Suggestions for amps for active speaker project

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Hi folks

Well, I have decide to bite the bullet and go for an active amps for my ongoing terminated TL project, as it will probably be easier to tweek the system using active crossovers. I have much experience of building boxes and playing with drivers, but have only ever used commercial amps with my previous active attempts.

For each side I will need 3 amps- high at 15-25w, mid 30-40w, and bass 60-80w, all into 8 ohms

I have read up on most of the amp kits generally around, but would like any suggestions from people who have constructed them, as to suitability, and if any of them can be modded to suit my needs.

Would I be better using different amp circuits for each application, or would it be easier just to use 3 of ESP's 60w amps?

I would prefer to use just one transformer for each speaker (with separate regulation for each amp module), so power line voltages must be similar for each amp.

Any comments will be greatfully received.
 
Amp selection

Hi

How did you get the powerrating af the amps?

The experience I have with active systems makes med beleave that it's the voltage sving of the tweater amp mere than the power that counts.

To explain this, it's a good idear to analyse the signal containing the music. Often there are large transients, these would be clipped in a smaller amp due to the simpel lack of volts on the rails.

My suggestion would have to be building 6 identical amps, perhaps giving them different PSU's, but using the same rail voltage for all.

Ofcause I haven't considered the sencitivity of the different drivers, but the adjustments can be done in the crossover.

I'm working on sometking not too different from what you are making.

Good luck

\Jens
 
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Hi Pink,

Might I suggest to start your speakers using what amplification you have available. The speakers are always the hardest part to get right (maybe not for all, but for me).

Then determine the efficiencies of your speakers and select a level of sound you wish to have at your listening position. You'll have to make some approximations so give yourself a few db of headroom. I went with a acoustic power level instead of SPL because it's easier to estimate. My goal has always been 1 acoustic Watt which equates to about 115db at 10ft in a reverberant living room (this is peak, not average or RMS).

Once you have your goal, and you've determined the efficiency of your speakers, you can calculate how much amplifier power you'll need to reach your SPL or acoustic power goal.

As Jens suggested, the tweeters will have a higher peak to average power level requirment so find an amp that has good transient capabilities. The mids (100Hz to 1000Hz) will have the highest average power requirement so you'll need an amp with a relatively high Watts per channel and can run at high levels continuously. And for the bass, I just put something with a lot of reserve (big and heavy). I had a Bryston 4B until my wife laid claim to it. Now it's just a NAD 2600. I know I don't have the displacement to output 1 acoustic Watt below about 40Hz but that ok because it's still flat response at lower levels. What's important in the bass is that you have good control and lots of reserve (than stick 'em in the corners).

Well, those are my suggestions, for what their worth.
Rodd Yamas***a
 
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Joined 2002
Thanks Rod, Jens..

How did you get the powerrating af the amps?

Roughly from experience, and the power handling of the drivers...

the tweeters will have a higher peak to average power level requirment so find an amp that has good transient capabilities.

Yes, I agree totally, but very few kit amps give that kind of information, so I was hoping for any practical experience of the various designs out there.

I had a Bryston 4B until my wife laid claim to it.

She may be a pain, but at least she has taste!!! :)

What I am really looking for is advice from people who have built these various amps and can tell me which work best for each task, I have no problem with speakers, it's all this electrickery that gets me confused!
 
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Joined 2002
Hi Pink,
What I am really looking for is advice from people who have built these various amps and can tell me which work best for each task, I have no problem with speakers, it's all this electrickery that gets me confused!
I guess I should've realized this was the case. The electronics doesn't confuse me so much as doesn't get the creative juices flowing as much as speakers do. My instincts aways ran more toward the mechanical as well.

In that regard, I've been watching a very interesting thread.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=3589

I plan on a variation of the Aleph 5 for my upper range (above 1200Hz). What is so interesting is to see how William's Aleph 5 reacts to the various changes he makes. Check it out, it might be a candidate for your upper range amp.

Rodd Yamas***a
 
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