Gain matching - audiolab 8000a / quad 405-2

[admin_exported]

Hi, some advice needed... I've just acquired an Audiolab 8000a and see from the back that you can easily bi-amp it if you have the appropriate power amp. I happen to have a Quad 405-2 knocking about at home and was wondering if they would work together? Am I right in thinking they need to be gain-matched? How do you find out if two amps are indeed gain-matched? Thanks in advance for any replies : )

 

[mitch65]

Hi, some advice needed... I've just acquired an Audiolab 8000a and see from the back that you can easily bi-amp it if you have the appropriate power amp. I happen to have a Quad 405-2 knocking about at home and was wondering if they would work together? Am I right in thinking they need to be gain-matched? How do you find out if two amps are indeed gain-matched? Thanks in advance for any replies : )

I'm pretty sure the audio lab is only gained matched to it's own power amps, I did use my 8000a with an 8000p which have different outputs and this was the case.

 

[Anonymous]

So as a general rule you can only attach a second (power) amp if it's the same brand?

-bush

 

[Anonymous]

...and how come you don't use the 8000p anymore??

 

[mitch65]

Unless the the 8000a has been modified to act as a preamp then yes as you can only add a power amp in a bi amp configuration. If yours is modified then any power amp can be used as the gain match will not matter. I got rid of the power amp only because I will be moving to a different amp altogether soon. FWIW the audio lab power amp is very good and probably a better match than the Quad but that's just my opinion.

 

[Anonymous]

Right, gotcha. Last question then (for now at least), how do you modify it so it'll run with any power amp? Thanks.

 

[lindsayt]

If the Quad has more gain than the Audiolab, you'd just need a volume control / set of resistors to pad it down to the same gain.

If you can get at your speaker crossover easily, or if it is already wired to easily enable active bi-amplification, you could get an adjustable active crossover such as an Ashly for active bi-amplification - which should give you better sonic results than passive bi-amplification.

I'm actively bi-amping with an 8 watt SET for the midrange and treble, and an 80 watt solid state for the bass, with a Pioneer SF-700 adjustable active crossover. This is with 45 year old speakers that were designed to be used either passively or actively bi or tri-amped.

 

[Anonymous]

Thanks, although it sounds a little complicated for my simpleton ways. I don't know what I was expecting mind...

 

[mitch65]

Right, gotcha. Last question then (for now at least), how do you modify it so it'll run with any power amp? Thanks.

It's a small adjustment inside the amp itself which most hifi repair shops should be able to do. Back in the old days your dealer would do it so might be worth trying your local Audiolab dealer. 🙂