Amp Purchase(NAD......

[B3Nut]

I said "in most cases." SDA's are one of those loudspeakers that *must* have very high power amplifiers in order to be properly driven. The reason your other amplifiers failed where the Bryston succeded was because they could not drive the load SDA speakers present them with. SDA's just don't "light up" unless you have a LOT of power on tap (BTW, this is why the Carver does well also as you noticed, it can sink a lot of power into a low-impedance and/or wildly fluctuating load.) There's nothing here that contradicts the established science, and no objectivist would argue with you on this one. Your other amps sounded "flat" because they were beginning to clip because they couldn't drive your particular load, they were not operating in a linear fashion at all. Mild clipping causes the sonic effects you noticed (flat soundstage, no dynamics, etc.) Had you driven those amplifiers any harder you would have jeapordized your tweeters. Into a more efficient and conventional 8-ohm load, they would have fared better.

As stated earlier, two amplifiers will sound alike in an ABX test if (1) they have high input impedance and low output impedance, (2) the frequency response is flat across the audio band, (3) distortion and noise are low (typically less than 1% THD and 90db S/N or better) and (4) *neither amplifier is allowed to clip*. #4 was where your Kenny and Sony fell flat on their faces, they clipped trying to drive what is an unusually difficult loudspeaker load.

Todd in Cheesecurdistan

 

[PENG]

I do want to get rid of the Kenwood , its useless to me . If you believe all Power amps sound the same at lower or any volume , buy it off me and AB to what ever you have .

I have not seen any one posted on this thread so far deserve this kind of rebuttal!

 

[Seth=L]

I have a Bryston 4b hooked up to Polk SDA's and the only Amp the polks have known since i bought them new ( many years ago ) . I took the bryston in for servicing ( before the 20 year warrenty was up ) . And hooked up 2 different amps , 1 a old Kenwood 2 channel ( 110 x 2 ) , That amp couldnt power up my speakers at all , No sound stage , no depth , no nothing , so i took another amp out of the closet a Sony n440 ( 4 channel ) , I tryed it and it had abit of a soundstage , but still couldnt listin to it , then tryed bridging it , hehe , what a joke , that baby was gonna fry ( the Polks are 6 ohm speakers and love the power ) .
At any listining level , my Polks didnt like the generic power amps , they just didnt have a soundstage and no Bass . Now with the Bryston 4b , the soundstage is unreal and when i push the Polks , they love it and sound awsome ( you should give a 4b a test run sometime , not a bad amp ) . I now have a Carver TFM35 ( 250 x 2 rms ) for a backup for the Bryston , It seems to match nicely with the Polks also .
I do want to get rid of the Kenwood , its useless to me . If you believe all Power amps sound the same at lower or any volume , buy it off me and AB to what ever you have .

If your Polk SDAs are anything like the other SDA series speakers I have heard they sound pretty damn good powered by most anything.

Edit: These are Polks words; "The recommended amplification is from 30 to 350 Watts/channel the impedance is 6 Ohms and the efficiency is 89.7 dB."

 

[wire]

I have not seen any one posted on this thread so far deserve this kind of rebuttal!

Hehe
you say Kenwood is that bad .

 

[wire]

If your Polk SDAs are anything like the other SDA series speakers I have heard they sound pretty damn good powered by most anything.

Edit: These are Polks words; "The recommended amplification is from 30 to 350 Watts/channel the impedance is 6 Ohms and the efficiency is 89.7 dB."

They are definetly power hunger . The more power the better for these speakers .

 

[Seth=L]

They are definetly power hunger . The more power the better for these speakers .

Their specifications indicate otherwise. Unfortunately there aren't any publicly available benchtests, as far as I can see, available for these speakers.

 

[PENG]

Hehe
you say Kenwood is that bad .

