...........go about bi-amping?

I have a pre-power amp sytem with just the one power amp, but have a chance of another power amp. I've already bi-wired my speakers.

So how does bi-amping work? One for the bass, one for the treble? or one for each speaker?

And how can you connect the pre-amp to TWO power amps? My pre-amp seems to only have ONE set of "OUT terminals?

Thanks, Alcazar

 

Bi Amping with two stereo power amps means you have one driving the bass frequencies & one driving the treble frequencies.
When you have monoblock power amps you have one driving each speaker or if you have 4 x monoblocks you can have two per speaker driving the seperate frequencies.

On your power amp, as well as the speaker connections and inputs do you have any outputs, (often marked 'load' or 'chain') so that you can daisy chain your power amps?

 

I believe the more common technique tends to be one amp for bass, one amp for treble. This would have the advantage that the big current swings etc associated with heavy bass are kept a bit more separated from the more "delicate" treble signals. However, it'll work fine either way.

If you have only one set of output channels from the preamp, you have two choices
1) a splitter type cable - i.e. one phono at one end to two at the other. I've made my own in the past, but you should be able to buy them
2) get the pre-amp modified to have a second set of output sockets. As long as there's room on the case, it's actually a very straightforward job to do, and does widen your choice of interconnects.

Option 3) is of course as Daz says if you've got a daisy-chainable connection on the power amps.

 

Cheers for the responses guys.
There's no daisy chain output on the power amps, so that's out.

Who would mod the pre-amp for me, or could I do it myself?

If not, what sort of a splitter ought I to buy/make?

Alcazar

 

just buy an active crossover and then ditch the crappy passive crossovers in your speakers. far better way of going on than using passive crossovers ....

 

You don't need to get your pre-amp modified. Connect one amp to the right input, the other to the left input of the pre-amp. You can even go mad and quad amp, driving each of the four individual inputs on the pre-amp with a separate power amp. Bi-amping definitely reaps benefits, quad amping in my opinion is very subjective.

 

Sorry if I'm being thick, but your post has baffled me.

What "inputs" do you mean? My POWER amp is at present connected to the PREamp OUTputs. There is only ONE pair of outputs from the preamp, hence my question?

Alcazar

 

Ok, what exactly have you got? A pure pre-amplifier and a power amp, or an integrated amplifier into which you've hooked an additional power amplifier?

 

Pure preamp and ONE stereo POWER amp.

Been into town and no-one sells "two RCA phonos into four", nor splitters with one RCA phono plug and two RCA phono sockets

Alcazar

 

Ok well that's easy then, you don't need any special cables. As i explained badly before, just use one power amp to run the left channel, and the other power amp to run the right channel. Effectively that means one output on each power amp will remain unused. The anoraks of the world (ahem) will swear that one power amp sounds better on left or right and vice versa, but it's up to you how much you experiment. Don't expect miracles though, bi-amping doesn't double the sound, but it does give you more of what you've already got.

The alternative to the above is to bridge your two power amps (they will have input sockets as well as outputs) and then run left AND right from the bridged power amplifier. Some people prefer to do this to eliminate any output differences between power amps, but if you've got decent kit this won't be an issue (and 99% of purpose-built power amps do fall into this category), and the first method will bring you better results. Try both though and see what you think. PM me if you need any further clarification.

 

Can you turn your stereo power amp into a monobloc? Using two amps in this mode, one for the left and one for the right, is far better than bi-amping. The reason is that a stereo amp will be much more powerful when used as a mono amp.

I did this years ago with some Arcam power amps and the improvement compared to bi-amping was very obvious. What amps do you have?

 

I agree Daryl, monoblocking gives better results. I'm running two Chord Electronics SPM-1400Es into Chord Electronics CPA-4000E (if that was directed to me?!).

 

Sorry Telboy, was asking alcazar what he had. Nice gear you've got there though - we're talking £20k aren't we?

 

if your going to bridge a standard amp 1 per channel, then you might aswell just have bought a decent amp in the first place!! it basically shows you that it wasnt big enough in the first place if you can hear a difference after bi-amping. best thing i ever did was forget all the crap the knobber at the hifi shop said bought a pro audio amp to do the job. the sound is 10 times clearer, has tonnes of power and headroom and doesnt cost the earth. only downside is that it is fan cooled but as it lives out the way in a cuboard its no issue.

 

Depends what you want though - sheer clout or musical dexterity. As Naim followers will tell you for example, an amp like the Nait with only 30w available sounds very sweet indeed, and doesn't improve with huge power amps strapped on, even of hi-fi quality, let alone industrial grade mini power stations! Additionally, huge power reserves do NOT guarantee clarity, i think you're approaching this from a different angle to most audio enthusiasts!


Daryl, something like that, yeah.

 

If you're only using one output on each amp to drive each side though you're not really bi-amping because only half of each amp is driving each channel. This is no different to just using one stereo amp to drive both sides, surely?

