useing 2 intergrated amps for biamping

[Anonymous]

No offence taken, you're probably right.

To (almost) quote Jake Thackray, I never use one or two words when a couple of thousand will easily do.

To be honest the posts are getting longer as I try to put more of my understanding into them to try to get a response that either suggests a spark of light dawning somewhere else, or suitably extinguishes the one forming in my own mind.

The temptation to waffle on now for another couple of sides of A4 is really really big...

 

[Anonymous]

Damn - why isn't there a recall message button - should have just replied :

 

[Anonymous]

Sorry not intended to be an insult and didn't actually read it back as one myself. And certainly no more so that the "oh dear wrong" that you've put in nearly every post so far.

We're clearly not going to agree, so I give up. You're quite right sir. All amplifiers are perfectly linear into all loads, have no internal resistance/back emf issues, and never, ever run out of the ability to supply current into a load at all ever. All clipping is purely related to applying too much gain to the voltage. This is why all amplifiers always double their output as the load impedence halves just as they should and why we have proof that Naim, Cyrus, Musical Fidelity, Audiolab, Arcam, What-Hi-Fi, and all the rest are just part of a great evil conspiracy to grab all the money in the world.

I stand completely corrected by you're superior belief in the perfection of modern circuitry.

 

[Anonymous]

Okay, the level of sarcasm there is actually over the top and I apologise.

I just really think you're missing the point. I know what you mean by clipping, but that's not the same as what I'm talking about here. Maybe there's another term?

Come on, enlighten me, tell me why my argument is wrong, not why you, different argument, is right (which is actually is!)

 

[hifikrazy]

OK, I'm not going to try pretending that I know what jimwall and oldphrt are talking about from the technical perspective, because I haven't a clue. However, I would just like to recall oldphrt's previous assertion that we should only be able to hear differences in equipment, cables, etc if it can be explained scientifically/technically.

Now the fact that you two who are obviously pretty well versed in electronics are unable to agree purely from a technical perspective on the subject of this thread tells me one thing.... that there is no all conclusive black and white answer regarding how electronics actually works and its relevant impact on sound.

As such, there is no way that any electronics expert can conclusively say with total certainty that the differences I hear between cables is, to quote a well worn saying in here "a placebo effect".

 

[Anonymous]

This is vintage Oldphrt. Highly entertaining, though at others expense.

The body count grows.

All the fun of the forum!

 

[Anonymous]

Body Count?

I think not. The man just admitted that PSUs sag under load but still can't accept that reducing the load on the psu by reducing the current drawn from it by pushing the signal through a high impedance filter that attentuates much of the signal could possible affect the sound!!!!!

The man's contradicting himself left right and centre.

 

[hifikrazy]

[quote user="jimwall"]
The man's contradicting himself left right and centre.

[/quote]

That may be so, but he's right....as always!!!

 

[Anonymous]

The only thing that's being achieved without the above is a doubling of
the available power because of the use of two amplifiers

It's not proper bi-amping, it's bi-wiring using two amplifiers.

and

LOL. Well of course nothing is perfect. Transistors aren't perfect switching devices and PSUs sag under load.

Think that covers it.

The clipping thing isn't actually nonsense I'm just using the wrong terminology. If you had actually bothered to read any of my posts rather than allowing your own preconceptions to do it for you, you would understand that I'm completely familiar with the principle of clipping as per - gain applied to input signal is such that output signal would need to exceed the top and bottom rails from the power supply, which they can't do unless you bridge the amp (even then they can't but the combined potential difference across the load can because it's a difference and it's relative). Happy?

What I'm suggesting, and if you can tell me I'm wrong with an explanation as to why I'll be quite happy to sit back and learn something, is that even if the amplifier is not clipping, the if the load is sufficient the amplifier will be unable to supply the required current to match what Ohms law would say is needed if you (naively) treat the amplifier as a black box with no internal structure beyond gain. At this point the sound will, must, be affected even though the amplifier isn't voltage clipping.

Another point you might like to consider is that since the potential difference between the top and bottom rails of each amplifier hasn't changed, rather the load that amplifier sees has been made easier, then the available power has not doubled as you suggest above.

 

[Anonymous]

Perhaps it was boxing parlance. A quick left right in this situation wouldn't go amiss!

 

[hifikrazy]

[quote user="Will Harris"]
Perhaps it was boxing parlance. A quick left right in this situation wouldn't go amiss!

[/quote]

And a few below the belts for good measure.

 

[Anonymous]

...and a left right and centre from me brutally returned by Oldphrt.

But I drag myself back up on the count of eight, attempt a quick reposte and then wait, tender but unbowed, for the killer knockout blow.

 

[Anonymous]

I need to get out more don't I?

 

[Anonymous]

No they don't, because the load is different. Ohm's law you see.

If you bi-amped "properly" via an active crossover before the amplification stage, then the would. In theory. I practice I suggest that you couldn't actually use the power because the high amplitude bass frequencies would clip so far before the treble that it would be entirely moot.

 

[Anonymous]

LOL! Fine remark, like it. No really - I'm genuinely not being sarcastic.

As you said - the voltage is amplified for the whole of the frequency range and you hit the top/bottom rails of the amp just as soon as you would mono-amped.

What you do get however is twice the available current.

The output power is determined by three, related, but different things - voltage, current, load.

You can never exceed the maximum voltage available - this is effectively the output voltage to the high and low rails of the PSU. This of itself kind of implies that you ain't going to get more "perfect world" power since the biggest voltage I can push across either of the speaker terminals hasn't changed.

In a non-perfect world, the power is also limited by the available current - i.e. the amplifier isn't a perfect black gain making box, it has internal resistance (this is DC Battery terminology, I don't know the correct term here) due to back emf and it's own inductance - which includes the problem of the psu output lines sagging under load.

BUT...

Bi-amped, the load is different! It's easier to drive (i.e. higher impedance) because of the damn great big high pass filter on the tweeter and low pass on the woofer. So the current demand on the amplifier is lower.

Which I think is where we were about 75003 posts ago.

 

[Anonymous]

Where?

 

[Anonymous]

You have twice the current available but you're not gaining extra wattage unless you increase the voltage output of the amplifiers.

 

[Anonymous]

Which isn't a contradiction.

Although I confess that I think the phrase "twice the available current" is probably misleading, even if probably technically true, since the current you actually draw depends upon the load and the voltage and the peak voltage is the same.

Perhaps it would be more accurate to say something like a far greater excess of current available. Or something.

 

[Anonymous]

Hi there kelly here the original post, Im ready to wire up my two intergrated c/a 640 amps, can anyone tell me
wich is the best way. option1. one amplifier driving the LFunit and the HFunit of the right speaker, and
other amplifier driving the LFunit and the HF unit of the left speaker. option2. one amplifier driving the LF
units on both speakers, and the other amplifier driving the HF units on both speakers. which is the best way or
doesn't it matter which way you do it . any help thanks kelly.

 

[Andrew Everard]

Kelly

As I indicated in my original reply - one amp to drive L/R HF, the other to drive L/R LF

 

[Anonymous]

Thanks andrew i thought you might come back and tell me.

 

[jetjohnson]

(With apologies to Brian Potter but..) ...have either of you ever kissed a girl?

 

[Andrew Everard]

I have, but I don't know if Kelly has!

 

[Anonymous]

Yes of course i have, (my mother). And i do hope you chaps know im speaking through my dad, im the one
with the computer, he's the one with the hifi, thats if im not useing it.

 

[Anonymous]

get a pre amp and 2 stereo power amps and a set of y adapters and you'll have biamping