Benefits of bi-amping

Being a bit of an audio dunce, can anyone tell me the actual benefits of adding a second solid state stereo power amplifier to an already existing pre and power, how it eases the load, and so on.....??????

 

I'll start and hopefully others will correct me.

I think it's only worth doing if you are happy with the basic sound of the existing amp, and by adding a more powerful amp for bass you can "get more of the same". It provides greater scope for tweaking. I.e. separate signal paths for low and higher frequencies and allows one to use different cables (i.e. low/high capacitance) for bass and treble etc.

The benefits can be marked, but sometimes you are better off just buying a better integrated, with the obvious advantage of fewer boxes (well, I think that's an advantage). Another route would be to change the speakers, this will probably provide the biggest change in sound.

 

Couple of approaches. Vertical bi-amping is aligning each power amp to one or other of the speakers, horizontal bi-amping is aligning each power amp to a different pair of drivers (eg one to both tweeters, one to both mid/bass drivers, and so on hence tri-amping where you have three drivers).

Technically, vertical is easiest to explain for the layman. It's channel separation, as with monoblocs. I understand (but am sure techies will correct me) that horizontal is around removing interference between the frequencies handled by each pair of speaker drivers at crossover.

I vertically bi-amped two Quad 405-2's in my second system. The sound widened, as if the speakers had been moved further apart. Definition of some instruments improved. This stacks up since the stereo is "purer". However there was no improvement in bass or upper range as people sometimes suggest, and I guess is more likely to be the case with horizontal bi-amping.

Two 405-2s are less than half the price of a new Quad 909, the next in line logical upgrade, so in this case it made good sense to me. I don't know what your power amp is but I'm not sure if I'd do it if the next upgrade option was closer in price. However - as a dyed-in-the-wool Hi-Fi Answers disciple I'd generally suggest source first as the best investment.

Pete

 

In my experience it is a stop gap measure - you can always get a better single amp that will sound better than the bi-amped attempt.

More is less in hifi; adding more active circuits to the sig path is not necessarily a good thing. Might sound impressive but ultimately less goodness (detail, timing, dynamics) gets through.

Same with bi-wiring - there may be specialist designs to which the about does not apply though.

 

Bi-Amping can be particularly good for the stereo image, and all sorts of low level detail which otherwise one might need headphones to detect. Bi-Amping sort of brings that to the fore without over-stressing the detail in a clinical way. It can also help with scale & dynamics.

Dev is definitely right when he states you should like the amp you have, it is very much more of the same. There is an old thread here, & here.

 

A while back I read an article by John Bamford in HiFi Answers advising Bi-amping with Edison 12s (the kit amp they were promoting at the time)- speakers were Snell E11s (which I happened to own). So I got 2 and was very happy with results. One drove the tweeters (4 on the Snells, (2 rear-firing)) and the other the bassmid. (They sounded different on top and bottom (!) so we selected the best arrangement.)
The idea here is that these valves amps are a bit puny but cheap so with less of a load for each amp to drive you got great 'bang for your buck'.
Well, recently I bought a VRR2000 valveamp of the same power and it beat the 2 Edisons for less money. (Well it has point topoint wiring andmore sophisticated power supply and its newer.)
To start with we used Chord Rumour speaker cable as 'jumpers' in the Snells as we were now single wiring (with the one amp). However, we soon noticed a marked reticence in the top end reproduction..what to do?
We hit on the idea of restoring the biwiring arrangement which was still lying on the ground in the bay - we could do this as the 'bass' cable was spade terminated and the Nordost Blue Heaven (which had been discarded in favour of the meatier bass cable) was banana-terminated.
This scheme wasmuch better and proved the value of biwiring with a single superior amp.

 

How does bi-wiring from a single amp work? It strikes me that this is essentially electrically identical to a single wire.

Regards,

Chris