Is anyone knowledgeable about bi-amping?

[twelvebears]

Specifically I'm trying to establish if it's possible to successfully bi-amp speakers with different amps.

By that I just mean different power outputs but same manufacturer, same gain sensitivity.

Intention is to drive the HF with the lower power amp and the LF with the more powerful one.

Am I an idiot? Will this simply not work?

Answers on an AOS postcard please.

[The Grand Wazoo]

Steve,
That's exactly what I do, & have for years.
A Mark Levinson ML9 on the bass & an ML11 on the mid/treble.

The gain for both of them is identical. I have a long cable going from the pre-amp into a little box I made with one input & four outputs. This allows me to tri-amp if I should choose to and to plug in a headphone amp when required. I used to tri-amp with my old speakers - I had a Radford STA15 driving the mid-range & a simple passive pot on a very short interconnect matching the level of it to the Levinsons.
It's easy enough to split the interconnect with a set of these though:

http://i30.twenga.com/garden-diy/t-piece-splitter/rca-phono-t-splitter-tp_3477516968716375066.png

[Barry]

Hello Steve,

This might be of help/interest to you:

http://theartofsound.net/forum/showthread.php?t=5818

Regards

[twelvebears]

Steve,
That's exactly what I do, & have for years.
A Mark Levinson ML9 on the bass & an ML11 on the mid/treble.

The gain for both of them is identical. I have a long cable going from the pre-amp into a little box I made with one input & four outputs. This allows me to tri-amp if I should choose to and to plug in a headphone amp when required. I used to tri-amp with my old speakers - I had a Radford STA15 driving the mid-range & a simple passive pot on a very short interconnect matching the level of it to the Levinsons.
It's easy enough to split the interconnect with a set of these though:

http://i30.twenga.com/garden-diy/t-piece-splitter/rca-phono-t-splitter-tp_3477516968716375066.png

Hi Chris.

OK, right, that's interesting.

Are the two amps an identical match in terms of power and/or gain?

The reason I ask is that I was going to attempt this myself with a pair of Chapter power amps. Both have identical quoted gain of 26db but one ( the one I intended to use for the bass drivers) is approx 50% more powerful than the other.

I've nothing to lose really as I can sell on either of the two if it doesn't work out, based on whichever I prefer sound wise, though I suspect they will be virtually identical apart from their power out put.

The though that occurred (too late after I'd purchased) was that the differences in power would result in the treble and bass being out of balance.

[The Grand Wazoo]

Yes, the gain on the Levinsons is the same but the quoted output power is 50 & 100 wpc at 8ohms.

In my case, the two amps are not identical in sound, with the lower rated ML11 being a little sweeter than the ML9, but the latter does bass rather better. The relative levels of the two are identical whichever way I wire them up.

[hifinutt]

i am no expert but i thought about using 2 different amps with my b&w 804s
an bc s300 on HF
and ref 1000 on LF . both have same gain i think until i read the manual

which seems to say this is a No No

The ear is at its most sensitive in the
midrange, so we recommend that, when
single wiring, you connect the cable from
the amplifier to the terminals that directly
feed the midrange driver.
Bi-amplification goes a stage further and
involves the use of two separate power
amplifier channels for each speaker. It is
not the same as having a fully active
system, because the speaker's internal
passive crossover is still used.
If using bi-amplification, ensure that each
amplifier channel has the same gain,
otherwise you will change the balance of
the speaker. Check the absolute polarity.
Some amplifiers invert the signal, and a
mixture of different types may cause a
dip in the overall response. If you have a
mixture of inverting and non-inverting
amplifiers, reverse the polarity of the
connections from any inverting amplifier
to the speaker.
Bear in mind that, even though midrange
and, even more so, tweeter drivers can
(and only need to) handle less
continuous power than bass drivers, the
amplifier feeding them needs to have an
adequate voltage swing in order to
supply the short-term high-frequency
peaks in music without distortion. A high
voltage capability implies high power, so
it is not particularly desirable to have a
lower powered amplifier feeding the
midrange and tweeter than is used for
bass drivers.

