Rotel 1068 pre-amp and 1077 amp driving B&W 804S

[Hugemongo]

Got this new set up, am bi-amping the front two B&W 804S but am needing quite a lot of juice (about 70-75) before the sound picks up enough to fill the room convincingly to be a good sound....

Is this a result of the underpower of the 1077? Anyone else seen lower volume levels capable of sounding full sounds (and on what speakers?)

Don't think this is an input problem as I am digital coaxing my CD input into the 1068...

If this is given, then guess I have no choice but to run it at 3/4 capacity!

Currently sound seems mediocre though, but surround is good - still need to jack the volume high though (have B&W HTM4 centre, PV1 sub, XT2 rears)

Any advice much appreciated!

[Kevin D]

The volume on the 1068 isn't linear, so 75 isn't 3/4 volume and 50 isn't half. Depending on how big a room you are trying fill and your definition of a full sound, it could easily take 70 to get there.

The digital amps also seem to have a lower gain on them, taking a little more signal to get the same volume as a regular amp. On mine I'm rarely under 50 and movies/digital surround I'm usually between 70 and 80.

Get an SPL meter and set the speaker levels. If the center and rears have close to the same output level you're fine. If the fronts have a significantly lower output level then I would check how you bi-amped the inputs and the speaker cabling.

Kevin D.

[style]

@Hugemongo,

How much ist your livingroom??

but combo Rsp1068 + Rmb1077 sorry but underpowered I think is a big word.


You can buy a Rb1092 for the mains and bi-ampi the center.

My living room is 10meter longh and 5.8breight: I have the Rsp1068 + rmb1075 (B&W803s-htm7-703rear-750sub) underpowered ???? NO.
today I have a 2xRB1092 and a RB1091+ rsp1068 but with the 1075 I don't believe is a underpowered combo.

Omar

[Ferres]

Allow the 1077 some break-in time. It's kinda weak out of the box, both volume and bass. Give it a week and you will be able to dial down the volume and get more bass.

Watch the bi-amping as well. Some combinations may cause sibilance. Fronts should be hooked to the tweeter.

[Hugemongo]

Thanks all for advice... sounds like its not an underpower thing.. PHEW.. was thinking I needed to start considering another stereo amp to specifically drive my front 2!

My room is not that big, 6 metres by 3.5 and my speakers are 2.7m apart and I'm sat 3m away so sounds like I need to be more patient for break in

SPL and bi wire checked and ok'd - so guess i just got to get used to the Volume gradients...

[Russ L]

A source can change the level needed. When I switched Cd players to one with a bigger power supply the volume needed dropped 10 notches on my Rotel. Don't know if thats true for all CD players with a bigger power supply but in my case it decreased volume needed. It may be that the noise floor drops or the notes are clearer as well... Regards, Russ

[mjb]

The 1077 is not as sensitive as the 1075 (1.2v/8kR vis 1v/33kR), so the volume knob will indeed need to be turned higher for the same sound pressure output (from the same source). An SPL meter is the only way to measure levels, a volume knob scale is rarely calibrated and even then its an indication of attenuation (or relative gain), and not sound pressure. Different sources may have different output levels, which will sound louder or softer without moving the volume knob.

Enjoy your setup!

[bleeding ears]

My 1068 and 100 watt per channel rb985 amp need to be up around 70 on the volume dial to get it loud.

It depends on the recording somewhat and can vary between about 60 and 75 on the volume dial to be loud. So 70 does seem to be commone on the volume level with the 1068.

Although the dial seems to be up relatively high, the sound quality does not seem to suffer so I could probably go louder to maybe 80, but I have fried speakers before (with a different amp at louder volumes) and so I fear to go much louder than 80 even if it sounds ok.

It would be nice to know how much is too much on the volume dial, before blowing speakers, but each set up being different would have differring levels.

Is there any way to know when you are reaching the point of damage before you actually hear that frighteningly loud cracking sound and your speakers are in need of repair?

Pete

[Hugemongo]

If it gives you any form of comfort, I've gone to max on my rotel 1068 (on my current 1077 amp) and my fronts seem to handle it easily.. (I actually get the impression they can handle even more...)

Obviously will be different for every other setup - but hope this datapoint can act as some help...