2 Rotel 1070's

[Zoidy]

To boost power to my front speakers i purchased a 1070 .. am wanting more power .. so considering buying another 1070 having one for each speaker..
each 1070 puts out over 300watts rms in bridge? this would be perfect for my fronts..
in theory this is do-able and in practice i cant see a prob.. anyone wanna throw some spanners in ?

also.. in bridge mode.. do i still need 2 phono inputs for each rotel? and if so i assume i would need to use phone splitters for each amp.


any thoughts or advice is welcome thx

 

[Zoidy]

btw.. my front speakers only have 1 pair of inputs each

 

[ShinObiWAN]

No need to run two phono's on the rotel. One to each is fine.

What speakers are you using BTW? I assume the have a low sensitivity/impedance.

 

[Zoidy]

no.. the rotels cant be bridged into low impedance..

the makers of my speakers say the nominal impedance is 4-8 ohms.. so i mailed them and they said no speaker is excatly 1 certain impedance but if he had to give a approx it would be 6 ohm.

just to confirm.. i run a single phono (left/white) to the rotel running the left hand speaker and a single phono (red/right) to the rotel running the right hand speaker?

 

[Zoidy]

seems i was being too lazy looked in the manuals and it has explained all on bridging 2 amps thanks for looking

 

[Orbital]

Hi Zoidy,

I think I’m right in saying that bridging a stereo amp is not the best solution. Also I've yet to come across a bridged amp that sounds better than the same amp run in normal stereo mode. I think it’s also true that you should only bridge an amp if the speakers are a very easy load.

Wouldn't it be better to bi-amp instead?

 

[ShinObiWAN]

He's bridging and bi-amping.

2 x 1070's you see,, both in bridged mode for higher output.

The thing about bridging is a myth, never have a heard a jot of difference on my Rotel or ever had any comments from friends who use a similar method.

 

[Zoidy]

i would bi amp.. less power i know. but i cant my speakers only have 1 set of inputs i spose i could try bridging my current 1070 on one speaker to hear the result before hand..

 

[Zoidy]

Originally posted by Orbital
Hi Zoidy

I think it’s also true that you should only bridge an amp if the speakers are a very easy load.

well in theory.. my speakers should be ok on the amp bridged.. but a set of m+ks would be a no no .
when you bridge an amp it halves the impedance .. so bridging on an 8ohm speaker runs the amp at 4ohms. but if you bridge a 4 ohm speaker the amp see's 2 ohms. and usually only krells and such are designed for this. anyone feel free to correct me if im wrong.

back in my car audio days some amps were capable of ¼ ohm loads. ive often thought of intergrating car audio subs into a home cinema system .. its a much more specialist market

 

[Orbital]

Originally posted by ShinObiWAN
The thing about bridging is a myth, never have a heard a jot of difference on my Rotel or ever had any comments from friends who use a similar method.

You do a search and see what other people have written about bridging and you'll find there's a lot more distinguished people than myself agree that bridging is sonically inferior, no myth.

Each to there own I guess.

 

[Orbital]

Originally posted by ShinObiWAN
He's bridging and bi-amping.

2 x 1070's you see,, both in bridged mode for higher output.

Zoidy's speakers only have one pair of inputs so he can't bi-amp (I've only just noticed that in Zoidy's earlier post else I wouldn't have mentioned it before)

He's basically using his pair of 1070’s as a monoblocs, one for each speaker, but each monobloc is still driving both high and low frequency drivers in his speaker so it's not bi-amping as I understand it.

 

[Reiner]

the makers of my speakers say the nominal impedance is 4-8 ohms.. so i mailed them and they said no speaker is excatly 1 certain impedance but if he had to give a approx it would be 6 ohm.

4-8 Ohm means the speaker is compatible to amps rated for 4-8 Ohm speakers.

A speaker rated 4-8 Ohms is usually a 4 Ohm speaker.
While it is correct to say that a speaker does not have exactly 1 certain impedance the value (e.g. 4 Ohm) probably indicates an average of the impedance or the DC resistance.

E.g. a Dynaudio Contour 1.3MkII is a 4 Ohm speaker, but it's imdepance varies from 3.5 to 14.4 Ohm (manufacturer's rating).

when you bridge an amp it halves the impedance .. so bridging on an 8ohm speaker runs the amp at 4ohms. but if you bridge a 4 ohm speaker the amp see's 2 ohms. and usually only krells and such are designed for this. anyone feel free to correct me if im wrong.

An amp does not have an impedance as such and it can't halve anyone's impedance, in particular not that of an speaker. And of course you bridge the amp, not the speaker - in other words the impedance of the speaker will not change.
Bridging might affect the amps handling of loads though, perhaps a 4 Ohm load is too tough for the amp in bridge mode and hence the use of a 8 Ohm speaker is recommended.

He's basically using his pair of 1070’s as a monoblocs, one for each speaker, but each monobloc is still driving both high and low frequency drivers in his speaker so it's not bi-amping as I understand it.

That's how I understand / see it, too.

 

[buns]

o be honest, if bridging is the only option, you might consider just sewlling up and getting a better stereo amp and be done with it...

ad

 

[Zoidy]

well i only thought of this.. as i can get another 1070 for not alot of money.. and total cost of the 2 would be around 600.. you think i could get a better stereo amp for the same money?


reiner i was told (im not too good at explaining things ) that if you bridge a 4 ohm speaker the amp in effect splits the impedence across the 2 stereo outputs, so each of the stereo outputs see's 2 ohms

i got this info from the top car stereo guy in the country and i assume audio impedance is the same for both home and car

 

[Reiner]

reiner i was told (im not too good at explaining things ) that if you bridge a 4 ohm speaker the amp in effect splits the impedence across the 2 stereo outputs, so each of the stereo outputs see's 2 ohms

I think I understand what you mean and note what I earlier said about the load before and after bridging.
The load itself doesn't change, but the amp's capabilities change when bridged.

Rotel confirms:

Can the RB 1070 handle a nominal impedance of 4 ohms or below?
The RB 1070 is specified to be stable for a nominal impedance of 4 ohms minimum, how it is not specified to handle any nominal impedance below 4 ohms.
When running in bridged mode, the RB 1070 is stable with a nominal impedance of 8 ohms minimum.

i got this info from the top car stereo guy in the country and i assume audio impedance is the same for both home and car

There is no difference in terms of impedance between car and home, that's correct.