[The Grand Wazoo]

I don't read that as a no-no at all.

But this bit............


If using bi-amplification, ensure that each
amplifier channel has the same gain,
otherwise you will change the balance of
the speaker.

...........answers Steve's question.

[Spectral Morn]

Hi Chris.

OK, right, that's interesting.

Are the two amps an identical match in terms of power and/or gain?

The reason I ask is that I was going to attempt this myself with a pair of Chapter power amps. Both have identical quoted gain of 26db but one ( the one I intended to use for the bass drivers) is approx 50% more powerful than the other.

I've nothing to lose really as I can sell on either of the two if it doesn't work out, based on whichever I prefer sound wise, though I suspect they will be virtually identical apart from their power out put.

The though that occurred (too late after I'd purchased) was that the differences in power would result in the treble and bass being out of balance.

Chapter amplifiers are very good if we are talking Cuplet but not so good if we are talking the first one the +. Firstly they are not very reliable Chapter had horrible problems with them. When mine went pear shaped Duncan Shipton replaced it with a Cuplet (I paid a bit towards the Cuplet) My Preface pre then went tits up. That they replaced with a rare Signature + preface pre FOC.

The other problem is the + has a distinct lack of presence and drive whereas the Cuplet drives well and has no suck out in the presence region.

Sorry to be a bit negative here but that's been my experience. In saying that I would not part with my Chapter pre-power. The pairing is a real taste of the ultra American high end, think British version of Bolder..only thing it lacks is a fixed level output I could use for a tapedeck. If it did I would use it more often.

Both power amplifiers sounded better balanced as well rather than single ended via RCAs. If you have a Cuplet you should with the volume turned down try the ground lift switch on the rear it will sound better either in or out, its worth trying.....as a wee tweak.

Hate to say this but if its a + power amplifier you will struggle to sell it on, as most people know about the problems with them.....sorry.

Regards D S D L

[hifinutt]

"so
it is not particularly desirable to have a
lower powered amplifier feeding the
midrange and tweeter than is used for
bass drivers. "

steve wants to do this which is precisely what b&w warn against isn`t it?

[DSJR]

The WB ACT series loved bi or even tri amping. if you can do this economically, then I recommend this highly. Whether you choose to separate the bass/mid units from the tweeters, or the bass from the bass/mid (can't remember if they're fully paralleled or if they're a proper three way, it's been so long), is up to you..

[The Grand Wazoo]

"so
it is not particularly desirable to have a
lower powered amplifier feeding the
midrange and tweeter than is used for
bass drivers. "

steve wants to do this which is precisely what b&w warn against isn`t it?

Well, if you are a speaker manufacturer who also happens to import extremely expensive Canadian power amplifiers, then you would say that, wouldn't you?

[DSJR]

Linn said the same thing because their speakers had awful loads, usually in the bass and mid, which got their amps to deliver more power than into the tweeter circuit, which was often a higher impedance. Having the more powerful amp on the tweeter sort of equalised this as the bass amps delivered more power into the lower impedance, if you see what I mean..

No hard and fast rules, just suck it both ways and see...

[The Grand Wazoo]

Yes - you should try it both ways as I did.


The relative levels of the two are identical whichever way I wire them up.

[twelvebears]

Steve,
That's exactly what I do, & have for years.
A Mark Levinson ML9 on the bass & an ML11 on the mid/treble.

