Newbie: Bridging and triggering old amps?

[likwidsh0k]

Hi all,

I have just entered the world of HT with Rotel separates and just have a couple of newbie questions to ask.

I used to have rotel stereo seperates with a rc960 and rb980 and the power switch on my pre-amp died so I thought it was about time I went HT, and just picked up a RSP976 and RB976mkII off eBay. I thought this was perfect because I can bridge the amp to give me 150w for my other 3 channels and have a 12v trigger spare to figure something out for the old RB980.

My 2 options were use the rb976 triggered for stereo and when I put on a DVD then switch on my RB980 for the rears. Or get some kind of trigger setup for my rb980 and use it for mains and the new amp for the 3 surround channels - the advantage being I now have a pre-amp with a tigger to start it.

With the bridging I have since read that this may cause distortion and would really like any information on the downside of bridging?

With my RB980 can anyone recommend a trigger setup? I think I just need some kind of relay and am going to check out JayCar here, an electronics kit shop, to see what they have I could use. Just wondering if turning my amp on using something like this a good idea? Is it dangerous to have it switched on and then hit it with juice? Edit: I ask because there is a 'protection' light and sequence it it goes through whenever it is powered on that it wouldn't have.

Thanks alot.

Andrew

[Kevin D]

Bridging an amp does increase the power output, but does increase the distortion. Bridging also increases the minimum allowed ohm load to the amp. If your speakers drop much below 6ohm at certain frequencies the 976 will go into protection mode. Whether the increased distortion is audible and/or worth the extra power is something you will have to decide for yourself.

As far as a DIY trigger, it's do-able but the relay to pass the required amount of power might get expensive. You would probably be better getting a pre-made one designed for it. Most manufacturers that do power centers/surge protectors have models with triggered outlets. Most will have delay times to keep any pops and thumps from going through when the amp turns on.

Kevin D.

[likwidsh0k]

Thanks alot Kevin.

The VAF speakers I am getting are apparently very easy to drive so 60watts should be plenty and would really like to keep my old rb980 for mains duties. Like you said will see how it sounds and could always use zone2 for the other channels some day anyway.

One of those sounds ideal. Thanks again.

Picking them up on Tuesday night

Cheers

[Kevin D]

Let us know what you think. You could easily bi-amp your center and rears with the 976 (if they support it).

Kevin D.

[likwidsh0k]

Just picked them up and WOW!! They are in mint condition like brand new, very happy chappy! And the build quality .. just the volume knob shouts quality! Now I *really* wish I had 5.1 speakers to hear this baby in action, only got stereo at the moment.

I was talking to the guy I bought them off and he said he would bi-amp the mains coz it would really make a difference. So I could bi-amp the mains and centre and use the rb980 for the rears. One of the main reasons I didn't mention for triggering the rb980 is because it doesn't have a remote and is a pain to turn on, and a bit concerned after my pre-amp power switched died.

The new speakers I am getting next are VAF DC7s and I am almost positive they support bi-amping. So I will have alot to compare - rb980 versus rb976 bridged and bi-amped.

One very happy Rotel owner :T