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Rotel Owners: Can you Bi-wire the RB1080 2 channel amp?

post #1 of 33
4/30/07 at 6:09pm
Thread Starter 
So after long consideration and a dying Onkyo reciever, we upgraded our 2-channel system to separates with the Rotel RSP-1068 pre-amp/pro and the RB1080 2 channel amplifier. So far, its working great and sounds wonderful. I'm very pleased with the results and the soundstage and its not even broken in yet. Anyway, something peculiar i ran into, i thought i'd share here. The speakers we use are the Klipsch Rf-83s, and they are bi-wireable. According to Rotel's own website and schematics/manual, this amp only has a single set of connectors per channel, as evidenced here:

http://www.rotel.com/support/pdfs/dr...B1080-back.pdf


However, the physical back panel on our unit is different. It does indeed feature 2 connectors per channel:




I'm sorry for the mess/wires but I just wanted to show the connectors themselves, so that people dont misunderstand what i mean. Anyway, I called Rotel but couldnt get a hold of someone, and there's no mention of it in the manuals or any place else.

I know that they have a now discontinued, even more powerful 2 channel amplifier that put out like 380wpc that did have the dual connectors. I'm wondering if this is a silent upgrade.

I dont know a lot about electricity and wiring, so I'm posting this here, because frankly i'm afraid to just go ahead and bi-wire it. What do you all think?
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post #2 of 33
4/30/07 at 6:20pm
Quote:
Originally Posted by Ou8thisSN View Post

So after long consideration and a dying Onkyo reciever, we upgraded our 2-channel system to separates with the Rotel RSP-1068 pre-amp/pro and the RB1080 2 channel amplifier. So far, its working great and sounds wonderful. I'm very pleased with the results and the soundstage and its not even broken in yet. Anyway, something peculiar i ran into, i thought i'd share here. The speakers we use are the Klipsch Rf-83s, and they are bi-wireable. According to Rotel's own website and schematics/manual, this amp only has a single set of connectors per channel, as evidenced here:

http://www.rotel.com/support/pdfs/dr...B1080-back.pdf


However, the physical back panel on our unit is different. It does indeed feature 2 connectors per channel:




I'm sorry for the mess/wires but I just wanted to show the connectors themselves, so that people dont misunderstand what i mean. Anyway, I called Rotel but couldnt get a hold of someone, and there's no mention of it in the manuals or any place else.

I know that they have a now discontinued, even more powerful 2 channel amplifier that put out like 380wpc that did have the dual connectors. I'm wondering if this is a silent upgrade.

I dont know a lot about electricity and wiring, so I'm posting this here, because frankly i'm afraid to just go ahead and bi-wire it. What do you all think?

Does it have "a" and "b" speaker outputs?

The short answer to your questions is that you only need one set of outputs to bi-wire. Just make or purchase some bi-wire cables. They have 2 jacks on one end and 4 on the other. Here are some that I made....





-Eli
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post #3 of 33
4/30/07 at 6:29pm
Thread Starter 
the instructions say nothing about speaker a/speaker b outputs. Like i said, it only shows one set of connectors per channel in the manual, so they make any mention of it. I would get cables like that but seeing as I have the second set of outputs, and based on what people say in this thread, i'd rather just run another set of cables to my speakers, it would probbaly be cheaper that way anyway.
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post #4 of 33
5/1/07 at 12:15am
I don't have a source, but i have read that thats a feature on the new rotel amps to allow for easy bi-wiring.
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post #5 of 33
5/1/07 at 12:21am
I don't have a source, but i have read that thats a feature on the new rotel amps to allow for easy bi-wiring.
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post #6 of 33
5/1/07 at 7:44am
Yes, the RB-1080 is set up for easy bi-wiring. Older version of the amp (several years ago) only had one set of speaker terminals, but the latest versions have two, just for this purpose.
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post #7 of 33
5/1/07 at 12:53pm
Thread Starter 
so, all i have to do is run another set of wires to my front speakers and i'm ready to go? do i have to enable anything or set any type of jumpers? i'm only asking because even though Rotel went to all this trouble to update their amps, they ddint include any documentation of what to do for a newB owner like myself.
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post #8 of 33
5/1/07 at 1:43pm
Quote:
Originally Posted by Ou8thisSN View Post

so, all i have to do is run another set of wires to my front speakers and i'm ready to go? do i have to enable anything or set any type of jumpers? i'm only asking because even though Rotel went to all this trouble to update their amps, they ddint include any documentation of what to do for a newB owner like myself.

