I can understand that but have you considered that with the WA passive x-over being over £300 and a Behringer CX3400 being just £72 at Amazon you'd have £250 towards the extra amps needed for active? And if you subsequently go active the passive x-over will be redundant. In fact I will have a set of passive x-overs with no purpose in life soon (because I'm going fully active)! You might make significant savings on speaker cable too depending on amp/speaker placement.
So you aren't thinking of bi-amping? It sounds as though you'll have a great system when you get the DIY done!
I don't think my Hi-Fi stand could take the weight of two 2 x 100W Class A amps, they weigh over 50Kg each.
I suppose I could try the smaller Pass F4 or F5 to drive the tweeters in bi-amped mode, leaving the massive Aleph to power the bass and mid units.
The 3400 does seem a good bargain on flea-bay.
The 3400 does seem a good bargain on flea-bay.
I'm still learning about the power requirements for each of the drivers.
One thing is for certain, the massive Aleph 4 goes to the bass speaker.
One thing is for certain, the massive Aleph 4 goes to the bass speaker.
OK so I've got a 100W amp on the bass.
Mid crossover is at 400Hz.
Assuming that the bass will max out at 40Hz, that's approximately 3.5 octaves. The passive crossover is 12dB/Octave, that leaves me to believe that the mid is some 42dB less than the bass.
And as the tweeter crosses over at 3.8kHz, the tweeter is some 6.5 octaves or some 78dB lower than the bass.
Am I correct here ???
Mid crossover is at 400Hz.
Assuming that the bass will max out at 40Hz, that's approximately 3.5 octaves. The passive crossover is 12dB/Octave, that leaves me to believe that the mid is some 42dB less than the bass.
And as the tweeter crosses over at 3.8kHz, the tweeter is some 6.5 octaves or some 78dB lower than the bass.
Am I correct here ???
I've just read on Rod Elliots pages that the starting point is generally considered to be 350Hz.
In that case the bass and mid both need 100W amps, and the tweeter is 50dB below them.
Two Aleph 4's isn't going to happen just yet.
In that case the bass and mid both need 100W amps, and the tweeter is 50dB below them.
Two Aleph 4's isn't going to happen just yet.
I'm not familiar with the F4 & 5 you mentioned earlier but I assume one is more powerful than the other.
In which case I'd suggest getting the bigger of the two and use it for mid&treble duty until you can swing the next smaller one and go fully active.
All you need is a little bit of restraint with the loud button until then but you probably have already enough to fall out with the neighbours.
How powerful are those things anyway?
In which case I'd suggest getting the bigger of the two and use it for mid&treble duty until you can swing the next smaller one and go fully active.
All you need is a little bit of restraint with the loud button until then but you probably have already enough to fall out with the neighbours.
How powerful are those things anyway?
The F4 and F5 in their standard format are only 25W.
The Aleph4 is 100W.
I use these as examples as they all come from the same stable and I've got the Aleph4.
The Aleph4 is 100W.
I use these as examples as they all come from the same stable and I've got the Aleph4.
I did have a friend of mine who was a complete Hi-Fi nutter and had the money to be a complete nutter.
I've heard a pair of B&W Nautilus (the snail shells) running tri-amped with 6 x Krell KSA250's.
Now that was NICE.
I've heard a pair of B&W Nautilus (the snail shells) running tri-amped with 6 x Krell KSA250's.
Now that was NICE.
The only change from standard I'm going to do to start with is to mount the crossover externally so that all three drivers have their own set of terminals on the rear of the speaker with nothing but wire from the terminals to the drivers themselves.
That is a wise decision if I may say so.
One thing though: If the F4&5 both produce 25W/ch what is the difference between them?
One thing though: If the F4&5 both produce 25W/ch what is the difference between them?
Most of the Pass amps produce 25W. The Aleph4 is one of the meatier beasts Pass produced.
The F4 and F5 just use slightly different approaches to the First Watt principle.
The Aleph4 is an incredible amp and drives my B&W 683's like an absolute dream. (They were also his)
Mine was built by my sadly gone Brother in Law - Here it its build
http://www.diyaudio.com/forums/pass-labs/172276-aleph-4-strickly-diy-project-build.html
The F4 and F5 just use slightly different approaches to the First Watt principle.
The Aleph4 is an incredible amp and drives my B&W 683's like an absolute dream. (They were also his)
Mine was built by my sadly gone Brother in Law - Here it its build
http://www.diyaudio.com/forums/pass-labs/172276-aleph-4-strickly-diy-project-build.html
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Cheers for that K&D!
