Pre-amp Newb

thehalo8

Well I have made big steps into the home theatre area since beginning in it. However it seems I read about new things everyday that I still don't understand. I have just finished upgrading all my speakers to the Polk Rti series. My Onkyo receiver puts out 100 watts per channel, and I am thinking about going pre-amp on my mains. Polk states they can handle 250 watts, but I still don't understand the home theatre specs. I come from years in the car audio sector and amps are always rated at peak and RMS. When Polk recommends that the RTi70 be amplified from 20-250 watts is that RMS? My receiver does not even say if its 100 watts are RMS or not.

I am currently running 5.1 setup and will eventually move up to 7.1 but that will be in a few years. So instead of buying another amp with 7.1 and more power per channel I am looking into getting separates. At this point I am only looking to get amp(s) for my mains. I have been looking into amps and see many different kinds. I can get two mono's or one stereo. Then I could get four mono's or two stereo's to bi amp my speakers. I have looked at NAD, Sunfire, Carver, Outlaw, and many others. Some of the THD on these amps have been .15%!!!!! From the car audio sector that would be horrible, you would never buy an amp over .05% THD and that is for amps that can even go down to 1 or 0.5 Ohms.

I guess my overall question is if I should invest into an amp to run my mains separately through my current receiver? When I upgrade to the 7.1 in 2-3 years I am also looking to upgrade to the LSi models. But for now I want to get the most out of my RTi models. I am scared to buy a 200 watt RMS amp and take a chance in damaging my speakers because they are labeled to handle 250 watts (I don’t know if that is RMS), and wasting money on the speakers & amp in the process. If some of you with much more knowledge than me could shed some light on the subject I would greatly appreciate it.

One last subject before I finish this post.....sorry it’s so long. I am just running my wire to the back of the speakers and receiver, and **** down the connecters on the bare wire. I read in the posts about banana plugs and other types of connectors. Do these really make that big of a difference? If so what is the difference? Thanks again in advance guys.

RuSsMaN

Forget the word RMS, it is 'continuous power'.

Now, the RTi70 will run fine on just about any amp you throw at it, the more power the better (so long as it is clean, un-clipped power). You are FAR more likely to damage your speakers by underpowering, vs overpowering.

Any high current amp would work great, such as Adcom, AMC, Rotel, NAD, Carver, SAE, Soundcraftsman, Marantz, Phase Linear...etc etc etc...

Definately get an external amp, you will more than likely want/need them anyway once you bag the low impedance LSi's. Separates is a GOOD thing at ANY level.

THD, SchmeeHD, the human ear cannot discern anything less than .5% yes, 1 half of 1 percent. A lot of amp manufacturers won't give a full-bandwidth rating, or they introduce a lot of negative feedback into the design (to get the number lower), which is NOT a good thing.

To nutshell it, bag as BIG an amp as you want/can, with a full bandwidth THD rating of no more than .5%, and you're GOLDEN.

Cheers,
Russ

Tour2ma

th8,

Ditto on Russ' post plus I'll add that amp THD ratings are at full output. At normal listening levels the percentage is very low.

As for separates... I am a proponent of them. Flexibility is one key advantage they offer.

Not sure I qualify as a guru, but I'll try to fill a couple of ATC's blanks...

As Russ stated speaker ratings are continuous power ratings so that's what the 4 watt RS can handle. At typical listening levels you are pushing maybe one-half to two watts depending on a speaker's sensitivity. Transient peaks in music demand more, often much more power, but they are transients and speakers can handle them.

On the bananas, I agree that convenience is a big factor. Sonically I did not hear a difference when I went to them. Some folks do, and that's fine. It's a balance between adding another connection in the circuit and increasing the contact area at the binder posts.

thehalo8

Hey Sean,

My Onkyo model is the TX-DS696. Another question for the amp guru's out there. Is it better to get the mono's, stereo, or a larger amp like 7.1 so that I will be power ready when I upgrade my system to 7.1 in the future?

goingganzo

actuley rms and continuous are 2 different mesurements. rms is .707 of peak and continuousis is a little lower. all these 2 words mean is your amps puts out a sign wave and to get the average power of the output you can take the rms or continuous avcerage.

i dont think the 696 has pre outs. or did they change that?