RS-II's and Pioneer SX-1280 protection mode

Lux Man

AK Subscriber
Subscriber
What does the impedance drop to on these RS-II's at decently high volume? I was testing out my Pioneer SX-1280 tonight. I had the volume at 11:00 or so. The Infinities were singing pretty loud but still sounding good. I then engaged the loudness switch for a second and the Pioneer went into protection mode. Just FYI this is about as loud as I would ever listen to anything, but my question is whether I should be looking at my SX-1280 for some internal issues or if this might fall into "I should expect that to happen mode with these RS-II's", mode.
 
I see the impedance is nominal 4ohms. I did just open up the SX-1280 and re-set the DC balance and idle current, it was off a little. I may not have let it warm up enough when I set them initially. Setting that aside just how demanding are they? My usual amp is a Carver Signature 600 which has never had any issue at any volume. However when I use it my preamp has no tone controls, it just runs flat.
 
rs ii

Im pretty sure the 1250s protection circuit is performing admirably. The impedance on the Infinities drops to below 2ohms at certain bass frequencies. Nominal is 3+ to 4. The sx-1250 is definitely old school current and can probably deliver decent (relatively loud) levels for the rest of your life. But it is a huge stretch for it to deliver +200 watts into 2 ohms for any long expanse of time. The Infinities WILL cause the Pioneer to clip (especially with the low freq loudness switched on). This WILL fry the emits eventually. The Infinities full and glorious load is definitely out of the league of the pioneer. Keep it tame, and you'll be ok. : )
 
If that is the case, these things are just too risky to use. I'll probably just set these Infinities out the curb tomorrow morning when I go to work, maybe they will be gone by the time I get home. I saw some Dogg Digital speakers on CL that the guy said were audiophile type speakers and they came with the boxes.
 
well, you could use the preamp on the sx1250 to drive the carver.. you would have tone control.. right? You would need to be careful of the high power, as you are now on the opposite side of the equation.
 
set them out on the curb!!.. yikes!!. They aint that bad. Hell, wheres your cube? I'll be there.. Properly set up and powered, they are pretty damn good. Oh well, good luck.
 
ok...relax, you only use the loudness feature at very low volume...its to enhance bass response when you are listening at very low levels....it happened as it was supposed to because you weren't using it properly...
 
point number one: RS II are rated at 4 ohms. certain kappa and quantum impedance issues have given rise to rumors of all infinitys having low impedance issues. no one has ever offered any evidence, let alone proof, the RS II dips to 2 ohms, and by most owner's accounts they are easy to drive.

point number 2: the SX-1280 owner's manual specifically states the receiver produces 200 wpc at 4 ohms, and can run 4 ohm speakers. however, it warns if running more than one pair of speakers all must be 8 ohms or higher. ("if speaker systems with impedances below 8 ohms are used the protection circuit may operate to prevent sound from being produced.")

point number 3: dogg digital speakers are white van speakers, and should be avoided at all costs.



.
 
Thank you all for your input. I'm going to call the SX-1280 healthy and not be concerned. Since I forgot to put the RS-II's out at the curb this morning, I have decided to keep them. Besides, I have no idea what I would replace them with for under $1500.
 
point number one: RS II are rated at 4 ohms. certain kappa and quantum impedance issues have given rise to rumors of all infinitys having low impedance issues. no one has ever offered any evidence, let alone proof, the RS II dips to 2 ohms, and by most owner's accounts they are easy to drive.

point number 2: the SX-1280 owner's manual specifically states the receiver produces 200 wpc at 4 ohms, and can run 4 ohm speakers. however, it warns if running more than one pair of speakers all must be 8 ohms or higher. ("if speaker systems with impedances below 8 ohms are used the protection circuit may operate to prevent sound from being produced.")

point number 3: dogg digital speakers are white van speakers, and should be avoided at all costs.



.


Actually, the only magazine article/review I've ever seen DOES state they tickle 2 Ohms on the graph.
3 Ohms at around 100-200 Hz and 2 Ohms from about 6000Khz up

Thanks to Seppo.... https://audiokarma.org/forums/index.php?threads/rs-ii-lab-test-article-w-full-measurements.621716/
 
Last edited:
ok...relax, you only use the loudness feature at very low volume...its to enhance bass response when you are listening at very low levels....it happened as it was supposed to because you weren't using it properly...

This makes the most sense to me. As long as I have been around audio I've read and heard the same regarding the use of loudness. Enhance bass at LOW volumes. 11 is not low.
 
This falls under the category of "OE"--operator error. The loudness is intended to only be engaged at lower volume levels. Why you would even want to add that much "bass boost" to the Infinity's at high volumes is beyond me. RSII's are no where near as "difficult" to drive as my Kappa 9's (which do drop below 1 ohm), so you should be fine with the SX-1280. At least you know the protection circuit works ;)
 
You're SX-1280 should work just fine. I know, as I used one with my RS-II's for about six months. Use the loudness if you are just enjoying while reading a book or something, not when your horns come out. There are a lot of good suggestions for "better" ways to power them, and you may take that step down the road, but keep these speakers! The RS-ii's are very special indeed. I will NEVER part with mine, or any vintage Infinity I own. Enjoy.
 
That SX-1280 looks like one heck of a gorgeous receiver. Pics please!

I used to drive my RS-II's using Onkyo A-9070 integrated (ca 80 wpc @ 8 Ohm, and ca 145 wpc @ 4 Ohm), but often at moderately loud volumes it would go to protection. Now I am using Emotiva SA-250 amp (250 wpc @ 8 Ohm, 400 wpc @ 4 Ohm), and it has never gone to protection. The bass response in particular improved as well even at moderate and low volumes, presumably thanks to more headroom. Power wise your receiver is half way between those too, so I would say that there is nothing wrong with your Pioneer...
 
An old thread, but my advise to anybody with an opportunity to own a pair of RSII's and they have a nice receiver like the 1250 Pioneer, is to not hesitate because amplification can always be future updated.
Meanwhile owner operated issues can be avoided and the speakers can be listened to albeit not to their fullest degree.
A receiver will start exhibiting out of the ordinary heat soon before it blows.
Volume up very slowly and use the hand/heat measure to make sure the receiver isn't being overburdened.

 
This falls under the category of "OE"--operator error. The loudness is intended to only be engaged at lower volume levels. Why you would even want to add that much "bass boost" to the Infinity's at high volumes is beyond me. RSII's are no where near as "difficult" to drive as my Kappa 9's (which do drop below 1 ohm), so you should be fine with the SX-1280. At least you know the protection circuit works ;)

Did someone say K9s. A fan of them as well. My first big infinity’s I bought 4 years ago were the 8.1s which are the easier speakers to drive out of the ones all listed here. Looking at them I figured I could use my 90s JVC 100 watt receiver to drive them. They sounded ok at low volumes but when I turned it up sounded distorted. They really didn’t wake up until I used 2 amps in bi amp mode. By the way 1973 what are u driving your K9s with. PS would love to try the 1280 on my 8.1s if I had one. Lol
 
Last edited:
I agree totally with tubed’s assessment. My very first Infinity speakers were abused RS ll’s and a nice Kenwood AVR receiver. It only took about 10 minutes if that, smoked that receiver.....LOL. Thus the journey started.
 
Back
Top Bottom