Chorus II and 7wpc SET amp?

[Hajj]

Just like the title says,

I've posted a WTB in the garage sale section for either a pair of La Scala's or Chorus II's

My choice was motivated mostly by the efficiency of these speakers, and the ease of having them shipped abroad (the reason behind the cornwalls being left out).

But with the numbers posted by all the members concerning power requirements for the Chorus (the lowest I found was 30 WPC, and that was an SS amp, all the way to 225 Wpc), makes me wonder if I'll be able to drive the Chorus pair with a meager 7wpc @ 8ohms SET tube amp (the Amp I have is capable of driving anything down to a few milliohms, and power increases as impedance decreases, and get them to produce decent bass.

I listen to anything from opera and complex classical music, but also Rolling stones, Pink floyd, Led Zepplin and a great deal of contrabass laden complex jazz.

Anyone with experience in that range of power, please chime-in.

My room is about 13x16 feet with a 10' ceiling.

Waiting for your input.

Regards

Nick

[troutboy]

Nick,

I recently bought a pair of 300b monoblocks to use with my Cornwall II's. Like you i was skeptical that 7 wpc would do much for me, but they opened my eyes very quickly. My room is of similar dimensions with an 8' ceiling. I had the pre set at about 50-60% gain, a surround processor with the volume set at around the same levels, and you couldn't stay in the room with the system. I was expecting to have to run every component wide open, but there was plenty left if you wanted to go louder. I do have a powered sub in the system, so not sure how that compares to your setup. Previously i had been running a Yamaha M80 with 200+ wpc in the system. Most of the time i am listening to classic rock and classic jazz on this system, but the classical stuff is very appealing because it sounds so good through the tubes. Hope this is the type of info you were after. Any specific questions feel free to pm me.

[tube fanatic]

7 wpc should be more than enough with either of the speakers. Many folks who claim the need for much greater power like to listen at ear damaging (in my opinion) sound pressure levels. In reality, even 1 wpc is more than enough with the Chorus or La Scala in most applications. Do you have access to a sound pressure level meter? If so, take a reading at your listening position at the loudest level that you are likely to use when listening. That will quickly allow you to determine how much power you need. Many of the people for whom I've designed and built amplifiers are amazed to find that they only need a fraction of a watt for room filling levels.

[jason str]

7 wpc should be more than enough with either of the speakers. Many folks who claim the need for much greater power like to listen at ear damaging (in my opinion) sound pressure levels. In reality, even 1 wpc is more than enough with the Chorus or La Scala in most applications. Do you have access to a sound pressure level meter? If so, take a reading at your listening position at the loudest level that you are likely to use when listening. That will quickly allow you to determine how much power you need. Many of the people for whom I've designed and built amplifiers are amazed to find that they only need a fraction of a watt for room filling levels.

If you want room filling sound buy a bose wave radio.

7 watts will drive Chorus II's but you would be missing out where the Chorus II's really shine, lots of power & live concert sound.

Comparing LaScala's to Chorus is like comparing apples to oranges, they are 2 different animals altogether.

In my opinion if you want to run tube equipment Chorus II's may not be your best choice, look for something that sounds a little better with less power such as Cornwalls, LaScala's Khorn ETC...

[Hajj]

Great input guys,

I was actually quite releived to hear that the flea power I have will be able to generate some bass.

I
run my pair of full-ranger speakers I have (said to be 99db/w/m
efficient) at around 2 watts, and that's more than enough in my listening
room.

So the main concern had always been the bass response on the 3 way klipsches.

As
for the choice of the shortlist (chorus II and La Scala), it was only
motivated by efficiency specs, and while it is obvious that these two
are different beasts, the reason the La Scala is there is

1- gotta love the utilitarian looks, i know i do

2- 105db/w/m!!!!

only down side is the lack of bass extension, and I'm left wondering if placing it in a corner will actually be of any help...

Hope someone responds to my WTB...

[tube fanatic]

only down side is the lack of bass extension, and I'm left wondering if placing it in a corner will actually be of any help...

Speaker placement is always a critical factor in bass response, as is listening position. Sometimes moving the speakers, or changing the listening position, a few inches can often have a profound effect at the bottom end. So, I wouldn't be afraid of the La Scalas somewhat limited bass specs. Good luck with whichever you purchase, and please post your comments about how things work out!

[troutboy]

I recently moved the 300b's i mentioned to the back room where i have KLF20's in the system. They are probably a better comparison than the Cornwalls in my other system because i think they are rated at 99 db SPL also. Took a little more gain on the preamp, but they still performed very well. The classic jazz stuff sounded very nice through the KLF20's. Listening to classis rock or something more modern, i tend to want to turn on the sub in the system for that deep bottom. I should mention that i am a bass player and my system output may be leaning towards that heavy bottom, so most "normal" people might be satisfied without the powered sub, but never hurts to have it there avaiable.

