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Need suggestions for a 4-Ohm rated vintage Quadraphonic Receiver... is there such a thing?

hnash53

hnash53

Super Member
I recently acquired some Infinity RS 5b speakers. However, they are rated at 4 ohms, and I have a Sanyo DCX3300KA quad unit that I do not have any data on regarding it's Ohm rating. I think it is rated at 20 watts/channel in quad, and I think it is rated at 8 Ohms, because all the Sanyo receivers I researched had 8-Ohm ratings.

Please make some suggestions for a vintage quad integrated/receiver that is rated @ 4 Ohms. I don't require huge amounts of power, because I don't play it loud ever... maybe 85 dB from 12 feet away.

Thanks!!
 
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I think overall there is too much concern about 4/8 ohm ratings in situations like this.

If one was planning an all-night jam fest I think the risk would be more concern. However, for "normal" playback levels I think the risk is overstated.

FWIW, Infinity's tech specs list the RS 5/B as 4-8 ohm.
 
hnash53 said:
... I don't require huge amounts of power, because I don't play it loud ever... maybe 85 dB from 12 feet away.
Click to expand...
You should not have any problems driving your new speakers to the moderate levels at which you listen. Hook the speakers up and give it a try.
 
There are no pre-outs on my Sanyo quad unit.

I had already connected the Infinitys to my Sanyo quad, and it played and sounded great. Then I read the tech specs about the speakers being rated at 4-8 Ohms. I checked to feel if the unit was getting any hotter, but seemed to be about the same as when powering 8 Ohm speakers. Over in the "Infinity loud speakers" forum, I was informed that my Sanyo was likely not adequate to drive the Infinitys properly.

I'm not meaning to pit one person's opinion against another here, but because of the varying responses to my inquiry, I am definitely confused and unsure about this.
 
I agree with the opinions of the Infinity forum. The speaker is recommended for use with amplifiers of 35 - 125 watts; the Sanyo is far less than the minimum recommendation.

I am not certain how the outputs are designed in Quadraphonic receivers however, if the receiver is designed 20 watts into 8 ohm, the real possibility exists of the speakers dipping down to 4 ohm at certain frequencies which will be very testing the operational limits of this unit.

Unless you are content with relatively low listening levels and never plan on "cranking" the system - even for brief periods - there is every possiblity the receiver will go into clipping and destroy the tweeters - all 4 of them.

In short, I would not recommend this arrangement.
 
Meh...those minimum recommendations nebulous at best. 90% of the time I'd venture to guess we all operate out speakers way under the minimum rating. Nothing happens to the speaker.

Age old methodology applies. If it sounds bad turn it down and you won't have any problems with broken bits.
 
Agreed about the "power recommendations" however the setup consists of 4 speakers whose impedance and sensitivity are not exactly the friendliest to the capabilites a modest quad receiver.

If we were talking, say, 4 Cornwalls, concerns would be minimal. But we're talking Infinity and not particularly sensitive at that.

Personally, I'd have a difficult time recommending this setup. But that's just me.

Thanks.
 
I'm not recommending anything. Just opining I don't believe anything in this pairing will be damaged when used by someone of average or better "stereo" responsibility.
 
My understanding of amplifier power is this: These speakers are about 85 dB sensitivity (or efficiency). That means that @ 1 watt of power, the sound pressure level (SPL) will be 85 dB from 1 meter away from the speaker. Since I listen at 85 dB max (and most often less), it seems that I would have plenty of reserve power for transient peaks. For every 3 dB increase in SPL, this requires a doubling of power. So if the SPL increases to 88 dB, that would double the required wattage to 2 watts... and so on. 91 dB requires 4 watts, 94 dB 8 watts, etc. Again, it seems that I would have enough reserve power given my lower listening levels. I really do not crank my system to high levels ever.
 
Earlier was mentioned 12ft listening distance.

Putting all the numbers in the Peak SPL Calculator, it spits out ~96dB. That's peak, so the max average you could sustain would be roughly 85dB.

