High power amplifiers for Heritage speakers

[KeyOfGee]

This has probably been talked about more times over the years than it needs to be, but I just want to understand what is going on with power amplifiers and Heritage speakers. Please don't be offended at my ignorance about this. Simple question, why is everyone recommending low powered amps for Heritage speakers for Home Theater when it's virtually impossible to find a high quality low powered 7 channel amplifier to run them?? In many of the post that I have seen, everyone is using saying don't use more than 50w per channel (because you don't have to), but the quality amps are rated from 125w to 250w. My guess is that a McIntosh MC207 or a ATI AT4007 is out of the question for (3) Klipsch LaScala up front and Heresy surrounds or am I just crazy for even thinking about amps like this?? OK, I'm ready for the beating.

[Schu]

No comment...

[BusaDude]

I once used a McIntosh MC 7270 (270 wpc) to drive my front L/R Chorus II's...

And I have a Parasound 1205A (140 wpc) running my current 5 LaScala surround setup...

Pretty sure I'm not crazy, but that's just my opinion.

[Islander]

I don't think everyone is recommending low-power amps for use with Heritage speakers.  You can do it, but the headroom will be limited, so musical peaks won't be as "peaky" as they should be.

 

On my system, the main speakers are bi-amped, and have 500 watts available to each driver.  That's 500 watts to each tweeter, and 500 watts to each woofer.  Some other members have more powerful systems.

 

The key word is "available".  Most of the time, the speakers are only sent a few watts, and more power only comes into play very briefly, to reproduce musical peaks.

 

The surround speakers are powered by the receiver, which probably puts out 60-70 Wpc when driving 4 channels.

 

With a high-power system whose speakers don't have high power ratings, the phrase to never forget is "Don't let the drunk near the volume control!"  That's when things could go wrong.  The system goes as loud as a sober person can handle, with lots to spare.  I've never tried to hear how loud it would go, since it would be painful.  It goes loud enough for me.

Edited April 5, 2016 by Islander

[teaman]

I run Emotiva all of my Klipsch Heresy 1, KP-250 and Slant Heresies with the Emotiva XPA-2 amplifiers. Each channel is 250-300 watts of power depending on my amp being Gen 1 or Gen 2. I am yet to hear anything wrong with high power amps powering any of them. My buddy uses a Bryston 4B to power his Fortes as well and they sound fantastic. The more headroom you have the more dynamic power you have stored away for those dynamic moments. I know you can run flea powered amps with these hyper sensitive speakers and there is nothing wrong with doing so but by all means go for the extra power if that is your thing. 

 

 

Tim

[Fjd]

Paul Klipsch had a Dope from Hope article on this subject - linked below for the entire article. These figures are based on single-speaker output into a 3000 ft^3 room while allowing peaks 10 dB above average to pass without clipping:

 

https://community.kl...attach_id=69980

 

 

 

 

 

[KeyOfGee]

OK, The replies were educating as well as refreshing. The first time I heard Klipsch speakers I never asked the owner what type of amp he was using, I was just mesmerized by how good Maynard Ferguson sounded. I think I'm getting the picture about amplification and Klipsch. Thank You

[mustang guy]

PWK is hard to read like Frued. True geniuses usually are, and don't bounce around trying to explain themselves. Is there anything he didn't cover in that DFH article? 

 

If you don't want the low power of SET but still want tubes Bob Carver sells some decent amps:

 

Silver Seven 700 - Specifications: Rated Power (8 ohms): 700 watts RMS continuous, 900 watts RMS with speech and music, Frequency Response: 2 Hz to 85 kHz (-3 dB), wt 45lbs ea, price $32,000 / pair

[jjptkd]

"Don't let the drunk near the volume control!"  That's when things could go wrong.   

 

Yes, agree 100% with the above statement. There is no such thing as "too much power," that is what the volume control is for. I think the important thing is quality amplification and with quality amplifiers the more powerful the more expensive. Klipsch speakers only need so much power so spending the extra money on watts that you will never use may be a waste, especially if the budget is tight and you could really use that extra cash in other parts of the system.

[jjptkd]

My dream is to someday own a pair of Carver tube amps, maybe the 305's? I've had the little 20 watt version and was extremely impressed with it. Original Silver 7's pictured below:

[Gorm]

Is it bad that I think my MC240 is "high powered" for my Cornscalas?

