Bi-Amping Question

[johnB]

My Cambridge Audio 840a has pre-out sockets....does this mean I could connect to a power amp (Quad 405 to be specific) and bi-amp my speakers? Anything to watch out for? Thanks.
John

[wee tam]

yes pre out means you can use a power amp , does it have pins connecting pre/main amp ? by pins i mean are there metal loops between the connectors or simply two outputs por pre ?

[The Grand Wazoo]

Hi John,
With bi-amping you have to make sure that the voltage gain of the two power amps is equal otherwise you will have to keep adjusting the volume on each amp separately for every different setting and if they are different, this means that you will need some sort of passive pot in front of the Quad.

[The Grand Wazoo]

Pre- out means you can use a separate power amp, yes - but it may just disconnect the pre & power amp sections. If this is the case, you may just be making the Cambridge power amp redundant and so you would need two separate power amps.

[Barry]

This might be of some help John: http://theartofsound.net/forum/showthread.php?t=5818

Regards

[The Grand Wazoo]

I found a manual on the CA website & it says the following about the pre-out sockets:


Preamp Out connections
The Preamp Out sockets are for connecting to the input sockets of a
power amplifier or active subwoofer. The diagram below shows how to
connect the amplifier to an active subwoofer via the Line In inputs on
the subwoofer.

It talks about a separate power amp but there's no mention that the internal power amp stays connected to the pre for bi-amping & I can't see any switch on the back panel to change the configuration.

[eds]

Hi Most of the newer CA gear will let you biamp with the standard preouts that are provided without disconnecting the internal power amp, but you need to make sure that both amps have the same gain otherwise the sound will be inbalanced.

[johnB]

Thanks for all the advice.
The pre-outs look like phonos , whilst the pre-in to my Quad 405 are 4 pin DIN.
How do I establish what the gain is on the CA840a and the quad 405?
Cheers
John

[DSJR]

The 405 in stock form will be far too sensitive, although this can be adjusted. If you sign up to the dada website, the library there has loads of downloadable docs regarding service and circuit details for all the popular Quads.

My advice though, is to look out for a Cambridge 800 series power amp to go with the integrated you have - they are around but possibly rare.

The thing is and in my opinion, much as I love the 405-2, if it's a mk1 version or a mk2 which hasn't been looked at for some years, these will need a darned good service to bring them up to standard, as the supply caps can be well thrashed, both thermally and electrically. The whole performance of the 405 series will be different to the Cambridge as well, being a much older design and more limited in current delivery.

If the Quad gives you an itch that must be scratched, then sell the Cambridge, buy another 405, preferably the 405-2 and a good valvey preamp like a Croft Micro-Basic (failing that a late 44 that you can fettle to bring it up to date with better IC's). The gain of the 405's can be reduced to modern levels (they were built high-sensitivity for the 33 preamp that can't deliver higher voltages and the noise and distortion performance is much improved by taming this).

[The Grand Wazoo]

I agree Dave, the Cambridge will be a far easier route, will integrate better & may well sound better.

[eds]

Personly I wouldn't consider the 405 with the CA for Biamping I've owned 405's and they are to different to CA. The 405 sounds totally different to CA equipment even if the input sensitivity matches the sonic signature is to different. I mainly run HT these day's but matching amps is still a bugger if I could find enough big Rotels I would have all the same. Makes life so much easier. Currently run a RMB1095 with an old Kenwood which is nice on it's own but way to different to the Rotel. Then the marantz SR8500 power stages are horible so they are not even being used:)
So what I'm trying to say is stick to the same brands if possible and better still same model of power amp.

[johnB]

Thanks all. As usual very good advice.
I'll look out for a Cambridge Power Amp and store away the Quad 44/405 until I have enough time to get it refurbished.
Cheers
John