My friend who installs HT’s and whole house audio systems came over yesterday to visit. He brought with him an Inter-M R300 professional Reference Power amplifier. This thing is rated at 150w@4 ohms and is a 2 channel amp. He said he uses it for his whole house audio because it’s very stable.

I know this is a pro amp because it doesn’t have RCA jacks on the back, just ¼ and XLR’s (he uses ¼ to RCA adapters for home use). I am assuming this is the type of amp that is used in recording studios, or PA applications. It looks like it belongs in a rack for Eddy Van Halen or somebody. He said this cost is around six hundred Canadian (although I have found in on the internet for half that).

Anyways, we hooked it up to my Rotel preamp and fed it to the M80’s. I was surprised at how good this thing sounded and how loud it would go before the clipping light started to briefly blink. Good solid tight bass with a nice punch. MIds were rich and full. The snare got me right in the gut. I like even more than my Rotel 6 channel amp which costs sig more (although the Interm had almost double the power of the Rotel).

Here are my three questions.

1. What does it mean when a company puts the word “reference” on amplifiers? Who decides if the product is “reference”, or is it just a marketing thing?

2. I read Alan Lofts great article’s on amplifiers on the Axiom site. So all things being equal is it better to have multiple 2 (or even 1) channel amp(s) then to have one 6 channel amp. I am thinking power supply requirements here.

3. This Interm amp we tested yesterday is not what you would typically see in an HT rack, however it sounded really really good, and is not expensive at all, at least compared to the Brystons, Rotels, and Krell’s of the world (keep in mind, I have never tested a Krell power amp). Am I missing something, why don’t more people look at professional style power amps for their HT’s. Is a home amp different than a professional amp? Or were my ears deceiving me yesterday and I might as well be on another planet.

Worf,

I don't know what "reference" means. I can tell you however that I purchased a no-name center speaker years ago with the word "reference" on it for $20 on clearance at Soundsaround. It did the job, although it was nothing like the VP150 that I have today.

I come from the school that says as long as an amp is not being pushed beyond its specifications, it should sound the same as any other amp. If you buy a 90W/ch amp, and you are listening to it at 45W/channel nominal, you definitely need a larger amp to handle the dynamics as most of the time you will be listening to clipped music. In my case, I run mine at a maximum of 1W nominal for music so I have about 20dB of headroom which is plenty with the exception of some classical and orchestral music.

Now having said the above, I recently listened to an old Sansui 340W/channel amp with Nuance speakers at my buddy's. The whole system sounded very tight and crisp. However, consider that this was a completely different room from mine and the listening session was not controlled. I therefore am not going to jump to the conclusion that the Sansui is somehow "better" than my Denon for my application. What I plan on doing however is bringing the Sansui to my house and A/Bing it with my Denon under more controlled conditions.

Hi Worf,

1. "Reference" really doesn't mean anything anymore; it's a marketing ploy. Originally it derived from recording studio applications, both for speakers and electronics, where "reference" suggested impeccable specifications and very linear frequency response. Tests have later shown that in terms of some classic studio "reference" speakers, they were anything but linear, however they were indestructible and could handle large amounts of input power and produce high SPL's.

2. For traditional Class A/B solid-state amplifiers, I would generally agree that simple, easy-to-cool two-channel amps or monoblocks are better than 5 or 7-channel power amps on one chassis. One exception is new technology, like Axiom's A1400-8 digital amplifier, which effectively puts 8 channels on a single chassis that barely runs warm. But that's because it's a digital amp, not analog, so it's very efficient, up to 93% at full output versus 50 to 60% for a Class A/B analog amp.

3. One of the reasons that pro amps don't find a market with home theater consumers is that little or no attention is paid to design cosmetics. They're just black boxes, often rack-mount, and, as you've noted, equipped with XLR or 1/4-inch phone connectors, which scares off a lot of lay folks familiar with only the lowly RCA connectors.

But there are certainly virtues in using in pro amps. Typically they're very rugged, with big power supplies and solid output power into low impedances with no persnickety protection circuitry that shuts down the amp when it smells a 4-ohm load.

Regards,

Thank Alan

True, this piece is not going to win any beauty contests.

I came across this artical on the web by Ian G. Masters.

http://www.mastersonaudio.com/audio/20020901.htm

Ian is well respected audio journalist. Could this really be true? Is the only real difference in quality amplifiers the power rating and the name of the manufacture?

Well if you look at the specs from manufacturer to manufacturer, those of the same price ranges all seem to have the same specs. Now how many different ways can they all produce those exact same specs? Pretty much only one way. Not much differece in the amplifier region. The DSP's and such they apply is where the differences come in.

That's right, worf. As Ian Masters points out, competently designed receivers/amplifiers simply amplify and don't add an audible sonic coloration. This is indicated by basic principles of audio technology, and claims to the contrary collapse when put to the(blind listening)test. Flat frequency response and inaudibly low noise and distortion are all there is, which comes at quite low cost these days.