The gain for both of them is identical. I have a long cable going from the pre-amp into a little box I made with one input & four outputs. This allows me to tri-amp if I should choose to and to plug in a headphone amp when required. I used to tri-amp with my old speakers - I had a Radford STA15 driving the mid-range & a simple passive pot on a very short interconnect matching the level of it to the Levinsons.
It's easy enough to split the interconnect with a set of these though:

http://i30.twenga.com/garden-diy/t-piece-splitter/rca-phono-t-splitter-tp_3477516968716375066.png

When the idea first occurred, I called Chapter and spoke to them. After establishing which two amps I had (earlier Chapter Two+ and slightly later Couplet), they confirmed that the gain on the two amps was identical, but I still wasn't sure if it would work.

[The Grand Wazoo]

It sounds to me like you'll be fine.

[twelvebears]

Thanks for the heads-up on possible reliability issues, however the Preface Plus and Couplet are due to go to Chapter for a full check-up/service at Audio Emotion's expense an the other Two+ is a circa 2003 vintage which is in perfect nick and still working perfectly, so I suspect if it was going to snuff-it ir would have done so by now.

Anyway, by the sound of things there's a good chance the bi-amping will work out, so selling it won't be an issue. Plus of course Chapter are still going strong, so I may also get them to give the Two+ a once over to make sure all is well too.

Thanks for the input guys, I'm looking forward to having a play over the next few days.

[Spectral Morn]

When Chapter is working its very good.

As you have the matching pre hook them up balanced and try the ground lift switch on the Cuplet power amplifier it does make a difference to the sound.

My original Preface pre developed a mind of its own. It would change inputs by itself, switch off, put the volume up by its self, change balance level. However it was the switching to full volume that was the scary thing. This problem was based on operating temperature. Leaving it in standby all the time and using it for a few hours in the summer and it would go mad. Problem was both the pre and the power need to be left in standby to sound their best.

Chapter are good guys they replaced the Preface with a Preface Signature pre for me as I said FOC. In saying that considering the issues (several attempts to fix it a Two+)with the power amplifier I would have been disappointed if they had not done something like that.

In my system a set of RDC cones under the Pre and Power sounded better....

My Chapter pre and power.....

http://i549.photobucket.com/albums/ii364/davros124/LeakTroughlineTuners041.jpg



Regards D S D L

[The Grand Wazoo]

As you have the matching pre hook them up balanced and try the ground lift switch on the Cuplet power amplifier it does make a difference to the sound.

Don't try having one power amp connected in balanced mode and the other one not though, as balanced usually gives you a lift in gain too, I think.

[twelvebears]

Neil.

Thanks, will keep all that in mind. As I say, Chapter are going to give the pair the once over to correct two minor issues - a cracked surround on the input selector and a slightly noisy power amp fan - but so far, no bonkers behavior so hoping all will be well.

Chris.

Don't worry, balanced connections all round. Mark is making me an XLR Y-lead to make life easy.

The TWO+ seems in amazing nick. It was Henley Design's demo unit from when they were Chapter distributors some years back, and hasn't missed a beat so far, so again, hoping for the best.

The TWO+ has switchable gain options 21db or 27db. I've requested that when the Couplet goes back, that it's measured and has it's gain tweaked to match the 27db of the
TWO+

[Mr. C]

Steve,

I am impressed you got Chapter to answer the phone! we had a repair issue with a power amp last year, the client had tried for weeks, we had left countless messages non were returned.
Interesting big industrial switch mode power supply sat in the middle of that amp :interesting:
I feel the pre is better than the power, it has grunt and control but no finesse, can be a bit of Bryston clone too in that it is very matter of fact unless you give it some really warm source like a Marantz or Moon that even's out a lot of sonics nicely. Pretty sure these guys are ex John Franks employees from Chord.
We had a few over the years does look nicely put together and the styling is clean and smart too.
I suspect you got a bit of a deal of Nick @UKD on those too :-)

[twelvebears]

Steve,

I am impressed you got Chapter to answer the phone! we had a repair issue with a power amp last year, the client had tried for weeks, we had left countless messages non were returned.
Interesting big industrial switch mode power supply sat in the middle of that amp :interesting:
I feel the pre is better than the power, it has grunt and control but no finesse, can be a bit of Bryston clone too in that it is very matter of fact unless you give it some really warm source like a Marantz or Moon that even's out a lot of sonics nicely. Pretty sure these guys are ex John Franks employees from Chord.
We had a few over the years does look nicely put together and the styling is clean and smart too.
I suspect you got a bit of a deal of Nick @UKD on those too :-)

Hey Mr C.

