What 200 WPC power amp??

[MrMcGoo]

The reason IMO that bigger solid state amps usually sound better on RF-7 at 15 one-hundredths of a watt is that the big amp can feed the low impedance load (2.8 ohm minimum) in a linear manner. The big high current amp can cleanly keep the transient peaks at the required voltage.

Home theaters are calibrated to 75 decibles of pink noise. Commercial theaters are run at 85 decibels so you can hear over the jerk talking through the movie. On rare occasions I have run at 85 decibels at home. When you add a 30 decible transient on top of the 85 decibels at 4 meters you get a very big number. It is the reason that I bought my Sunfire Stereo amp aka Ampzilla.

Some of the big amps have very clean first watts. If the first watt is clean, why not have the headroom and high current capability of a big amp? The amps that I use do not draw much current or generate much heat when they loaf along. Yet the first watt is cleaner than the 140 watt B&K amp that I have used in the past.

I have no doubt that DeanG is correct when he says that a 60 watt tube amp is usually sufficient for listening to music on the RF-7s. His tube amps had a 4 ohm tap. Solid state amps lack such a feature and therfore usually lack low impedance capability until you get to the bigger amps.

Bill

[psg]

A person running a first

order network like the Type A or DHA might find 85-90dB

steady state with 100dB peaks extremely loud due to the amount of power

being dumped into the drivers. Consider this

statement: "A tweeter with a third order high pass filter with a

crossover frequency of 5000 Hz driven by the 100 watt amplifier...will

receive about 1.6 watts at 2500 Hz versus 25 watts with a first order

filter at full output." So, you could take two Klipschorns, load them

up with different networks, run each up to 85dB or so, and find

that though the volume levels are perfectly matched -- one will sound louder than the other.

Why anyone would want to dump a 100W single tone in a loudspeaker is

beyond me, so normally you'd get very little power overlap between

drivers.

So even if you did... So you'd have 75W of 2500Hz produced by the mid

and 25W produced by the tweeter (if it hasn't blown by then). I

see why it would sound different than 98.4W produced by the mid and

1.6W by the tweeter, but I don't see why it would be louder...

[minn_male42]

Bill seems to be the only one in this thread that has hit the nail on the head...

the low impedance dips in the lower register are difficult to

handle.... most low power solid state amplifiers cannot reproduce low

frequencies well on RF-7's (or KLF-30's)....

i use a carver pro ZR1000 digital amp that is rated for 225 watts per

side at 8 ohms.... it does an amazing job on my KLF-30's.... on the

first watt as well as when the musical peaks happen to go over 100

watts....

[cjgeraci]

But I am also fond of really letting it rip, probably to Dean's levels...

Now what in the hell is that supposed to mean Carl? I hardly think 125dB constitutes "letting it rip."

Folks really need to make a distinction between steady state and peak because there's a world of difference. Also, "loudness" is somewhat linked to the network type you are running. For example: a person running a first order network like the Type A or DHA might find 85-90dB steady state with 100dB peaks extremely loud due to the amount of power being dumped into the drivers. Consider this statement: "A tweeter with a third order high pass filter with a crossover frequency of 5000 Hz driven by the 100 watt amplifier...will receive about 1.6 watts at 2500 Hz versus 25 watts with a first order filter at full output." So, you could take two Klipschorns, load them up with different networks, run each up to 85dB or so, and find that though the volume levels are perfectly matched -- one will sound louder than the other. Incidently, I've done this many times, and can assure you that unless everyone in this thread is using the same speaker/network/driver configuration -- everyone is speaking a different language. There is so much more to this, but I'ze got to git back to work!

Uhhh, damn loud.........? (intended as a compliment)

And getting louder since the recent changes.

And yes, we are all speaking a different language.

Carl.

[Duke Spinner]

irregardless ...

Rokin'Bob .. bein a Band kinda guy ...

Is gonna want 105 dB, or more ....

RRRROTEL ......[]

[Deang]

Why anyone would want to dump a 100W single tone in a loudspeaker is beyond me, so normally you'd get very little power overlap between drivers.

You missed it -- no one said anything about "a single tone". A first order network is 6dB per octave. If the crossover is at 5000, one octave below that (2500) the tweeter would be getting 25 watts of it (if a 100 watts were being used). The example was kept simple by using a two-way and 100 watts. With a first order filter, "normal" means considerable overlap. So, what single tone are you talking about -- all the tones between 5000 and 2500?

[psg]

Why anyone would want to dump a 100W single tone in

a loudspeaker is beyond me, so normally you'd get very little power

overlap between drivers.

You missed it --

no one said anything about "a single tone". A first order network is

6dB per octave. If the crossover is at 5000, one octave below that

(2500) the tweeter would be getting 25 watts of it (if a

100 watts were being used). The example was kept simple

by using a two-way and 100 watts. With a first order filter,

"normal" means considerable overlap. So, what single tone are you

talking about -- all the tones between 5000 and 2500?

What single tone you ask? The only way that tweeter is getting 25W

leaking from mid frequencies would be because the entire 100W is at 2500 Hz. So it's that

single tone. If the 100W is spread over the full bandwidth,

there's no way the tweeter is going to get 25W because of the

first-order filter. Agreed?

[MrMcGoo]

Dean has done an excellent job explaining why Heritage speakers blew so many tweeters when solid state amps replaced tube amps in the 1970s. The slope on the crossover was a mistake. Zener diodes were not the answer; a better network was the answer.

