Mc275 to horns, what amp to woofers w/ La Scala's w/K-402 Horns & K-691 driver

Bill Rogers

New Member
I was told about 2 different ways to hook up my La Scala's. 1) Have two mc275's & use one for each speaker. or 2) Use an mc275 to run the K-402 horns & get another less expensive amp to run the woofers. What I have now is; One mc275 IV amp & a c-2600 pre. I'm working on getting a Tom Danley DTS-10 & have a Crown XTI-1002 on it's way to run it. I'm getting either a Xilica XP4080 or an Ashley Protea 4.8 processor. Also a MCT-450 player. Probably a turn table in the future. I was originally thinking I would get another mc275 & hook it up that way. But then someone said I could get a less expensive amp to run the woofers. Are the woofers less sensitive than the horns? Would it sound that much better with the mc275? If another amp is good then what would you folks recommend? Thank You! Bill

ps. I'm a new-be but tried to explain my intentions correctly... ;)
 
La scalas are extremely efficient, I wouldnt bother to bi-amp, especially with such a powerful amp to begin with.
 
STOP buying amps for these speakers!!!

What cross over are you using?

And since you already have two mc275s

I would at this point use one MC275 for each speaker and use the speakers xover. So you mono block the amps using one for each channel and that gives you right about 180 wpc.

With these speakers and 180 watts of tube power, you will have a setup that will be louder than a jet engine when you want to rock. Then just pure bliss at normal listening levels.
 
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Many hornies who bi-amp favor a somewhat powerful SS amp on the basshorn and tubes on the compression drivers; many are of the opinion that SS does better than tubes on the woofers and that SS bass and tube treble is the tits. That's what I did on several systems, results were satisfactory.

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My best bi-amping results with LaScalas were using the LaScala basshorns below 400hz and Magnepan MG IIs above 400hz.
 
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Many hornies who bi-amp favor a somewhat powerful SS amp on the basshorn and tubes on the compression drivers; many are of the opinion that SS does better than tubes on the woofers and that SS bass and tube treble is the tits. That's what I did on several systems, results were satisfactory.

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My best bi-amping results with LaScalas were using the LaScala basshorns below 400hz and Magnepan MG IIs above 400hz.

Damn, and I sold my MGIIs before I read this. That's a combination I would never have dreamt up - must have been one full room!
 
Thank You for all the replies everyone! 62caddy, mkane & maxhifi, So if all I need is one mc275 for both speakers after I add the horns then I'm good to go! ;)... 4-2-7, I only own one mc 275. For some reason I thought I needed to have two amps for powering the La Scala's when I use the K-402's so I was going to buy another amp. If I did need another amp I was looking to get something cheaper than the mac. Don't know what crossover yet... Tom, interesting using an SS amp for just the woofers. I don't think there as huge an expense as the tubes so think I'll play around with this idea once I get the horns added. What kind of SS amp have you had the best luck with? Thanks again everyone! Bill
 
... Tom, interesting using an SS amp for just the woofers. I don't think there as huge an expense as the tubes so think I'll play around with this idea once I get the horns added. What kind of SS amp have you had the best luck with?

I used a 125 wpc Yamaha, I forget the model name. I used it to power Peavey FH-1 basshorns and various Altec and JBL bassbins. I also did well with an inexpensive 200 wpc QSC prosound amp from Guitar Center on bassbins.IMG_3850.JPG
 
One thing to keep in mind, la scalas can either go really really loud with a powerful amp, or they can go quite loud with a low powered amp. If you used the mcintosh with non horn speakers before, be prepared to be blown away by how loud 75W gets with the klipsch speakers.

They're so efficient it's almost unbelievable, 5 watts per channel can really rock the house with la scalas.

Once you use them for a while you will figure out how much power you actually need. They're one of the few reasonable priced speakers which can really get the most out of low powered tube amplifiers.
 
The woofer section and the horn sections of a La Scala are equal. Systems that cross over near the 400 to 500 Hz spectrum share equal amounts of power. Altec when James Lansing was working for them proved that. Now a horn is acoustically load the woofer, like an acoustic suspension box does, but not to as low of frequency. So bi amping is not really important in this case. Bi amping was developed to match drivers with different efficiencies. Why have a 500 watt operating full range coupled to speakers through a passive cross over, when a 250 watt amp on the bottom and a 50 watt amp on the top could do the same thing. Then when you realize the professional system might have 15 or 20 amps on the bottom and a much smaller number on top that bi-amping becomes economically advantageous. Musicians started experimenting as did home owners and they found they could use tube amps on top with SS amps on the bottom to get different sounds.

