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Re: M100 or LFR1100
iloveturbo #405050 06/04/14 05:04 PM
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Thx guys.

AV8801 and a5000 are both great contenders . I just throw Denon to the mix but really didn't really like the spec of it. AV8801 has everything I am looking for and more. Especially the it looked like a quality build which is what i am after. Dakkon I am tempted....lol (wife must not know....)

-Howard

Re: M100 or LFR1100
J. B. #405051 06/04/14 05:36 PM
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Originally Posted By: J. B.
i went the simplest way by using cable with RCA to TR (1/4" phone) on the ends.

when a manufacturer specifies an output of 1 volt, it only indicates the output level for a specific input level;
normally preamp outputs should swing higher than that level.

i haven't checked with my current equipment, but on my former preamp, the max undistorted output was something like 16 Vrms, and a standard output of 2 V.
I'm certain it is less with my current preamp, but so far, i've never lacked power in my small room.
maybe in a large room the preamp outs would not give a signal high enough to drive the amps to max output when needed; then, i would try XLR cables, and i also would increase the sensitivity settings of the amps: my surround amps are set at -6 dB and the front amps at -10 dB.
there are some "adapter boxes" made that go between the preamp and the proamp to increase the available voltage in case the preamp output is too low.

Weight: it has nothing to do with sound quality, but everything to do with the type of power supply and the class of amplification used.



Just for the record JB , I did not say anything about the weight having anything to do with sound quality. As an example , Pioneer and their ICE amps. At the time I wrote that I missed where it mention on Crown's site that it was class D and later when I found some pics with the top off and saw the innards. I am old school I admit, in my mind Class D is more suited to subwoofers which is where you most likely to find them and in pro sound where lots of power and efficiency are key. Their is reason they are labeled pro amps, you need to know how to properly implement them, too much gain can equal extra noise and most people like to exceed the limits without understanding the principles. I have seen plenty of sub amps with the gain cranked up because it goes louder. Consumer grade electronic are designed so they play well with each other so the general public doesn't need a degree in electrical engineering to enjoy music. I take it you have the ability and equipment to test these sorts of things based on your above reply, I would love for you to share more of the specs of your equipment, information is always welcome. A lot of specs are left out unfortunately by manufacturers that would help the uninitiated like myself to properly match components. As an example crown does not list voltage gain , though that may be because it as gain controls and a pro would set them with proper equipment (speculation).

Richard


DOG is GOD spelled backwards.
What others think of me is none of my business.
M80 V3 MY GLOSS Cherry
Re: M100 or LFR1100
Gr8_White_North #405053 06/04/14 05:58 PM
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Originally Posted By: Socketman
As an example crown does not list voltage gain , though that may be because it as gain controls and a pro would set them with proper equipment (speculation).

Richard


Hi Richard, I thought I will chime in on the subject a little bit. I am an electrical engineer by trade and my company deal with IC design on daily basis so I understand the varies fundamental approach to amp design. To me the move away from discrete components to IC carries multiple advantages, not just cost and weight saving. Without bored everyone to death here, let me just say the Crown drivecore IC (from Texas Instrument) is really a bless and move in the right direction. Much like your mobile phone now the day, we are doing things that we dreamed about only ten years ago all thanks for advancement in IC design and manufacturing process. Anyway, I choice Crown XLS not because that's all I can afford. But rather to reward them for make such of wonderful product. Is it perfect? I doubt it, but it's a step in the right direction. It's only going to get better as time progress and other companies following suit.

As for the gain calculation, I quote Avi from Crown

An amp with a voltage gain of X40 will output 40 times it's input sensitivity spec to reach full power on the output, on the XLS series the input sensitivity is 1.4V.
That means that if we put 1.4V on the amps input we get at 8 ohm for the XLS 1000 215W per channel. So we'll calculate the maximum output voltage:
V out max = SQR(P max X R) = SQR(215 X 8) = SQR(1720) = 41.473V
The amps voltage gain is the ratio between the input sensitivity and the amps maximum output voltage. So we take the two figures (Voltage sensitivity=1.4V and Maximum output voltage=41.473V) and find the ratio between them, that's:
R = V1 / V2 = 41.473 / 1.4 = 29.625

Let's redo it for 4 ohm load:
V out max = SQR(P max X R)=SQR(350 X 4) = SQR(1400) = 37.417V
R = V1 / V2 = 37.417 / 1.4 = 26.726"

http://www.crownaudio.com/forums/index.php?showtopic=4459&#entry16750

I will be testing the XLS series soon and will give you guys an honest feedback on what I think of it.

Cheers

Howard

Re: M100 or LFR1100
iloveturbo #405054 06/04/14 07:04 PM
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Thanks for chiming in. Sadly ( or maybe not) most people aren't EE's and that what I was pointing out. I am not an EE but but I have a decent handle how these things work. Something to pontificate: If class D was all that, why don't the big makers like Denon et al go that route. Imagine the saving on shipping Millions of receivers across the pond if you could cut their weight by half. This could lead us down a dark road on the subject of all amps sound the same so lets no go there.:) As I said before I look forward to your impressions and opinions .

