Klipsch La Scalas with 750watts - In theory any problems?

[Chris81]

I only have a review with measurements from the LaScala MKII but the impedance drops to 3.5Ohm.

I would keep that in mind if I would look for an SET amp. (Not directed to anyone)

 

[stevec67]

I'm sure your sample group of 1 proves it beyond any doubt There is no possibility that different topology and differing amounts of NFB have any effect whatsoever. It HAS to be due to the different output power capability....

As I say, I'm not discounting the possibility that I imagined it. You should know by now my views on the reliability of pink fleshy audio measuring equipment.

 

[stevec67]

Fond memories of when I wired up a rather nice Audio Synthesis power amp (175W) to my homebuilt TQWT omnidirectional cabinets with Lowther PM6Cs in. The power on thump made one of the voice coils ping right out of one of the drive units. I may have cried. But my local amp repair guy used to run a pair of Living Voice Air Scouts (105dB) with ridiculous coffee-table-sized SS monoblocks (might have been Krell, easily 400W). He did burn out a drive unit listening to Shania Twain from the opposite end of his rather long house, however.

Anyone who listens to Shania Twain deserves everything they get.

 

[Yank]

I suppose it depends on how good the first watt of the MF amp is? In the old days, with something like a Crown DC300 or Phase Linear amp into efficient speakers, you'd never get out of the crossover distortion zone.

 

[Yank]

Fond memories of when I wired up a rather nice Audio Synthesis power amp (175W) to my homebuilt TQWT omnidirectional cabinets with Lowther PM6Cs in. The power on thump made one of the voice coils ping right out of one of the drive units. I may have cried. But my local amp repair guy used to run a pair of Living Voice Air Scouts (105dB) with ridiculous coffee-table-sized SS monoblocks (might have been Krell, easily 400W). He did burn out a drive unit listening to Shania Twain from the opposite end of his rather long house, however.

"Man, I feel like rubbing voice coil"

 

[stevec67]

I suppose it depends on how good the first watt of the MF amp is? In the old days, with something like a Crown DC300 or Phase Linear amp into efficient speakers, you'd never get out of the crossover distortion zone.

More or less what I said, but Arkless here says it's impossible.

 

[wainwj]

Currently driving 95db open baffle speakers and also 98db DIY single driver speakers with a pair of heavily modified Musical Fidelity mono blocks that are likely putting out around 600w into 8 ohms and many more as this drops. It is providing some of the best sound I have had so far.

The MF mono blocks were bought to drive a pair of B&W 800 Diamonds that I treated myself to. Since I had read that they need plenty of power. However the speakers completely underwhelmed me, so I very quickly reverted to my previous favourites.
I had previously tried these high sensitivity speakers with a large number of different amps. Mostly low powered Class A offerings. Surprisingly though none were as good as with these MF monsters.
I don't understand any of the technicalities involved, but it just goes to show. Sometimes you can't predict which combos will work, just try it and see. If it sounds good, it is good.

 

[Arkless Electronics]

I suppose it depends on how good the first watt of the MF amp is? In the old days, with something like a Crown DC300 or Phase Linear amp into efficient speakers, you'd never get out of the crossover distortion zone.

That's in the old days as you say... and with amps which were basically high quality PA amps and knowingly compromised very low power performance to run as cool as possible with the least ventilation possible. They would possibly still do OK though (DC300 anyway) as it in effect runs in class A down at the 100mW type level and when the "current dumpers" (no nothing like Quad 405) come on there is no "chunk missing" and so the huge NFB would probably sort the job.
I have a DC300 and FWIW it measures stunningly good in many ways even though it was originally a '69 amp. Mine is a slightly later DC300A and I measured about 0.003% THD from it!

A quote from the manufacturer in the original Stereophile rave review from 1970 is interesting in this regard:

"Dynamically, the DC-300 is, as far as we know, without peer. Its ultra-low distortion required the development of an ultra-low-residual IM meter (less than 0.005%) to allow for actual measurement of distortion at levels down to 10 milliwatts output. (Harmonic analyzers are not sensitive enough.) The common practice of measuring IM down to no lower than 1 watt is not an adequate test for crossover notch distortion, as large amounts of IM are often produced between 10mW and 1W, while distortion above 1W is acceptably low. It is the DC-300'S extremely low distortion below 1W, plus its very low hum and noise, that make it sound so outstandingly good at low listening levels.

Incidentally, its noise is so low (typically 115dB below 150W into 8 ohms) that special voltmeters having a full-scale sensitivity of 100 microvolts had to be built in order to allow meaningful production-line testing of the amplifier.—Crown"

 

[Rick_F]

I once bought a pair of Sugden Masterclass monoblocks to try on my Audio AN/E's. They worked, but sounded flat and lifeless at normal listening volumes. The amps just didn't start to wake up until I was listening at volume levels I couldn't get away with. The amps had to go and I learnt efficient speakers and high powered amps weren't for me.

 

[GT]

Hi everyone

My dad has a pair of La Scalas, I think they are c.101db.

A friend of his has offered him a pair of Musical Fidelity 750w monos for a silly low price. In theory is there a problem using such high powered amps with high efficiency speakers? Or is a good amp just a good amp and watch the volume control?
Cheers

It's more to do with how much gain the MF amps produce and how good their signal to noise is.

 

[Thetiminator]

M8 700 monos. Their S/N seams very good but can’t find any info in the gain....what would be considered too much gain...ballpark?

 

[GT]

Depends on the rest of your system, preamp, source etc.