The first few pages reminded me again why I build speakers rather than amps. ;-)
The first few pages reminded me again why I build speakers rather than amps. ;-)
I've caught the bug. It's like an AIDs virus, once caught you are dead meat.
Andy once said to me, "Can you hear the difference", my answer was a definite YES.
I've always wanted to build something, I wasn't sure what. I'm no carpenter nor can I design something myself. I just found the WA Platinums in one of my searches and the seed was sewn.
Andy once said to me, "Can you hear the difference", my answer was a definite YES.
I've always wanted to build something, I wasn't sure what. I'm no carpenter nor can I design something myself. I just found the WA Platinums in one of my searches and the seed was sewn.
A couple of big advantages to going active:
1. The power amps won't require the current capability of a stand-alone amp designed to drive a passive crossover. A passive loudspeaker can have all kinds of nasty dips in its impedance plot and a good power amp is designed to handle these. So large current capability, big power supply, big heatsinks = expensive. That's why your Passamp is so good with your present B&Ws.
An active system has the amps directly connected to the drive unit, which is a much more uniform load - usually 4 or 8 ohms minimum. No high current capability required - in fact, it would be entirely wasted. This considerably cuts down the cost, not only on the parts mentioned earlier but even on cases - unless they're on show, the amplifiers can be built into almost anything, even the base of the speaker.
Lack of high current requirement means you can reduce cable costs too (if exotic cables are your thing).
Plus, as you've said, you can tailor the size of amp to the drive unit. The Rod Elliott point about power distribution is a good one.
2. His other point is that an active system sounds twice as loud as the power going into a passive system. So 3x 50 watts will sound like 300 watts going into a passive system. Quite a few studio actives have surprisingly modest power amps in them (Genelec, for example).
I have commercial active speakers here and wouldn't revert to passive. The stop-start control and headroom takes the system a big step closer to sounding real, particularly on orchestral music.
Footling around with a DIY design, I costed up running the DIY speakers passive vs active. Using Gainclones and Rod Elliott's x/over boards, the cost of active was not significantly higher than a reasonable grade passive, which would only have been junked later.
1. The power amps won't require the current capability of a stand-alone amp designed to drive a passive crossover. A passive loudspeaker can have all kinds of nasty dips in its impedance plot and a good power amp is designed to handle these. So large current capability, big power supply, big heatsinks = expensive. That's why your Passamp is so good with your present B&Ws.
An active system has the amps directly connected to the drive unit, which is a much more uniform load - usually 4 or 8 ohms minimum. No high current capability required - in fact, it would be entirely wasted. This considerably cuts down the cost, not only on the parts mentioned earlier but even on cases - unless they're on show, the amplifiers can be built into almost anything, even the base of the speaker.
Lack of high current requirement means you can reduce cable costs too (if exotic cables are your thing).
Plus, as you've said, you can tailor the size of amp to the drive unit. The Rod Elliott point about power distribution is a good one.
2. His other point is that an active system sounds twice as loud as the power going into a passive system. So 3x 50 watts will sound like 300 watts going into a passive system. Quite a few studio actives have surprisingly modest power amps in them (Genelec, for example).
I have commercial active speakers here and wouldn't revert to passive. The stop-start control and headroom takes the system a big step closer to sounding real, particularly on orchestral music.
Footling around with a DIY design, I costed up running the DIY speakers passive vs active. Using Gainclones and Rod Elliott's x/over boards, the cost of active was not significantly higher than a reasonable grade passive, which would only have been junked later.
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Another good article on the subject
active loudspeakers [english]
The author specifically mentions using lower-spec Naim amps in an active set up was better than a high end Naim into passive.
active loudspeakers [english]
The author specifically mentions using lower-spec Naim amps in an active set up was better than a high end Naim into passive.
Thanks Colin, an excellent read.
Now, I've got the Aleph4 which is undoubtedly the better quality of my two amps.
I've also got a "Hi-Fi" amplifier that was born from an article in one of the electronics mags many years ago, I seem to recall it is reasonably good and about 150W.
As there is more detail in the Treble / HF range, am I correct in assuming that the Aleph would be better in that region leaving the Class AB amp to drive the bass ?
Now, I've got the Aleph4 which is undoubtedly the better quality of my two amps.
I've also got a "Hi-Fi" amplifier that was born from an article in one of the electronics mags many years ago, I seem to recall it is reasonably good and about 150W.
As there is more detail in the Treble / HF range, am I correct in assuming that the Aleph would be better in that region leaving the Class AB amp to drive the bass ?
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