[StephenM]

For what it's worth:

As others note, thanks to the impressive sensitivity of the Chorus IIs (and most Klipsch speakers in general), it takes very little in the way of wattage to get them going reasonably loud. Seven watts probably won't get you to party levels, but this ought to give you some idea of how the wattage of your amp relates to volume:

http://myhometheater.homestead.com/splcalculator.html

With that said, the main reason people recommend high powered amplifiers is because such amplifiers tend to do a better job driving complex loads. Speakers aren't 8 ohm resistors, and sometimes it takes a pretty beefy amplifier to get the most out of a pair of speakers. However, since you seem confident in your amplifiers ability to deliver under a reasonably demanding load, I'd imagine it will probably do the job.

[DrWho]

Do you know the damping factor or output impedance of your SET amp? The Chorus II is really using a 4ohm driver on the bass, and the 101dB sensitivity is measured with a 2.83V input. However, the real reason I ask is because tbe Chorus II has an unfortunate spike in the impedance response right around 3k to 6k or so (I don't remember off hand), which can create some harshness with a high output impedance. Also, the woofer is naturally voiced a few dB soft relative to the mids, which is why a lot of people feel the need to increase the volume (Fletcher Munson equal loudness). So all that to say, I prefer the Chorus II over the Lascala, but I would investigate some xover mods if you're gonna run with SET amps.

[Hajj]

I'm afraid I do not know the damping factor, nor the output impedance of the amp, i'm still waiting for the manufacturer to give me the numbers, although i'm sure I once saw them on their website, and mademental note about it being either very low or very high compared to other tube amps (yup, i'm afraid, it's not much help...)

Very informative reply, thanks.

So if I'm getting this right, you're saying that many people tend to go for high power because we as humans tend to be more sensitive to higher frequencies, and thus need to crank up the volume to feel the bass.

The corrolary of that fact would mean that we would need speakers with a frequency response that follows that of the human ear's sensitivity, which to put it mildl, looks more like a rollercoaster than the typical "ruler flat" ideal frequency response we look for in our speakers.

So unless a speaker's frequency response is corrected to human ear'ssensitivity curves, our continuous quest for a speaker with of a ruler flat frequency response curve is a moot quest, and most importantly a very flawed approach to the ideal speaker.

Please feel free to bring any correction to the above.

And btw, If the Chorus II has a nasty impedance spike in the 3 to 6k region, why would you prefer it over the La Scala? But also, why would the woofer be voiced softer than the mid and tweeter if what we need is a relatively higher SPL from the lower frequencies to get the same perceived loudness?

I hope I'm still making sense.

[StephenM]

Audio enthusiasts seek a speaker that faithfully reproduces the original event, not one which attempts to mold the event to our hearing. In other words, we'd like to hear a guitar from our speakers sound the same as it would as if we were there live.

[Hajj]

Audio enthusiasts seek a speaker that faithfully reproduces the original event, not one which attempts to mold the event to our hearing. In other words, we'd like to hear a guitar from our speakers sound the same as it would as if we were there live.

Fair enough, I forgot to dial in the recording step of the process.

No wonder I thought I was going mad!

Thanks for clearing that up.

[Ski Bum]

Hello Hajj-

I've got some Decware amps I've used for forte ii's. The integrated you have is more powerful than what I use (se84c's).

With one se84, similarly sized room, able to reach mid 90's peak spl at my seat. Two se84's bridged gave notable increase in headroom, but I could still drive the amp to clipping before reaching my personal max sound threshold. Keep in mind that is with peaks at my chair near or slightly above 100db. Since your integrated will match what my se84's do bridged, and both the Chorus and 'Scalas are even more efficient than my fortes, I think you'll be fine.

Scalas are more efficient, but kind of overkill for such a small room, and lack the bass of the Chorus. My $.02.

[Hajj]

Sky Bum, thanks for chipping in.

This might just be as close to the ideal reply as possible.

Based on your input I can now rest assured I won't be running out of power with any one of these speakers

If my memory serves me well, I rarely listen to my music at more than 98 db at my listening position, unless I get carried away with one of those magnificient Jimmy Page guitar solo's or Arturo Sandoval's trumpet weeping with joy on the brink of apoplexia.

Btw, only roday did I notice your presence on the decware forums.

Regards

Nick

[Ski Bum]

Keep in mind that I was referring to peak levels. My average listening level is much less than that. One zen on forte's allows average levels in high70's to low 80's, two bridged allowed average levels mid 80's. You'll only do slightly better than that with the zen integrated and chorus. Will that be enough for you? (Probably, but then again I think 90db is freakin loud.) Steve makes some sick sounding amps, but even with Chorus efficiency they'll only give you so much. I do have times when I want more. Very few times like that, but they do happen. When it does, I'll haul up one of the ss amps, blast away, and quickly realize once again why I got into SE amps in the first place. They just sound so much better.

The spl calculator which someone posted a link to above is actually pretty close to the readings I'm gettting at home, amazingly enough, so you may want to check it out.