I believe the SRA would do their best with some powerful amps, but if that old Kenwood can output 110 W RMS and is not defective or worn out, it should at least do okay without clipping at normal listening levels. If you are going to prove a point, use a new amp or a used one that you know is in top shape. The way you described how that old kenwood was doing (or not doing), I doubt it can even do anything with a RTi6. Good luck in trying to sell it!

Merry Christmas!

 

[cfrizz]

What manufacturers put in their specs are simply a guideline. It is up to the end user to discover what the product can actually handle if they choose to do so.

That is why I have learned to pay more attention to my ears rather than any numbers or specifications. They are simply guidelines not hard & immovable rules.

The only way to discover & learn new things is to try them.

Their specifications indicate otherwise. Unfortunately there aren't any publicly available benchtests, as far as I can see, available for these speakers.

 

[mtrycrafts]

(4) *neither amplifier is allowed to clip*. #4 was where your Kenny and Sony fell flat on their faces, they clipped trying to drive what is an unusually difficult loudspeaker load.

Todd in Cheesecurdistan

So? Those amps have the capacity to operate properly right up to their desin limits that happen at some peaks perhaps and not for most operation. With those speaker's sensitivity in the room, 94dB spl, I seriously doubt any issues up to 114 dB spl. Soundstage is not an amp issue, anyhow, please. And certainly not up to the limits of the amps, 114dB spl for lack of power. What was perceived was just unreliable perception, biased, period.

 

[mtrycrafts]

If your Polk SDAs are anything like the other SDA series speakers I have heard they sound pretty damn good powered by most anything.

Edit: These are Polks words; "The recommended amplification is from 30 to 350 Watts/channel the impedance is 6 Ohms and the efficiency is 89.7 dB."[/QUhttp://forums.audioholics.com/forums/images/smilies/biggrin.gif
OTE]

Urban legends and myths are hard to eradicate
Once a false premise is implanted, it is impossible to get rid of it

 

[hecklerdd]

Thanks

Once again, he doesn't NEED to have a reason to want to purchase separate amplification. It is perfectly acceptable for him to WANT it.

He will quickly discover that it makes a significant improvement to his system. He will have that 200wpc amplifier already there if/when he decides he WANTS to get new speakers. Which will drive his current and future speakers with ease. It will make it that much easier to upgrade from a receiver to a preprocessor which will give his system yet another overall improvement.

He can thoroughly enjoy his system knowing that he HAS all the power that the system demands, rather than having to worry about pushing his receiver beyond it's limits. He won't have to worry about hearing distortion from his speakers or the receiver shutting down in protect mode. It is better to have it & not need it rather than find out the hard way that it is needed & not have it!

He will discover the joy of being able to hear his music clearly even though the volume is very low.

Since it is not any of our money that he is spending, he should do as he wishes & from all indications he wishes to discover the wonderful world of separate amplification.

Stop trying to talk him out of it, since there are no rules saying that neither he nor anyone else should ever want to have it.

I appreciate the back up. I like my speakers even though they are not high end. I heard a big difference when I upgraded to the NAD from a Yamaha.I believe I will notice a difference. I will post pics of the theater when I'm done(FEB2008). I will have a acoustic ceiling and panels on the upper part of the walls.The bottom have will be wood.

 

[Seth=L]

I appreciate the back up. I like my speakers even though they are not high end. I heard a big difference when I upgraded to the NAD from a Yamaha.I believe I will notice a difference. I will post pics of the theater when I'm done(FEB2008). I will have a acoustic ceiling and panels on the upper part of the walls.The bottom have will be wood.

We aren't trying to tear you down, we are trying to get your a difference in sound that is worth the money. But in the end, it is your dollar and you decide what has value. Just trying to lend a helping hand.

 

[Soundman]

Don't forget to consider Emotiva. Excellent products for the money.

Didn't this thread start out as a way to give him suggestions? I agree with rnatalli. For the price, Emotiva is tough to beat. Gotta love those pretty lights!

http://www.emotiva.com/amplifiers.html