Edited April 5, 2016 by Gorm

[MORE KLIPSCH PLEASE]

I'm with mustang guy on this. 

 

Most all my Klipsch are driven with Bob Carver power. I don't own any of Bob tube amps. I use the old SS amps from the 90's. Most of my Carver amps are the TFM and the "t" series. For me, it's what Heritage speakers I'm playing at the time. My LaScala's I might put a few watts at em. But if I want to shake the foundation of my home I'll power up the Chorus with a big TFM-55x and feed 375+ watts at em....... Is it too much??? It's what  I'm listing to. I like to feel the music...

Do I listen to music a high volumes all the time???..... ahhh no..... But I want to really jam out and "feel" the music I'll put the watts to my Heritage speakers. 

 

jjptkd....... I also dream of Silver 7's...... or the big TFM-75......yea I'll keep dreaming lol lol

 

MKP :-)

[mustang guy]

PWK from article:

 

 

That says it all. It would be a nice thing for one of the smart folks here to come up with just such a protection plan for those of us who want the overhead.

[jason str]

I can see somebody new to the scene tempted to overturn the volume knob trying to get every last bit of volume out of their system.

 

The rest of us should be able to hear when our components are straining and back off the volume a bit.

 

Good thing Bob is around to assure our loudspeakers some insurance in case of accidental stupidity.

[twistedcrankcammer]

KeyOfGee,

 

I own seven Klipsch TSCM's, which are the Pro theatre version of the Klipschorn.

 

I run four 2 channel stereo amplifiers to get my seven channels of amplification.

 

I run two Nakamichi PA-7II's at 225 watts RMS per channel to drive my front three channels, and I run two Nakamichi PA-7's at 200 watts RMS per channel to drive the four remaining channels.

 

These are A A/B amplifiers and will never operate outside of class A at anywhere near listening levels.

 

A big amplifier with big caps and an over abundance of reserve will also provide better Bass at low listening levels as well.

 

My end plan will be to eventually tri-amp these speakers with time delay built into the mids and highs.

 

Roger

[Zen Traveler]

In many of the post that I have seen, everyone is using saying don't use more than 50w per channel (because you don't have to), but the quality amps are rated from 125w to 250w. My guess is that a McIntosh MC207 or a ATI AT4007 is out of the question for (3) Klipsch LaScala up front and Heresy surrounds or am I just crazy for even thinking about amps like this?? OK, I'm ready for the beating.

Wouldn't an upperend AVR drive this system nicely in a medium to large Home Theater situation? I also gather a sub or two would be used to take up the lower end.

Edited April 5, 2016 by Zen Traveler

[twistedcrankcammer]

 

In many of the post that I have seen, everyone is using saying don't use more than 50w per channel (because you don't have to), but the quality amps are rated from 125w to 250w. My guess is that a McIntosh MC207 or a ATI AT4007 is out of the question for (3) Klipsch LaScala up front and Heresy surrounds or am I just crazy for even thinking about amps like this?? OK, I'm ready for the beating.

Wouldn't an upperend AVR drive this system nicely in a medium to large Home Theater situation?

 

 

 

Receiver amplification is a compromise in both price and space and does not hold up to the quality of separates.

 

there is a reason that my four 2 channel amps weigh 75 pounds each for a total of about 300 pounds to drive seven channels.

 

Roger

[babadono]

10 db peaks you say over average? Just remember 10 db = 10X the power.

1 Watt + 10dB = 10 Watts

10 Watts + 10 dB = 100 Watts

50 Watts + 10 dB = 500 Watts

etc.....etc......

[Fjd]

10 db peaks you say over average? Just remember 10 db = 10X the power.

1 Watt + 10dB = 10 Watts

10 Watts + 10 dB = 100 Watts

50 Watts + 10 dB = 500 Watts

etc.....etc......