That should be all you need to do. While you are out buying more speaker wire, swing by Guitar Center and pick up a set of balanced XLR cables to hook your pre/pro to your amp. Those Nintendo cables you have them hooked up with dont belong on a Rotel.

-Eli
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post #9 of 33
5/1/07 at 2:27pm
Quote:


While you are out buying more speaker wire, swing by Guitar Center and pick up a set of balanced XLR cables to hook your pre/pro to your amp.

What difference would it make? his source is unbalanced.

Instaed of buying more wire, why not just buy the proper gauge, since all you will accomplish by "bi-wiring" is to increase the wire gauge.
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post #10 of 33
5/1/07 at 2:28pm
Thread Starter 
So, I also have the RSP-1068 pre-amp processor that I bought along with this amplifier, and it doesnt have XLR inputs. I have been told that they are fairly useless at this price point and the difference i get, even with the 'nintendo cables', is astounding and well worth the investment.
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post #11 of 33
5/1/07 at 2:30pm
Thread Starter 
Quote:
Originally Posted by Targus View Post

What difference would it make? his source is unbalanced.

Instaed of buying more wire, why not just buy the proper gauge, since all you will accomplish by "bi-wiring" is to increase the wire gauge.

well if that was true, then why would Rotel and/or Klipsch go through all the trouble of providing two sets of outputs just for bi-wiring? btw... my speakers are only about 10 feet from the source, at that distance do i need a lower speaker wire gauge? i'm using 16 gauge right now...
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post #12 of 33
5/1/07 at 2:45pm
Quote:


well if that was true, then why would Rotel and/or Klipsch go through all the trouble of providing two sets of outputs just for bi-wiring?

They provided two sets of binding posts, connected to the same amplifier...this impresses you?

Quote:


at that distance do i need a lower speaker wire gauge?

What do the marketing droids tell you to do?
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post #13 of 33
5/1/07 at 3:01pm
Quote:
Originally Posted by Ou8thisSN View Post

So, I also have the RSP-1068 pre-amp processor that I bought along with this amplifier, and it doesnt have XLR inputs. I have been told that they are fairly useless at this price point and the difference i get, even with the 'nintendo cables', is astounding and well worth the investment.

I just assumed that the Rotel Pre had balanced outputs. my bad.

-Eli
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post #14 of 33
5/1/07 at 3:33pm
Thread Starter 
Quote:
Originally Posted by Targus View Post

They provided two sets of binding posts, connected to the same amplifier...this impresses you?



What do the marketing droids tell you to do?


ok i really think thats a silly argument. biwiring is hardly going to 'clinch' a product over another when a consumer is deciding. if they really wanted to be superficial about it, they would put some other distraction thats much more outward and aesthetically noticable to market.
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post #15 of 33
5/1/07 at 3:47pm
Quote:


ok i really think thats a silly argument.

It's not an argument, it's a (silly) fact. They connected two sets of binding posts to the same amplifier...what's so difficult to understand about this?
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post #16 of 33
5/1/07 at 4:22pm
Quote:
Originally Posted by Ou8thisSN View Post

ok i really think thats a silly argument. biwiring is hardly going to 'clinch' a product over another when a consumer is deciding. if they really wanted to be superficial about it, they would put some other distraction thats much more outward and aesthetically noticable to market.

Well, actually, it's not a silly argument.

Clinch a sale just because of the extra terminals? Well, that's what Rotel is counting on.

If it comes down to little details, it might just be the added feature that sways an indecisive customer - especially one that is inclined to perceive bi-wiring as a "high end" feature. Those extra posts perfectly compliment his (probably) bi-wire-capable speakers.
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post #17 of 33
5/1/07 at 10:14pm
I am not sure how much bi-wiring gains you if anything in sound quality or control. Bi-amping on the other hand can be fun, but obviously more expensive... Works great with Martin Logan speakers. Run the Stat panel with tube power and the woofers w/ SS power, makes for a really nice combo!

My new 1080 is just like yours and if you are so inclined just run another set of wires to your speakers.