So, if by 85dB listening you mean 85dB peak you should be covered. If you mean 85dB average then it'd be pretty much maxed out for your requirement. Maybe cutting it too close if the metric is to have 85dB average capability at your listening position (12 ft away).
 
OK... so my Sanyo quad unit is on the margins of use regarding these Infinity speakers.

I have (but don't really like) a home theater receiver (Sherwood Newcastle R-772) that touts its power at 115 watts per channel with 5 channels driven. All of the specs provided quote the ohm rating at 6 Ohms. This should have adequate power, with room to spare, to drive these Infinity's,... right?
 
You are using a quad unit, and asking for recommendations for another quad unit...but I haven't seen you mention how many speakers AT THE SAME TIME you intend to run.
If you are planning on the Infinitys PLUS another pair, an upgrade of power may be wise.
If only running the Infinitys and at a moderate volume you'll probably be ok.
More power (used wisely) is almost always a good thing.
 
goodolpg said:
You are using a quad unit, and asking for recommendations for another quad unit...but I haven't seen you mention how many speakers AT THE SAME TIME you intend to run.
If you are planning on the Infinitys PLUS another pair, an upgrade of power may be wise.
If only running the Infinitys and at a moderate volume you'll probably be ok.
More power (used wisely) is almost always a good thing.
Click to expand...

I have four speakers, the two Infinity's (front) and 2 Polk Monitor 40s (rears). I sometimes listen in 2-channel mode... others times in quad. The Polks' efficiency rating is 89 dB... a bit higher (therefore easier to drive) than the Infinity's. I do realize, now, that I am pushing the envelope using these Infinity's with this Sanyo quad unit. This Sanyo quad unit lets me choose 2-channel stereo mode along with several quad modes.

I have never ever driven any speakers close to their limit... nor would I ever want to. I have hearing loss and wear an aid, and so want to protect the hearing I've got left. I'm 62 years young and want to be able to continue hearing... and listening to... music for another 3 decades.

As for the "more power is always better," I still remain to be convinced of that adage. Most people listen to music at about 1 watt most of the time. But I've been through this argument on AK already before... and prefer not to engage in it again. So, yes it's probably true that if listening to the Infinity's in 2-channel mode, there's adequate power up to and a bit beyond the speakers' efficiency rating of 85 dB.

When I first got these, I connected them up in 2-channel mode having researched that the quoted specs stated 4-8 Ohms. And they sounded great. I pushed them up to their efficiency rating... about 85 dB, and had lots of reserve power... though I never pushed them beyond that. I sensed no distortion or any degradation of the sound.
 
While the Sanyo may not speak to the specs, most of those mid-70s 4-channel (aka: Quad) receivers provided a method to raise the power output by strapping 2 of the 2 channels together. Spec-wise, however, the recommended speaker impedance changed to 2x what was spec'd in 4-channel mode.

In the case of the Marantz 4430 receiver, for instance, if you used lower impedance speakers with the receiver set up for the strapped/2-channel mode, when the amp ran out of power from being driven hard, the clipping amps would oscillate in the clipping section. This particular model was unique as I never saw or measured any others doing the same thing. How do I know this? I ran a Marantz warranty station at the time and tried to convince Marantz's US distributor that this needed to be fixed. At the time, they refused to citing the fact that the amp was being driven out of specification.

I agree with those who are suggesting that using the under-powered Sanyo with the more inefficient Infinities will not be a satisfying experience. That doesn't mean you can't do it but I am saying that given the size of the room, etc, do not expect a lot of glory.

The other message I'm trying to send is: 4-channel amps, when new, were best operated without the strapping feature. It adds complications you can do without.

