Two RB-1080s with one Pre-Amp?

[rantzmar]

Just wondering is there any way I can use two Rotel amps with one preamp...like in mono each side?

[srb]

The RB-1080 is not bridgeable to mono.

If you think you need more power for low sensitivity speakers, you could passively vertical biamp if your speakers are equipped with two pairs of biamp binding posts, using one RB-1080 for each speaker with one channel on the woofer and the other on the mid/tweeter.

This would lessen the load on the power supply of each amp as each would only be powering one woofer. The performance gain could be marginal and if you don't already own a pair of RB-1080s, you would likely have much better results replacing the RB-1080 with a more powerful stereo amplifier such as the RB-1090 or a pair of monoblocks from another manufacturer.

P.S. I was fortunate (and somewhat surprised) to have the Dexter Gordon Quartet host a jazz workshop at my local community college in Tucson, AZ in late 1977.

Steve

[rantzmar]

The RB-1080 is not bridgeable to mono.

If you think you need more power for low sensitivity speakers, you could passively vertical biamp if your speakers are equipped with two pairs of biamp binding posts, using one RB-1080 for each speaker with one channel on the woofer and the other on the mid/tweeter.

This would lessen the load on the power supply of each amp as each would only be powering one woofer. The performance gain could be marginal and if you don't already own a pair of RB-1080s, you would likely have much better results replacing the RB-1080 with a more powerful stereo amplifier such as the RB-1090 or a pair of monoblocks from another manufacturer.

P.S. I was fortunate (and somewhat surprised) to have the Dexter Gordon Quartet host a jazz workshop at my local community college in Tucson, AZ in late 1977.

Steve

thanks for the infomation about the 1080...I was pretty much just wondering...

And wow on the Dexter Gordon work shop...im sure that was a real treat!

[HDBLU]

I Had the 1080 and works very well for Bi-amping.

But if you want a Mono Bridging amplifier have a look at the Parasound A23 HALO will put out 400w at 8ohms 1ch (Mono) I have one and they are awesome.

[rantzmar]

what would be the purpose of bi amping

[hurin]

If you want to improve your setup, I suspect the weakest link is not the amp but your Canton/Klipsh combo.

[BWzes03]

what would be the purpose of bi amping

I notice from your signature, you have the same pre-amp as I do.
The RC-1090 has two RCA outputs you can use to connect a power-amp to.

This is exactly what I'm doing, I'm bi-amping my Nautilus 802's with two RB-1080's.
That is, a single RB-1080 per speaker, one channel on the woofers(LF) and one channel on the mid&tweeter(HF).

Why vertical bi-amping is beneficial ? Due to the same input and output signals, the 'inter-channel interference' is a moot point, since its the same signal throughout the amp, and having the impedance swings 'balanced' over two full power amp channels, reduces the stress on the power supply buffers on a per channel basis.

If there is a peak power needed by the woofers due to impedance dips, it doesn't influence the power output on the mid and tweeters.

[rantzmar]

If you want to improve your setup, I suspect the weakest link is not the amp but your Canton/Klipsh combo.

What makes you say that? Im interested in your opinions.

[rantzmar]

I notice from your signature, you have the same pre-amp as I do.
The RC-1090 has two RCA outputs you can use to connect a power-amp to.

This is exactly what I'm doing, I'm bi-amping my Nautilus 802's with two RB-1080's.
That is, a single RB-1080 per speaker, one channel on the woofers(LF) and one channel on the mid&tweeter(HF).

Why vertical bi-amping is beneficial ? Due to the same input and output signals, the 'inter-channel interference' is a moot point, since its the same signal throughout the amp, and having the impedance swings 'balanced' over two full power amp channels, reduces the stress on the power supply buffers on a per channel basis.

If there is a peak power needed by the woofers due to impedance dips, it doesn't influence the power output on the mid and tweeters.

Would any of that translate to what I can hear? Would there be a improvement in sound?

[hurin]

The problem list of reasons for bad audio is.

1: Acoustics. Hard surfaces such as glass or concrete, speaker/room mismatch, speakers are to big or to small for the room.

2: Speakers. Good speakers are expensive, but many expensive speakers such as Bose are no good.

3. The amp is underpowered. However choice of amp is a matter of personal taste. Class A is expensive but they're not 'better'. There are many good class AB and D amps that are relatively cheap.

.
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10. Cables.

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20. Tweak of the weak.


Ideally a 3 way crossover (bas midrange tweeter) should look like this


In real life we are not so fortunate unless prepared to spend a small fortune.

I'm guessing there is a huge gab between your sub and your midrange. Try playing playing some test tones with different Hz. ideally they should sound equally loud.

http://mdf1.tripod.com/test-tones.html

[rantzmar]

Thanks for the advice hurin...

...But I no longer use the sub, havent used it for a while. I mostly play acoustic Jazz...The Cantons are wonderful speakers...and my system does not sound bad at all....I love it. But when I did use the sub, I had it dialed in perfectly. I only asked about the mono amps and now bi amps to tweak the system a little. Do you know if the advantages of bi-amping will result in better audible fidelity?