 

 

 

Maybe I'm missing something here and someone with more specific knowledge can clarify further; however, babadono's calculations bring up a good point I'm trying to reconcile; and a good point in that it would seem important that a person should understand how their amplifier was rated.  For example, did the manufacturer use terms such as "peak," or "max" or "dynamic" and add the term "power" afterward or use acronyms such as PMP (Peak Music Power) or PMPO (Peak Music Power Output) to rate the amplifier, then I have serious doubts about 2 watts driving Klipschorns at 100dB levels and have enough left over for 10dB peaks in the way PWK's table outlines.  However, if the manufacturer used true RMS (Root Mean Squared) calculations in arriving at 2 watt RMS power to drive Klipschorns at 100dB SPL with music peaks (noting that peaks are specific, extremely short bursts and not necessarily a broad-based raise of SPL across the entire spectrum) of 10dB, would we be in a position to demonstrate that PWK is not correct by using the calculations above as evidence that 2 watts is not enough (e.g., going from ~ 0.9 watts continuous to ~ 3 watts available for the peaks doesn't appear to cover the 10dB change)?  Does this situation mean that people are regularly driving the 2 watt SET amplifier into clipping and adding more distortion with the amplifier in a state of clipping on a regular basis?  If not, why not?

 

When PWK evaluated amplifiers and had shown in his table that a 2 watt amplifier used in conjunction with a Klipschorn (104dB sensitivity) would be sufficient for 100dB of average SPL (basically using less than one watt of amplifier power except for instances of the very specific short bursts) from the speaker with 10dB peaks in music, I tended to believe that PWK was a smart enough guy in that he was talking about 2 watts using the RMS calculation for power output that is typically applied to voltage or current.  For example, for an AC-type music signal sine wave, I believe that the mathematical calculation would be the peak value (measured?), divided by the square root of 2 (e.g., 1.414).  In addition, it would seem that in music that the entire wave form wouldn't be a peak, but something more specific like a guitar may specifically produce a transient resulting in a 5V peak, with an average level of only 500mV, which would be an example of a 10dB peak.  However, when comparing RMS power to peak in this context would not necessarily seem to be thought of in the same way as the amount of power needed to drive a "peak" in the context of the speaker at 100dB average SPL (e.g., 2 watts) vs the amount of power needed to drive the speaker at 110dB average SPL (e.g., 20 watts) for which this type of 10dB difference is highlighted in PWK's table, or would it?

 

 

 

 

 

 

 

 

 

 

 

 

 

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Edited April 5, 2016 by Fjd

[Islander]

 

Wouldn't an upperend AVR drive this system nicely in a medium to large Home Theater situation? I also gather a sub or two would be used to take up the lower end.

 

 

AVRs have a lot of stuff inside their cabinets, from pre-amp to power amp, to tuner, maybe phono pre-amp, multiple format decoders, and so on, all priced to make the receiver affordable.  This means there will be lots of compromises, far more than you get with a simple power amp that has a power supply, an amp section, protection circuits, an on-off switch, and not much more.  As well, two-channel power amps may have dual-mono architecture, with a power supply for each channel, instead of the usual stereo or multi-channel arrangement with a single power supply for all channels, plus the power supply will be driving all the other features in the AVR's cabinet.

 

Yes, the upperend AVR would drive the system and sound fine, but separate power amps would almost certainly sound better, and the better the speakers, the easier it is to hear the difference.  A good power amp, even at the same price as the AVR, will almost always sound much better.  More detail for sure, plus more power and "authority", since it's actually delivering its rated power, unlike the typical AVR that's rated when driving one or two channels at a time, not all seven or nine or eleven, or whatever.  With all channels driven, many AVRs see their power per channel drop to less than half of the rated figure.

 

In my setup, running just the main speakers and sub sounds so much better than running it in surround mode.  When I cut in the lesser-quality AVR amp and lesser speakers (almost stock 1st-gen La Scalas, stock Belle and stock Heresy III) to watch a movie, for example, you can't miss how the sound quality is "diluted", or compromised, but once you get into the movie, the surround effects make the change less noticeable.

 

The solution in my case would be to have a complete set of JubScalas surrounding me, all powered by appropriate matching power amps, but like nearly everyone, I do have limits to my budget.  Since two-channel music is my prime interest, that's where the majority of the audio budget went, at the expense of the surround gear.  Some forum members went the other way, like the two I'm aware of that have all-La Scala surround systems.  I'm sure that movies and multi-channel music sounds really great with those systems.