To answer some of the other ??? about bi-wiring and the need for dual posts and such. I have seen some speakers that have the two binding posts to far away from each other to use just one speaker wire with the 4 end 2 end set up. Of course those speakers tend to be about 10X to 50X the cost of a Rotel 1080 too so the chances this amp would get paired with them are NIL!
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post #18 of 33
6/4/07 at 4:57pm
ous8

you may like to read these threads...bi-wiring worked for me improved all
the aspects of music soundstage...but you must remove the speaker
terminal bridge plate then wire speaker a to mids and tweet section
then speaker to woofer section...

here are 2 links to encourage you:

http://www.audiokarma.org/forums/sho...=111077&page=3

http://www.soundstage.com/synergize/synergize031998.htm

Far less expensive than adding a 2nd amp !!

Enjoy!!
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post #19 of 33
1/6/09 at 4:38am
How would the RB1080 sound if you BI-AMP them with 2 RB1080 has anyone done this.
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post #20 of 33
1/6/09 at 10:04am
Quote:
Originally Posted by hdblu View Post

How would the RB1080 sound if you BI-AMP them with 2 RB1080 has anyone done this.

It would sound twice as good as one RB1080.
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post #21 of 33
1/6/09 at 12:13pm
Then how would 2 Rb1080 Bi-Amp vs 1 Parasound A21
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post #22 of 33
11/22/09 at 10:53am
Borrowing this 'old' thread for a while

So I have one RB-1080 with two set of connectors per channel.
I would like to try to have twin mains per channel whereas each of the connector sets will be connected to its own main (which would result in 4 mains, two rights and two lefties). I'm fully aware that it might _not_ be the best 'hifi' experience, BUT nevertheless a fun thing to try.
Given that the mains have an impedance of 8ohms each, is there anything that one should consider before trying?
Thx in advance!
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post #23 of 33
11/22/09 at 10:58am
Quote:
Originally Posted by arcticblue View Post

Borrowing this 'old' thread for a while

So I have one RB-1080 with two set of connectors per channel.
I would like to try to have twin mains per channel whereas each of the connector sets will be connected to its own main (which would result in 4 mains, two rights and two lefties). I'm fully aware that it might _not_ be the best 'hifi' experience, BUT nevertheless a fun thing to try.
Given that the mains have an impedance of 8ohms each, is there anything that one should consider before trying?
Thx in advance!

The only thing you should realize is that when you connect two 8ohm speakers to a channel in parallel (as they will be connected if you use the ROTEL's dual binding posts), that amp channel will then be presented with 4ohms of impedance. Provided the speakers really are 8ohm speakers and that their impedance doesn't ever drop too low, the ROTEL should be fine with that load.
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post #24 of 33
11/22/09 at 12:51pm
Quote:
Originally Posted by sivadselim View Post

The only thing you should realize is that when you connect two 8ohm speakers to a channel in parallel (as they will be connected if you use the ROTEL's dual binding posts), that amp channel will then be presented with 4ohms of impedance. Provided the speakers really are 8ohm speakers and that their impedance doesn't ever drop too low, the ROTEL should be fine with that load.

How can one know for certain that the mains aren't going too low (except from trying that is)? Also, what can happen in worst case... a blown-up amp, or just a blown fuse?
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post #25 of 33
11/22/09 at 1:10pm
Quote:
Originally Posted by arcticblue View Post

How can one know for certain that the mains aren't going too low (except from trying that is)? Also, what can happen in worst case... a blown-up amp, or just a blown fuse?

You can't really. If the speakers are rated as being 8ohm speakers I am sure the ROTEL will be fine with the 4ohm load. It is definitely rated as being capable of 4ohms so it can go lower than that, even. Worst case is a blown amp but the ROTEL will kick onto 'protect' mode or blow a fuse before that happens. I wouldn't worry.
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post #26 of 33
11/26/09 at 4:31am
Quote:
Originally Posted by Ou8thisSN View Post

the instructions say nothing about speaker a/speaker b outputs. Like i said, it only shows one set of connectors per channel in the manual, so they make any mention of it. I would get cables like that but seeing as I have the second set of outputs, and based on what people say in this thread, i'd rather just run another set of cables to my speakers, it would probbaly be cheaper that way anyway.