Anyone with a 5 db per octave crossover on their tweeter should probably replace it unless they use a small SET amp.

Bill

[krispykoilz]

My recommendation would be to look at a Bryston 4B. The older ones at 200 WPC can be had for less than $5oo.oo, newer ones for more. Excellent/articulate bass response.

I have a question about the "Amplifier Power Required" calculater. From what I see this is for checking using only one speaker. Wouldn't you need to add an extra 3 db for each additional speaker you are using into the Loudspeaker Sensitivity chart to get a proper measurement?

[MrMcGoo]

For music, there can be up to a 3 b increase. Bass cancellations etc will usually add less than 3 db.

In movies, many explosions or other loud events happen on one side of the screen. Others happen at center screen where three speakers may be involved.

However, the system is calibrated with 75 decibels of pink noise. If you run at reference level, the preamp and amps are being run at the 75 decibels per channel level with 30 decibel peaks possible. Home reference level is -10 db on my system. Some folks claim to run at 0 db, theater reference at 85 db per channel, too darn loud.

Bill

[mdbrien]

If I were you, I'd look for an Aragon 8008BB or 8008MKII. The 8008BB and 8008MKII are the same amp, just cosmetic differences. I have an Aragon 8008BB with LaScalas. One word "AWESOME"

My preamp is the Aragon Aurum.

Hope this helps!!!

[gibby214]

Mdbrien,

God Bless you New Orleans folks. Hope you and your Klipsch headed for high ground last week.

[edwinr]

I get a little lost when the argument turns technical. But my ears don't.

You stick a big 200 watt, well designed S/S amplifier on the end of any loudspeaker, but I'm talking Heritage at the moment, and compare this amplifier with a puny 50 odd watt per channel S/S (this could describe some of the cheaper surround sound receivers) and the result is like chalk and cheese.

Big amps sounds very tube like. Smooth, clean, liquid in their presentation. Smaller S/S sounds harsh, brittle, well - I guess it sounds like most people expect S/S to sound. But S/S doesn't HAVE to sound like that.

I love the sound of well designed tube amps. I also love the sound of well designed S/S monsters. I would find it hard to argue against anyone who buys a 200 watt S/S monster power amp, fronting it with a nice tube pre-amp.

[Duke Spinner]

Exactly what i have, edwinr............

Quicksilver tube pre > Crown K-2, all 500 wpc @ 8*

the power amp has no rated distortion in the milliwatt range > right to probably 15 dB above rated power

do you want Slam ..???

my 6l6 based power amp no can do it ....

[mdbrien]

Thanks gibby214 for your blessings. My family and I ran to Arkansas to escape the horrible damage it causesd to New Orleans. I live 25 miles West of New Orleans and lucky enough for me and my family the storm turned East at the last minute which put us more on the West side of the storm. So other than minimal damage to my home with NO flooding and my utilities being out for a week, my Klipsch and I made out ok. I think it's going to be a very long time before people can begin to get over the horror this storm created, which some may never get over.
I must comment on what Edwinr said about "Big amps sounds very tube like. Smooth, clean, liquid in their presentation. Smaller S/S sounds harsh, brittle, well - I guess it sounds like most people expect S/S to sound. But S/S doesn't HAVE to sound like that." I've had my LaScalas now for about 17 years and for the most part of that I've used a Sony ES700 integrated amp 110wpc. Until I upgraded to the S/S monster Aragon 8008BB with the Aragon Aurum preamp I could not believe what I was missing all those years. Very Smooth, clean, liquid in their presentation. I could not be happier.
My next upgrade will be the THX KW-120 Subs.

[krispykoilz]

MrMcGoo, thanks for the info. IIRC you're using the same reciever as I have for a preamp but are using more powerful amps. Right now I'm using 240/250/240 across the front and 110/110/110 across the rears. I agree at -10 it is plenty loud enough and even then I've seen peaks approaching 90 db in the room on some movies. As for amplifier size I do agree that bigger is better just for the sake of headroom. Although there are some wonderful sounding 50 W. S/S amps out there one better be prepared to keep their listening levels well within the amps range unless they're prepared to spend the money repairing broken/blown speakers.

[sunburnwilly]

Dean has done an excellent job explaining why Heritage speakers blew so many tweeters when solid state amps replaced tube amps in the 1970s. The slope on the crossover was a mistake. Zener diodes were not the answer; a better network was the answer.

Anyone with a 5 db per octave crossover on their tweeter should probably replace it unless they use a small SET amp.

Bill

Perhaps it also had something to do with the soundpressure level in the room making the tone-arm or stylus JUMP . At least this was the problem with an old friend of mines La Scalas . He went through 3 tweets that I know of .

[jpm]

To all non-believers:

Hook up a Carver ZR1600 to a set of RF7s. That will be the end of the discussion.

[psg]

To all non-believers:

Hook up a Carver ZR1600 to a set of RF7s. That will be the end of the discussion.

That would only prove that you need an amp capable of difficult

loads for speakers that offer difficult loads. But what about

other speakers such as the KHorn?

[jpm]

Same deal. Brys runs a set of Khorns thru a ZR1600 and it'll peel your wig.

I don't buy the "tubes for purity" jive. I'm sure tubes are fine, and I like hobbys too, but don't sit there and poo poo powerful SS amps. That just don't wash.