Amps with low damping factors are easily in influenced by the reactive load of the speaker, where SS amps with high damping factors are not. So its a process of match or mismatch and what ever sounds best to you. Then different amps just sound different. A Mac 2105 sounds different than a Crowm DC-300A or a Marantz from that period. BGW, Crest, QSC, all have different sounds. Personnally I much prefer Crowns Reference and PSA2 amps to the amps they build today, Mac amps 2105, 2505, sound different than todays 152 from earlier 202. But yet they don't. Mac has a certain signature even though there are other differences. Its like buying a Steinway piano. Big concert pianos should sound all the same, yet they don't. Some seem to have a faster action and response time, some are a bit bigger sound some a touch brighter, but yet all are easily recognized from a Baldwin or Buesendorfer.

The same goes for amps. Different tube amps will give you the widest change in voicing of a La Scala , but different SS amps will have a different but not as broad of change. Personally I would try a Mac 7200 on the bottom with the understanding Klipsch woofers don't like much more than 60 watts continuous. Every system I ever sold using split La Scalas, I had to pull the K-33 woofer and replace it with either a trimmed down 16 " Altec or Gauss woofer. The spider wires would fail every time, and I used 70HZ high pass filters of a crossover when crossing over to either MWMS klipsch boxes with Gauss or Altec woofers or Altec subs with dual 18 inch woofers.
A La Scala in a home environment is a very strong speaker, so maybe a smaller 7100 or 754 might make you happy. Even a little Crown DC 150 A would be a good match with your 275. But remember you are going to need a 400 HZ low-pass filter for the La Scala bottom section to interface the woofer with the horn using the passive Klipsch crossover. Removing the top passive Kipsch crossover section will open a real can of worms do to all the level matching going on between the horns and the woofer section.
 
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I'm using a pair of MC30's to drive Crites Upgraded Lascalas in a fairly big room with a lot of volume....26x16 with 15ft ceilings and I can tell you from personal experience that I can drive them much louder than I would ever listen to with those amps....I'm sure you will have MORE than enough power with the single MC275. The Lascalas are 104db efficient. I don't use a sub with them and I'm happy with the sound but I have never been one to want a giant thumping bass. Most of my listening revolves around listening to bass lines and acoustic guitar and the Lascalas reproduce them very well.

As far as I have heard(mainly the klipsch forum)...people that try to couple Lascalas with a powered direct radiating sub are not happy with the sound. They claim it doesn't mesh well. Most people are very happy with a horn loaded sub. Take that for what it's worth. I have no experience with either but if I decided to get a sub for my lascalas I would buy a horn loaded design. The Lascalas sound so pure I wouldn't want to risk compromising the sound of them.
 
As far as I have heard(mainly the klipsch forum)...people that try to couple Lascalas with a powered direct radiating sub are not happy with the sound. They claim it doesn't mesh well. Most people are very happy with a horn loaded sub. Take that for what it's worth. I have no experience with either but if I decided to get a sub for my lascalas I would buy a horn loaded design. The Lascalas sound so pure I wouldn't want to risk compromising the sound of them.

A problem with direct radiating subs used with basshorns is an inability of the sub to track the dynamics of the horn--the sub runs out of gas before the mains do and tonal balance changes as volume goes up. But in my opinion and experience a large array of direct radiators works very well as a subwoofer with basshorns. Lots of cone area keeping excursion low. I used a pair of JBL Pro 4648 (each with a pair of 2226 15" drivers) to augment my A5 bassbins; with wall placement and 6db of boost at 30hz they were flat to 25hz and even with the boost their sensitivity was 100db. Driven by about 100-150 watts they were able to track the dynamics and low distortion of the A5s.
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A problem with direct radiating subs used with basshorns is an inability of the sub to track the dynamics of the horn--the sub runs out of gas before the mains do and tonal balance changes as volume goes up. But in my opinion and experience a large array of direct radiators works very well as a subwoofer with basshorns. Lots of cone area keeping excursion low. I used a pair of JBL Pro 4648 (each with a pair of 2226 15" drivers) to augment my A5 bassbins; with wall placement and 6db of boost at 30hz they were flat to 25hz and even with the boost their sensitivity was 100db. Driven by about 100-150 watts they were able to track the dynamics and low distortion of the A5s.
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That's great that you were able to get those to work well with your horn loaded speakers...I wouldn't have the space for those in my room. If i eventually end up doing a sub it'll probably be one of the Low Profile THT DIY subs from http://www.billfitzmaurice.com/ I could build one 6ft long and 15"x18". It could actually serve a dual purpose and be used as a stand for my amps and preamp. I'm almost finished with my Khorns tough so I probably won't feel the need for a sub once they are put back together.
 
Thank You bcary13 & Tom! No, I'm not going with a direct radiating. I'm getting a Tom Danley DTS-10... I listen to some rap & the La Scala's don't cut it there. But for everything else? Wow! ;)
 
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