Max Dunlap

I was looking at two multi channel amps MTX Thunder 684 and JBL PX300.4 I really like the way the JBL looks but it has a 76snr and the MTX has a 110snr. Am I really going to be able to tell the difference or are my inifinty kappas going to have to suffer if i choose JBL since they are rated at 95snr.

NEEDAZ

What are you going to be doing with the amp? If you're powering subs, you'll never hear the difference. If mids and highs you may be able to hear the difference in the 76 and 110. I'm on the picky side of things through when it comes to the noise floor. Listening to classical you really can pickup on the noise floor.

Jim85IROC

iTrader: (2)

76dB signal to noise ratio seems unusually low for an amplifier. I can't say that I've ever seen one specc'ed that low, and I'm starting to wonder why. It's either a really noisy amp, or has very little headroom.

The S/N ratio will have more of an impact than just how high the noise floor is. Typically a lower S/N ratio will mean a less dynamic sound, because the available range from "nothing" to "maximum" is smaller.

I have a cassette deck with a S/N ratio of around 75 or 76dB. Tapes recorded on that deck with Dolby C noise reduction and replayed on that deck have an inaudibly low noise floor, but the lack of dynamic range is certainly audible. When comparing something to it's CD counterpart, the cd will be more dynamic. Louder parts of the recording (like cymbal crashes) stand out from the rest. With less dynamic range, the loud stuff doesn't stick out as much, and the quiet stuff can sometimes get lost completely.

I basically agree with NEEDAZ in his recommendation though. For subs, I doubt it'll be audible. For powering something else though, that unusually low S/N ratio might be a valid consideration.

For what it's worth, there is no S/N ratio associated with speakers. But, the S/N limit for compact disk is 96dB, and once it passes through the head unit, RCAs, and every other part of the signal chain, it's not going to get any better. In reality, 90-95dB is probably the best S/N ratio that you're probably going to achieve.

FastElectrics

Also, (correct me if I'm wrong).. But doesn't a better signal to noise ratio mean the amp doesn't have to pump out as much power to produce clean/clear audio, v.s. an amp with a lower S/N ratio. Or am I confising that with the THD?

ScrapMaker

what about the Creative Audigy 2 with the 110db S/N? are the people who buy them just fools?

Jim85IROC

iTrader: (2)

I'm not familiar with that product, but if they're playing a 16 bit cd through it, it's capabilities aren't being utilized.

ScrapMaker

in that respect... why on earth does my headunit have a 24-bit Burr-Brown decoder?

Jim85IROC

iTrader: (2)

How the analog waveform is reconstructed from the digital data will have an effect on what you hear. In theory. Whether or not it's a big enough difference to be audible is a debate that won't end until there's a better DAC to debate over instead.

AudioDEO

From hearing both of those amps i dont think you would notice much of a difference. Their topology and parts make up are very simular. What i would do though is ask your local stereo shop to give you an audition of the amps have them set them up in a car or a very quiet room and let them put them on an a\b system so you can hear the difference between the two.
Never trust the ratings from a manufacture. unless thier Cea rattings and then even those can be misrepresented but they are the only ones that can even be half way trusted.
But dont buy it unless you can hear it. Or you really trust your sales person and they will let you take it back if you dont like it.