Blue Jeans has the Canare bi-wire speaker cable for about $1.35 a foot and they can be used without terminators so it's just a matter of stripping and using if you don't want to add terminators. I first tested bi-wire by adding a second set of regular wire and wasn't impressed, almost thought it sounded worse. But I did feel like it was better when I used better wire (in my case built bi-wire out of 2 Blue Jean twisted 10awg cables wrapped with Techflex casing). It was a very unscientific test and speaker wire differences are debatable, but if you're going to do biwire and $1.35 a foot is within budget, it might be worth making the modest investment.
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post #27 of 33
11/26/09 at 8:57pm
Try looking inside the speaker and see what wire is connected from the binding post to the VC. More than likely you will find nothing larger than 14awg stranded hookup wire.

Bi-wiring from the amp to the single VC speaker does zilch unless the wire you are using to start with is less than 14awg. The only effect you get is a slightly larger gauge.

Bi AMPING is another story. That also requires either and electronic or passive crossover. The advantage is that you have more ability to adjust the FR as opposed to depending on a passive EQ to do the job and you can pump more power if you wish to the individual drivers if you like the gut thumper bass or earschplittenloundenboomer mids and highs.

When we put in a high power sound reinforcement or concert system, we always bi amp and sometime tri-amp. That way we have a full control of the overall FR and effect control.
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post #28 of 33
11/27/09 at 6:03am
Quote:
Originally Posted by sivadselim View Post

The only thing you should realize is that when you connect two 8ohm speakers to a channel in parallel (as they will be connected if you use the ROTEL's dual binding posts), that amp channel will then be presented with 4ohms of impedance. Provided the speakers really are 8ohm speakers and that their impedance doesn't ever drop too low, the ROTEL should be fine with that load.

I was curious about this, so tried measuring with an ohm meter on my speakers. Resistance across the amp side of cables was 6.2 ohms when connected in bi-wire. The resistance didn't change when the bi-wire was jumpered together on the speaker side. When the lower set only was connected to the speakers, resistance remained 6.2 ohms, when the upper set alone was connected to the speakers, it was infinite resistance. I guess this means that the lower set is connected directly to a driver and the upper set is connected to the crossover, so not sure what this means for the overall impedance the amp sees for varying music signals versus what is seen with an fixed ohm meter test signal.
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post #29 of 33
11/27/09 at 6:29am
Quote:
Originally Posted by pjp View Post

I was curious about this, so tried measuring with an ohm meter on my speakers. Resistance across the amp side of cables was 6.2 ohms when connected in bi-wire. The resistance didn't change when the bi-wire was jumpered together on the speaker side. When the lower set only was connected to the speakers, resistance remained 6.2 ohms, when the upper set alone was connected to the speakers, it was infinite resistance. I guess this means that the lower set is connected directly to a driver and the upper set is connected to the crossover, so not sure what this means for the overall impedance the amp sees for varying music signals versus what is seen with an fixed ohm meter test signal.

First, you are measuring DC resistance, not impedance.

Second, if you did measure the impedance of the HF terminals or of the LF terminals, independently, you would find that each measures about 8ohms (variable) within its passband. This is what you expect since it is exactly the rising impedance of the network that blocks the out of bandpass signals (i.e., keeps lows out of the tweeter and highs out of the woofer).

Third, connecting them in parallel (exactly as does mono-wiring with the jumpers) results in the same 8 ohms, dominated by the in-band impedance.
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post #30 of 33
11/27/09 at 8:32am
Quote:
Originally Posted by Kal Rubinson View Post

First, you are measuring DC resistance, not impedance.

Second, if you did measure the impedance of the HF terminals or of the LF terminals, independently, you would find that each measures about 8ohms (variable) within its passband. This is what you expect since it is exactly the rising impedance of the network that blocks the out of bandpass signals (i.e., keeps lows out of the tweeter and highs out of the woofer).

Third, connecting them in parallel (exactly as does mono-wiring with the jumpers) results in the same 8 ohms, dominated by the in-band impedance.

Thanks Kal -- this is a great explanation both about measuring and understanding how the passband makes the impedance stay relatively the same even though they're in parallel (whether bi-wire or straight). Testing (even though DC resistance is clearly a poor test) helped crystallize in my mind how different the loads on the HF and LF paths are, so it starts to become apparent how having a separate path to each in bi-wire could make a difference where previously I had a tough time rationalizing how it would make a difference whether they were tied together at the speaker side or the amp side. Out of curiosity, do you believe bi-wire makes a significant difference?
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