Bi-amping with stereo amps would be done either by using one stereo amp driving the left and right bass and the other on the left and right mid/highs, as stated above and known as horizontal bi-amping, OR using one stereo amp per side with one channel driving the bass and the other the mid/highs. This is known as vertical bi-amping and is quite popular in the US.

 

Horizontal bi-amping is a different ballgame though. You need a separate crossover to segregate the current into low and high frequencies, and this of course introduces another component into the chain. Added to the fact that the amp driving the woofers will work much harder than the one driving the tweeters, so the low range amp can bottom out a lot quicker if pushed hard, leading to a very muddled bass at best. I've only heard a few systems amped in this way, but i've never heard them re-wired monoblock fashion, so i can't honestly say i've ever compared the results like for like. Although monoblocking might not seem to offer much advantage, most people can hear the difference in "wallop" for want of a better word. The whole thing opens up and takes on a much greater sense of effortlessness. Hard to explain, but definitely worth it.

 

I was referring to passive horizontal bi-amping where the speakers crossover is still used, not the vastly superior active variant where the frequencies are divided by an active crossover which sits between pre-amp and power amps and the speakers crossover is removed from the circuit. Apologies if this was not clear.

I agree with you that passive horizontal bi-amping is a bit of a waste of time though - and expense - because you're not driving the speakers drive units directly; there's still the speakers crossover for the delicate signal to pass through. Having an active crossover in place isn't a problem sound quality wise because the signal is still at line-level when it's divided, and a line-level signal is much more durable than a speaker level one. And the sound quality gains with an active set up are great IMO.

 

I've never tried passive horizontal bi-amping on my system actually, mainly because rearranging the speaker cable would be a pain now. But all this talk of it has made me curious as to whether i'm missing out on something, lol! No, Tel, step away, leave it alone!!

 

Hmmmmmmm, this has got even MORE technical, not less

I have, at the moment, a Technics preamp with onboard DAC. It's from about twenty years ago, and was very highly rated for it's time

Then I have ONE Technics SU-A50 POWER amp, which is rated at 110Wpc.

I have a chance of a second power amp the same as the first.

Looking at the manual that came with the power amp, it can be monoblocked, (bridged?) into a single mono amp.

Maybe this is the way to go? One for left, one for right?

Alcazar

 

That's the easiest, most popular and arguably most effective option, yes. Give it a go.

 

Definitely!

 

yes do that alcazar. as telboy sad you will get a more punchy sound due to the fact you now have loads more headroom.

telboy your next objective should be to get an active crossover and ditch the passives in the speaker box, wiring the drivers direct to the amps
looking at the specs for your chord amps they look fairly beasty although you will probably be supprised but the specs for my pro amp arnt much different, still class A/B and with a s/n ratio above 106dB and 700w rms per channel into 2 ohm, etc. i agree some of the newer big power amps dont sound too great with there switch mode power supplies, they dont seem to have the grunt that the old fashion psu designs have.

 

I'll mail Krell and tell them i'm ditching their speaker crossovers, i'll let you know what they say.


Regarding amps, again, "spec" isn't everything. It's a guide i'll grant you but like all things, two amps which on paper look identical can sound very very different in the real world. Professional amps are made for different uses, their components are much more robust usually, but the downside to this is that they often lack finesse or real "musicality". A decent home system has a lot of power in reserve, but rarely has to draw on it. That's what allows the timing, soundstage, detail and so on to come right out in a more rounded presentation. But i'll also admit that i've never experienced a hi-fi with the wort of unit you're describing so for all i know it might blow my Chords into the weeds!

 

i do agree with you Telboy, im an electronic engineer by trade and used to work installing and building audio equipment. ive seen plenty of crap costing lots of ££ offering something it fails to produce.
im just going by my previous experience and my home system now seems to do what i want with a relatively cheap budget (most stuff s/h). i have the usual marantz se cd player coupled to a rotel preamp which then feeds to an active crossover, which then goes off to my crest audio power amps. to me its the best its ever sounded but as allways its all a matter of personal preference.

 

Alcazar - two monoblocs is definitely the easiest way to go. Depends on the design as to whether monobloc sounds better than bi-amping, and you probably don't need the extra power, but it'll certainly give you an easy improvement.

If you wanted to do a splitter, it just needs to be a pair of straight phono-2phono leads, but obviously using decent quality cable. If you wanted to mod the pre-amp, there may be specialists around who could do it for you, or you could do it yourself if you're confident enough. Use decent PTFE insulated (ideally silver plated) wire in very short runs and fit decent quality sockets, just daisy chained in parallel with the existing pre-outs.

 

As I see you already recognise a brand that gives huge clout and unsurpassed musical dexterity

I went from stereo power amp to monoblocks and yes it was worth it, especially with more complex and dynamic music.

Certainly the best option given the raw materials that you have.