Axiom Home Page Forums General Discussion Advice from Axiom Owners General Help, Suggestions, Advice, Discussion

Thanks Matt.

I'm sure the answer is not a short one but how do I sort through these endless amplifier choices and find "true clean power". I figure there has to be method to comparing amps. For starters, like the suggestion above, how do I assess the "cleanness" of the QSC-GX5. The stats look pretty impressive to me but what am I missing? I'm a very scientific person so I'm convinced there is a way to get make a better comparison.

Frank, my thought is that you have to determine the setup for all those speakers(which you now say that you'll do "over time")before you can intelligently analyze powering them. The 4306 may or may not be fully capable of the job.

Keep in mind that regardless of the maximum power capability of an amplifier, with speakers of average sensitivity such as the Axioms about 1 watt per speaker is used at a comfortably loud average level at the listening position in the mid 80s of decibels. Brief peaks use much more, of course, but at safe(to your hearing)levels receivers anywhere in the 100-150 watt area are capable of handling such brief peaks. Unused amplifier headroom is simply that: unused.

mistake...

Clo, being a scientist myself, i tried some instantaneous A/B switching comparisons between a few receivers and amps (including a tube amp) years ago. This was the most objective way to hear for myself any significant differences among these amp units.
Final conclusion was that if any audible differences exist, they could not be reliably detected.

Specs will certainly help with some comparisons such as max. power output, ohm rating, etc., however as JohnK often points out, an amp should not impart any sound quality that differs from the source. They should only reproduce and amplify the sound signal exactly as it is received. Most competently built amps will do just that.

The concept of 'clean' sound relates more to the subjective reasoning provided by those who judge with their eyes (whether they know it or not).

I'm with Matt. Use preouts and buy some decent amplification. right now is not the best time to pull the trigger on a new AVR. Unless you dont obsess over the minute details that some of us do.....

The whole Watts spec and quoting Ohms law is not meaningful. These equations are theoretical and are only valid into purely resistive loads. Ie. Voltage and current are in phase. The exact opposite of a loudspeaker over its range.

The best explanation to sum it up in plain language came from a podcast with Laurie Fincham. To parhrase: "We concern ourselves with watts but this is not important at all. Amplifiers are a voltage supply device. We need to find out if a given amplifier is stable into a variable load at the required voltage. Then we must confirm there is no sag in voltage or current during impedance swings during program material." There is no one spec that determines this in a user manual. The best specs are checking for double down and if the manufacturer gives an all ch driven 20-20 output figure at 1% distortion. Most dont and cant deliver respectable numbers if so.

I also agree that Cambridge units sound fantastic, but I found out their reliability and firmware is problematic. I was so close to buying a 650R. I own another quirky British unit and it was a major upgrade over my previous Pioneer. Even at a quoted 50wpc less.....

I will disagree based on my experience of how speakers work. They are basically a set of electromagnets with a cone attached to one end. Your speaker driver uses the coil inside to either attract or repel from the fixed magnet at the base of the speaker. The effectiveness of the speaker to reproduce the sounds you want is controlled by how well the coil can react to the changes in direction to overcome it's own velocity to reproduce the sound wave.

I personally found that a high current amp seems to produce a more pleasing sound for my listening than one that is based on high voltage (with similar wattage output)

For whatever reason, my 15 year old Nakamichi AV1 sounds far better and reproduces music acoustically cleaner than my new Pioneer Elite SC1227 that is a higher wattage and supposedly high current, but is a D-class amp. The pioneer seems to give music an empty feeling to me depending on the passage of music at a given time.

Your receiver does have pre-out's so you can hook up an external amp if you find your receiver isn't giving you the sound quality that you are wanting. I'd try using a different amp to improve the sound as the speakers are very capable to reproduce music.

Yeah, thats how a speaker physically works, but not the circuit of a speaker. You forgot the crossover network. Load impedance varies with frequency. Speakers are a reactive load, like a motor. Higher voltage by default means higher current. Its if the Amp is up to the task or not. Some units have current limiting power supplies.

I think we agree, and are just using different terms.