And thanks for the sound wave...i'l check it out

Thanks

[madmac]

I personally do not believe that Bi-amping is necessarily going to get you a huge improvement in sound. The amp itself...the source, and most importantly the speakers and their placement (and the room itself!!) are going to get you the biggest improvement in sound.

[Glen B]

I only asked about the mono amps and now bi amps to tweak the system a little. Do you know if the advantages of bi-amping will result in better audible fidelity?

What attributes do you feel are lacking in your system that makes you want to "tweak" it ?

[rantzmar]

What attributes do you feel are lacking in your system that makes you want to "tweak" it ?

Nothing really...it sound fine. Just wondering if it can be improved upon. You really never know until you try something.

[BWzes03]

Would any of that translate to what I can hear? Would there be a improvement in sound?

I personally found an improvement in bass control and extention, an extention in the highs, and the stereo field was much improved.
What I mean is, the stereo image seemed to be much wider, deeper (reaching farther beyond the speakers ) and in focus (vocals and instruments having a stationary place in the sound field.)
With a single RB-1080 I experienced this as well, but in lesser degrees.

This was with my previous Nautilus 804's, which I played with a single RB-1080 for at least 1 year before I found another RB-1080 (second-hand) to try bi-amping with.

Of course, since music is highly personal and matter of taste, your milage may vary.
If you are in a position to 'try' the extra amp in your system for a week or two, before purchase.... that'd be ideal...

[specialized]

[QUOTE=BWzes03]I personally found an improvement in bass control and extention, an extention in the highs, and the stereo field was much improved.
What I mean is, the stereo image seemed to be much wider, deeper (reaching farther beyond the speakers ) and in focus (vocals and instruments having a stationary place in the sound field.)
With a single RB-1080 I experienced this as well, but in lesser degrees.


I have a b&w 803s and i was doing biamp with two RB-1080 and one PreaAmp (McIntosh C2300). There was improvement from one to second RB-1080. But when i tried Krell FBP-300C i realized real huge imrovement. So i realized that maybe it's not worth to do biamp compare to bigamp .

At the end when i treid Benchmark DAC1 with Krell i sold McIntosh C2300 and one Rotel and now im using DAC1 Pre with Krell FPB-300C. It's offer amazing sound specialy when i play 24bit 96 Khz flacs (HDTracks are amazing)

Greetings

Darko

[BWzes03]

There was improvement from one to second RB-1080. But when i tried Krell FBP-300C i realized real huge imrovement. So i realized that maybe it's not worth to do biamp compare to bigamp .

Darko

There is a HUGE price difference between a 600 Eur. second-hand Rotel RB-1080 and a 10000 US$ new Krell FPB 300C. Even if you find a second-hand Krell, it will never be near the 1400 Eur. I payed for 2x RB-1080's.

Granted, a big amp will get better response out of your speakers, but there is such a thing as the rule of 'diminishing returns' on investment.

[specialized]

There is a HUGE price difference between a 600 Eur. second-hand Rotel RB-1080 and a 10000 US$ new Krell FPB 300C. Even if you find a second-hand Krell, it will never be near the 1400 Eur. I payed for 2x RB-1080's.

Granted, a big amp will get better response out of your speakers, but there is such a thing as the rule of 'diminishing returns' on investment.

Of course.. I agree with u.. But Krell FPB are far from 10000 usd in this moment (i get it for around 3000 eur second hand). It's twice more then 1400 eur, but for first time 803s sound that clear and open and natural. Also maybe instead of buying two rb-1080 for 1400 it's better to get one RB-1090 for around the same price even less. Belive me until i didnt try this Krell i was sure that two rb-1080 are real thing and all negative things i had i was explaining with my poor room acoustic. When i tried this combo (DAC1 PRE + Krell), all that negatives gone.. For first time as im in Hi Fi i just want to listen and getting music and not to test and get new hardware. For first time in my life i dont want to experiment with new preamp, cables or something else.. I guess i reach the lucky point when im satisfied how it sound.. B&W 800 series definitly need proper amp to sound properly.. Too bad many of the owners dont ever hear what those speakers can do..

Greetings

Darko

[rantzmar]

Thanks BWzes03...I may just try it soon...
darko, seeing I already have one 1080, it would be just better for me to get a used 1080 to biamp....thanks for your thoughts as well.

[specialized]

Thanks BWzes03...I may just try it soon...
darko, seeing I already have one 1080, it would be just better for me to get a used 1080 to biamp....thanks for your thoughts as well.

Since i still have three 1080 (one for center, one for rears one for my second setup (B&W Cm1), and since i was using two amp combo more then year, check as well situation to sell 1080 and and to get Rb-1090. This is even cheaper since u save one interconnect compared to two rb-1080, and im sure one RB-1090 would sound better then two RB-1080.

Greetings

Darko