yay or nay

jayman_1975

Simply put...can i run speaker wire from both A and B channels to each front speaker and then run the reciever on A an B as opposed to just one set of wires coming from A to each speaker. Will this increase the power going to each speaker? Amp specs are:
Rate minimum sine wave RMS power output
20Hz-20 kHZ both channels driven
0.05% total THD 100WPC (6olm)

1 kHz continuous power output both channels driven
0.05% THD 105WPC(6olm)
Total Harmonic Distortion
rated power at 20 Hz - 20 kHz 0.05%(6olm)
half power at 1 kHz 0.03%(6olm)
Power bandwith
both channels driven, -3db 10 Hz- 100kHz (6olm, 0.9%)
Power output each channel driven
0.9% THD at 1 kHz
Front(L/R) 130W (6olm)
Center 130W(6olm)
Surround(l/r/back) 130W(6olm)

Low frequency damping factor 45(6olm)
Load impedance
Front(L/R)
A or B 4-8olm
A and B 8olm
Center 6-8olm
Surround (L/R/back) 6-8olm


I sure wish i could make any sense out of all that. Anyone care to help me out would be great. I notice that the power is rated at 6olm, problem is my speakers are all 8olm M70, Cs1, M40. Does this mean that it's not getting enough power? If so....i'd like for someone to recomend a decent higher end reciever for around $1200-$1500 canadian. I use about 50-50 music and HT.

heiney9

Nay....most receivers with A and B speakers when running 2 sets simultaneously will run them in series effectively doubling the impedence. By doubling the impedence you cut the output in 1/2 (all other things being equal). You will gain absolutely nothing and even may lose something by doing this. You won't hurt anything, just won't be running an optimal set-up.

H9

heiney9

N/M had a brain ****....if feel better now

H9

okiepolkie

I'm not sure which receiver you are looking at, but from what I can tell, it is a Yamaha.

As for your other question, you will not be gaining any more power to speaker by running them off of the A-B channels. Since everything will be running off the same power supply, you won't be gaining anthing. If each channel had its own power supply, like many separate amplifers, then there would be a gain, but that is not the case with most receivers.

As far as receiver recommendations for that price range, take a look at a Denon 3805(last years model with a lot of good features). Another suggestion would be to look at the Outlaw receiver-www.outlawaudio.com. I'm not sure how much it would cost to get it to Canada, but I know it is a good receiver coming from a good company.

There are other options as well, like an H/K 635, or a multitude of other companies, but it boils down to the features you want compared to the cost you are willing to pay.

Hope this has been of some help.

dudeinaroom

heiney9 wrote:

Nay....most receivers with A and B speakers when running 2 sets simultaneously will run them in series effectively doubling the impedence. By doubling the impedence you cut the output in 1/2 (all other things being equal). H9

I'd say it's more like 50/50 Most receivers I have used will run the a and b speakers in parallel. my pos techics will run them that way, and if you have it in low impedance mode it will only run a or b. I'v found a good way to tell if it runs the a and b's in parellel it says on the back

a or b 4 - 8 Ohms
a and b 6 - 8 ohms or even just 8 ohms

not all are this way though depends on the manufacturer

kmartin971

Check the manual!

heiney9

dudeinaroom wrote:

I'd say it's more like 50/50 Most receivers I have used will run the a and b speakers in parallel. my pos techics will run them that way, and if you have it in low impedance mode it will only run a or b. I'v found a good way to tell if it runs the a and b's in parellel it says on the back

a or b 4 - 8 Ohms
a and b 6 - 8 ohms or even just 8 ohms

not all are this way though depends on the manufacturer

OK....but do you understand electronics. There are only 2 ways to hook them up series (doubles the resistance) or parallel (halves the resistance). Sure there could be compensating cicuitry (like a resistor) when both A and B are engaged, but I'm talking from a purely electrical POV. Because resistance is variable based on the signal amplitude and speakers aren't a perfect load. So general rule is as described. The ratings you are quoting are nominal.

FWIW

H9

kmartin971

what receiver is he trying to bi-amp with?

heiney9

Problem is for most if not all receivers that hook speaker A & B in parallel is that the protection circuitry will come into play very early, not a good thing. Only time this may not be a problem is if the receiver is actually rated to drive a 4 ohm load (real rating 20hz-20khz) and the 2 pairs of speakers in question are 8 ohm or higher and rather effecient. If you take 2 pairs of LSi 7's and hook them to a receiver where A & B speakers are hooked in parallel, you won't get far before the protection kicks in. Having A & B terminals hooked in parallel is not close to the norm and ones that are will go into protect more often than not.

H9

cfrizz

Hi Jay,welcome to Club Polk.

It is obvious that you want more power than any receiver can give. So buy whatever receiver suits you fancy that has preouts & plan on adding separate amplification later on.