Richard


DOG is GOD spelled backwards.
What others think of me is none of my business.
M80 V3 MY GLOSS Cherry
Re: M100 or LFR1100
Gr8_White_North #405056 06/04/14 07:47 PM
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Let's not forget that Axiom amps are class D. The brains at Axiom obviously think that class D is sufficient smile


M60|VP150|2xQS8|PSA XS30+Epik Empire|Pioneer Kuro 6010FD|PS3|Denon AVR-X4000|Parasound 5250v.2|
Re: M100 or LFR1100
Crimson Wrath #405057 06/04/14 07:54 PM
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Originally Posted By: Crimson Wrath
Let's not forget that Axiom amps are class D. The brains at Axiom obviously think that class D is sufficient smile


With a HUGE power supply. I think Richard was coming from the perspective of a Class D amp with a wimpy power supply. Axiom uses one of the largest power supplies for the rated power that i've seen; which is one of the most important parts of the overall performance of the unit.

Re: M100 or LFR1100
iloveturbo #405063 06/04/14 09:12 PM
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Thanks Alex , you echoed my thought exactly. Looking inside the crown xls reveals a lot of barren land LOL. It weighs 10lbs the Axiom is 58, so I think they serve 2 entirely different markets. Still the fact remains that for most listening we seldom exceed even a few watts.


DOG is GOD spelled backwards.
What others think of me is none of my business.
M80 V3 MY GLOSS Cherry
Re: M100 or LFR1100
iloveturbo #405064 06/04/14 09:35 PM
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Originally Posted By: iloveturbo
Originally Posted By: Socketman
As an example crown does not list voltage gain , though that may be because it as gain controls and a pro would set them with proper equipment (speculation).

Richard


As for the gain calculation, I quote Avi from Crown

An amp with a voltage gain of X40 will output 40 times it's input sensitivity spec to reach full power on the output, on the XLS series the input sensitivity is 1.4V.
That means that if we put 1.4V on the amps input we get at 8 ohm for the XLS 1000 215W per channel. So we'll calculate the maximum output voltage:
V out max = SQR(P max X R) = SQR(215 X 8) = SQR(1720) = 41.473V
The amps voltage gain is the ratio between the input sensitivity and the amps maximum output voltage. So we take the two figures (Voltage sensitivity=1.4V and Maximum output voltage=41.473V) and find the ratio between them, that's:
R = V1 / V2 = 41.473 / 1.4 = 29.625

Let's redo it for 4 ohm load:
V out max = SQR(P max X R)=SQR(350 X 4) = SQR(1400) = 37.417V
R = V1 / V2 = 37.417 / 1.4 = 26.726"

http://www.crownaudio.com/forums/index.php?showtopic=4459&#entry16750

I will be testing the XLS series soon and will give you guys an honest feedback on what I think of it.

Cheers

Howard


Howard, dude, I thought you said you weren't going to bore
us! I was just beginning to trust you. This sets us back.


Always call the place you live a house. When you're old, everyone else will call it a home.
Re: M100 or LFR1100
Gr8_White_North #405065 06/04/14 09:57 PM
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Originally Posted By: Socketman
Thanks for chiming in. Sadly ( or maybe not) most people aren't EE's and that what I was pointing out. I am not an EE but but I have a decent handle how these things work. Something to pontificate: If class D was all that, why don't the big makers like Denon et al go that route. Imagine the saving on shipping Millions of receivers across the pond if you could cut their weight by half. This could lead us down a dark road on the subject of all amps sound the same so lets no go there.:) As I said before I look forward to your impressions and opinions .

Richard


Richard, No doubt the power supplies are on the light side. It's designed in a way so if my wife found out I spend more money on audio equipments she is able to pick it up and throw at me eek

Seriously though, pro audio gears are designed to be on the go hence they often try to be as light as possible. Maybe that's why XLS series carry 0.5% or <0.5% THD. It's a compromise that the designer is willing to take. Again, that's my guess. If one ask me if XLS is the best thing since slice bread, that would be a no. I still own big heavy monoblocks and I don't think they are leaving my house soon. But it's pretty impressive to see that much power being pack into 1U height that weights 11lbs with frequency response of 20 Hz to 20 kHz): +0 dB, –1 dB @1W yet has 103dB SNR. I think they couldn't done it at this price point without going the IC approach. It retail so little five sets cost me lesser than one of my used Parasound A21 smile I admit, it feels good to be cheap sometimes lol.

-Howard

Re: M100 or LFR1100
BobKay #405066 06/04/14 10:02 PM
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Originally Posted By: BobKay

Howard, dude, I thought you said you weren't going to bore
us! I was just beginning to trust you. This sets us back.


Guilty as charged. It is pretty boring blush blush

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