Well it wasn't just me, I got hold of someone and so did Mark from Audio Emotion, so perhaps things are getting better! No reply to website messages but it's a pretty poor site so may well just be broken.

Lacking finesse or not, they certainly show my old M3 a clean pair of heels, so it's a significant improvement for me, especially for what it cost me.

Only time will tell if it's a good idea or not. :mental:

[Mr. C]

Steve,

I would would be deeply depressed if it did not left the M3 for dead!
Pretty am sure you will come to enjoy it, as it is polar opposite to the MF, it does thrive on transparancy and dynamics and if you have the system to expoilt them, they will be very rewarding, still feel the pre is star of the two there.
Congrats on your purchase Steve.

[twelvebears]

Steve,

I would would be deeply depressed if it left the M3 for dead!
Pretty am sure you will come to enjoy it, as it is polar opposite to the MF, it does thrive on transparancy and dynamics and if you have the system to expoilt them, they will be very rewarding, still feel the pre is star of the two there.
Congrats on your purchase Steve.

You're right in that it is a very different presentation to the MF, after 10 years with the M3 it did come as a bit of a shock, but the more I listen to things I know really well, the happier I am about the change.

It may just be the way they seem to work with the ACTs but I'm very happy with things right now. :cool:

[Spectral Morn]

Neil.

Thanks, will keep all that in mind. As I say, Chapter are going to give the pair the once over to correct two minor issues - a cracked surround on the input selector and a slightly noisy power amp fan - but so far, no bonkers behavior so hoping all will be well.

Chris.

Don't worry, balanced connections all round. Mark is making me an XLR Y-lead to make life easy.

The TWO+ seems in amazing nick. It was Henley Design's demo unit from when they were Chapter distributors some years back, and hasn't missed a beat so far, so again, hoping for the best.

The TWO+ has switchable gain options 21db or 27db. I've requested that when the Couplet goes back, that it's measured and has it's gain tweaked to match the 27db of the
TWO+

Thought so. They had one left when the one I had, had problems (it too was Henley stock). It has taken them forever to move that one on.....hope you got a cracking deal on it.

Its sort of my fault that Henley did Chapter as I heard that pair at a show on the end of a big pair of TD12 (think that's the right model number the art deco looking ones with silver strips either sides of the cabinet) Tannoys. I raved about the sound and Ralph explored the option of doing them and then did but it did not work out well for Henley.

Chapter abandoned the gain setting button on the Cuplet.

I have got your PM I will dig out the instruction book later.

Mr C impressions match my own based on the original pre power. The source needed to have presence, drive and musicality or things just seemed flat and lacking and as he say matter of fact; you could also say it was totally neutral lacking any character at all but doing that with out being bright or thin. What it did fantastically well was to have a great sense of spatiality, depth, separation and totally silent backgrounds.

The Signature pre and Cuplet power amplifier are totally different, though a wee touch of warmth in the source is still a good thing imho...like a Marantz SA7 or as Mr C suggests a Moon (I have an Andromeda) or the AMR Cd77 which works very well with it too. The Preface sig pre with my Music Reference power amplifier works very well too, its just a pity it has no tape out. It is an excellent pre amplifier imho.

Cabling is important. I found Audience AU 24 worked well but it was Atlas Marvos that really made the Chapter pair sing, in the context of my set up. I suspect that Mark Grant G1000s will also work well. Oh, yes mains cables are important because of the switch mode design so you will benefit from using good ones. I found Audience and Analysis Plus worked well.




Regards D S D L