You can actually get a cheap receiver/w preouts since you will be getting separate amps later on.

dudeinaroom

heiney9 wrote:

OK....but do you understand electronics. There are only 2 ways to hook them up series (doubles the resistance) or parallel (halves the resistance). Sure there could be compensating cicuitry (like a resistor) when both A and B are engaged, but I'm talking from a purely electrical POV. Because resistance is variable based on the signal amplitude and speakers aren't a perfect load. So general rule is as described. The ratings you are quoting are nominal.

FWIW

H9

Yes I understand. I was just stating what I have seen over the years. Also I have noticed that recevers that run speaks in series when using a + b outputs will say some think like...

A and/or b 4-8ohms
or
a or b 6-8 ohms,
a and b 4-8 ohms.

I know they are normal

My pos techics in regular( not in 4 ohm mode as they call it) will run my sda2's(4 ohms) and my junk panasonics( 8 ohms) up to resonable levels, and yes like you said it will cut out and go into protect(like I expected, but at a higher volume than I expected) considering it was running with a 2.667 ohm load applied to it

Not trying to start a big debate, or even a fight(like we realy need to fight over what some one elses receiver will handle), Just what I have noticed

And I agree with what your saying heiney so no reason to get twisted all out of shape

Have fun,
Ted

shack

Ah....Ghetto bi-amping rears it's ugly head again......

http://www.polkaudio.com/forums/showthread.php?t=774

Troy actually hit the nail on the head with this comment:

....the A/B speakers run off the same power supply on most receivers so it isn't like you are using two separate amps

jayman_1975

well i just tried it out and found out that it actually sounds worse than with just one set of wires run off speaker A to each main. So that settles it...thanks for all the info

heiney9

dudeinaroom wrote:

Yes I understand. I was just stating what I have seen over the years. Also I have noticed that recevers that run speaks in series when using a + b outputs will say some think like...

A and/or b 4-8ohms
or
a or b 6-8 ohms,
a and b 4-8 ohms.

I know they are normal

My pos techics in regular( not in 4 ohm mode as they call it) will run my sda2's(4 ohms) and my junk panasonics( 8 ohms) up to resonable levels, and yes like you said it will cut out and go into protect(like I expected, but at a higher volume than I expected) considering it was running with a 2.667 ohm load applied to it

Not trying to start a big debate, or even a fight(like we realy need to fight over what some one elses receiver will handle), Just what I have noticed

And I agree with what your saying heiney so no reason to get twisted all out of shape

Have fun,
Ted

It's all good...just having a friendly discussion, no twisting here . What Technics is it? About what year ? There was a time in the late 80's I sold Technics along side the other major brands and they made some decent gear, so that's probably why it can handle a bit more load w/o shutting down. Interesting :cool:

Have Fun as well,

H9

dudeinaroom

It's a sa-dx950. I think I bought it in 98 or 97 It had dd, dts decoding, and pro logic(pre pro logic II) It's not bad for a $200 dollar receiver it's rated 100w/ch I wanna say that it was mesured 1 ch. driven at 1khz overall responce is 30hz-20khz. After about - 20 on the volume is where it starts to distort and max volume is -0(which it never see above -22 normal listening is around -45 - -40) It's not bad for what it is , just want better, alot better. In 2 ch with my sda's while watching a movie It has a real convincing "center channel" and it's hard to tell if the surounds are on or off" their has been a few times I've watched movies, and did not realize that it was in 2 channel until 3/4 of the way through the movie. gonna have fun when the adcom gets here, it has no pre out (the technics)so I'm going to do this http://www.polkaudio.com/forums/showpost.php?p=421030&postcount=17
so for now until I can afford a pre/pro it's gonna have to work.

Later

heiney9

dudeinaroom wrote:

It's a sa-dx950. I think I bought it in 98 or 97 It had dd, dts decoding, and pro logic(pre pro logic II) It's not bad for a $200 dollar receiver it's rated 100w/ch I wanna say that it was mesured 1 ch. driven at 1khz overall responce is 30hz-20khz. After about - 20 on the volume is where it starts to distort and max volume is -0(which it never see above -22 normal listening is around -45 - -40) It's not bad for what it is , just want better, alot better. In 2 ch with my sda's while watching a movie It has a real convincing "center channel" and it's hard to tell if the surounds are on or off" their has been a few times I've watched movies, and did not realize that it was in 2 channel until 3/4 of the way through the movie. gonna have fun when the adcom gets here, it has no pre out (the technics)so I'm going to do this http://www.polkaudio.com/forums/showpost.php?p=421030&postcount=17
so for now until I can afford a pre/pro it's gonna have to work.

Later

That model is a bit after my time, really don't know anything about it, but upgrading is always fun and you will be rewarded.

H9