Sony Str-db940

[LEAFS264]

Yes I know this is 5 years old. But It has a 4-8 switch on the back. And my new PSB Stratus Silveri's are rated at 4. Does that mean that sony thinks this Reciever can power 4 rated speakers without to much difficulty.

[edtyct]

Yes I know this is 5 years old. But It has a 4-8 switch on the back. And my new PSB Stratus Silveri's are rated at 4. Does that mean that sony thinks this Reciever can power 4 rated speakers without to much difficulty.
No, it probably means that with a 4-ohm load, the amplifier section requires additional protection against overload. Such circuitry usually entails a noticeable loss in performance. The very presence of the switch implies that the receiver's power supply isn't up to the challenge on its own terms. If your receiver doesn't publish any power ratings at 4 ohms, and leaves you guessing about power capacity in general, proceed with caution.

Ed

[Woochifer]

Such circuitry usually entails a noticeable loss in performance. The very presence of the switch implies that the receiver's power supply isn't up to the challenge on its own terms.

Or it simply means that the manufacturer is trying to obtain UL certification, which I believe has gotten more stringent in recent years. Nowadays, you won't find too many receivers without an impedance selector switch of some kind (even if you can't find the switch in the back, some newer receivers now have the impedance selector on the setup menu). That impedance switch simply reduces the voltage output to the power supply as a safeguard against overloading with low impedance speakers.


Yes I know this is 5 years old. But It has a 4-8 switch on the back. And my new PSB Stratus Silveri's are rated at 4. Does that mean that sony thinks this Reciever can power 4 rated speakers without to much difficulty.

It means that your receiver can power those at least one pair of them. But, if you're trying to put together a 5.1 setup, a lot of receiver manufacturers have guidelines advising against hooking up more than one pair of low impedance speakers. The power supplies on Sony receivers are also notoriously unreliable. So if your receiver has preouts, hooking up an external amp might be the way to go if you intend to eventually build a multichannel setup around the PSB Stratus series.

[LEAFS264]

Thanks for the info, but the Silvers are the only 4. the others are 8. So i hope i won't have any problems.....i still keep the switch at 4 though right?? Even if the others are 8.

[Woochifer]

Thanks for the info, but the Silvers are the only 4. the others are 8. So i hope i won't have any problems.....i still keep the switch at 4 though right?? Even if the others are 8.

Yes. The 4 ohm position is used if any of the speakers are low impedance.

[Slosh]

I would leave the switch in the 8 ohm position unless the receiver is shutting itself down or getting excessively hot. Sony's DB series were supposed to be a step up from their entry-level models with regard to amp quality so you may be alright. I have an old ES receiver that I use as a center/surround amp and have no problems with 4 ohm speakers, although that being said I'm only running those speakers down to 80 hz so it's probably not hitting low impedance dips all too often.

If you find your speakers are in fact too hard to drive with your receiver and you don't want to replace the receiver, I would look into buying a separate two channel amp (perhaps even used) and switch the selector to the 4 ohm position only as a temporary measure. In fact, even if you do one day decide to upgrade your receiver I think getting a separate stereo amp is still a good idea.

[LEAFS264]

Thanks for the help. I'll try this reciever on the new speakers and see what happens.