistor “switching noise” out of the audible signal.

To adequately reproduce the audible range, (20Hz to 20KHz) the “Class D” PWM would have to switch at a minimum of 200KHz, which represents the upper range (and cost) ofPWMcapability.

Post by **Bfowler** » Tue Apr 28, 2009 8:41 am

dont mean to hijack this into a class d debate...but from the way i understand it. class d emits a high pitched noise by design, so to counter that. they make the amp sterile above about 600hz.

so if your crossover at 75hz @24db you are technically missing out on some upper harmonics....but personally i don't hear them. if a class d is made with high tolerance components i don't see why it couldn't be a sq oriented amp. of course that typically isn't the case. that said. i CAN tell a difference between a cheap 600rms amp and a well built class d amp like a xenon. (which i use)

Post by **Bfowler** » Tue Apr 28, 2009 8:42 am

wow...interesting read. i made my post before i saw that post

dBincognito · Post by **dBincognito** » Tue Apr 28, 2009 8:42 am

As a result,

“Class D” is generally used only in low frequency or low fidelity applications where the performance level of
PWM is acceptable.

“Class D” is load-specific.“Class D” amplifiers require output filters to eliminate spurious digital “switching noise” from the output signal. The slow switching speed of “Class D” necessitates a large, built-in, high-value output filter that acts as a passive crossover and is dependent
upon the correct speaker impedance.

Additionally, “Class D” operates at a relatively low voltage, much like a high current amplifier, and must be used into low impedances to make power with current. This emphasis on current requires a larger output
filter that is more critical to impedance load matching.

This is why “Class D” amplifiers are specific “1 Ohm” or “1/2 Ohm”, etc. Failure to observe the exact recommended speaker load is akin to connecting an improper speaker load to a passive crossover
network, and will result in degradation of the already limited “Class D” frequency response.

“Class D” is (was) a step in the right direction. It does work, and works rather well in certaininstances. It is, however, a crude and incomplete technology.

dBincognito · Post by **dBincognito** » Tue Apr 28, 2009 8:45 am

So...Class D is awesome in the fact that it can generate large amounts of power at a very efficient rate...but on a scale of SQ it would not rank above a AB or A amp.....class D is great for what it was designed for....but the question here was for a comparison amp...

qwerty · Post by **qwerty** » Wed Apr 29, 2009 12:39 am

but what the difference from mps2500 and ms275 and zpa 0.5?

but probably the ms275 isn't suitable for an sub section.

The zpa 0.5 ?

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