Interesting Article on Powering Speakers

[beden1]

http://members.aol.com/_ht_a/pjay99/guruscordell.htm that I found in an AVS discussion.

[joetama]

Very very interesting read.

He explains things well in a way that makes perfect sense.

Does anyone know what amplifiers/preamplifier he has worked on?

[SPACEMANRICK]

A couple of points from the article that agree with what some of the posters here have been saying that the speakers are the most important part of the the sound system and most amplifiers past a certain point are very similar in sound quality.......

Without giving the standard weakest link answer, how important is the amp as a component?
It is very important, but not nearly as much so as the loudspeaker

Someone recently said that if not driven to clip, all SS sound the same. Do all SS amps sound the same?
No, because they all misbehave differently. However, well-designed SS amps operating well below clipping, that are not misbehaving, and which have high damping factor across the band, will tend to sound the same.

[Jeffk]

Unfortunately, while interesting, unless we possess his level of knowledge and can take apart each of the amps we are considering and assess their construction, we are still left with our ears and the opinions of others to try to judge the actual sonic performance and attributes of an amplifier, preamp, etc. In fact, it is clear that, while transparency, clarity and lack of coloration should be every mftr's goal, it is the actual coloration itself that we all hear and either like or don't like, as in the everlasting arguments of tubes vs SS, cheap vs expensive cable, etc. The one thing that was made clear, at least from my perspective, is that lots of power is a good thing. This may be the most valuable piece of advice to take to the bank. Just my two cents.

[beden1]

I don't know, I found a number of points that helped me understand things better:

"It is especially important that adequate short-term current reserves be available for when musical peaks demand that large currents be delivered to the loudspeaker."

"Power supplies with larger power transformers and larger amounts of filter capacitance will help an amplifier sound better. Put simply, the power supply is important to the extent that it is under-sized."

"The amplifier power supply draws almost all of its current from the a.c. line only during the short time interval at the top and bottom of the sine wave when the rectifiers are conducting. This time interval may only be 10 percent of the total cycle."

"Thus, when your amp demands a burst of 12 Amps from a nominal 120V line with an impedance of one Ohm, you'll lose about 12 volts at the peak, or about 10% of your supply voltage. Since power goes as the square of voltage, the peak output power capability of your amp will drop 20% as compared to a perfect 120V line voltage source. This sounds bad, but the simplest cure is to use a slightly larger power amplifier in the first place."

"Better house wiring, and maybe a dedicated 10 AWG line to a 20-Amp breaker will help a lot (much more than a $100 6-ft beefy boutique power cord). If the power supply is well-designed, fancy power cords, outlets and power conditioners shouldn't matter much."

"Getting rid of hash, RF noise and transients on power lines is the job of a power conditioner, not an expensive power cord. Spend $50 on a good power strip with an EMI filter to protect your equipment, and you'll have most of the benefit you need."

"The argument for boutique power cords is far weaker than the argument for boutique speaker cables, and even the latter is on thin ice at times."

"the power supplies in pre-amps and CD players want to be regulated well and with low noise. Of course, if you are paying $500 or more for a preamp, it should darn well already have an excellent power supply."

"Power supply upgrades are most likely to make a difference in inexpensive mass-market components where every penny was pinched (or in high-end gear where the designer didn't know much about power supplies)."

"well-designed SS amps operating well below clipping, that are not misbehaving, and which have high damping factor across the band, will tend to sound the same. Note that some very expensive SS amps do not meet the criteria of this caveat - sometimes as a result of misguided design decisions intended to "improve" the sound."

"Different SS amplifiers will often sound different if they are driven into clipping (which happens more often than some realize)."

"Finally, some (often high-end) amplifiers are designed with inadequate stability margin when driving capacitive loads, like some boutique speaker cables. I had this happen to my amplifier using Transparent Cables. After shutting down the amplifier, I would get a sound like a fireworks rocket shooting up into the sky. It was due to the cables with whatever capacitor they have in them. The problem is gone now that I went to straight speaker wire. It also created a dull hum while playing which is now gone as well.

"Absence of any kind of misbehavior and graceful clipping, lots of power, high current capability, graceful or no protection circuits, absence of coloration (flat frequency response when driving actual speaker loads), and stability under capacitive loads."

"I strongly prefer MOSFET output stages to bipolars, and their cost premium is continuing to come down."

"Do preamps affect the sound more than power amps?
Only if they are really bad, or, perhaps deliberately, incorporate circuitry and technology that will color the sound."

"Preamps that use poor-quality voltage-controlled gain circuits in place of high-quality potentiometers might also introduce some degradation as well."

"Spec sheets in many ways are nearly worthless. Forget about spec sheets for boutique amps."

"Without getting into how power is measured, how much power do we really need?
Much more than we think. Ideally, if you are really serious about high-end audio, your amplifier should never, ever clip. In reality, amps clip more often than we think, especially on well-recorded music that has high dynamic range,"

"High-end audio will forever embrace "big-iron" power amplifiers. However, on the average there will be migration toward more use of IC power amps, like the LM3886, and the use of Class-D amplifiers. However, it seems unlikely that one will ever make a Class-D amplifier that can sonically outperform the best-designed Class A-B amps. The newer, less expensive and more compact amplifier technologies may also help foster the migration of the power amplifiers into the cabinets of active loudspeakers."

"If you like uncolored sound, go solid state. If you like the coloration that tubes add to the sound, then go with tubes, recognizing that the coloration will often be a strong function of what speakers are used."

[SPACEMANRICK]

Here is a link to his website and some of the work he has been involved in

http://www.cordellaudio.com/aboutme.shtml

[beden1]

Here is a link to his website and some of the work he has been involved in

http://www.cordellaudio.com/aboutme.shtml

Nice work finding this. :T

[RobP]

I'm going to move this thread guys, other members who don't visit club B&W may want to read this as well...

[mjb]

From the link above, his current interests include MOSFET amps and active loudspeakers. No wonder he speaks highly of both. Otherwise, lots of truth to what he says.

[t2t]

I was present at this event. Pjay is a big contributor to the DIY forums on speaker building. The tests were performed in one of the upstairs bedrooms with one watt of power. It was amazing how the music would command/demand more power at times based on the requirements of the music. Just that simple, single watt would get pulled into a few hundred watts for a percentage of a second.

The music material used during some of the testing was a Rickie Lee Jones CD.

BTW, I used to frequent this board under another name - but, couldn't recall my nick - and, after a move, my e-mail address was no longer current to retrieve my password.

Edit: On the day of the DIY event, Bob Cordell presented his DIY speakers with Morel drivers. They were quite impressive. Sadly, one of the driver surrounds was torn, which changed the characteristics of the sound. It would have been great to hear those speakers perform with all their glory.