F5 amp for three way active speakers

[AntonTR]

Hello the regarded community!
I hesitated were to start the topic but deceided here because I need to attach my F5 amp at least.
My F5 project has been started 6 years ago but postponed by some reasons and at last it is almost finished now.
The problem is that I have a plan now to build a three way active speakes based on sealed box design.
So, I need two more amps now)))

If you have an idea which way is best to use my F5 here (for woofer or midrange)?
What amps you'd suggest for other ways (Firstwhatt series or other)?
If 4 Ohm coils are the problem for single ended class A (less power is expected in class A)?

I already have Wavecor WF182BD03 for midrange and Wavecor TW030WA11 for tweeters (both are 4 Ohm).
Woofer is 8 Ohm Scan-Speak Discovery 26w-8534g00 planned but not purchased yet.

Thanks for any advice about the system, Anton

 

[Zen Mod]

you have already sorted active xover for intended project?

 

[AntonTR]

Not yet.
Still considering DIy xover or to buy it to save energy)
If you have an idea about it?

Br, Anton

 

[Zen Mod]

dunno ........ I decided years ago that life is simpler with passives , and simpler speakers

 

[AntonTR]

Simplier means fullrange?
I m just not sure that I can make proper passive filters.

 

[Zen Mod]

fullrange is one option , coax speakers is another

I have some RCA and Tannoys

however , do not think that I'm against your choice in any way , I was just asking about your plans ..... thinking that only after you finish planning phase for your speakers , only then you can choose proper amplifiers

though , more sensitive and more efficient speakers are more in spirit of low wattage A class amps ..... not "regular hi-fi" boxes

 

[AntonTR]

Your idea is clear, thank you!
Speakers design is almost fixed now, i just need to buy woofers.
I thought in the whay that three small amps may be even louder than one common. Especially assuming losses in passive filters.
Hope to realize the system in such manner.

 

[Zen Mod]

F5 is good amplifier , no doubt

first determine is it F5 enough for bass duty ...... if not , make bigger (some of Turbo iterations) F5

then - least complicated way - make smaller F5 for mid driver , and (if possible ) even smaller F5 for high driver

example :
F5 Turbo V1. for bass
regular F5 for mid
F5 made with lesser dissipation and , say , IRF510/9510 outputs for highs

amps for mid and high can have common PSU

 

[AntonTR]

I really like your approach.
Actually I also thought - damn it, take F5 for all of them!)))

Please let me know what is your idea about 510/9510?
Why not to use 240/9240 as usual for highs?

My doubt here is that my mid and high drivers have 4 ohm resistance. This means that I still have to set high enough Iq to maintain the power in class A (peak power is 27W at 1.3A).
The woofer will have 8 ohm coil, so regular F5 can give 25W output here.
According to my sealed box calculations my woofer is limited to 20-25W by linear excursion limits at low end.
But maybe you are right and F5T would be nice here for margin. Actually, i dont listen music too loud.
So, taking into account that bass needs 50% of power while mid and high has 4 ohm coils, seems all F5 should be just right in proportion, right? Maybe slightly less Iq for highs as you wrote.

 

[Zen Mod]

consideering that high drivers are using less than 10% of overall power , I was thinking that , say, 7-8W F5 should suffice ...... and you can use smaller sized mosfets , and they have smaller intrinsic capacitances , thus better behaving in high registry

 

[AntonTR]

amps for mid and high can have common PSU
Yeah, I supposed to go this way since my PS now has 600W trafo.

 

[AntonTR]

consideering that high drivers are using less than 10% of overall power , I was thinking that , say, 7-8W F5 should suffice ...... and you can use smaller sized mosfets , and they have smaller intrinsic capacitances , thus better behaving in high registry

I see... Thank you!
But does it really matter if standard F5 has 200kHz bandwide?

 

[Zen Mod]

it's neither too much nor too less

 

[AntonTR]

it's neither too much nor too less

Are you about trafo power or about smaller mosfets for highs?)))

 

[Zen Mod]

you asked for bandwidth

 

[AntonTR]

Yeah... thank you for the conversation!
Helped me a lot.
Good night!

 

[KevinHeem]

"...not regular hi-fi" boxes

Wait a minute...my speakers resemble that remark

 

[AntonTR]

Hello, Kevin!
So, what are your speakers? And what is driving them (I mean the amp)?

 

[EUVL]

I will not advice anyone what to do.
But I am happy to tell them what I am doing.

These are my 3-way speakers (now somewhat modified) :
http://xen-audio.com/documents/accuton/130701 Accuton CELL Public.pdf

The mid-range and the tweeters have passive crossover, and are both driven by the same F5X.
The crossover between bass and mid/high is analogue line level (active but not digital).
The bass units will be each driven by 3x LM4780 in parallel balanced mode.

http://www.xen-audio.com/documents/accuton/130818 Accuton CELL Public 2.pdf


Cheers,
Patrick

 

[AntonTR]

Thanks for your reply, EUVL!
Very nice job really.
I also thought about angled baffle but at the moment I have no idea how to design it properly for time alighnment .
I also heard about the river off-axis listening in this case.
How do you find it with your speakers?
Probably, it depends also on the listening height and driver's height, right?