Enough power for RT25i?

marker

I scored an Onkyo MC35 TECH system from CC for $200 this week for my office rig. www.onkyousa.com/model.cfm?m=MC35TECH&class=Audiosys&p=i

I just happen to have a pair of RT25i and 303 sub laying around which I'm not currently using.

Can this little Onkyo receiver drive the RT25i? Here are the specs on the receiver:
Amplifier Section
Power output
20 watts per channel, min RMS, at 4
ohms, both channels driven 1 kHz,
with no more than 0.6% THD
15 watt per channel, min RMS, at
8 ohms, both channels driven 1 kHz,
with no more than 0.6% THD
2 X 20 watts at 4 ohms, 1 kHz, DIN
2 X 17 watts at 6 ohms, 1 kHz, DIN
2 X 15 watts at 8 ohms, 1 kHz, DIN
2 X 29 watts at 4 ohms, 1 kHz, EIAJ
Dynamic power output
2 X 24 watts at 4 ohms
2 X 17 watts at 8 ohms
Total harmonic distortion
0.6% at rated power
IM distortion
0.6% at rated power
Damping factor
30 at 8 ohms
Frequency and response
10 to 50,000 Hz +0 / –3 dB
Power supply
AC 120 V, 60 Hz
AC 230-240 V, 50 Hz
Power consumption
61 W (120 V, 60 Hz)
54 W (230-240 V, 50 Hz)
Dimensions (W X H X D)
205 X 91 X 302 mm
8-1/16" X 3-9/16" X 11-7/8"
Weight
3.4 kg, 7.5 lbs

I know Polk recomends 20 watts min. for the Rt25i, but the speakers from Onkyo included with the system are 5 OHM, and they have a lower efficiency rating than the Polks (84 db/W/m), so if anything, it looks to me like the Polks would be an even easier load for the little Onkyo receiver to drive than the speakers it came with, especially since the drivers in the RT25i are of very comparable size to the ones in the stock Onkyo speakers.

The room is very small, I'm guessing 10' X 10' at the most, plus, it's not like I can really crank up the volume too much anyway.

The little receiver does have a subwoofer output, but I don't think it has a crossover though.

Lastly, how does Onkyo amps mate with the trilams? I seem to remember reading here that some people don't like the Polk/Onkyo combination, but I think it's GOT to be better than the stock Onkyo speakers.

Can I safely do this, or is there a chance that I could damage the speakers and/or the receiver (although it does supposedly have a shutdown protection circuit)? Any thoughts on this?

Polkfan

faster100

1 watt could drive the Rt25i's.. Although not to loud.. You will be fine at moderate to low volumes. That speaker is small and effeciant and doesnt take much to drive at all. I have a pair also on a old Optimus receiver in my bedroom... and it works great. for easy listening and even cranking now and then. Your not going to damage anything if you remember the wattage you are working with,

VR3

Well I went from 100 watts to 60 watts (the 100 watt was a receiver) the 60 watt was an Adcom -- and it absolutely could rock out! I still miss those things!

15 watts is pretty low though, maybe if it has a ton of current...

Tour2ma

Not likely to have more than a couple pounds of current....

Not going to drive them, but in an office rig that's likely not an issue...

marker

Thanks for the responses guys. It sounds like a mixed bag as far as opinions if it will work or not.

I'm going to go ahead and try it tomorrow. Just to be on the safe side, I absolutely will not turn the volume past the 12:00 position under any circumstance. Besides, I probably wouldn't ever be able to play it that loud anyway.

I still say that based on the specs alone, it looks to me like the RT25i should be an even easier load for the little receiver to drive than the Onkyo speakers which come with it. 8 OMM vs 5 OHM, 89 db/W/m vs 84, and the bass driver in the Polks is only about 1" bigger in diamiater than the ones in the Onkyo speakers.

Would it help even further if I ran speaker wire connections to the 303 sub instead of the sub pre out, then speaker wire connections from the sub to the 25i, and then set the sub's internal crossover at say 90 HZ? Would that help reduce the load on the little amp any?

Tour2ma

You bet... Any duties that you move to the sub, will lessen the job the Onk has to do...

As you said, play with it...

rskarvan

Hey Sid the Kid, I'm going to cut you a little slack on this one since you "aren't claiming to be smart" (your last posting).

"15 watts is pretty low though, maybe if it has a ton of current..."

Here is a basic physics/electronics lesson:
Power = Current x Voltage.
Example: 1 amp x 15 volts = 15 watts.

Of course, if you want, you can just throw in the
T-O-W-(optional-E)-L.

- Ron

bigsexy1

Sid, what has going from a 100 watt receiver to a 60 watt seperate power amp got to do with a mini system?

Marker, hook those RT25is up and forget it! That little receiver will surprise you with it's drive and will run the Polks louder than you can stand it! Clean and with no distortion.

I have the exact same mini system and I hooked a pair of RT15is up to it and it drove them with no problems at all. I went back to the Onk speakers with it though because I couldn't really hear a dramatic difference between them and the RT15is. The Onkyo speakers really aren't half bad themselves.

I fully agree that the RT25is will be an easier load for it to drive than the Onkyo speakers, especially if you run them high passed through the sub. I would guestimate that that little receiver is probably putting out around 10 watts per channel at 8 ohms from 20 to 20khz, and in a small room like that, it will be more than enough. Especially since, as you say, you can't really blast it too much anyhow.

That will be a bitchin' little office set up! I say go for it!

marker

I hooked 'em up and it works fine! The micro sized receiver has more than enough power to run the RT25i to levels that will literally run you out of the whole office complex, much less the room. And that is by hooking up the sub through the sub pre out without using speaker wires with the subs internal crossover. In other words, the RT25i are set to "large" so to speak.

The Polks are a MASSIVE upgrade over the stock Onkyo speakers included in the set, and the sub adds in the bottom end like neither speaker set would have own their own.

I would rather have Denon, Marantz, HK, or NAD amps, but at least the Onkyos have a reputation of above average tuners.

This system rocks! I'm VERY pleased with it. The whole thing set me back a grand total of $318 tax and all since the RT25i and the 303 sub were open box at CC and I got deals on them. That is less than the list price of the Onkyo desk top system alone which is $400.

TroyD

In an office rig type system 15wpc is fine. In fact, for most listening applications given a reasonably efficient speaker, 15 wpc is fine. I've driven a number of speakers on my Marantz 2215b receiver to quite satisfying levels.

BDT

LittleCar_w/12s

I've found a decent mini system is a car receiver. It takes some modding to make it work, but it is functional, and small enough to have right next to the monitor. If it has audio-in you can use your PC as a source as well. Additionally, most 4ch 4ohm car rec's can be bridged to run 2ch, 8ohm by using the front positive and rear negative leads from each side.

So if you have one dying in a box somewhere like I do... try it.