Can I use bi-amping with my A21?

[lofi-ear]

Hi,

Is it possible to successfully bi-amp my loudspeakers so that the A21 would take care of all the audio range except treble, which would be handled by my old Creek 5350SE? As good as the A21 is, I find the high frequencies of 5350SE to be a bit more lively and airy with classical and jazz.

Here's the technical specs for the bi-amp candidate: http://www.stereophile.com/integrate...27/index4.html

What do you think? A doomed attempt?

[Kal Rubinson]

Not doomed but, imho, useless. Get a pair of Y-cables so you can split the preamp feed to both the A21 and an aux input on the Creek. Hope that the Creek has higher gain than the A21 (it should) and use a test tone and meter to balance the outputs of the two amps. Your move.

[Peter Nielsen]

Are your speakers 2- or 3-way? If they are three way, then one amp should handle the woofer and the other amp should handle the midrange and tweeter.

You should modify the speakers and rip out the passive crossover. If you have 3-way speakers the crossover for the tweeter is left in place. For two way speakers it's easy: just rip it all out. Then you get an active crossover (e.g. Marchand Electronics) that go between your preamp and power amps (A21 + Creek).

[Kal Rubinson]

Are your speakers 2- or 3-way? If they are three way, then one amp should handle the woofer and the other amp should handle the midrange and tweeter.

You should modify the speakers and rip out the passive crossover. If you have 3-way speakers the crossover for the tweeter is left in place. For two way speakers it's easy: just rip it all out. Then you get an active crossover (e.g. Marchand Electronics) that go between your preamp and power amps (A21 + Creek).

Sure but show me one, from Marchand or elsewhere, that will replace the customization inherent in the factory crossover.

[Glenee]

I'm Sorry, Peter and No Offense Intended. I usually don't get involved in these things. I know of very rare instances where the cossover in the speakers is not the better crossover for that paticular speaker manufactures Speakers. The reason I say that is think of the time and research that has gone int mating, tweeking and voicing a set of speakers. If you want to change the house sound of a set of speakers there are other ways. Most of the people here own upper end speakers and to mess with that is a mistake. I may be wrong but I just believe this. I don't have the skills to make a better crossover than the manufacture and 99 % of the people here don't either. LoFi Don't mess with those crossovers in the speakers.

[lofi-ear]

Thanks to everybody for information. And no, I will not touch the X/O network, as it is extremely complicated, the speaker being a 4-way system. So I was just thinking of passive bi-amplification with a dedicated amp for the tweeter (4000Hz and up).

This was just some whim-idea. I don't know how well it will work in practice, but I believe Kal is right with that it's hard to combine the good traits of two different amplifiers with this kind of setup. But as it costs almost nothing, it's worth a try. Does it make a difference if I put the attenuator (resistor) in series with the RCA cable or the speaker cable?

[Kal Rubinson]

Thanks to everybody for information. And no, I will not touch the X/O network, as it is extremely complicated, the speaker being a 4-way system. So I was just thinking of passive bi-amplification with a dedicated amp for the tweeter (4000Hz and up).

This was just some whim-idea. I don't know how well it will work in practice, but I believe Kal is right with that it's hard to combine the good traits of two different amplifiers with this kind of setup. But as it costs almost nothing, it's worth a try. Does it make a difference if I put the attenuator (resistor) in series with the RCA cable or the speaker cable?

Why would you use an external attenuator? Since the HF amp is an integrated amps and is likely to have a higher sensitivity than the other, why not just use its own VC?

[Peter Nielsen]

Sure but show me one, from Marchand or elsewhere, that will replace the customization inherent in the factory crossover.

The huge advantage of bi-amping is to get rid of the passive components.

Making a good passive crossover is a challenge. It's much easier to make a better active crossover. Passive crossovers are never as perfect as an active one...

However, if you don't know the crossover frequency and slope of the original passive crossover, then replacing it with an active one might be a challenge...

[Peter Nielsen]

I'm Sorry, Peter and No Offense Intended. I usually don't get involved in these things. I know of very rare instances where the cossover in the speakers is not the better crossover for that paticular speaker manufactures Speakers.

I'm not saying you should mess with the crossover frequency or slope. I'm saying that you should implement the same crossover in an active fashion. Don't redesign anyting. Just reimplement it in a better way. No matter how expensive and well done the passive crossover is, an inexpensive active version will easily do the job equally well or better. Removing the passive crossovers will make the speakers more efficient (less strain on the amps) and the speakers will become more dynamic.

Enough said. As always it is easier to just buy package deals. For instance Genelec has excellent active speakers.

[Peter Nielsen]

What do you think? A doomed attempt?

Passive bi-amping is usually not worth it. Active bi-amping is a different story, but requires changing of the internal XOs, which will possibly be a doomed attempt with your 4-way speakers (unless the internal XOs happen to be designed in such a way that makes it easy - probably not the case)

[Peter Nielsen]

Oh, and since it may not be obvious (I thought it was <grin>), the Marchand crossover needs to be customized (=built) to your exact specifications (frequency/slope). In practice this means selecting specific resistor values.

Show me a high-end passive crossover that is less expensive to manufacture than an equally or better performing active one. This can't be done (unless you do trick things like manufacturing from scrap parts or something else that can't be done in serial production).

Speakers have passive crossovers because they are convenient and make for a simple to use speaker. Active crossovers are WAY better, but you just can't expose the consumer to the complexity of multiple amps, crossover settings and the total user unfriendliness: wrong crossover settings may damage the speakers! It's not worth wile to sell speakers like this...

Anyone who builds speakers know the merits of getting rid of the passive crossover. If you can afford it (cost of amps and possible user convenience issues), it should always be done!

It's soon 2010 and we have not come farther than this?... :roll:

[Kal Rubinson]

The huge advantage of bi-amping is to get rid of the passive components.

Making a good passive crossover is a challenge. It's much easier to make a better active crossover. Passive crossovers are never as perfect as an active one...

However, if you don't know the crossover frequency and slope of the original passive crossover, then replacing it with an active one might be a challenge...

On most speakers, there's more to the crossover than the frequency and slope. Many have multiple slopes and/or corrections elsewhere in the passband. A textbook active crossover may have advantages in efficiency and dynamics but will have new problems.

[Kal Rubinson]

Anyone who builds speakers know the merits of getting rid of the passive crossover. If you can afford it (cost of amps and possible user convenience issues), it should always be done!

I agree with you fully including the opening line. Almost no one who raises this query is a speaker builder but is an audiophile looking for something new.

[lofi-ear]

Why would you use an external attenuator? Since the HF amp is an integrated amps and is likely to have a higher sensitivity than the other, why not just use its own VC?

I use the creek as a preamp itself.

The concept of active crossover started to fascinate me. I googled a bit and found out that someone has actually tried to multi-amp that same speaker I have (in thread http://www.audioheritage.org/vbullet...ad.php?t=1647). However, having not enough technical knowledge in such stuff I will leave it to some other day

[Peter Nielsen]

The concept of active crossover started to fascinate me. I googled a bit and found out that someone has actually tried to multi-amp that same speaker I have

:B :T :T :T

(BTW, those are nice speakers! I love the fact that JBL publishes the specifications and schematics. I will probably use JBL for my HT upgrade).

[lofi-ear]

:B :T :T :T

(BTW, those are nice speakers! I love the fact that JBL publishes the specifications and schematics. I will probably use JBL for my HT upgrade).

Try to get an audition of JBL Everest :T I've read only good things about those.