Cheers,

David
 
There's a pretty good chance that the power supply in the Sanyo bests the one in the Sherwood HT receiver. That's where it all starts. Setting power ratings aside etc. I'd just roll with the Infinity's and Polks on the Sanyo if that's your preference. At the moderate listening levels your talking about I can't see where your going to have issues. I had a Pioneer QX-646 4 ch unit rated at a whopping 10 watts/ per that I tried some KLH Model 5's and 6's in 4ch mode and it didn't break a sweat at moderate volumes. Both set's are rated at around 87db as I recall. Even on the underpowered 646 the KLH's performed and sounded the same as when powered on larger units as long as I didn't push it.
 
David, thanks for your comment, though I don't understand it all. Plus, your comment and some others (including the quoted one below) are contradictory, but I am not wanting to get into any kind of debate over this. But I do appreciate your effort to provide some info about some of the quad units from the mid-70s.

gbroot said:
There's a pretty good chance that the power supply in the Sanyo bests the one in the Sherwood HT receiver. That's where it all starts. Setting power ratings aside etc. I'd just roll with the Infinity's and Polks on the Sanyo if that's your preference. At the moderate listening levels your talking about I can't see where your going to have issues. I had a Pioneer QX-646 4 ch unit rated at a whopping 10 watts/ per that I tried some KLH Model 5's and 6's in 4ch mode and it didn't break a sweat at moderate volumes. Both set's are rated at around 87db as I recall. Even on the underpowered 646 the KLH's performed and sounded the same as when powered on larger units as long as I didn't push it.
Click to expand...

I appreciate you sharing this. What you describe has been my experience with lower wattage receivers. There were lots and lots of lower wattage receivers built by many well-known manufacturers of audio equipment in the 70s. And the speakers of that time were large. It seems logical to assume that the manufacturers would not have made such low wattage receivers if they would not have been able to drive lots of large speakers during that era. I have to trust that the manufacturers knew what they were doing... and they did, as evidenced by the longevity of those silver-faced, low-wattage beauties that are still pounding out the tunes today.

You said "Even on the underpowered 646 the KLH's performed and sounded the same as when powered on larger units as long as I didn't push it." Again, that has been my experience. I've played "musical receivers," switching various ones in and out, including some pretty powerful home theater receivers, with my 4 speakers. And time and time again, I come back to the lower wattage vintage receivers. The sound is just as good as the more powerful receivers. But it is true that if I were pushing the SPLs up into the mid-90s and beyond I could be maxxing out my Sanyo. Honestly, though, I couldn't be (and wouldn't want to be) in the same room with the SPL much above 90.

I'll likely keep using the Sanyo with the Infinity's, often listening in 2-channel mode (the Infinity sound stage is pretty awesome), and then doing some quad listening from time to time. As for movies, again, I don't turn it up that loud during movies (plus, I'm not an "action/adventure" movie buff who likes explosions), so I don't think I'll over tax the Sanyo.

I appreciate everyone's contributions to this thread... and to my understanding. I hope that this does not turn south with any arguments or thread-crapping.

Again, it's all about the sound... and of course, the equipment to reproduce it.:banana:

Cheers!!:beerchug:
 
I also had a pioneer QX-949 rated at 40/watts per in 4ch mode that I sold about a year ago in a momentary lapse of sense. But I tripled my money! Of all the receivers I have had both stereo and 4ch the 949 is my favorite. It's sound signature is nearly identical to the SX-626,727,828 but with all those extra inputs and the ability to drive 4 sets of speakers it just sets itself apart. That said, when I was feeding 4ch audio in from my Denon DVD player when watching movies it didn't handle explosions and dynamic crescendos well. It would go into protection for a split second. My big Yamaha RX-V2092 can also run 4 sets of speakers simultaneously and is a superstar in handling the explosions etc. The 949 just didn't have the headroom I needed when drinking beer and watching 007 at theater volume. But for music even at loud levels the 949 bests the Yamaha. DSCF2571.JPG DSCF2573.JPG
 
Any of the Sansui QRX models were rated for 4-8ohm. QRs were rated for 4-16ohm. Only restriction is they do recommend you match output on all four amps.
 
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