Another Receiver Question

[Guest SteveG]

For all of you with engineering bachground (school and experience!!)

I picked up a Pioner receiver at a second-hand shop recently for under $100. It is a model VSX-D1s, and was their top receiver about 13 years ago, short of the elite line. I knew it was rated at 130 w/ch and it says 4 to 16 ohm at the main speaker terminals on the back. So I figured this would be sufficient for a pair of 11's. The thing weighs a rather massive 35 pounds, and has massive aluminum finned heat sinks inside, with holes all over for air flow. So I figured the thing was built pretty well.

Well, I got a hold of an owners manual, and discover that for its operation it has 2 modes. Mode 1 says 130w/ch to mains but recommends 8-16 ohm speakes, 50 w center and 40w/ch rear. Mode 2 says 70 w/ch front and center, plus 50 w/ch rear, and in mode 2 it says 4-16 ohm front pair.

So before I knew of these specs, I had it in mode 1 for the past week (130w/ch) and running a pair of 11's. I have played it for many hours as the store said they would give me a week to retun if any problem. No problem. The 11's sound great even at pretty high volume levels. Receiver not running hot (just warm) and no sign of strain.

I assume to get the higher watts per ch in this mode 1 there must be some kind of bridging, and that is why they are not recommending 4 ohm loads. But it has been handling a very hungry 4 ohm load at high volume fine. This is not adcom I know, and it is not the pioneer MOSFET line either. But with what must pretty hefty power supplies, weighing in at 35 pounds, I am wondering if perhaps Pioneer was just rating conservatively.

The good thing about these Pioneer receivers is that they are cheap, reliable, and have an excellent FM section.

So I am wondering if you all would recommend keeping it in the mode 1 with something like bridging, or going to the conservative mode 2 at half the rated power, but possibly more stable.

Looking forward to thoughts.

Thanks

SteveG

[Guest Nigel]

Hi Steve;

The mode switch reduces the supply voltage, it is not a bridging thing. The reason to reduce the supply voltage is that there will be less stress on the output devices with lower impedance loads.

If your music does not have a great deal of very low frequency content (for example pipe organ or cannon fire, etc..) it probably will not make any difference.

The conservative approach (for the output devices) for all applications is to run in the lower setting, BUT that also increases the chance of clipping which is very very bad for your tweeters. The price you quoted above is less than the cost of a pair of replacement tweeters........

[ToastedAlmond]

I recently read that a great many modern receivers incorporate the 4/8 ohm operation switch simply to pass UL's rigorous testing standards for 4 ohm certification. They also indicated that just because there is no switch, nor indication at the speaker terminals that it is 4 ohm capable, does NOT mean that a receiver or amp won't work just fine into 4 ohms.

[Guest SteveG]

Nigel and TA,

Thanks very much for the insights. There is no question at all which I would rather put at risk, a pioneer receiver or a pair of Classic AR speakers. even though I will actually be using this with a pair of 58s speakers, I'll still risk the output devices. So high voltage all the way.

The forum comes through again. Thanks

SteveG