Anyone Bridge two RB-1070's and use as two Monoblocks??

[GSamF]

I am planning to later upgrade my front's power.

I was just looking through my Rotel catalogue (I have been doing this quite often in anticipation of my demo next week of the 68,98,75,&95). I noticed the 1070 (130w x 2) can be bridged to have 1 channel at 330 watts. The RB 1070 being $499 each, that would make a grand for two channels at 330 watts each, compared to a grand for the 1080 200w or $2,000 RB 1090 at 380w.

Has anyone done this and how did it sound, and/or do you lose a lot in bridging and thus the 1080 still gives you more power?

Thanks in advance,
Sam

[JonLeach]

Hi Sam, i have an RB1080, and 2x RB981's in normal stereo mode as i have 4 ohm speakers.

As far as i know the the RB1070 is a RB981, might have been tweaked a little bit, but i only paid 150ea for them 2nd hand, and 400 for the 1080. on an A B comparison the 1080 is far superior than the 981's. in mono mode i could not say, but i bought them off a guy who had them setup for mono, they sounded good but IMO not as good as the 1080 but different rooms different speakers and sources.

i would dem them and hear for yourself. have a look on the 2nd hand market, Rotel power amps are bomb proof.
saying that my 981's hum a bit, a bit of bue tac has cured that issue, well a lot of blue tac actually.

Jon

[aud19]

Sam, if possible I'd recommend bi-amping with two 1070's to your mains over bridging. Bridging tends to introduce more noise in to the system. What speakers do you own? Do they have dual posts?

Jason




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[GSamF]

Aud19,

I own b&w's 804's. What's the difference between bi-amping and bridging (still new to this separate thing)? And would this give more power and/or be cleaner than the 200w 1080?

thanks for your help,
Sam

[aud19]

Bi-amping allows you to use one channel of the amp for the tweeter and mid range and the other channel for the bass/woofer driver. I would contact B&W to find out what percentage of power each section uses in your 804's as you might be best off using say the 1070 for the tweeters and midrange and a 1080 for the woofer if it has greater power requirements or the two 1070's might be perfect if the ratio is close to 50/50.

Bridging tends to introduce noise which is a no-no in my books.

Jason




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[Adz]

Sorry, can you explain the bi-amping procedures and benefits in a bit more details. I have a 1080 for my fronts. If I bought another one, I assume I could take advantage of the bi-amping? I assume I need another set of speaker cables? What would the watts be per channel after that? In my current set-up, my speakers are not bi-wired but I have bi-wire jumpers in place between the connections.

Thanks,




Adz

[Bam!]

Hey guys!

I am working on Bi amping my speakers too...getting them upgraded and away we go...

Bi amping...you have two amps with 2 outs...O.K.
You take one of the outs of one of the amps and connect it to either the top binding posts or bottom binding posts and you repeat this 4 times (you must have 4 binding posts in back of your speaker..one for highs and one for low frequencies)

The advantages are stunning...your B&W will sing, open up your soundstage and give a nice deep bass which those B&W are thirsty for....

My plan is to buy a Class A amp at 40 watts *2(yes you heard right a class a 40 watts!!!)(I won`t mention the name since we will go off topic) for the highs and well I haven`t figured out what to put for the bass...yet....

Ahhh the joys of sound!

Hope this helps duders!

edit to "Gsamf" to follow up on what Jason said you would need 4 monoblocks...and bridging 2 channel amps into one makes noise....you`d be better off buying 4 * 7Bsst from Bryston but you would probably have to morgage off your house!




Bam!

[Adz]

I think I got it. So, one would need two more speaker cables for biamping the front L&R. My speakers have mid and low connections. Is it a negative to have two 1080s which would mean 200 watts connected to my mids? Also, that would seem to make my nitro bi-wire jumpers superfluous (i.e., no longer useful and they weren't cheap!).




Adz

[aud19]

Yes those jumpers would need to be removed...sorry ops:

Is it a negative to have two 1080s which would mean 200 watts connected to my mids?

Well first of all it's not going all to your mids it's also going to your tweeter and no it's very positive That doesn't mean you'll be putting the full 200w into them though. You'll still be listening at levels that are normal to you. You'll just have more power available to cleanly power the speakers.

I still recommend contacting B&W to find out what percentages of power goes whewre so you can get the appropriate amps.

Jason




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[ejfiii]

No one ever explains how you go from one preamp out on your processor to two amplifier inputs on your (now) two amp channels for a single channel when bi-amping. I am assuming that you just use a y adapter off the processor rca connector and then run an interconnect to each amp channel? I would be interested to hear some empirical evidence that this split does not degrade the signal at all.

Just thinking out loud here.

Thanks,

E. J.




My HT

[aud19]

That's how you do it and depending on how you do it will depend on how much/if the signal degrades. Doug (Cat Cables) has made some nice sets of "Y's" for people to use in bi-amping situations before I'd suggest contacting him if you decide to go the bi-amp route.

Jason




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[ejfiii]

Thanks Jason. Just figured if some noobie was surfing through the thousands of biamping posts on this forum, he would start to wonder how to phiysically make the connections. Lord knows, we all know how to wire our speakers for a biamp setup.

E. J.




My HT